**Table 1.**

*Chemical composition of different by-products from agro-industrial processing.*

diets through supplementary concentrate can potentially enhance milk production and improve growth rate, body weight gain, and reproductive performance [50, 51].

There are further feedstuffs also valuable as an alternative feed for ruminants, such as palm fiber, chickpea, orange pulp, rapeseed meal, cottonseed meal, and palm kernel cake (PKC), which because of its nutritional content may be described as an energy food. In addition, palm kernel cake supplies protein and energy but is usually classified as a source of protein, which may vary from 10.1 to 16.6% (**Table 1**). This protein content of PKC is regarded as sufficient to meet the needs of most ruminants [52, 53]. Proteins are the principal constituents of the organs and muscles and are required by ruminants for metabolic functions [38, 54]. Palm kernel cake also contains a large amount of crude fiber (CF; 19.3%), dry matter ranging from 91.9 to 95.8%, ether extract (EE; 7.8 to 10.8%), ash (3.1 to 3.5%), neutral detergent fiber (NDF; 64.1 to 71.4%), acid detergent fiber (13.5 to 56.0%) (**Table 1**), nitrogen-free extract (NFE; 46.7 to 58.8%), total carbohydrates (78.7%), nonfibrous carbohydrates (NFCs) (7.31%), hemicellulose (HEM) (25.98%), and lignin (4.28%) [38, 55]. The metabolizable energy (ME) of palm kernel cake for ruminants is 2.5 to 2.6 Mcal kg−1, which is considered suitable for most ruminants [55].

Animals must be fed diets containing the earlier-mentioned essential nutrients for healthy growth and increased production. The ether extract is the main source of lipids which constitutes the principal component of sperm cells. It also stimulates cholesterol biosynthesis and testosterone secretion to sustain semen production in males [56]. Other fibrous components are sources of carbohydrates which are converted to acetic acids and used by the cows for energy and precursor of fat in milk [57]. It is also essential for animal health, since it is required by ruminants to support an appropriate rumen function and physiology [58].

#### **3.2 Dietary effects on reproductive performance of ruminant livestock**

The process of reproduction is aligned closely with the food supply. It is a coordinated function of many tissues, cell types, and regulatory systems which is possible only when animals are provided with sufficient quantities of dietary nutrients [59]. In tropical regions such as Africa, ruminants raised on smallholder farms face constraints of improper nutritional management, which may negatively affect their growth, health, and reproductive performance [60, 61]. For instance, puberty is usually delayed in grazing ruminants because grasslands in semiarid zones in the tropics do not provide enough protein and other nutrients, which leads to insufficient production of rumen microbial protein to support optimum growth rate [60]. Thus, nutrition plays a pivotal role in maintaining the body condition and reproductive efficiency of animals.

Nutrition consists of different nutrients such as protein, fat, carbohydrates, and micro-elements. Carbohydrates and proteins provide substrates for rumen fermentation, which results in the production of volatile fatty acids (VFAs). Ruminants utilize these VFAs as their main source of energy for maintenance, milk production, and reproductive performance. Malnutrition resulting from inadequate, excess, or imbalanced nutrient intake may lead to the loss of body weight. Low body condition delays the onset of puberty (up to 1 year in sheep and goats), reduces ovulation and lower conception rates, compromises embryonic and fetal survival, increases the postpartum interval to conception, interferes with normal ovarian cyclicity by decreasing gonadotropin secretion, increases the chances of infertility, and influences the rate of genetic progress [62, 63]. So, it seems to be clear that the initial reproductive events are sensitive to fluctuations in nutrient availability [61].

#### *Alternative Animal Feeding for Intensive Livestock Farming Systems and Their Impact… DOI: http://dx.doi.org/10.5772/intechopen.106061*

An inverse relationship between growth rate and age at puberty also exists in males. Low-quality feeding has been shown to delay puberty by about 5 months in bulls. The animals had poor testicular development and smaller ejaculates as compared to their normal counterparts. On the other hand, bulls kept on grazing plus concentrate feed showed a better growth rate than those on grazing only, with an earlier age at puberty and a greater scrotal circumference [60]. Even at maturity, the size of the testicles of underfed animals can be smaller [59] resulting in a lower sperm concentration in the semen. It has also been reported that the seminal vesicles contain less fructose and citric acid as well as smaller Leydig cells and seminiferous tubules and decreased testosterone levels under protein stress conditions [64]. Restriction of both protein and energy also prevented Merino lambs from reaching puberty in their first potential breeding season, with reduced testicular size and sperm quality in the ejaculate. Feed restriction also reduces libido in rams [60].

