Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their F1 Crossbreeds

*Tadesse Amare Sisay, Gebeyehu Goshu Negia and Berhan Tamir Mersso*

## **Abstract**

In the study area, sheep flocks are managed under traditional extensive systems with no or minimal inputs and improved technologies, which results in low productivity. The available natural pasture lands are overloaded with livestock beyond optimum carrying capacity that has resulted in overgrazing and land degradation. This indicates the critical need of supplemental feed during feed-deficient period. The objective of the research was assessment of productive performance through on-station feedlot and natural pasture grazing effect on weight gain and carcass yield characteristics evaluation. The average daily weight gain (ADG), total body weight change and final body weights of supplemented groups significantly higher than (p < 0.05) non-supplemented groups. Hence, supplemented and nonsupplemented Awassi crossbreds had higher daily weight gain and followed by supplemented Wollo highland group. Between genotypes, there is significant difference (p < 0.05) of rib-eye area, empty body weight, hot and cold carcass weight and cold carcass dressing percentage. Conversely, Wollo highland sheep has exhibited compensatory growth rate than others. Awassi crossbred lambs has higher weight gain and faster growth performance followed by Washera crossbred one. Therefore, local breed productive performance improvement practices have to continue and need adjustment of breeding strategies with a definite breeding plan.

**Keywords:** body weight, carcass, Awassi and Washera, F1 crossbred and Wollo highland

## **1. Introduction**

Ethiopia is not only rich in sheep population but also rich in sheep genetic diversity, which developed by natural selection and potential genetic resources of sheep breeds [1]. In the highlands of the country, about 75% of sheep population are found, while the remaining 25% are distributed in the lowlands [2]. Sheep production is a major component of the livestock sector in Ethiopia, owing to the large population of 30.70 million sheep are estimated to be found in the country, out of which about 72.14% are females, and about 27.86% are males [3]. The small

ruminants account for 40% of cash income earned by farm households, 19% of the total value of subsistence food derived from all livestock production, and 25% of total domestic meat consumption [4]. Smallholder sheep production is the major source of food security serving a diverse function, including cash income, savings, fertilizer, socio-cultural functions and fiber production. Sheep are particularly important for farmers in the subalpine highlands and pastoralist/agropastoralist where crop production is unreliable. Moreover, despites its socio-cultural importance, sheep resources significantly contributed for foreign currency earning accounting for the live animal exports [1].

The cool highland sheep production systems in most highland areas are characterized by erratic and unevenly distributed rainfall, recurrent drought, and scarcity in livestock feeds and feed that is poor in quality [5]. In those production environments, the role of sheep in supporting the livelihood of smallholder farmers is increasing due to recurrent crop failure [5, 6]. However, the sheep flocks are managed under traditional extensive systems with no or minimal inputs and improved technologies, which results in low productivity. They depend on natural pasture and fibrous crop residues for their survival, growth and reproduction. The available natural pasture lands are overloaded with livestock beyond optimum carrying capacity that has resulted in overgrazing and land degradation [7, 8]. This indicated the critical need of supplemental feed during the feed-deficient period and wise management of communal and private natural pasture grazing. A limited supply of nutrients in the sheep's diet can lead to weight loss, low fertility, high mortality, increased risk of disease and poor wool growth. Sheep need a balanced diet containing energy (fat and carbohydrates), protein, vitamins, minerals, and water. Sheep and goat production in Ethiopia suffers feed shortages at all levels with an estimated 40% deficit in the national feed balance. This is aggravated by seasonal availability of forage and crop residues in the highlands and by recurrent and prolonged drought in the lowlands.

**2.2 Experimental design and treatments**

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

experimental animals.

*Description of the study area.*

**Figure 1.**

**Table 1.**

**61**

A 3 2 factorial experimental design arrangement of three genotype and two feeding type factors with six treatment levels (three genotypes by two feeding type's combinations) and six replications were used. The three genotypes belonging to 50% Awassi F1 crosses, 50% Washera F1 crosses and 100% local Wollo highland lambs were grouped in to three by their genotypes and in to two by their feeding types of supplemented and non-supplemented groups for each genotypes. The supplemented and non-supplemented feeding types randomly assigned for each 36

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

Both supplemented and non-supplemented groups grazed for 8 hours/day as a basal diet with rotational grazing system and animal holding of 36 sheep/0.5 ha paddock/day. The supplemented group fed at the rate of 1% of their body

**Local name Scientific name Growth form** Akirma *Cynodon nlemfuensis* Grass—perennial Tult *Asarum canadense* Herb—annual Sindedo *Urochloa brizantha* Grass—perennial Serdo *Cynodon dactylon* Grass—annual Gicha *Cyperus rotundus* Grass—annual Gazia *Dactylis glomerata* L. Grass—perennial Arintata *Trifolium repens* Herb—annual

Others — —

Bare land — —

*Species composition of private owned natural pasture grass land.*

Muja Snowdenia polystachya Grass—annual Gudign *Dichondra repens* Herb—annual Ketema *Cyperus polystachyos* Grass—perennial

Therefore, the study was accomplished on, assessment of productive performance through on-station feedlot based and natural pasture grazing weight gain performance and carcass yield characteristics evaluation of indigenous Wollo highland sheep breed and their F1 crossbreds with 75% Awassi and pure indigenous Washera breed rams.

The specific objectives of the study are:


## **2. Material and methods**

#### **2.1 Description of the study area**

This research was conducted from 2018 to 2019 in the two selected areas of Dessie Zuria and Kutaber districts in South Wollo Zone of Amhara Region, Ethiopia. The geographical location of South Wollo Zone is delimited with North Shewa and Oromia region in the Southern part, East Gojjam in the West, South Gondar in the Northwest, North Wollo in the North, Afar Region in the Northeast and Argobba district of the Oromia Zone in the Eastern part (**Figure 1**).

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

**Figure 1.** *Description of the study area.*

ruminants account for 40% of cash income earned by farm households, 19% of the total value of subsistence food derived from all livestock production, and 25% of total domestic meat consumption [4]. Smallholder sheep production is the major source of food security serving a diverse function, including cash income, savings, fertilizer, socio-cultural functions and fiber production. Sheep are particularly important for farmers in the subalpine highlands and pastoralist/agropastoralist where crop production is unreliable. Moreover, despites its socio-cultural importance, sheep resources significantly contributed for foreign currency earning

The cool highland sheep production systems in most highland areas are characterized by erratic and unevenly distributed rainfall, recurrent drought, and scarcity in livestock feeds and feed that is poor in quality [5]. In those production environments, the role of sheep in supporting the livelihood of smallholder farmers is increasing due to recurrent crop failure [5, 6]. However, the sheep flocks are managed under traditional extensive systems with no or minimal inputs and improved technologies, which results in low productivity. They depend on natural pasture and fibrous crop residues for their survival, growth and reproduction. The available natural pasture lands are overloaded with livestock beyond optimum carrying capacity that has resulted in overgrazing and land degradation [7, 8]. This indicated the critical need of supplemental feed during the feed-deficient period and wise management of communal and private natural pasture grazing. A limited supply of nutrients in the sheep's diet can lead to weight loss, low fertility, high mortality, increased risk of disease and poor wool growth. Sheep need a balanced diet containing energy (fat and carbohydrates), protein, vitamins, minerals, and water. Sheep and goat production in Ethiopia suffers feed shortages at all levels with an estimated 40% deficit in the national feed balance. This is aggravated by seasonal availability of forage and crop residues in the highlands and by recurrent and

Therefore, the study was accomplished on, assessment of productive performance through on-station feedlot based and natural pasture grazing weight gain performance and carcass yield characteristics evaluation of indigenous Wollo highland sheep breed and their F1 crossbreds with 75% Awassi and pure indigenous

• to evaluate on-station feedlot weight gain and carcass yield characteristics of Wollo highland sheep and their F1 crossbreds of Awassi and Washera sheep

• to assess natural grass grazing value as basal diet for the study breeds

This research was conducted from 2018 to 2019 in the two selected areas of Dessie Zuria and Kutaber districts in South Wollo Zone of Amhara Region, Ethiopia. The geographical location of South Wollo Zone is delimited with North Shewa and Oromia region in the Southern part, East Gojjam in the West, South Gondar in the Northwest, North Wollo in the North, Afar Region in the Northeast

and Argobba district of the Oromia Zone in the Eastern part (**Figure 1**).

accounting for the live animal exports [1].

*Sheep Farming - An Approach to Feed, Growth and Health*

prolonged drought in the lowlands.

The specific objectives of the study are:

supplemented by concentrated feed.

Washera breed rams.

breeds.

**60**

**2. Material and methods**

**2.1 Description of the study area**

## **2.2 Experimental design and treatments**

A 3 2 factorial experimental design arrangement of three genotype and two feeding type factors with six treatment levels (three genotypes by two feeding type's combinations) and six replications were used. The three genotypes belonging to 50% Awassi F1 crosses, 50% Washera F1 crosses and 100% local Wollo highland lambs were grouped in to three by their genotypes and in to two by their feeding types of supplemented and non-supplemented groups for each genotypes. The supplemented and non-supplemented feeding types randomly assigned for each 36 experimental animals.

Both supplemented and non-supplemented groups grazed for 8 hours/day as a basal diet with rotational grazing system and animal holding of 36 sheep/0.5 ha paddock/day. The supplemented group fed at the rate of 1% of their body


#### **Table 1.**

*Species composition of private owned natural pasture grass land.*

weight/day of concentrate mix diet, whereas the non-supplemented group fed only natural pasture grazing area for 8 hours/day from 8:00 AM to 5:30 PM with a 1 hour rest from 12:30 AM to 1:30 PM and had free access of drinking water.

where Yijklm = average daily gain (ADG) and body weight change, μ = overall

Model 2. Weight and linear body measurements of male lambs (90–365 days of

where Yij = body weight and linear body measurements at 90, 180, 270 and 365 days of age, μ = overall mean, Bi = fixed effect of the ith breed (i = Awassi F1 crossbred, Washera F1 crossbred and local Wollo highland breed), Btj = fixed effect

where Yijk = body weight gain, carcass and non-carcass parameter, μ = mean, Bi = effect of the ith breed (i = Awassi F1 crossbred, Washera F1 crossbred and local Wollo highland breed), Fj = the fixed effect of feeding type (j = supplemented, nonsupplemented), Wk = the random effect of body weight (k = birth weight, preweaning weight ADG, weaning weight, post-weaning weight ADG and yearling weight, empty body weight, pre-slaughter weight), eijk = effect of the kth random

According to a 3 � 2 factorial statistical designs of the breed and diet as main effects and the PROC GLM of multivariate analysis package of the SAS Windows 9.0-2004 system used for those data fitted with the main factors of breed, feeding type, sex, birth type and parity effects on body weight gain response variable in the model. Initial body weight was also used as a covariate factor in the model to control the residual effects of initial body weight on consecutive rate of body weight gain. The dependent variables include body weight, average daily weight gain, survival rates, linear body measurements, reproductive traits and carcass yield characteristic parameters were considered in the GLM multivariate analysis of variance. The stepwise procedure of Pearson correlation of the SAS system was used to see the effects of association between body weight and linear body measurement traits. Tukey's standardized range significance test was used to compare the different

**3.1 Effects of genotype and supplementation feed on ram lambs growth rate**

Genotype and supplementation diet effect on ram lambs' average body weight and their daily weight gain is presented in **Table 2**. Initial body weight had significant (p < 0.05) difference between genotypes and used in the covariate analysis model to avoid its residual effect on consecutive body weight gain and to quantify the genotype effect. However, it has non-significant difference within genotypes. The between and within genotype variations were continued throughout 10, 20 and

of the jth birth type (j = single, twins), eij = effect of the oth random error. Model 3. Body weight gain, carcass and non-carcass parameters:

Yij ¼ μ þ Bi þ Btj þ eij (4)

Yijk ¼ μ þ Bi þ Fj þ Wk þ eijk, (5)

mean, Bi = fixed effect of the *i*th breed (i = Awassi F1 crossbred, Washera F1 crossbred and local Wollo highland breed), F*<sup>l</sup>* = fixed effect of the feeding type (1 = supplemented, 2 = non-supplemented), (B*<sup>i</sup>* � F*l*)*il* = breed by feeding type

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

interaction effect and eil = effect of the nth random error.

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

age):

error.

**2.5 Data analysis**

groups of mean.

**3. Results**

**63**

#### **2.3 Experimental animals grazing management**

The grazing land characterized by both annual and perennial grass such as *Cyperus rotundus*, *Dactylis glomerata Cynodon nlemfuensis*, *Cynodon dactylon*, *Cyperus polystachyos* and *Urochloa brizantha* (**Table 1**). The size of natural pasture grazing area was 2.5 ha of land and that sub-divided into five paddocks with each individual paddock size was 0.5 ha.

## **2.4 Body weight gain and linear body measurements**

Lambs were weighed at 15 days of interval for 1 year in the last week of each month using a 0.1 kg precision scale. Lambs were weighed at birth and fortnightly thereafter up to weaning. After weaning at the age of about 90 days they were weighed in 15 days interval together with the rest of the flock. Lamb body weights were adjusted by age.

The average daily weight gain (ADG) was calculated using the following formula at on-farm growth performance study:

$$ADG = \frac{dW2\,\,Kg + W1\text{Kg}}{A} \, \ast 1000\,\tag{1}$$

where ADG g = average daily gain in gram, W1 kg = birth weight or weight at the preceding age, W2 kg = weight at a given age, and A = age in days or days between weighing dates.

