**Acknowledgement**

The authors thank Professors Olfa Frouja Sayadi and Zeineb Dkhili for the language revision and for prompting this research. The authors also thank OEP for making the data available.

Effects of Environmental Factors on Milk Yield, Lactation Length and Dry Period in Tunisian Holstein Cows 161

#### **6. References**

160 Milk Production – An Up-to-Date Overview of Animal Nutrition, Management and Health

production of the dairy cow.

**5. Conclusion** 

investigations.

**Author details** 

Mahdi Bouallegue

Yosra Ressaissi

Satinder Kaur Brar

Mohamed Ben Hamouda

**Acknowledgement** 

available.

*Institution of Research and Agriculture* 

Naceur M'hamdi and Saoussen Frouja *Department of Animal Sciences. Higher Institute of Agronomy of Chott-Mariem, Sousse, Tunisia* 

*and Natural Sciences of Tunis, Tunis, Tunisia* 

*National Institute of Agronomy of Tunis, Tunisia* 

*National Institute for Scientific Research, Quebec, Canada* 

*Higher Education (IRESA), Ministry of Agriculture, Tunisia* 

The authors thank Professors Olfa Frouja Sayadi and Zeineb Dkhili for the language revision and for prompting this research. The authors also thank OEP for making the data

*Faculty of Mathematical, Physical* 

periods decrease the average annual production of the cow by extending the calving interval beyond the normal 13-14 month interval and causing a decrease in the lifetime

In this study, there was increase of milk yield level according to previous research [16]. This may result from improvement in breeding, feeding and management conditions (selection for milk yield and culling in the herd etc.). Although, lactation duration was found almost at ideal value, dry period was estimated as higher than the ideal value. In order to make animals more profitable, it is essential to make them be pregnant as soon as possible during the service period in order to shorten the dry period. It can be concluded that Holstein cattle is raised successfully for milk yield under Tunisian environmental conditions. It is concluded that milk yield and lactation length are affected by year and season of calving. Adjusted milk yield (adjusted for lactation length) and lactation length are affected by year into season of calving interaction but actual milk yield is not affected by year by season of calving interaction. Age within parity, also, affected lactation length and milk yield. Negative phenotypic trend in milk yield is alarming and needs further

	- [16] Bilgic N, Alic D. Milk yield traits of Holstein Friesian cows raised in Polatli state farm. Ziraat Fakultesi, S.U. Dergisi, 2005; 19: 116-119.
	- [17] Hansen JV, Friggens NC, Højsgaard S. The influence of breed and parity on milk yield and milk yield acceleration curves. Livestock Sci., 2006; 104: 53- 62
	- [18] Pelister B, Altinel A, Gunes H. An investigation on the milk yield characteristics of black pied cattle of different origin in commercial farm conditions. Istanbul Univ. Vet. Fak. Derg., 2000; 26: 201-214
	- [19] Ozelik M, Arpacik R. The effect of lactation number on milk production and reproduction in holstein cows. Turk. J. Vet. Anim. Sci., 2000; 24: 39-44.
	- [20] Cilek S. Estimation of factors for standardizing lactations to mature age and 305 days and heritability and repeatability of milk yield for brown Swiss cattle reared at Ulas State farm. Ph.D. Thesis, Selcuk University the Institute for Health Sciences, Konya, Turkey, 2002; pp: 5-57.
	- [21] Duru S, Tuncel ME. The correlations between dry period, service period and age at first calving with some milk yield traits in Holstein Friesian cattle. Uludag Univ. Ziraat Fak. Derg., 2004; 18: 69-79.
	- [22] Kaya I, Uzmay C, Kaya A, Akbas Y. Comparative analysis of milk yield and reproductive traits of Holstein-Friesian cows born in turkey or imported from Italy and kept on farms under the Turkish-ANAFI project. Ital. J. Anim. Sci., 2003; 2: 141- 150.
	- [23] Zambrano SZ, Gloria C, Manuel P, Homero C, Tim O, Antonio Landaeta-Hernández.. Milk yield and reproductive performance of crossbred Holstein × Criollo Limonero cows. Revista Científica, 2006; Vol 16, No 2. 155.164
	- [24] Cilek S, Tekin ME. Calculation of adjustment factors for standardizing lactations to mature age and 305 days and estimation of heritability and repeatability of standardized milk yield of Simmental cattle reared on Kazova State Farm. Turk. J. Vet. Anim. Sci., 2006a; 30: 283-289.
	- [25] Cilek S. Estimation of adjustment factors for standardizing lactations to mature age and 305 days of milk yield of Holstein cattle reared at Polatli state farm in Turkey. J. Vet. Anim. Adv. 2008; 7: 1056-1060.
	- [26] Bormann J, Wiggans GR, Druet T, Gengler N. Within-herd effects of age at test-day and lactation stage on test-day yields. J. Dairy Sci., 2003; 86: 3765–3774.
	- [27] Javed K, Afzal M, Sattar A, Mirza RH. Environmental factors affecting milk yield in Friesian cows in Punjab, Pakistan. Pakistan Vet. J. 2004; 24 (2):( 58-61).
	- [28] Tekerli M, Akinci Z, Dogan I, Akcan A. Factors affecting the shape of lactation curves of Holstein cows from the Balikesir province of Turkey. J. Dairy Sci. 2000; 83, 1381-1386
	- [29] Thorpe W, Kang'ethe P, Rege J.E.0., Mosi R.0., Mwandoto B A.J, Njuguna f. Crossbreeding Ayrshire, Friesian and Sahiwal cattle for milk yield and preweaning traits of progeny in the semiarid tropics of Kenya. J. Dairy Sci. 1993; 76: 2001-2012