#### *3.2.1 Effect of coconut meal on goat reproductive performance*

To assess the effectiveness of coconut meal as an alternative feed and its effect on beef goats' reproductive performance, a study was conducted in Brazil in 2016. Fortyeight males with initial body weight ranging from 26.04 to 28.54 kg were assigned in a completely randomized design into four groups with 12 replicates each under a semi-intensive system. The animals were kept indoors during the night and moved to graze in the morning on a pasture composed of *Brachiaria decumbens (*nonlegume forage plant). In the afternoon, the animals were supplemented with a concentrate containing 0% of coconut meal (group 1), 15% of coconut meal (group 2), 30% of coconut meal (group 3), and 45% of coconut meal (group 4) (**Table 2**). Before feeding the animals, the nutritional composition of coconut meal, soybean bagasse, corn meal, and pasture was assessed for dry matter, ash, ether extract, crude protein, neutral detergent fiber, total carbohydrates, hemicellulose, and lignin, and the results are shown in **Table 3**. In our study, coconut meal was included in four different levels (0%, 15%, 30%, and 45% of coconut meal) as a source of fatty acids and protein as well as a substitute for soybean meal, which is one of the most expensive feedstuffs in animal feed. In addition, the levels of cornmeal were also reduced while increasing the level of coconut meal. The animals' body weight and testicular parameters were recorded every 15 days, and the semen was collected and assessed for volume, wave motion, progressive motility, sperm concentration, and sperm vigor according to the methodology suggested by CBRA [65]. In addition, the total number of sperm and the total number of viable spermatozoa were estimated according to the methodology described by Martin-Rillo [66].

Our results showed an increase in the scrotal circumference and testicular volume of goats fed with concentrates containing 30% and 45% of coconut meal (**Table 4**). This result suggests that concentrates with high amounts of coconut meal may be more effective than those with lower amounts in improving goat's testis. Also, the data in **Table 4** suggest that scrotal circumference and testicular volume may increase as the body weight of goat increases, indicating a positive relationship between nutrition and goats' testis size or reproductive efficiency. Males with a larger testis tend to produce more semen and offspring that reach puberty at an earlier age and release more ovules during each estrous period [68]. Oldham et al. [69] found that a 25% increase in testicular size led to an 81% increase in the production of spermatozoa. Also, Cameron et al. [70] found that an 86% increase in testicular size led to a 250% increase in the production of spermatozoa. The positive relation between testicular


#### **Table 2.**

*Level of coconut meal (treatments) in diet supplied to the goats.*


#### **Table 3.**

*Chemical composition of forage and feedstuffs used in concentrated feed for goats in 2016.*

biometric parameters and body weight concerning nutrition effects was also reported by Martinez et al. [71].

The diets with 30% and 45% of coconut meal showed higher levels of ether extract (**Table 5**) which is a saturated fatty acids source, such as lauric (C12:0), myristic (C14:0), palmitic (C16:0), and stearic (C18:0) acids and unsaturated fatty acids such as myristoleic (C14:1), palmitoleic (16,1), oleic (C18:1), and polyunsaturated fatty acids (PUFA) that include linoleic (C18:2) and linolenic (C18:3) acids, compared with other diets. So, it may be possible that the fatty acids in coconut meal may have increased the concentration of serum cholesterol which may lead to improved testosterone levels in goats. However, changing nutrition in small ruminants alters not only the total mass of testicular tissue but also the efficiency with which the spermatozoa are produced by that tissue [77].

It has been classically admitted that in both the mid and the long terms, variations in growth, testicle parameters, and fluctuations in live weight as a result of nutritional status affect also semen quality of ruminants, as nutrition appears to be the major modulator of sexual efficiency in small ruminants [71]. In our previous study with sheep managed under extensive range grazing conditions and fed with palm kernel cake as an