Average daily gain was calculated for the following stages of growth: (a) pre-weaning weight average daily gain (PreADG) ADG = birth to 90 days of age, (b) post-weaning weight average daily gain (PoADG) = birth to 365 days of age, and (c) weaning weight = at average body weight at 90 days.

Average daily weight gain of ram lambs in the on-station growth performance evaluation was also calculated using the following formula:

$$ADG = \frac{FWT\,Kg + IWT\,Kg}{AD} \, \* 100\,\tag{2}$$

where FWT = final body weight, IWT = initial body weight, and D = number of fattening days.

Linear body measurements were taken together with 3 months of interval measurements (from 3 months of age to 12 months). All body measurements were taken with a measuring tape in centimeter and measured to the nearest 0.5 cm. Linear body measurements traits were taken: (a) heart girth is the circumference of the chest posterior to the forelegs at right angles to the body axis, (b) wither height is the highest point measured as the vertical distance from the top of the shoulder to the ground, (c) body length is the distance between the crown and the sacrococcygeal joint, (d) tail width is directly behind the tuber ichiad, and (e) tail circumference is directly behind the tuber ichiad.

Model 1. On-station growth of initial and final body weight, average daily gain (ADG) of ram lambs (9 months–365 days of age):

$$\text{Yijklm} = \mu + \text{Bi} + \text{F}\_l + (\text{B}\_i \times \text{F}\_l)\text{ijn} + \text{eijklm} \tag{3}$$

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

where Yijklm = average daily gain (ADG) and body weight change, μ = overall mean, Bi = fixed effect of the *i*th breed (i = Awassi F1 crossbred, Washera F1 crossbred and local Wollo highland breed), F*<sup>l</sup>* = fixed effect of the feeding type (1 = supplemented, 2 = non-supplemented), (B*<sup>i</sup>* � F*l*)*il* = breed by feeding type interaction effect and eil = effect of the nth random error.

Model 2. Weight and linear body measurements of male lambs (90–365 days of age):

$$\text{Yij} = \mu + \text{Bi} + \text{Btj} + \text{eij} \tag{4}$$

where Yij = body weight and linear body measurements at 90, 180, 270 and 365 days of age, μ = overall mean, Bi = fixed effect of the ith breed (i = Awassi F1 crossbred, Washera F1 crossbred and local Wollo highland breed), Btj = fixed effect of the jth birth type (j = single, twins), eij = effect of the oth random error.

Model 3. Body weight gain, carcass and non-carcass parameters:

$$\text{Yijk} = \mu + \text{Bi} + \text{Fj} + \text{Wk} + \text{eijk},\tag{5}$$

where Yijk = body weight gain, carcass and non-carcass parameter, μ = mean, Bi = effect of the ith breed (i = Awassi F1 crossbred, Washera F1 crossbred and local Wollo highland breed), Fj = the fixed effect of feeding type (j = supplemented, nonsupplemented), Wk = the random effect of body weight (k = birth weight, preweaning weight ADG, weaning weight, post-weaning weight ADG and yearling weight, empty body weight, pre-slaughter weight), eijk = effect of the kth random error.

#### **2.5 Data analysis**

weight/day of concentrate mix diet, whereas the non-supplemented group fed only natural pasture grazing area for 8 hours/day from 8:00 AM to 5:30 PM with a 1 hour

The grazing land characterized by both annual and perennial grass such as *Cyperus rotundus*, *Dactylis glomerata Cynodon nlemfuensis*, *Cynodon dactylon*, *Cyperus polystachyos* and *Urochloa brizantha* (**Table 1**). The size of natural pasture grazing area was 2.5 ha of land and that sub-divided into five paddocks with each individual

Lambs were weighed at 15 days of interval for 1 year in the last week of each month using a 0.1 kg precision scale. Lambs were weighed at birth and fortnightly thereafter up to weaning. After weaning at the age of about 90 days they were weighed in 15 days interval together with the rest of the flock. Lamb body weights

The average daily weight gain (ADG) was calculated using the following

*ADG* <sup>¼</sup> *dW*<sup>2</sup> *Kg* <sup>þ</sup> *<sup>W</sup>*1*Kg*

Average daily gain was calculated for the following stages of growth: (a) pre-weaning weight average daily gain (PreADG) ADG = birth to 90 days of age, (b) post-weaning weight average daily gain (PoADG) = birth to 365 days of

*ADG* <sup>¼</sup> *FWT Kg* <sup>þ</sup> *IWTKg*

the ground, (c) body length is the distance between the crown and the

circumference is directly behind the tuber ichiad.

(ADG) of ram lambs (9 months–365 days of age):

age, and (c) weaning weight = at average body weight at 90 days.

evaluation was also calculated using the following formula:

where ADG g = average daily gain in gram, W1 kg = birth weight or weight at the preceding age, W2 kg = weight at a given age, and A = age in days or days

Average daily weight gain of ram lambs in the on-station growth performance

where FWT = final body weight, IWT = initial body weight, and D = number of

Linear body measurements were taken together with 3 months of interval measurements (from 3 months of age to 12 months). All body measurements were taken with a measuring tape in centimeter and measured to the nearest 0.5 cm. Linear body measurements traits were taken: (a) heart girth is the circumference of the chest posterior to the forelegs at right angles to the body axis, (b) wither height is the highest point measured as the vertical distance from the top of the shoulder to

sacrococcygeal joint, (d) tail width is directly behind the tuber ichiad, and (e) tail

Model 1. On-station growth of initial and final body weight, average daily gain

Yijklm ¼ μ þ Bi þ F*<sup>l</sup>* þ ð Þ B*<sup>i</sup>* � F*<sup>l</sup>* ijm þ eijklm (3)

*<sup>A</sup>* <sup>∗</sup> <sup>1000</sup> (1)

*AD* <sup>∗</sup> <sup>100</sup> (2)

rest from 12:30 AM to 1:30 PM and had free access of drinking water.

**2.3 Experimental animals grazing management**

*Sheep Farming - An Approach to Feed, Growth and Health*

**2.4 Body weight gain and linear body measurements**

formula at on-farm growth performance study:

paddock size was 0.5 ha.

were adjusted by age.

between weighing dates.

fattening days.

**62**

According to a 3 � 2 factorial statistical designs of the breed and diet as main effects and the PROC GLM of multivariate analysis package of the SAS Windows 9.0-2004 system used for those data fitted with the main factors of breed, feeding type, sex, birth type and parity effects on body weight gain response variable in the model. Initial body weight was also used as a covariate factor in the model to control the residual effects of initial body weight on consecutive rate of body weight gain. The dependent variables include body weight, average daily weight gain, survival rates, linear body measurements, reproductive traits and carcass yield characteristic parameters were considered in the GLM multivariate analysis of variance. The stepwise procedure of Pearson correlation of the SAS system was used to see the effects of association between body weight and linear body measurement traits. Tukey's standardized range significance test was used to compare the different groups of mean.

## **3. Results**

#### **3.1 Effects of genotype and supplementation feed on ram lambs growth rate**

Genotype and supplementation diet effect on ram lambs' average body weight and their daily weight gain is presented in **Table 2**. Initial body weight had significant (p < 0.05) difference between genotypes and used in the covariate analysis model to avoid its residual effect on consecutive body weight gain and to quantify the genotype effect. However, it has non-significant difference within genotypes. The between and within genotype variations were continued throughout 10, 20 and


crossbred lambs had higher final body weight gain than supplemented Wollo highland breed lambs. The final body weight of non-supplemented Washera crossbred

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

Carcass and non-carcass yield characteristics included, pre-slaughtered weight, slaughter body weight, empty body weight, fasting loss, hot carcass weight, cold carcass weight, total edible proportion, non-carcass organs, rib-eye area, fat and

Slaughtered and empty body weight bases of the supplemented and nonsupplemented groups did not significant difference for each genotype. However, significant variations recorded between the three genotypes. Subsequent to 24 hours of fasting period (except water) the body weight losses and hot carcass weight had comparable value within breeds. However, Awassi crossbred lambs lost more than Washera crossbred and Wollo highland breed lambs. Even though Awassi F1 crossbred lambs lost higher body weight than others during fasting period, it is significantly (P < 0.05) higher hot carcass weight than Washera F1 crossbreds and Wollo highland ram lambs. Nevertheless, fasting loss and hot carcass weight have comparable value between supplemented and non-supplemented

Fat thickness of both supplemented and non-supplemented groups of Awassi

Slaughtered body weight had strong positive and significant correlation with

inverse correlation with commercial yield % (cold carcass weight/slaughtered body weight � 100) carcass trait. Empty body weight has strong and positive correlation

Hot carcass weight had perfect positive significant correlation with rib-eye area

poorly correlated with amount of commercial yield (**Table 3**). The cold carcass weight trait has positive and intermediate correlation with rib-eye area and with lean meat thickness and poorly positive correlation with commercial yield feature. Likewise, rib-eye area carcass trait contents had medium positive association with fat thickness and lean meat thickness attribute. However, it had poor and positive correlation with commercial yield percentage composition, while fat thickness amount of the carcass had positive and medium correlation with lean meat thickness in the

entire carcass, but negatively correlated with commercial yield percentage

) of lean meat composition, medium positive correlation with fat thickness and

).

), fat thickness

). However, it had

). However, poor and

crossbred lambs had significantly higher than Wollo highland and nonsupplemented Washera crossbred lambs. Despite the fact that, supplemented Washera crossbred lambs, had comparable fat thickness with supplemented Awassi crossbred lambs. Awassi crosses had significantly higher a total non-carcass weight than both Washera and Wollo highland breed lambs, but did not show within breed difference. Between supplemented and non-supplemented Washera genotype and supplemented local Wollo highland breed did not have significant variation of total non-carcass components and non-supplemented Wollo highland lambs significantly

lambs had higher than non-supplemented Wollo highland lambs.

**performance**

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

lower than others.

(mm<sup>2</sup>

(cm2

**65**

**3.2 Genotypes and supplementation effect on carcass characteristic**

lean meat thickness and commercial yield were presented in **Table 2**.

Wollo highland and Washera crossbred lambs.

**3.3 Carcass yield traits correlation coefficient analysis**

with cold and hot carcass weight, and rib-eye area (cm2

positively associated with lean meat thickness (mm<sup>2</sup>

empty body weight, hot and cold carcass weight, rib-eye area (cm2

) and slight positive correlation with lean thickness (mm2

*\* P < 0.05, \*\*P < 0.01, \*\*\*P < 0.001.*

*ABW, average body weight gain; FBW, final body weight gain; BWC, body weight change; ADG, average daily weight gain; T1, supplemented; T2, not-supplemented; superscript with the same letter is not significant and different letters has significant difference (across the row); SE, standard error of the mean.*

#### **Table 2.**

*Genotype and supplemented diet effect on ram lambs body weight gain.*

30 days experimental period except supplemented Washera F1 crossbreds and Wollo highland breed lambs and which were significantly higher than their nonsupplemented group at 10 and 20 days treatment period, respectively. Despite the fact that at 30, 40, 50 and 60 days of feed treatment period the supplemented group of Wollo highland breed lambs had non-significant differences with both supplemented and non-supplemented Washera crossbred lambs and between breed variation eliminated. At 40 and 50 days, treatment period, except Wollo highland lambs the other genotypes have insignificant differences between supplemented and non-supplemented groups. Conversely, at 60 days of treatment period supplemented Wollo highland breed lambs had non-significant variation with both supplemented and non-supplemented Washera F1 crossbred lambs and vice versa. Awassi F1 crossbred lambs significantly (p < 0.05) higher average weight gain than both Wollo highland and Washera F1 cross ram lambs throughout the experimental period (**Table 2**).

The total body weight changes from initial to final body weight higher in supplemented Awassi crossbred lambs and followed by their non-supplemented group. Supplemented and non-supplemented Wollo highland lambs observed better growth performance than Washera F1 crossbreds. Therefore, on-station feed supplementation effect had fastest growth performance record with Awassi F1 crossbred lambs than Wollo highland and Washera F1 crossbred lambs. Supplemented Wollo highland lambs had faster growth rates than their nonsupplemented group. Supplemented Washera crossbred lambs had a comparable body weight change to non-supplemented group.

Even though, Wollo highland breed had faster body weight change and average daily gain than Washera F1 crossbred lambs, the supplemented group of Washera

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

crossbred lambs had higher final body weight gain than supplemented Wollo highland breed lambs. The final body weight of non-supplemented Washera crossbred lambs had higher than non-supplemented Wollo highland lambs.

## **3.2 Genotypes and supplementation effect on carcass characteristic performance**

Carcass and non-carcass yield characteristics included, pre-slaughtered weight, slaughter body weight, empty body weight, fasting loss, hot carcass weight, cold carcass weight, total edible proportion, non-carcass organs, rib-eye area, fat and lean meat thickness and commercial yield were presented in **Table 2**.

Slaughtered and empty body weight bases of the supplemented and nonsupplemented groups did not significant difference for each genotype. However, significant variations recorded between the three genotypes. Subsequent to 24 hours of fasting period (except water) the body weight losses and hot carcass weight had comparable value within breeds. However, Awassi crossbred lambs lost more than Washera crossbred and Wollo highland breed lambs. Even though Awassi F1 crossbred lambs lost higher body weight than others during fasting period, it is significantly (P < 0.05) higher hot carcass weight than Washera F1 crossbreds and Wollo highland ram lambs. Nevertheless, fasting loss and hot carcass weight have comparable value between supplemented and non-supplemented Wollo highland and Washera crossbred lambs.