Effects of Environmental Factors on Milk Yield, Lactation Length and Dry Period in Tunisian Holstein Cows 163

[30] Bilal. Productive and reproductive profile of Holsteins kept in Balochistan province. M.Sc. thesis, 1996; Dept. of Livestock Management, University of Agriculture, Faisalabad, Pakistan.

162 Milk Production – An Up-to-Date Overview of Animal Nutrition, Management and Health

farm. Ziraat Fakultesi, S.U. Dergisi, 2005; 19: 116-119.

Vet. Fak. Derg., 2000; 26: 201-214

Konya, Turkey, 2002; pp: 5-57.

Ziraat Fak. Derg., 2004; 18: 69-79.

Vet. Anim. Sci., 2006a; 30: 283-289.

Vet. Anim. Adv. 2008; 7: 1056-1060.

150.

1381-1386

[16] Bilgic N, Alic D. Milk yield traits of Holstein Friesian cows raised in Polatli state

[17] Hansen JV, Friggens NC, Højsgaard S. The influence of breed and parity on milk

[18] Pelister B, Altinel A, Gunes H. An investigation on the milk yield characteristics of black pied cattle of different origin in commercial farm conditions. Istanbul Univ.

[19] Ozelik M, Arpacik R. The effect of lactation number on milk production and

[20] Cilek S. Estimation of factors for standardizing lactations to mature age and 305 days and heritability and repeatability of milk yield for brown Swiss cattle reared at Ulas State farm. Ph.D. Thesis, Selcuk University the Institute for Health Sciences,

[21] Duru S, Tuncel ME. The correlations between dry period, service period and age at first calving with some milk yield traits in Holstein Friesian cattle. Uludag Univ.

[22] Kaya I, Uzmay C, Kaya A, Akbas Y. Comparative analysis of milk yield and reproductive traits of Holstein-Friesian cows born in turkey or imported from Italy and kept on farms under the Turkish-ANAFI project. Ital. J. Anim. Sci., 2003; 2: 141-

[23] Zambrano SZ, Gloria C, Manuel P, Homero C, Tim O, Antonio Landaeta-Hernández.. Milk yield and reproductive performance of crossbred Holstein ×

[24] Cilek S, Tekin ME. Calculation of adjustment factors for standardizing lactations to mature age and 305 days and estimation of heritability and repeatability of standardized milk yield of Simmental cattle reared on Kazova State Farm. Turk. J.

[25] Cilek S. Estimation of adjustment factors for standardizing lactations to mature age and 305 days of milk yield of Holstein cattle reared at Polatli state farm in Turkey. J.

[26] Bormann J, Wiggans GR, Druet T, Gengler N. Within-herd effects of age at test-day

[27] Javed K, Afzal M, Sattar A, Mirza RH. Environmental factors affecting milk yield in

[28] Tekerli M, Akinci Z, Dogan I, Akcan A. Factors affecting the shape of lactation curves of Holstein cows from the Balikesir province of Turkey. J. Dairy Sci. 2000; 83,

[29] Thorpe W, Kang'ethe P, Rege J.E.0., Mosi R.0., Mwandoto B A.J, Njuguna f. Crossbreeding Ayrshire, Friesian and Sahiwal cattle for milk yield and preweaning traits of progeny in the semiarid tropics of Kenya. J. Dairy Sci. 1993; 76: 2001-2012

and lactation stage on test-day yields. J. Dairy Sci., 2003; 86: 3765–3774.

Friesian cows in Punjab, Pakistan. Pakistan Vet. J. 2004; 24 (2):( 58-61).

Criollo Limonero cows. Revista Científica, 2006; Vol 16, No 2. 155.164

yield and milk yield acceleration curves. Livestock Sci., 2006; 104: 53- 62

reproduction in holstein cows. Turk. J. Vet. Anim. Sci., 2000; 24: 39-44.

	- [43] Winnicki S, Głowicka-Wołoszyn R, Helak B, Dolska M, Jugowa J.L. Wpływ długości okresu zasuszenia krów na wydajność i jakość mleka w następnej laktacji (Effect of a dry period length on milk production and quality in next lactation). Prace i materiały Zootechniczne. 2008; 65, 176

**Chapter 9** 