Fat thickness of both supplemented and non-supplemented groups of Awassi crossbred lambs had significantly higher than Wollo highland and nonsupplemented Washera crossbred lambs. Despite the fact that, supplemented Washera crossbred lambs, had comparable fat thickness with supplemented Awassi crossbred lambs. Awassi crosses had significantly higher a total non-carcass weight than both Washera and Wollo highland breed lambs, but did not show within breed difference. Between supplemented and non-supplemented Washera genotype and supplemented local Wollo highland breed did not have significant variation of total non-carcass components and non-supplemented Wollo highland lambs significantly lower than others.

## **3.3 Carcass yield traits correlation coefficient analysis**

Slaughtered body weight had strong positive and significant correlation with empty body weight, hot and cold carcass weight, rib-eye area (cm2 ), fat thickness (mm<sup>2</sup> ) and slight positive correlation with lean thickness (mm2 ). However, it had inverse correlation with commercial yield % (cold carcass weight/slaughtered body weight � 100) carcass trait. Empty body weight has strong and positive correlation with cold and hot carcass weight, and rib-eye area (cm2 ). However, poor and positively associated with lean meat thickness (mm<sup>2</sup> ).

Hot carcass weight had perfect positive significant correlation with rib-eye area (cm2 ) of lean meat composition, medium positive correlation with fat thickness and poorly correlated with amount of commercial yield (**Table 3**). The cold carcass weight trait has positive and intermediate correlation with rib-eye area and with lean meat thickness and poorly positive correlation with commercial yield feature. Likewise, rib-eye area carcass trait contents had medium positive association with fat thickness and lean meat thickness attribute. However, it had poor and positive correlation with commercial yield percentage composition, while fat thickness amount of the carcass had positive and medium correlation with lean meat thickness in the entire carcass, but negatively correlated with commercial yield percentage

30 days experimental period except supplemented Washera F1 crossbreds and Wollo highland breed lambs and which were significantly higher than their nonsupplemented group at 10 and 20 days treatment period, respectively. Despite the fact that at 30, 40, 50 and 60 days of feed treatment period the supplemented group

*ABW, average body weight gain; FBW, final body weight gain; BWC, body weight change; ADG, average daily weight gain; T1, supplemented; T2, not-supplemented; superscript with the same letter is not significant and different*

*letters has significant difference (across the row); SE, standard error of the mean.*

*Genotype and supplemented diet effect on ram lambs body weight gain.*

*Sheep Farming - An Approach to Feed, Growth and Health*

**Awassi genotype Wollo genotype Washera genotype**

IBW 31.6 1.0<sup>a</sup> 31.5 0.8<sup>a</sup> 21.9 0.7<sup>b</sup> 21.4 0.5<sup>b</sup> 26.4 0.7<sup>c</sup> 26.6 0.7c \*\*\* 10 days 33.4 0.9<sup>a</sup> 34.0 0.9<sup>a</sup> 26.9 0.9<sup>b</sup> 24.5 0.9<sup>b</sup> 29.0 0.5<sup>c</sup> 27.5 0.5d \* 20 days 33.3 1.1a 34.1 1.1a 26.6 1.1c 24.2 1.1<sup>b</sup> 28.8 0.6c 26.9 0.6c \* 30 days 36.7 1.3a 36.9 1.3a 28.4 1.3b,c 26.3 1.3b 30.3 0.7<sup>c</sup> 29.0 0.7c \* 40 days 37.8 1.3a 37.7 1.3a 29.3 1.3b 27.0 1.3<sup>d</sup> 30.6 0.7<sup>c</sup> 29.2 0.7c \* 50 days 38.3 1.7a 36.1 1.7b 30.8 1.7c,e 28.4 1.7d 31.1 0.9<sup>e</sup> 29.4 0.9c,d \* 60 days 38.8 1.8a 35.8 1.8<sup>b</sup> 32.4 1.7c 29.8 1.8d 32.1 1.0<sup>c</sup> 29.9 1.0d \*\* 70 days 39.9 1.8a 37.3 1.8b 33.3 1.8d 30.4 1.8c 32.2 1.0c,d 30.6 1.0e,c \*\* 80 days 41.4 1.8a 38.2 1.8b 34.4 1.8<sup>c</sup> 31.1 1.8d 33.1 1.0<sup>c</sup> 31.3 1.0d \*\* FBW 45.5 1.4<sup>a</sup> 42.4 1.4<sup>b</sup> 35.2 1.3c 31.6 1.4<sup>d</sup> 34.4 0.7<sup>c</sup> 32.4 0.7d \*\*\* BWC 16.1 1.1<sup>a</sup> 13.4 1.1b 8.9 1.1<sup>c</sup> 7.5 1.1<sup>d</sup> 6.0 0.6<sup>e</sup> 5.9 0.6e \*\* ADG (g) 178.5 12.3a 148.3 12.4<sup>b</sup> 98.4 12.2<sup>c</sup> 83.5 12.3d 66.6 6.7<sup>e</sup> 65.2 6.7e \*\*

**T1 T2 T1 T2 T1 T2 Sig.L**

supplemented and non-supplemented Washera crossbred lambs and between breed variation eliminated. At 40 and 50 days, treatment period, except Wollo highland lambs the other genotypes have insignificant differences between supplemented and non-supplemented groups. Conversely, at 60 days of treatment period

supplemented Wollo highland breed lambs had non-significant variation with both supplemented and non-supplemented Washera F1 crossbred lambs and vice versa. Awassi F1 crossbred lambs significantly (p < 0.05) higher average weight gain than both Wollo highland and Washera F1 cross ram lambs throughout the experimental

The total body weight changes from initial to final body weight higher in supplemented Awassi crossbred lambs and followed by their non-supplemented group. Supplemented and non-supplemented Wollo highland lambs observed better growth performance than Washera F1 crossbreds. Therefore, on-station feed supplementation effect had fastest growth performance record with Awassi F1 crossbred lambs than Wollo highland and Washera F1 crossbred lambs. Supplemented Wollo highland lambs had faster growth rates than their nonsupplemented group. Supplemented Washera crossbred lambs had a comparable

Even though, Wollo highland breed had faster body weight change and average daily gain than Washera F1 crossbred lambs, the supplemented group of Washera

body weight change to non-supplemented group.

of Wollo highland breed lambs had non-significant differences with both

period (**Table 2**).

**64**

**ABW (kg)**

*\**

**Table 2.**

*P < 0.05, \*\*P < 0.01, \*\*\*P < 0.001.*


lambs. Between supplemented and non-supplemented groups of Wollo highland

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

The carcass composition of lean meat weight amount is significantly higher with Awassi crossbred lambs than Washera crossbred and Wollo highland breed lambs. Supplemented Wollo highland lambs and Washera crossbred lambs had proportional amount of lean meat weight. The carcass compactness index is measured by grams of lean meat per centimeters of its length. Carcass compactness index, chest and shoulder width had comparable records for all genotypes except chest width for

**3.5 Genotype and supplementation feed effects on non-carcass fat distribution**

The effects of genotype and supplementation diet effect on non-carcass fat distribution presented in **Table 5**. Thus, the non-carcass fat contents around the scrotal fat organ had not significant variation between supplemented and non supplemented group of each genotypes. However, between Wollo highland breed and Awassi crossbred lambs had a significant variation of scrotal fat contents. Likewise, Washera and Awassi crossbred lambs had significant differences between supplemented and non supplemented groups of scrotal fat contents. While, kidney fat composition of Awassi crossbred lambs and Wollo highland breed lambs had

Whereas, significant difference recorded between three genotypes of total non carcass fat contents. Both supplemented and non supplemented group of Awassi F1 crossbred lambs had higher composition of total non-carcass fat contents followed by Washera crossbred lambs. In general all supplemented groups were comprised of higher numerical value of non carcass fat composition, but not significantly differ-

significantly lower than that of Washera crossbred lambs (**Table 5**).

**3.6 Genotype and feed effects on non-carcass edible and non-edible**

According to intellectual prohibited cultural and religious taboo of the local communities the edible components of non-carcass organs were presented as liver, tongue, heart, kidney, empty gastrointestinal part and tail fat were the most

Carcass length (cm) 74.3 1.2<sup>a</sup> 73.7 1.2<sup>a</sup> 63.0 1.9b 64.0 1.9b 70.3 2.2c 68.0 2.2<sup>c</sup>

Lean meat weight (kg) 0.7 0.03<sup>a</sup> 0.7 0.03<sup>a</sup> 0.5 0.1<sup>b</sup> 0.5 0.1<sup>b</sup> 0.6 0.1<sup>b</sup> 0.5 0.1<sup>b</sup> Lean meat length (cm) 55.3 1.2<sup>a</sup> 54.7 1.2<sup>a</sup> 44.0 1.9<sup>b</sup> 45.0 1.9b 51.3 2.2c 49. 2.2<sup>c</sup>

Chest width (cm) 13.9 0.6a 13.7 0.6<sup>a</sup> 9.2 1.0<sup>b</sup> 8.1 1.0<sup>b</sup> 10.9 0.9<sup>b</sup> 8.8 0.9<sup>b</sup> Shoulder width (cm) 17.7 0.6 18.1 0.6 14.4 0.6 14.2 0.6 17.1 0.6 15.0 0.6 *T1, supplemented; T2, non-supplemented; cm, centimeters, kg, kilograms, mm, millimeters, g, gram. Superscript with*

*the same letter is not significant and different letters has significant difference.*

*Between and within genotype carcass morphometric traits variability.*

**Awassi F1 crossbreds Wollo highland breed Washera F1 crossbreds T1 T2 T1 T2 T1 T2**

12.5 2.4a 11.0 2.4<sup>a</sup> 9.0 0.7<sup>b</sup> 6.4 0.7<sup>c</sup> 12.0 0.5<sup>a</sup> 6.3 0.5<sup>c</sup>

12.1 0.8 12.0 0.8 11.8 0.8 11.9 0.8 12.4 0.9 10.5 0.9

breed and Washera, crossbred lambs had significant difference.

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

Awassi genotype.

ent with non supplemented groups.

**components**

**morphometric traits**

Lean meat thickness

Compactness index

**Carcass**

(mm)

(g/cm)

**Table 5.**

**67**

*T1, supplemented; T2, non-supplemented; SBW, sloughter body weight; EBW, empty body weight; HCW, hot carcass weight; CCW, cold carcass weight; HCWDP, hot carcass weight dressing percentage; CCWDP, cold carcass weight dressing percentage; TEP, total edible propertion; REA, rib-eye area; TNCW, total non-carcass weight. Superscript with the same letter is not significant and different letters has significant difference.*

#### **Table 3.**

*Analysis of variability for genotype and diet effects on carcass traits.*

composition. In other ways lean meat content of the carcass had poor positive correlation with commercial yield of the whole carcass composition (**Table 3**).

#### **3.4 Genotype and supplementation effects on carcass morphometric traits**

Carcass morphometric characteristics of the present study were described by carcass length, lean meat weight, lean meat length, compactness index, chest width, shoulder width, and lean meat thickness presented in **Table 4**. Hence, the length of the carcass and lean meat had significantly higher for Awassi and followed by Washera crossbred lambs. Between the supplemented and non-supplemented groups of each genotypes, comparable carcass and lean meat length were recorded, however, significantly different between genotypes. Lean meat thickness significantly higher for both supplemented and non-supplemented Awassi F1 crossbred


*SBW, slaughter body weight; EBW, empty body weight; HCW, hot carcass weight; CCW, cold carcass weight; REA, rib-eye area; LMT, lean meat thickness; CY, commercial yield.*

*\*\*\*Correlation is significant at the 0.001 level (two-tailed). \*\*Correlation is significant at the 0.01 level (two-tailed).*

*\* Correlation is significant at the 0.05 level (two-tailed).*

#### **Table 4.**

*Pearson correlation coefficient of carcass yield characterestics.*

## *Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

lambs. Between supplemented and non-supplemented groups of Wollo highland breed and Washera, crossbred lambs had significant difference.

The carcass composition of lean meat weight amount is significantly higher with Awassi crossbred lambs than Washera crossbred and Wollo highland breed lambs. Supplemented Wollo highland lambs and Washera crossbred lambs had proportional amount of lean meat weight. The carcass compactness index is measured by grams of lean meat per centimeters of its length. Carcass compactness index, chest and shoulder width had comparable records for all genotypes except chest width for Awassi genotype.

## **3.5 Genotype and supplementation feed effects on non-carcass fat distribution**

The effects of genotype and supplementation diet effect on non-carcass fat distribution presented in **Table 5**. Thus, the non-carcass fat contents around the scrotal fat organ had not significant variation between supplemented and non supplemented group of each genotypes. However, between Wollo highland breed and Awassi crossbred lambs had a significant variation of scrotal fat contents. Likewise, Washera and Awassi crossbred lambs had significant differences between supplemented and non supplemented groups of scrotal fat contents. While, kidney fat composition of Awassi crossbred lambs and Wollo highland breed lambs had significantly lower than that of Washera crossbred lambs (**Table 5**).

Whereas, significant difference recorded between three genotypes of total non carcass fat contents. Both supplemented and non supplemented group of Awassi F1 crossbred lambs had higher composition of total non-carcass fat contents followed by Washera crossbred lambs. In general all supplemented groups were comprised of higher numerical value of non carcass fat composition, but not significantly different with non supplemented groups.

## **3.6 Genotype and feed effects on non-carcass edible and non-edible components**

According to intellectual prohibited cultural and religious taboo of the local communities the edible components of non-carcass organs were presented as liver, tongue, heart, kidney, empty gastrointestinal part and tail fat were the most


*T1, supplemented; T2, non-supplemented; cm, centimeters, kg, kilograms, mm, millimeters, g, gram. Superscript with the same letter is not significant and different letters has significant difference.*

#### **Table 5.**

*Between and within genotype carcass morphometric traits variability.*

composition. In other ways lean meat content of the carcass had poor positive corre-

**Awassi F1 crossbreds Wollo highland breed Washera F1 crossbreds T1 T2 T1 T2 T1 T2 Sig. L**

) 15.9 0.2a 15.5 0.2<sup>a</sup> 7.3 0.1<sup>b</sup> 6.5 0.1<sup>b</sup> 9.2 0.1<sup>c</sup> 7.3 0.1b \*\*

TNCW (kg) 14.5 1.3a 12.2 1.3a,b 10.8 1.3b 6.9 1.3c <sup>10</sup> 1.3b 12.9 1.3b \* FT (mm) 0.3 0.1<sup>a</sup> 0.3 0.1a 0.2 0.0<sup>b</sup> 0.2 0.0<sup>b</sup> 0.3 0.2<sup>a</sup> 0.2 0.2b \* *T1, supplemented; T2, non-supplemented; SBW, sloughter body weight; EBW, empty body weight; HCW, hot carcass weight; CCW, cold carcass weight; HCWDP, hot carcass weight dressing percentage; CCWDP, cold carcass weight dressing percentage; TEP, total edible propertion; REA, rib-eye area; TNCW, total non-carcass weight. Superscript*

SBW (kg) 47.4 0.8<sup>a</sup> 44.6 0.6<sup>b</sup> 32.5 1.4<sup>c</sup> 29.3 1.1d 32.6 0.5<sup>c</sup> 32.2 0.5c \*\*\* EBW(kg) 35.3 1.3a 32.4 1.3a 24.5 1.7<sup>b</sup> 20.5 1.7b 26.9 0.9<sup>c</sup> 26.8 0.9c \*\* HCW (kg) 20.8 1.6<sup>a</sup> 20.2 1.6a 14.7 1.2<sup>b</sup> 13.5 1.2<sup>b</sup> 16.0 0.5<sup>c</sup> 13.2 0.5b \*\*\* CCW (kg) 18.3 1.4<sup>a</sup> 18.2 1.4<sup>a</sup> 11.7 1.0<sup>b</sup> 11.6 1.0<sup>b</sup> 14.9 0.4<sup>c</sup> 12.5 0.4c,b \*\* HCWDP (%) 43.9 3.2<sup>a</sup> 45.3 3.2<sup>b</sup> 45.2 3.2<sup>b</sup> 46.1 3.2<sup>b</sup> 49.1 0.3<sup>c</sup> 41.0 0.3d \* CCWDP (%) 38.6 2.9<sup>a</sup> 40.8 2.9<sup>b</sup> <sup>36</sup> 5.2c 39.6 5.2a,b 45.7 1.8d 38.8 1.8a \* TEP (kg) 25.1 1.8a 23.8 1.8a 17.4 1.6<sup>b</sup> 17.2 1.6<sup>b</sup> 19.6 0.7<sup>c</sup> 17.6 0.7b \*\*

Carcass morphometric characteristics of the present study were described by carcass length, lean meat weight, lean meat length, compactness index, chest width, shoulder width, and lean meat thickness presented in **Table 4**. Hence, the length of the carcass and lean meat had significantly higher for Awassi and followed by Washera crossbred lambs. Between the supplemented and non-supplemented groups of each genotypes, comparable carcass and lean meat length were recorded, however, significantly different between genotypes. Lean meat thickness significantly higher for both supplemented and non-supplemented Awassi F1 crossbred

**3.4 Genotype and supplementation effects on carcass morphometric traits**

**Body weight (kg) SBW EBW HCW CCW REA LMT**

) 0.52\* 0.50\* 0.54\* 0.554\* 0.54\* CY (%) 0.15 0.01 0.42 0.36 0.42 0.08

*SBW, slaughter body weight; EBW, empty body weight; HCW, hot carcass weight; CCW, cold carcass weight; REA,*

) 0.82\*\* 0.77\*\* 0.99\*\*\* 0.98\*\*\*

EBW 0.87\*\*

REA (cm<sup>2</sup>

**Carcass traits**

REA (cm<sup>2</sup>

**Table 3.**

LMT (mm<sup>2</sup>

*\**

**66**

**Table 4.**

HCW 0.82\*\* 0.77\*\*

CCW 0.86\*\* 0.79\*\* 0.98\*\*\*

*rib-eye area; LMT, lean meat thickness; CY, commercial yield. \*\*\*Correlation is significant at the 0.001 level (two-tailed). \*\*Correlation is significant at the 0.01 level (two-tailed).*

*Pearson correlation coefficient of carcass yield characterestics.*

*Correlation is significant at the 0.05 level (two-tailed).*

lation with commercial yield of the whole carcass composition (**Table 3**).

*with the same letter is not significant and different letters has significant difference.*

*Analysis of variability for genotype and diet effects on carcass traits.*

*Sheep Farming - An Approach to Feed, Growth and Health*


**4.2 Effects of genotype and supplementation on body weight gain performance**

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

Genotypes and supplementation feed effects on ram lambs' body weight gain presented in **Table 2**. Initially the body weight gain of the three genotypes significantly different (p < 0.05) each other and the differences were come from breed effects but not significant differences within group in each treatment. To avoid the effects of initial body weight on the successive body weight gain, covariate analysis was used and the adjusted initial body weight at 26.56 kg of all genotypes. In the present study, significantly higher average daily weight gain observed on the supplemented group implied that they were adequately fed and their maintenance and growth nutrient requirements were satisfied compared with non-supplemented

The average daily weight gain (ADG), the rate of body weight change and final body weights of supplemented group of Awassi, and Washera F1 crossbred and Wollo highland breed ram lambs were significantly higher (p < 0.05) than nonsupplemented groups. As a result, Awassi F1 crossbred lambs' growth rate had significantly greater (p < 0.05) than both Wollo highland and Washera F1 cross-

supplementing Wollo highland breed ram lambs. The reason behind this might be the genetic potential difference of the three genotypes affecting average daily weight gain efficiency with different extent. Therefore, genotype is the limiting factor affecting average daily weight gain of lambs and in agreement with reported by Hammell and Laforest [12] for Polled Dorset, Hampshire and Romanov breeds. The total amount of body weight change and the rate of daily weight gain indicated Wollo highland breed lambs were significantly greater than both

supplemented and non-supplemented groups of Washera F1 crossbred lambs. This indicated improved grazing management condition and supplementation diet of Wollo highland breed lambs can have comparable body weight gain potential with

In general the Awassi F1 crossbred ram lambs have a promising growth performance with supplementation of local available concentrate feed. Hence, with controlled management condition of natural pasture grazing has contributed to better growth performance of ram lambs body weight gain. Furthermore, Washera F1 crossbreed lambs have an imperative body weight change and can be another alternative to enhance genetic potential of pure local Wollo highland breed, and in addition to this, inbreeding coefficient risk can be reduced. Moreover, costeffective concentrate feed supplementation on natural pasture grazing need appropriate attention by fatteners, and other sheep producers. Together with this private controlled grazing management, system had also played a great role to improve the

**4.3 Effects of genotype and supplemented feed on carcass yield characteristics**

Carcass composition used as tool to characterize breeds for possible identification of potential genetic resource for lean lamb production and also to identify management alternatives to suit different breeds [16]. Therefore, breed is known to influence not only carcass composition and quality but also carcass conformation as well, differences in carcass merits between breeds is likely to govern the choice and

supplemented groups variation not significant for all genotypes. The reason behind

supplemented body weight before slaughter and relatively comparable amount of

their Washera F1 crossbreds with the same management condition [13–15].

body weight gain of ram lambs through quality pasture production.

Slaughter and empty body weight between supplemented and non-

this might be less significant variation between supplemented and non-

development of breeds for specific production objectives.

**69**

bred ram lambs throughout the experimental period and followed by

groups (grazing only).

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

## **Table 6.**

*Non-carcass fat distribution traits variability between and within genotypes.*

common. Hence, liver and heart weight had comparable value for Wollo highland and Washera crossbred lambs; however, Awassi crossbred had significantly higher amount of liver and heart weight. At the same time, non-significant record was observed between supplemented and non-supplemented groups of all genotypes. While the kidney and empty gastrointestinal weight had comparable value for all genotypes and feeding type factors, there was no significant difference both within and between genotypes and feeding types. Whereas the tail weight had comparable value between the three genotypes, Washera crossbred had a numerically higher quantity of tail weight than others (**Table 6**).

Except kidney weight of non-supplemented Awassi and Washera F1 crossbreds and supplemented Wollo highland breed lambs, the edible non-carcass components not significant variation between supplemented and non-supplemented groups. However, except kidney weight and GIT empty weight, genotype had significant variation on non-carcass edible components. Except tail fat weight composition, in all edible noncarcass components of the Awassi crossbred lambs had the largest portion (**Table 6**).

Wollo highland breed had a comparable tail fat composition with Awassi crossbred lambs. However, both genotype and supplementation diet did not had significant differences with kidney and empty gastrointestinal weight of supplemented and non-supplemented groups. Subsequently, the non-edible, non-carcass components were skin, head, testicle and genital organ, blood, bladder, pancreas, feet, digestive contents and spleen which prohibited by the local communities cultural and religious taboo.

## **4. Discussion**

## **4.1 Genotype and supplemented diet effects on body weight gain and carcass traits**

The availability and supply of animal feed in the tropics is not constant in terms of both quantity and quality particularly in arid and semiarid regions seasonal fluctuation in the growth rate of animal in these regions [9, 10]. This is particularly true in the study area, where the main source of animal feed is grazing on natural pasture. For this reason, to use whatever available resource more economically, it will be advantageous to identify those breeds of animals which are more efficient meat producers [11] or animals which have high performance in feed conversion efficiency to produce saleable products [11].

## **4.2 Effects of genotype and supplementation on body weight gain performance**

Genotypes and supplementation feed effects on ram lambs' body weight gain presented in **Table 2**. Initially the body weight gain of the three genotypes significantly different (p < 0.05) each other and the differences were come from breed effects but not significant differences within group in each treatment. To avoid the effects of initial body weight on the successive body weight gain, covariate analysis was used and the adjusted initial body weight at 26.56 kg of all genotypes. In the present study, significantly higher average daily weight gain observed on the supplemented group implied that they were adequately fed and their maintenance and growth nutrient requirements were satisfied compared with non-supplemented groups (grazing only).

The average daily weight gain (ADG), the rate of body weight change and final body weights of supplemented group of Awassi, and Washera F1 crossbred and Wollo highland breed ram lambs were significantly higher (p < 0.05) than nonsupplemented groups. As a result, Awassi F1 crossbred lambs' growth rate had significantly greater (p < 0.05) than both Wollo highland and Washera F1 crossbred ram lambs throughout the experimental period and followed by supplementing Wollo highland breed ram lambs. The reason behind this might be the genetic potential difference of the three genotypes affecting average daily weight gain efficiency with different extent. Therefore, genotype is the limiting factor affecting average daily weight gain of lambs and in agreement with reported by Hammell and Laforest [12] for Polled Dorset, Hampshire and Romanov breeds.

The total amount of body weight change and the rate of daily weight gain indicated Wollo highland breed lambs were significantly greater than both supplemented and non-supplemented groups of Washera F1 crossbred lambs. This indicated improved grazing management condition and supplementation diet of Wollo highland breed lambs can have comparable body weight gain potential with their Washera F1 crossbreds with the same management condition [13–15].

In general the Awassi F1 crossbred ram lambs have a promising growth performance with supplementation of local available concentrate feed. Hence, with controlled management condition of natural pasture grazing has contributed to better growth performance of ram lambs body weight gain. Furthermore, Washera F1 crossbreed lambs have an imperative body weight change and can be another alternative to enhance genetic potential of pure local Wollo highland breed, and in addition to this, inbreeding coefficient risk can be reduced. Moreover, costeffective concentrate feed supplementation on natural pasture grazing need appropriate attention by fatteners, and other sheep producers. Together with this private controlled grazing management, system had also played a great role to improve the body weight gain of ram lambs through quality pasture production.

## **4.3 Effects of genotype and supplemented feed on carcass yield characteristics**

Carcass composition used as tool to characterize breeds for possible identification of potential genetic resource for lean lamb production and also to identify management alternatives to suit different breeds [16]. Therefore, breed is known to influence not only carcass composition and quality but also carcass conformation as well, differences in carcass merits between breeds is likely to govern the choice and development of breeds for specific production objectives.

Slaughter and empty body weight between supplemented and nonsupplemented groups variation not significant for all genotypes. The reason behind this might be less significant variation between supplemented and nonsupplemented body weight before slaughter and relatively comparable amount of

common. Hence, liver and heart weight had comparable value for Wollo highland and Washera crossbred lambs; however, Awassi crossbred had significantly higher amount of liver and heart weight. At the same time, non-significant record was observed between supplemented and non-supplemented groups of all genotypes. While the kidney and empty gastrointestinal weight had comparable value for all genotypes and feeding type factors, there was no significant difference both within and between genotypes and feeding types. Whereas the tail weight had comparable value between the three genotypes, Washera crossbred had a numerically higher

Scrotal fat 8.7 2.9<sup>c</sup> 10.7 2.1<sup>c</sup> <sup>33</sup> 6.7<sup>b</sup> <sup>40</sup> 6.7b 13.7 4.4<sup>c</sup> 15.7 4.4c Pelvic fat 29.3 3.5<sup>a</sup> 26.7 3.5<sup>a</sup> 30.7 3.1a 27.7 3.1<sup>a</sup> 47.0 10.6<sup>c</sup> 38.3 10.6<sup>c</sup> Kidney fat 25.3 2.0<sup>a</sup> 23.3 2.0a <sup>60</sup> <sup>18</sup><sup>a</sup> <sup>63</sup> 18.0<sup>a</sup> 171.0 52.4<sup>c</sup> 89.3 52.4<sup>c</sup>

Overall 117.7 12.6a 103.6 12.6<sup>a</sup> 537.7 54.7c 448.4 54.7<sup>d</sup> <sup>465</sup> 129.7<sup>c</sup> 288.3 129.7<sup>b</sup> *T1, supplemented; T2, non-supplemented; g, grams. Superscript with the same letter is not significant and different*

**Wollo highland breed Awassi F1 crossbreds Washera F1 crossbreds T1 T2 T1 T2 T1 T2**

55.3 8.5a 43.3 8.5<sup>a</sup> <sup>414</sup> 38.7<sup>b</sup> 317.7 38.7<sup>b</sup> 233.3 64.1<sup>c</sup> 145.0 64.1c

Except kidney weight of non-supplemented Awassi and Washera F1 crossbreds and supplemented Wollo highland breed lambs, the edible non-carcass components not significant variation between supplemented and non-supplemented groups. However, except kidney weight and GIT empty weight, genotype had significant variation on non-carcass edible components. Except tail fat weight composition, in all edible noncarcass components of the Awassi crossbred lambs had the largest portion (**Table 6**). Wollo highland breed had a comparable tail fat composition with Awassi crossbred lambs. However, both genotype and supplementation diet did not had significant differences with kidney and empty gastrointestinal weight of supplemented and non-supplemented groups. Subsequently, the non-edible, non-carcass components were skin, head, testicle and genital organ, blood, bladder, pancreas, feet, digestive contents and spleen which prohibited by the local communities cultural

**4.1 Genotype and supplemented diet effects on body weight gain**

The availability and supply of animal feed in the tropics is not constant in terms

of both quantity and quality particularly in arid and semiarid regions seasonal fluctuation in the growth rate of animal in these regions [9, 10]. This is particularly true in the study area, where the main source of animal feed is grazing on natural pasture. For this reason, to use whatever available resource more economically, it will be advantageous to identify those breeds of animals which are more efficient meat producers [11] or animals which have high performance in feed conversion

quantity of tail weight than others (**Table 6**).

*Non-carcass fat distribution traits variability between and within genotypes.*

*Sheep Farming - An Approach to Feed, Growth and Health*

and religious taboo.

**and carcass traits**

efficiency to produce saleable products [11].

**4. Discussion**

**68**

**Noncarcass fat traits (g)**

Mesentery fat

**Table 6.**

*letters has significant difference.*

fasting loss. Nevertheless, significant variations between the three genotypes recorded, and which in agreement with Orr [17] and Lakew et al. [18]. Subsequent to 24 hours of fasting period, the body weight losses had a comparable amount for all genotypes and not significant variation observed. The loss of rumen contents through defecation and urination effects of fasting period not significantly different among genotypes (**Table 7**).

[21] for Chilote and Suffolk breeds in Chile Island. The chilling loss of cold carcass weight may vary between 1 and 7%, usually found close to 2.5% [22]. Moreover, sex, weight, fat covering of the carcass, temperature, and humidity in the cold storage chamber and the handling of the carcasses [23, 24] influence cold carcass

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

Dressing percentage is described as the proportion of carcass weight to slaughtered body weight and it helps to assess meat productivity of the animals. Nutrition influences dressing percentage through variation in weight of mesentery contents and variation in actual organ weights [25, 26]. In agreement with the present finding, Awgichew [10] reported, regardless of the clear tendency of Horro lambs having a heavier hot and cold carcass weight, but did not differ significantly from Menz breed in dressing % and the loss of carcass moisture (shrinking %) after an overnight cooling. The present finding reported, hot carcass weight dressing percentage (HCCWDP) does not have significant difference both between and within genotype and which in agreement with Awgichew [10] and Jorge et al. [21]. Concurring with this report, an experimental trial conducted by Mazemder et al. [27] on grazing local sheep supplemented and with non-supplemented of 100, 200 and 300 g of concentrate feed/day; dressing percentage was similar among the

Rib-eye muscle area is mostly used as a tool to indicate the proportion of carcass

muscling [28, 29]. In the present study the supplementation diet did not have a significant impact on rib-eye muscle area but numerical difference was observed. In line with the current finding, Gizaw [1] reported supplementation did not have significant effect on rib-eye muscle area in Somali goats fed hay and supplemented with different levels of peanut cake and wheat bran mixture. However, unlike this finding, Matiwas et al. [28] and Alemu [32] reported supplementation diet had a significant and positive effect on rib-eye muscle area. In concurrence with this finding, Matiwas et al. [31], Alemu [32]; Simret and Gizaw [30] reported rib-eye area had a significant variation between breeds. However, did not significant variation between supplemented and non-supplemented groups of Awassi crosses and Wollo highland breed lambs (**Table 7**). Nevertheless, supplemented and nonsupplemented groups of Washera crossbreds had significant differences of rib-eye area composition. This fact is an indicator of better muscle development of supplementing Washera crosses than non-supplemented one. Hence, this rib-eye area muscle development is one of the merits to select Washera F1 crossbred lambs for meat production objective. Both supplemented and non-supplemented Wollo highland and non-supplemented Washera crossbred lambs have relatively compa-

Except dressing percentage, almost all carcass characteristic extent both supplemented and non-supplemented Awassi crossbred had significantly higher than Wollo highland and Washera F1 crossbred lambs. Hence, crossbreeding effect on genetic improvement practices using Awassi exotic breed had significant response associated with growth and carcass yield characteristic traits. As a result Awassi F1 crossbred lambs had potential effect on meat production improvement objective and advisable to be selected for further breed productivity improvement program.

**4.4 Genotype and supplemented feed effects on non-carcass fat distribution**

The effects of genotype and supplementation diet on non-carcass fat distribution was presented in **Table 6**. Thus, non-carcass fat contents around the scrotal organ had not significant variation between supplemented and non-supplemented groups of the three genotypes. However, between Wollo highland breed lambs and Awassi F1 crossbred lambs, significant variation of fat around scrotal organ observed.

rable rib-eye area muscle development (**Table 7**).

characteristic.

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

treatments.

**71**

Hot carcass weight has comparable value between supplemented and non-supplemented groups. However, between genotypes a significant variation (p < 0.001) reported and which in agreement with Orr [17] and Lakew et al. [18]. Therefore, Awassi F1 crossbred ram lambs significantly higher (p < 0.001) hot carcass weight than Wollo highland and Washera F1 crosses (**Table 2**). This is because of higher slaughtered body weight and higher average daily weight gain (ADG) effect and their comparable fasting loss. Assefu [19, 20] reported there was no breed effect in hot carcass weight between Horro and Washera breeds and which disagree with present study.

Cold carcass weight used as commercial carcass yield indicator trait used for productive performance tools to evaluate the productivity of a given meat animals. Awassi crossbred lambs' cold carcass weight significantly (p < 0.05) greater than both Washera crosses and Wollo highland breed lambs. Within each genotype, cold carcass weight did not have significant difference because of the higher amount of chilling loss rate of supplemented groups (**Table 7**). This indicated that, the supplemented feed does not bring significant impact on cold carcass weight and agreement with Awgichew [10] for Menz and Horro breed lambs and Jorge et al.


*T1, supplemented; T2, non-supplemented; ns, non-significant; GIT, gastrointestinal track and SE, standard error of the mean. Superscript with the same letter is not significant and different letters has significant difference.*

#### **Table 7.**

*Genotype and diet effects on edible and non-edible non-carcass components.*

## *Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

[21] for Chilote and Suffolk breeds in Chile Island. The chilling loss of cold carcass weight may vary between 1 and 7%, usually found close to 2.5% [22]. Moreover, sex, weight, fat covering of the carcass, temperature, and humidity in the cold storage chamber and the handling of the carcasses [23, 24] influence cold carcass characteristic.

Dressing percentage is described as the proportion of carcass weight to slaughtered body weight and it helps to assess meat productivity of the animals. Nutrition influences dressing percentage through variation in weight of mesentery contents and variation in actual organ weights [25, 26]. In agreement with the present finding, Awgichew [10] reported, regardless of the clear tendency of Horro lambs having a heavier hot and cold carcass weight, but did not differ significantly from Menz breed in dressing % and the loss of carcass moisture (shrinking %) after an overnight cooling. The present finding reported, hot carcass weight dressing percentage (HCCWDP) does not have significant difference both between and within genotype and which in agreement with Awgichew [10] and Jorge et al. [21]. Concurring with this report, an experimental trial conducted by Mazemder et al. [27] on grazing local sheep supplemented and with non-supplemented of 100, 200 and 300 g of concentrate feed/day; dressing percentage was similar among the treatments.

Rib-eye muscle area is mostly used as a tool to indicate the proportion of carcass muscling [28, 29]. In the present study the supplementation diet did not have a significant impact on rib-eye muscle area but numerical difference was observed. In line with the current finding, Gizaw [1] reported supplementation did not have significant effect on rib-eye muscle area in Somali goats fed hay and supplemented with different levels of peanut cake and wheat bran mixture. However, unlike this finding, Matiwas et al. [28] and Alemu [32] reported supplementation diet had a significant and positive effect on rib-eye muscle area. In concurrence with this finding, Matiwas et al. [31], Alemu [32]; Simret and Gizaw [30] reported rib-eye area had a significant variation between breeds. However, did not significant variation between supplemented and non-supplemented groups of Awassi crosses and Wollo highland breed lambs (**Table 7**). Nevertheless, supplemented and nonsupplemented groups of Washera crossbreds had significant differences of rib-eye area composition. This fact is an indicator of better muscle development of supplementing Washera crosses than non-supplemented one. Hence, this rib-eye area muscle development is one of the merits to select Washera F1 crossbred lambs for meat production objective. Both supplemented and non-supplemented Wollo highland and non-supplemented Washera crossbred lambs have relatively comparable rib-eye area muscle development (**Table 7**).

Except dressing percentage, almost all carcass characteristic extent both supplemented and non-supplemented Awassi crossbred had significantly higher than Wollo highland and Washera F1 crossbred lambs. Hence, crossbreeding effect on genetic improvement practices using Awassi exotic breed had significant response associated with growth and carcass yield characteristic traits. As a result Awassi F1 crossbred lambs had potential effect on meat production improvement objective and advisable to be selected for further breed productivity improvement program.

## **4.4 Genotype and supplemented feed effects on non-carcass fat distribution**

The effects of genotype and supplementation diet on non-carcass fat distribution was presented in **Table 6**. Thus, non-carcass fat contents around the scrotal organ had not significant variation between supplemented and non-supplemented groups of the three genotypes. However, between Wollo highland breed lambs and Awassi F1 crossbred lambs, significant variation of fat around scrotal organ observed.

fasting loss. Nevertheless, significant variations between the three genotypes recorded, and which in agreement with Orr [17] and Lakew et al. [18]. Subsequent to 24 hours of fasting period, the body weight losses had a comparable amount for all genotypes and not significant variation observed. The loss of rumen contents through defecation and urination effects of fasting period not significantly different

*Sheep Farming - An Approach to Feed, Growth and Health*

Hot carcass weight has comparable value between supplemented and non-supplemented groups. However, between genotypes a significant variation (p < 0.001) reported and which in agreement with Orr [17] and Lakew et al. [18]. Therefore, Awassi F1 crossbred ram lambs significantly higher (p < 0.001) hot carcass weight than Wollo highland and Washera F1 crosses (**Table 2**). This is because of higher slaughtered body weight and higher average daily weight gain (ADG) effect and their comparable fasting loss. Assefu [19, 20] reported there was no breed effect in hot carcass weight between Horro and Washera breeds and which

Cold carcass weight used as commercial carcass yield indicator trait used for productive performance tools to evaluate the productivity of a given meat animals. Awassi crossbred lambs' cold carcass weight significantly (p < 0.05) greater than both Washera crosses and Wollo highland breed lambs. Within each genotype, cold carcass weight did not have significant difference because of the higher amount of chilling loss rate of supplemented groups (**Table 7**). This indicated that, the supplemented feed does not bring significant impact on cold carcass weight and agreement with Awgichew [10] for Menz and Horro breed lambs and Jorge et al.

> **Wollo highland breed (means)**

Liver (g) 717.0<sup>a</sup> 541.3<sup>a</sup> 332.0<sup>b</sup> 384.3<sup>b</sup> 445.0<sup>c</sup> 453.0<sup>c</sup> 76.0 \*\* Tongue (g) 137.8a 143.2a 109.3<sup>b</sup> 114.3<sup>b</sup> 91.9<sup>c</sup> 89.8<sup>c</sup> 7.0 \*\*\* Heart (g) 190.3<sup>a</sup> 127.3<sup>a</sup> 61.3<sup>c</sup> 68.3c 68.3<sup>c</sup> 75.3<sup>c</sup> 25.5 \*\* Kidney (g) 63.3<sup>a</sup> 66.0<sup>b</sup> 64.3a,b 59.0c 54.0<sup>c</sup> 66.0<sup>b</sup> 31.4 \* GIT empty (g) 1900.0 1633.3 1611.3 2215.0 1779.3 1633.3 330 ns Tail fat (g) 987.3 951.0 1106.7 920.0 1151.3 1213.3 100.9 ns

Skin (g) 3600.0<sup>a</sup> 3766.7<sup>a</sup> 3700.0<sup>a</sup> 3133.3<sup>b</sup> 5100.0<sup>c</sup> 5033.3c 255.0 \*\* Head (g) 1773.3a 1733.3<sup>a</sup> 2110.0<sup>b</sup> 2206.7b 2660.0<sup>c</sup> 2763.3<sup>c</sup> 134.9 \*\* Testicle (g) 420.0<sup>a</sup> 420.0<sup>a</sup> 310.0<sup>b</sup> 310.0<sup>b</sup> 540.0a 430.0a 56.0 \*\*\* Blood (g) 1336.7<sup>a</sup> 1300.0<sup>a</sup> 873.3b 937.3b 2033.3<sup>c</sup> 1823.3<sup>c</sup> 181.3 \*\* Bladder (g) 67.3<sup>a</sup> 68.7a 57.3<sup>b</sup> 63.3b 72.3.0<sup>a</sup> 64.0<sup>a</sup> 2.3 \*\* Feet (g) 247.7a 249.7<sup>a</sup> 214.0<sup>a</sup> 194.7<sup>b</sup> 203.7<sup>b</sup> 217.7<sup>a</sup> 16.4 \* Digestive content (g) 8400.0c 8300<sup>c</sup> 4222.0<sup>a</sup> 5551.7b 3466.7a 4337.3<sup>a</sup> 725.2 \*\* Spleen (g) 41.7 44.0 32.7 45.0 33.7 30.3 4.7 ns *T1, supplemented; T2, non-supplemented; ns, non-significant; GIT, gastrointestinal track and SE, standard error of the mean. Superscript with the same letter is not significant and different letters has significant difference.*

**Washera crosses (means)**

**T1 T2 T1 T2 T1 T2 SE P-value**

among genotypes (**Table 7**).

disagree with present study.

**I. Edible non-carcass traits**

**II. Non-edible non-carcass traits**

**Table 7.**

**70**

**Non-carcass components Awassi crosses**

**(means)**

*Genotype and diet effects on edible and non-edible non-carcass components.*

Likewise, between supplemented and non-supplemented groups of Washera and Awassi F1 crossbred lambs have significant difference fat around scrotal organ recorded. Subcutaneous fat content between Wollo highland and Awassi crossbred lambs had comparable value. However, Awassi crossbred and Wollo highland breed lambs significantly lower subcutaneous fat content than Washera crossbred lambs. The reason behind this, on fat deposition efficiency of Washera F1 crosses genotype effect has more noticeable than Awassi crosses and Wollo highland breed.

carcass components compared with all genotypes, which aligned with Teklu [40]. This implies animals consume more feed, their stomach enlarged to accommodate the larger ingesta and thicker to resist the workload on it and this may increase the

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

Except lung with trachea and spleen, all non-edible offal components were not affected by supplemented diet and indicating that variation of supplementation diet not influenced the non-edible non-carcass components. The non-edible non-carcass

(p < 0.05) among genotypes and this might be slaughtered body weight differences and the inherent genotype effect. In agreement with the current study, Prasad and Kirton [41] reported live weight status of the animals could affect the production efficiency of carcass offal and considered as depressing factor for hot and cold carcass weight extent and their dressing percentage. However, the nutritional effect not significantly visible for most non-edible non-carcass component weight and which in agreement with Teklu [40] but disagree with Michael and Yaynshet [42]. In general the larger extent of non-carcass non-edible components could be reduced the edible carcass and non-carcass amount, hence, through breed selection task,

The study conducted at feedlot productive performance evaluation of Wollo highland sheep breed and their F1 crossbreeds of Awassi and Washera sheep in Ethiopia. The objectives of the research is grazing and feedlot based productive performance evaluation of Wollo highland sheep breed and their F1 crosses.

The average daily weight gain (ADG), total body weight change and final body weights of supplemented group Awassi F1 crossbred and Wollo highland ram lambs significantly higher than non-supplemented groups. Awassi F1 crossbred lambs growth performance significantly higher than Wollo highland and Washera F1 crossbred lambs and followed by supplemented Wollo highland breed lambs. Wollo highland breed had ability to increase their body weight compared with other selected indigenous breed types of the country and have potential value for fattening purpose and productive potential genetic improvement practice, as far as their

The effect of genotypes on average daily weight gain of Awassi crossbred ram lambs had the largest value of breed selection in the current study. Therefore, the effect of both genotype and supplementation diet have an advanced value for lamb body weight gain improvement practices. Moreover, cost effective concentrate feed supplementation on natural pasture controlled grazing have to give appropriate

Carcass composition used as a tool to characterize breeds for possible identification of potential genetic resource of lean meat type of lamb production and identify management alternatives to suit different breeds. Differences in carcass merits between genotypes are likely to govern the choice and development of breeds for specific production objective. Natural pasture controlled grazing management important alternative for productive and organic product improvement practices. Supplementation diet does not have significant effect on hot carcass weight dressing percentage however, further research is important to confirm at different level of supplementation feeding trial. Cold carcass weight dressing percentage (CCWDP) has a significant difference between supplemented and non-

supplemented groups of each of the three genotype in the present study and its

important parameter for carcass productivity improvement practice.

contents of head, digestive content and blood volume significant difference

need to be considered the non-carcass non-edible content of genotype.

**5. Conclusion and recommendation**

nutritional requirement is maintained.

**73**

attention by smallholder sheep producers and fatteners.

volume and weight of the gastrointestinal tract as a whole.

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

The current study showed mesentery fat, kidney fat and subcutaneous fat decreased in non-supplemented ram lambs fed on natural pasture forage diet only. The current result is in agreement with reported by Karim et al. [33] and Papi et al. [34] on the concept of lambs with high forage quality tended to deposit less subcutaneous and intestinal fat contents. Lambs fed a concentrate diet displayed considerably greater fat accumulation than lambs raised on forage based diets [35]. The reduced non-carcass fat attributed to lower energy intake from forage [33]. In addition, high starch consumption the supplemented concentrate diets produces higher amounts of propionate, which ultimately increases insulin secretion and stimulates fat synthesis [35]. In agreement with this finding, Ibrahim et al. [29], Salo et al. [36], Roberto et al. [37] and Abebe and Tamir [38] reported the total fat contents of non-carcass components were significantly affected by the type of diet used. However, in the current finding, in addition to the effects of diet, genotype effects also significant (P < 0.05) different on total non-carcass fat contents. Even though, supplemented Awassi and Washera crossbred lambs had comparable total non-carcass fat composition, Washera F1 crossbred lambs showed comparatively higher fat contents than Awassi F1 crossbreds in relation to their body weight difference.

## **4.5 Genotype and supplemented feed effects on edible and non-edible, non-carcass part**

Accordingly, intellectual prohibited cultural and religious taboo of local communities, edible components of non-carcass organs, which presented as liver, tongue, heart, kidney, empty gastrointestinal content and tail fat are the most common and presented in **Table 6**. Hence, liver and heart weight comparable value between Wollo highland and Washera crossbred lambs; however, Awassi crossbred lambs had significantly (p < 0.05) higher than the other. The reason behind this might be larger body size and physiological appearance of the genotype. However, non-significant variation between supplemented and non-supplemented groups of all genotypes were recorded, while the kidney and intestine weight had a comparable amount for all genotypes and feeding type. Roughage part of animal feed obvious to feel rumen content and the the green forge grazing was equally accessible to all genotypes and which was the reason for comparable intestinal weight. Whereas the tail size had comparable value for Awassi crossbred and Wollo highland breed ram lambs, Washera crossbred lambs had a significantly (P < 0.05) larger tail size than other two genotypes. This also indicated that Washera F1 crossbred ram-lambs shown larger fat development nature and that might be because of largest tail weight.

In agreement with current finding, Riley et al. [39] and Teklu [40] were reported the majority of edible offal components was not affected (P > 0.05) by the supplemented feed. As a remarkable feature of Awassi crossbred lambs more advanced with liver, tongue and heart weight. This perceptible difference resulted from large body size and genotype effect. In concurrence with the current result, Riley et al. [39] indicated that differences in internal organs were more influenced by age, breed and sex of the animals rather than plane of nutrition, whereas kidney and empty gastrointestinal track weight cover the larger portions of edible non*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

carcass components compared with all genotypes, which aligned with Teklu [40]. This implies animals consume more feed, their stomach enlarged to accommodate the larger ingesta and thicker to resist the workload on it and this may increase the volume and weight of the gastrointestinal tract as a whole.

Except lung with trachea and spleen, all non-edible offal components were not affected by supplemented diet and indicating that variation of supplementation diet not influenced the non-edible non-carcass components. The non-edible non-carcass contents of head, digestive content and blood volume significant difference (p < 0.05) among genotypes and this might be slaughtered body weight differences and the inherent genotype effect. In agreement with the current study, Prasad and Kirton [41] reported live weight status of the animals could affect the production efficiency of carcass offal and considered as depressing factor for hot and cold carcass weight extent and their dressing percentage. However, the nutritional effect not significantly visible for most non-edible non-carcass component weight and which in agreement with Teklu [40] but disagree with Michael and Yaynshet [42]. In general the larger extent of non-carcass non-edible components could be reduced the edible carcass and non-carcass amount, hence, through breed selection task, need to be considered the non-carcass non-edible content of genotype.

## **5. Conclusion and recommendation**

The study conducted at feedlot productive performance evaluation of Wollo highland sheep breed and their F1 crossbreeds of Awassi and Washera sheep in Ethiopia. The objectives of the research is grazing and feedlot based productive performance evaluation of Wollo highland sheep breed and their F1 crosses.

The average daily weight gain (ADG), total body weight change and final body weights of supplemented group Awassi F1 crossbred and Wollo highland ram lambs significantly higher than non-supplemented groups. Awassi F1 crossbred lambs growth performance significantly higher than Wollo highland and Washera F1 crossbred lambs and followed by supplemented Wollo highland breed lambs. Wollo highland breed had ability to increase their body weight compared with other selected indigenous breed types of the country and have potential value for fattening purpose and productive potential genetic improvement practice, as far as their nutritional requirement is maintained.

The effect of genotypes on average daily weight gain of Awassi crossbred ram lambs had the largest value of breed selection in the current study. Therefore, the effect of both genotype and supplementation diet have an advanced value for lamb body weight gain improvement practices. Moreover, cost effective concentrate feed supplementation on natural pasture controlled grazing have to give appropriate attention by smallholder sheep producers and fatteners.

Carcass composition used as a tool to characterize breeds for possible identification of potential genetic resource of lean meat type of lamb production and identify management alternatives to suit different breeds. Differences in carcass merits between genotypes are likely to govern the choice and development of breeds for specific production objective. Natural pasture controlled grazing management important alternative for productive and organic product improvement practices.

Supplementation diet does not have significant effect on hot carcass weight dressing percentage however, further research is important to confirm at different level of supplementation feeding trial. Cold carcass weight dressing percentage (CCWDP) has a significant difference between supplemented and nonsupplemented groups of each of the three genotype in the present study and its important parameter for carcass productivity improvement practice.

Likewise, between supplemented and non-supplemented groups of Washera and Awassi F1 crossbred lambs have significant difference fat around scrotal organ recorded. Subcutaneous fat content between Wollo highland and Awassi crossbred lambs had comparable value. However, Awassi crossbred and Wollo highland breed lambs significantly lower subcutaneous fat content than Washera crossbred lambs. The reason behind this, on fat deposition efficiency of Washera F1 crosses genotype

effect has more noticeable than Awassi crosses and Wollo highland breed. The current study showed mesentery fat, kidney fat and subcutaneous fat decreased in non-supplemented ram lambs fed on natural pasture forage diet only. The current result is in agreement with reported by Karim et al. [33] and Papi et al. [34] on the concept of lambs with high forage quality tended to deposit less subcutaneous and intestinal fat contents. Lambs fed a concentrate diet displayed considerably greater fat accumulation than lambs raised on forage based diets [35]. The reduced non-carcass fat attributed to lower energy intake from forage [33]. In addition, high starch consumption the supplemented concentrate diets produces higher amounts of propionate, which ultimately increases insulin secretion and stimulates fat synthesis [35]. In agreement with this finding, Ibrahim et al. [29], Salo et al. [36], Roberto et al. [37] and Abebe and Tamir [38] reported the total fat contents of non-carcass components were significantly affected by the type of diet used. However, in the current finding, in addition to the effects of diet, genotype effects also significant (P < 0.05) different on total non-carcass fat contents. Even though, supplemented Awassi and Washera crossbred lambs had comparable total non-carcass fat composition, Washera F1 crossbred lambs showed comparatively higher fat contents than Awassi

*Sheep Farming - An Approach to Feed, Growth and Health*

F1 crossbreds in relation to their body weight difference.

**non-carcass part**

because of largest tail weight.

**72**

**4.5 Genotype and supplemented feed effects on edible and non-edible,**

Accordingly, intellectual prohibited cultural and religious taboo of local communities, edible components of non-carcass organs, which presented as liver, tongue, heart, kidney, empty gastrointestinal content and tail fat are the most common and presented in **Table 6**. Hence, liver and heart weight comparable value between Wollo highland and Washera crossbred lambs; however, Awassi crossbred lambs had significantly (p < 0.05) higher than the other. The reason behind this might be larger body size and physiological appearance of the genotype. However, non-significant variation between supplemented and non-supplemented groups of all genotypes were recorded, while the kidney and intestine weight had a comparable amount for all genotypes and feeding type. Roughage part of animal feed obvious to feel rumen content and the the green forge grazing was equally accessible to all genotypes and which was the reason for comparable intestinal weight. Whereas the tail size had comparable value for Awassi crossbred and Wollo highland breed ram lambs, Washera crossbred lambs had a significantly (P < 0.05) larger tail size than other two genotypes. This also indicated that Washera F1 crossbred ram-lambs shown larger fat development nature and that might be

In agreement with current finding, Riley et al. [39] and Teklu [40] were reported the majority of edible offal components was not affected (P > 0.05) by the supplemented feed. As a remarkable feature of Awassi crossbred lambs more advanced with liver, tongue and heart weight. This perceptible difference resulted from large body size and genotype effect. In concurrence with the current result, Riley et al. [39] indicated that differences in internal organs were more influenced by age, breed and sex of the animals rather than plane of nutrition, whereas kidney and empty gastrointestinal track weight cover the larger portions of edible non-

Awassi F1 crossbred progenies designated for promising attributes for higher body weight gain and carcass yield characteristics productive trait and good fertility rate; however, further research verification activities suggested with different blood level of crossbred progenies performance evaluation. The genotype and supplementation diet effect has profound factors to enhance productive and farmers' production objectives decision. Hence, researchers need to investigate farmers' interest and potential of available breed type through genetic and phenotype performance study. Effective concentrate feed supplementation on controlled natural pasture grazing had significant impact on ram lambs productive performance improvement and it is crucial to create appropriate understanding for fatteners, traders and other sheep producers.

## **Acknowledgements**

Mehamed Ali (private sheep farm owner) and Dessie Zuria District smallholder farmers have participated with allowed their sheep flocks for inventory purpose. Medhin G/Cherkos, Tadesse Mergiaw, Tilahun Gezahegn and Ayiten Mekete participated through data collection as enumerator. Addis Ababa (AAU) and Wollo University (WU) have participated in providing Research Grant. Department of Animal Production Study (DAPS) in Addis Ababa University, participated through assistance from the beginning to the end of data collection process and the whole thesis work.

## **Conflict of interest**

The authors declare no conflict of interest.

## **Funding**

The work of this research project has done by the funding support of Addis Ababa University thematic project, Minister of Education, and Wollo University collaboration.

**Author details**

Ethiopia

**75**

Tadesse Amare Sisay<sup>1</sup>

\*, Gebeyehu Goshu Negia<sup>2</sup> and Berhan Tamir Mersso<sup>2</sup>

1 Department of Animal Science, College of Agriculture, Wollo University, Dessie,

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

2 Department of Animal Production Studies, College of Veterinary Medicine and

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Agriculture, Addiss Ababa University, Bishoftu, Ethiopia

provided the original work is properly cited.

\*Address all correspondence to: tadesse.amare2002@yahoo.com

## **Abbreviations**


*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

## **Author details**

Awassi F1 crossbred progenies designated for promising attributes for higher body weight gain and carcass yield characteristics productive trait and good fertility rate; however, further research verification activities suggested with different blood level of crossbred progenies performance evaluation. The genotype and supplementation diet effect has profound factors to enhance productive and farmers' production objectives decision. Hence, researchers need to investigate farmers' interest and potential of available breed type through genetic and phenotype performance study. Effective concentrate feed supplementation on controlled natural pasture grazing had significant impact on ram lambs productive performance improvement and it is crucial to create appropriate understanding for fatteners,

Mehamed Ali (private sheep farm owner) and Dessie Zuria District smallholder farmers have participated with allowed their sheep flocks for inventory purpose. Medhin G/Cherkos, Tadesse Mergiaw, Tilahun Gezahegn and Ayiten Mekete participated through data collection as enumerator. Addis Ababa (AAU) and Wollo University (WU) have participated in providing Research Grant. Department of Animal Production Study (DAPS) in Addis Ababa University, participated through assistance from the beginning to the end of data collection process and the whole

The work of this research project has done by the funding support of Addis Ababa University thematic project, Minister of Education, and Wollo University

traders and other sheep producers.

*Sheep Farming - An Approach to Feed, Growth and Health*

**Acknowledgements**

thesis work.

**Funding**

collaboration.

**Abbreviations**

**74**

**Conflict of interest**

The authors declare no conflict of interest.

CSA Central Statistics Authority EPA extension planning area

SPS sanitary and phytosanitary standards

UNCTD United Nations Conference on Trade and Development

Tadesse Amare Sisay<sup>1</sup> \*, Gebeyehu Goshu Negia<sup>2</sup> and Berhan Tamir Mersso<sup>2</sup>

1 Department of Animal Science, College of Agriculture, Wollo University, Dessie, Ethiopia

2 Department of Animal Production Studies, College of Veterinary Medicine and Agriculture, Addiss Ababa University, Bishoftu, Ethiopia

\*Address all correspondence to: tadesse.amare2002@yahoo.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **References**

[1] Gizaw S, Johan A, Olivier H, Hans K, Johann S, Dessie T, Van der Z, Herbert H. Sheep resources of Ethiopia: Genetic diversity and breeding strategy [PhD thesis]. Wageningen, the Netherlands: Wageningen University; 2008a

[2] CSA. Agricultural Sample Survey, 2012, Volume II: Report on Livestockand Livestock Characteristics (Private Peasant Holdings) Statistical Bulletin 585. Addis Ababa, Federal Democratic Republic of Ethiopia: CSA; 2017

[3] Hirpa A, Abebe G. Economic significance of sheep and goats. In: Yami A, Merkel RC, editors. Sheep and Goat Production Handbook for Ethiopia. Ethiopia, Addis Ababa: Ethiopia Sheep and Goat Productivity Improvement Program (ESGPIP); 2008; pp. 1-4

[4] Bogale S, Melaku S, Yami A. Matching livestock systems with available feed resources in the Bale Highlands of Ethiopia. Outlook Agricultural Journal (OAJ). 2008;**37**: 105-110

[5] Mukasa-Mugerwa E, Lahlou-Kassi A. Reproductive performance and productivity of Menz sheep in the Ethiopian highlands. Journal of Small Ruminant Research (JSRR). 1995;**17**: 167-177

[6] Dejene A. Integrated Natural Resources Management to Enhance Food Security: The Case for Community-Based Approaches in Ethiopia. Working Paper No. 16. Rome, Italy: FAO; 2003

[7] Yeheyis L, Sebsibe A, Girma A. On-farm evaluation of the effect of supplementing grazing Menz sheep during the dry season in Gerakeya Woreda, North Sea. In: Proceedings of the 12th Annual Conference; 12-14

August. Addis Ababa, Ethiopia; 2004. pp. 371-375

tailed sheep. Journal of Small Ruminant Research (JSRR). 1996;**22**:155-162

*DOI: http://dx.doi.org/10.5772/intechopen.92340*

Journal of Revista Nacional da Carne, São Paulo (JRNDCSP). 2008;**1**(381):

Fernandes SR, Souza JC, et al. Carcass and meat traits and non-carcass components of lambs fed ration containing increasing levels of urea. Journal of Ciências Agrárias (JCA).

[25] Warmington BG, Kirton AH. Genetic and non-genetic influences on growth and carcass traits of goats. Journal of Small Ruminant Research

[26] Payne WJ. An Introduction to Animal Husbandry in the Tropics. Vol. 44. New York, United States: Longman

Scientific and Technical; 1999.

[27] Mazemder MA, Hossain MM, Khter SA. Effect of levels of concentrate supplement on live weight gain and carcass characteristics in sheep on restricted grazing. Journal of Animal

Science (JAS). 1998;**11**:17-20

[29] Ibrahim A, Mutassim M, Abdullah H, Rifat U, Mohamed Y, Al-Saiady R, et al. Effect of alfalfa hay on growth performance, carcass characteristics, and meat quality of growing lambs with ad-libitum access to total mixed rations. Journal of Revista Brasileira de Zootecnia (JRBZ). 2016;

[30] Smachew G. Effects of

supplementation with maize bran, noug seed cake (*Guizotia abyssinica*) and their

2008;**119**:137-144

**45**(6):302-308

[28] Mathios S, Solomon M, Adugna T. The effect of different level of cotton seed cake supplementation on feed intake, digestibility body weight change and carcass parameter of Sidama goats. Journal of Livestock Science (JLS).

[24] Rozanski S, Vivian DR, Kowalski LH, Rogerio PO,

2017;**38**(3):1577-1593

(JSRR). 1990;**3**:147-165

pp. 233-240

76-90

*Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their…*

[16] Snowder GD, Glimp HA, Field R. Carcass characteristics and optimal slaughter weights in four breeds of sheep. Journal of Animal Science (JAS).

[17] Orr RM. Animal production, animal physiology. In: Haley RT, editor. The Agricultural Note Book. 17th ed. London: Butterworths and Co. (Publishers) Ltd.; 1982. pp. 305-318

[18] Lakew M, Haile-Melekot M, Mekuriaw G. Evaluation of growth performance of local and Dorper � local crossbred sheep in eastern Amhara region, Ethiopia. Iranian Journal of Animal Science. 2014;**4**:123-126

[19] Assefu G. Comparative feedlot performance of Washera and Horro sheep fed different roughage to concentrate ratio [MSc thesis]. Diredawa, Ethiopia: Haramaya

[20] Taylor SC, Murray JI, Thonney ML. Breed and sex differences between equally mature sheep and goats, carcass muscle fat and bone. Journal of Animal Production (JAP). 1989;**49**:385-409

[21] Jorge RR, Rodrigo M, Eugenia M, Rodrigo B. Effect of breed and feeding on the carcass characteristics of the Chilote breed lamb. Chilean Journal of

[22] Walstra P, de Greef KH. Aspects of development and body composition in pigs. In: Ender K, editor. Proceedings of 2nd Dummerstorf Muscle Workshop. Muscle growth and Meat Quality; 1995; Rostock. 2nd ed. 1995. pp. 183-190

[23] Moreno G, Loureiro C, Souza H. Carachterísticas of qualitative ovina.

Agricultural Research (CJAR). 2013;**73**(1). version On-line ISSN: 0718-5839; DOI: 10.4067/S0718-

58392013000100007

**77**

1994;**72**:932-937

University; 2012

[8] Tibbo M. Productivity and health of indigenous sheep breeds and crossbreds in the central Ethiopian highlands [PhD dissertation]. Uppsala, Sweden: Swedish University of Agricultural Sciences; 2006. pp. 11-63

[9] Gatenby RM. Sheep Production in the Tropics and Subtropics. New York: Longman Inc.; 1986. p. 351

[10] Awgichew K. Comparative performance evaluation of Horro and Menz sheep of Ethiopia under grazing and intensive feeding conditions [PhD dissertation]. Berlin, Germany: Humboldt University; 2000

[11] Parker WJ, McCutcheon SN, Wickham GA. Effect of administration and ruminal presence of chromic oxide controlled release capsules on herbage intake of sheep. New Zealand Journal of Agricultural Research (NZJAR). 1991; **34**:193-200

[12] Hammell K, Laforest J. Evaluation of the growth performance and carcass characteristics of lambs produced in Quebec. Canadian Journal of Animal Science. 1999;**71**:68-74. Available from: www.nrcresearchpress.com

[13] Notter DR, Copenhaver JS. Performance of Finnish Landrace crossbred ewes under accelerated lambing. Journal of Animal Science (JAS). 1980;**51**(5):1043-1050

[14] Burfening PJ, Kress DD. Direct and maternal effects on birth and weaning weight in sheep. Journal of Small Ruminant Research (SRR). 1993;**10**: 153-163

[15] Bathaei S, Leroy P. Growth and mature weight of Mehraban Iranian fat *Body Weight Gain and Carcass Yield Characteristics of Wollo Highland Sheep and Their… DOI: http://dx.doi.org/10.5772/intechopen.92340*

tailed sheep. Journal of Small Ruminant Research (JSRR). 1996;**22**:155-162

**References**

2008a

2017

105-110

167-177

**76**

[1] Gizaw S, Johan A, Olivier H, Hans K,

*Sheep Farming - An Approach to Feed, Growth and Health*

August. Addis Ababa, Ethiopia; 2004.

[8] Tibbo M. Productivity and health of indigenous sheep breeds and crossbreds in the central Ethiopian highlands [PhD dissertation]. Uppsala, Sweden: Swedish University of Agricultural Sciences;

[9] Gatenby RM. Sheep Production in the Tropics and Subtropics. New York:

Longman Inc.; 1986. p. 351

[10] Awgichew K. Comparative performance evaluation of Horro and Menz sheep of Ethiopia under grazing and intensive feeding conditions [PhD

dissertation]. Berlin, Germany: Humboldt University; 2000

[11] Parker WJ, McCutcheon SN, Wickham GA. Effect of administration and ruminal presence of chromic oxide controlled release capsules on herbage intake of sheep. New Zealand Journal of Agricultural Research (NZJAR). 1991;

[12] Hammell K, Laforest J. Evaluation of the growth performance and carcass characteristics of lambs produced in Quebec. Canadian Journal of Animal Science. 1999;**71**:68-74. Available from:

www.nrcresearchpress.com

[13] Notter DR, Copenhaver JS. Performance of Finnish Landrace crossbred ewes under accelerated lambing. Journal of Animal Science (JAS). 1980;**51**(5):1043-1050

[14] Burfening PJ, Kress DD. Direct and maternal effects on birth and weaning weight in sheep. Journal of Small Ruminant Research (SRR). 1993;**10**:

[15] Bathaei S, Leroy P. Growth and mature weight of Mehraban Iranian fat

pp. 371-375

2006. pp. 11-63

**34**:193-200

153-163

Herbert H. Sheep resources of Ethiopia: Genetic diversity and breeding strategy

[2] CSA. Agricultural Sample Survey,

Livestockand Livestock Characteristics (Private Peasant Holdings) Statistical Bulletin 585. Addis Ababa, Federal Democratic Republic of Ethiopia: CSA;

significance of sheep and goats. In: Yami A, Merkel RC, editors. Sheep and Goat Production Handbook for Ethiopia. Ethiopia, Addis Ababa: Ethiopia Sheep and Goat Productivity Improvement Program (ESGPIP); 2008; pp. 1-4

[5] Mukasa-Mugerwa E, Lahlou-Kassi A.

Johann S, Dessie T, Van der Z,

[PhD thesis]. Wageningen, the Netherlands: Wageningen University;

2012, Volume II: Report on

[3] Hirpa A, Abebe G. Economic

[4] Bogale S, Melaku S, Yami A. Matching livestock systems with available feed resources in the Bale Highlands of Ethiopia. Outlook Agricultural Journal (OAJ). 2008;**37**:

Reproductive performance and productivity of Menz sheep in the Ethiopian highlands. Journal of Small Ruminant Research (JSRR). 1995;**17**:

[6] Dejene A. Integrated Natural Resources Management to Enhance

[7] Yeheyis L, Sebsibe A, Girma A. On-farm evaluation of the effect of supplementing grazing Menz sheep during the dry season in Gerakeya Woreda, North Sea. In: Proceedings of the 12th Annual Conference; 12-14

Food Security: The Case for Community-Based Approaches in Ethiopia. Working Paper No. 16. Rome,

Italy: FAO; 2003

[16] Snowder GD, Glimp HA, Field R. Carcass characteristics and optimal slaughter weights in four breeds of sheep. Journal of Animal Science (JAS). 1994;**72**:932-937

[17] Orr RM. Animal production, animal physiology. In: Haley RT, editor. The Agricultural Note Book. 17th ed. London: Butterworths and Co. (Publishers) Ltd.; 1982. pp. 305-318

[18] Lakew M, Haile-Melekot M, Mekuriaw G. Evaluation of growth performance of local and Dorper � local crossbred sheep in eastern Amhara region, Ethiopia. Iranian Journal of Animal Science. 2014;**4**:123-126

[19] Assefu G. Comparative feedlot performance of Washera and Horro sheep fed different roughage to concentrate ratio [MSc thesis]. Diredawa, Ethiopia: Haramaya University; 2012

[20] Taylor SC, Murray JI, Thonney ML. Breed and sex differences between equally mature sheep and goats, carcass muscle fat and bone. Journal of Animal Production (JAP). 1989;**49**:385-409

[21] Jorge RR, Rodrigo M, Eugenia M, Rodrigo B. Effect of breed and feeding on the carcass characteristics of the Chilote breed lamb. Chilean Journal of Agricultural Research (CJAR). 2013;**73**(1). version On-line ISSN: 0718-5839; DOI: 10.4067/S0718- 58392013000100007

[22] Walstra P, de Greef KH. Aspects of development and body composition in pigs. In: Ender K, editor. Proceedings of 2nd Dummerstorf Muscle Workshop. Muscle growth and Meat Quality; 1995; Rostock. 2nd ed. 1995. pp. 183-190

[23] Moreno G, Loureiro C, Souza H. Carachterísticas of qualitative ovina. Journal of Revista Nacional da Carne, São Paulo (JRNDCSP). 2008;**1**(381): 76-90

[24] Rozanski S, Vivian DR, Kowalski LH, Rogerio PO, Fernandes SR, Souza JC, et al. Carcass and meat traits and non-carcass components of lambs fed ration containing increasing levels of urea. Journal of Ciências Agrárias (JCA). 2017;**38**(3):1577-1593

[25] Warmington BG, Kirton AH. Genetic and non-genetic influences on growth and carcass traits of goats. Journal of Small Ruminant Research (JSRR). 1990;**3**:147-165

[26] Payne WJ. An Introduction to Animal Husbandry in the Tropics. Vol. 44. New York, United States: Longman Scientific and Technical; 1999. pp. 233-240

[27] Mazemder MA, Hossain MM, Khter SA. Effect of levels of concentrate supplement on live weight gain and carcass characteristics in sheep on restricted grazing. Journal of Animal Science (JAS). 1998;**11**:17-20

[28] Mathios S, Solomon M, Adugna T. The effect of different level of cotton seed cake supplementation on feed intake, digestibility body weight change and carcass parameter of Sidama goats. Journal of Livestock Science (JLS). 2008;**119**:137-144

[29] Ibrahim A, Mutassim M, Abdullah H, Rifat U, Mohamed Y, Al-Saiady R, et al. Effect of alfalfa hay on growth performance, carcass characteristics, and meat quality of growing lambs with ad-libitum access to total mixed rations. Journal of Revista Brasileira de Zootecnia (JRBZ). 2016; **45**(6):302-308

[30] Smachew G. Effects of supplementation with maize bran, noug seed cake (*Guizotia abyssinica*) and their mixtures on feed utilization and carcass characteristics of Washera sheep fed hay [MSc thesis]. Ethiopia: Haramaya University; 2009. pp. 33-41

[31] Wolf BT, Smith C, Sales DI. Growth and carcass composition in the crossbred progeny of six terminals sire breeds of sheep. Journal of Animal Production (JAP). 1980;**31**:307-313

[32] Alemu W. Effects of supplementing hay from natural pastures with oil seed cakes on feed intake, digestibility and body weight change of Sidama goats [MSc thesis]. Ethiopia: Haramaya University; 2008. p. 62

[33] Karim SA, Powell K, Kumar S, Singh V. Carcass traits of Kheri lambs maintained on a different system of feeding management. Journal of Meat Science (JMS). 2007;**76**:395-401

[34] Papi N, Mostafa-Tehrani A, Amanlou H, Memarian M. The effects of dietary forage-to-concentrate ratios on performance and carcass characteristics of growing fat-tailed lambs. Journal of Animal Feed Science and Technology (JAFST). 2011;**163**:93-98

[35] Jacques J, Berthiaume R, Cinq-Mars D. Growth performance and carcass character rustic of Dorset lambs fed different concentrates, forage rations or fresh grass. Journal of Small Ruminant Research (JSRR). 2011;**95**:113 -11

[36] Salo S, Urge M, Animut G. Effects of supplementation with different forms of barley on feed intake, digestibility, live weight change and carcass characteristics of Hararghe highland sheep fed natural pasture. Journal of Food Processing Technology (JFPT). 2016;**7**(3):2157-7110

[37] Roberto GC, José T, Wandrick H, Severino GN, Marta SM, Angelina BF. Effect of diet and genotype on carcass characteristics of feedlot hair sheep. Journal of Revista Brasileira de

Zootecnia (JRBZ). 2010;**39**(12): 2763-2768

[38] Abebe H, Tamir B. Effects of supplementation with pigeon pea (*Cajanus cajan*), cowpea (*Vigna unguiculata*) and lablab (*Lablab purpurium*) on feed intake, body weight gain and carcass characteristics in Wollo sheep fed grass hay. International Journal of Advanced Research Biological Science (IJARBS). 2016;**3**(2):280-295

[39] Riley RR, Savell JW, Shelton M, Smith GC. Carcass and offal yields of sheep and goats as influenced by market class and breed. Journal of Small Ruminant Research (JSRR). 1989;**2**(3): 265-272

[40] Teklu WF. The effects of feeding different varieties of faba bean (*Vicia faba* L.) straws with concentrated on feed intake, digestibility, body weight gain and carcass characteristics of Arsi-Bale sheep [MSc thesis]. Ethiopia: Haramaya University; 2016

[41] Prasad V, Kirton S. Carcass and non-carcass traits of Muzaffarnagri lambs at different maturity levels. Indian Journal of Animal Science (IJAS). 1992;**62**(2):159-164

[42] Michael Y, Yaynshet T. Feed utilization, digestibility and carcass parameters of Tigray highland sheep fed wheat straw supplemented with mixtures of wheat bran and cotton seed cake, in Tigray, Ethiopia. Journal of ABC Research Alert (JABCRA). 2014;**2**(1):12-15

**79**

**Chapter 5**

Sheep

**Abstract**

**1. Introduction**

Use of Computed Tomography and

Thermography for the Diagnosis

of Respiratory Disorders in Adult

Respiratory diseases are one of the main causes of death and economic losses in sheep farming. The prevention and treatment of these diseases must be based on a correct diagnosis, which improves the results of health plans and optimizes the responsible use of medicines. Diagnostic imaging techniques are important working tools to diagnose this kind of disorders but have not always been sufficiently used in sheep. X-ray, although widely used in small animals, is not a valuable tool in field conditions. Ultrasonography is a noninvasive technique easily applied in sheep farms and very useful for the diagnosis of respiratory diseases; however, many articles have been already published on this topic. The present paper proposes and illustrates the use of thermography and computed tomography (CT) to support and improve the aforementioned techniques, taking into consideration that thermography is only useful for upper respiratory tract disorders and CT scan is an expensive technique for routine use but very illustrative to understand the pathogenesis of the

*Luis Miguel Ferrer, Juan José Ramos, Enrique Castells,* 

*Héctor Ruíz, María Climent and Delia Lacasta*

different disorders and to improve the in vivo diagnosis.

be used to describe the respiratory disorders in this paper.

**Keywords:** thermography, computed tomography, sheep, respiratory diseases

The respiratory system consists of a series of organs responsible for performing a set of physical and chemical processes that aim to absorb the air oxygen (O2), essential for the oxidative phenomena that occur in the tissues, and the elimination of products resulting from these same oxidative phenomena, especially carbon dioxide (CO2) [1]. The airways begin in the nares or external nasal openings and end at the level of the terminal bronchi, already within the lungs. These airways include an upper respiratory tract (nasal cavity, paranasal sinuses, nasopharynx, and larynx) and a lower respiratory tract (trachea and lung). This classification will

The development of effective health plans and the optimization of the use of drugs require an accurate diagnosis that assures that the treatment is addressed against the cause responsible for the pathological process. In this sense, diagnostic

## **Chapter 5**

mixtures on feed utilization and carcass characteristics of Washera sheep fed hay [MSc thesis]. Ethiopia: Haramaya

*Sheep Farming - An Approach to Feed, Growth and Health*

Zootecnia (JRBZ). 2010;**39**(12):

[38] Abebe H, Tamir B. Effects of supplementation with pigeon pea (*Cajanus cajan*), cowpea (*Vigna unguiculata*) and lablab (*Lablab*

*purpurium*) on feed intake, body weight gain and carcass characteristics in Wollo sheep fed grass hay. International Journal of Advanced Research Biological Science (IJARBS). 2016;**3**(2):280-295

[39] Riley RR, Savell JW, Shelton M, Smith GC. Carcass and offal yields of sheep and goats as influenced by market

[40] Teklu WF. The effects of feeding different varieties of faba bean (*Vicia faba* L.) straws with concentrated on feed intake, digestibility, body weight gain and carcass characteristics of Arsi-Bale sheep [MSc thesis]. Ethiopia: Haramaya University; 2016

[41] Prasad V, Kirton S. Carcass and non-carcass traits of Muzaffarnagri lambs at different maturity levels. Indian Journal of Animal Science (IJAS).

[42] Michael Y, Yaynshet T. Feed utilization, digestibility and carcass parameters of Tigray highland sheep fed

wheat straw supplemented with

mixtures of wheat bran and cotton seed cake, in Tigray, Ethiopia. Journal of ABC Research Alert (JABCRA).

1992;**62**(2):159-164

2014;**2**(1):12-15

class and breed. Journal of Small Ruminant Research (JSRR). 1989;**2**(3):

2763-2768

265-272

[31] Wolf BT, Smith C, Sales DI. Growth

crossbred progeny of six terminals sire breeds of sheep. Journal of Animal Production (JAP). 1980;**31**:307-313

[32] Alemu W. Effects of supplementing hay from natural pastures with oil seed cakes on feed intake, digestibility and body weight change of Sidama goats [MSc thesis]. Ethiopia: Haramaya

[33] Karim SA, Powell K, Kumar S, Singh V. Carcass traits of Kheri lambs maintained on a different system of feeding management. Journal of Meat Science (JMS). 2007;**76**:395-401

[34] Papi N, Mostafa-Tehrani A,

(JAFST). 2011;**163**:93-98

weight change and carcass

2016;**7**(3):2157-7110

**78**

Amanlou H, Memarian M. The effects of dietary forage-to-concentrate ratios on performance and carcass characteristics of growing fat-tailed lambs. Journal of Animal Feed Science and Technology

[35] Jacques J, Berthiaume R, Cinq-Mars D. Growth performance and carcass character rustic of Dorset lambs fed different concentrates, forage rations or fresh grass. Journal of Small Ruminant Research (JSRR). 2011;**95**:113 -11

[36] Salo S, Urge M, Animut G. Effects of supplementation with different forms of barley on feed intake, digestibility, live

characteristics of Hararghe highland sheep fed natural pasture. Journal of Food Processing Technology (JFPT).

[37] Roberto GC, José T, Wandrick H, Severino GN, Marta SM, Angelina BF. Effect of diet and genotype on carcass characteristics of feedlot hair sheep. Journal of Revista Brasileira de

University; 2009. pp. 33-41

and carcass composition in the

University; 2008. p. 62
