Environmental factors affecting milk, fat and protein yields in Jersey cattle in Zimbabwe

Abstract

A study was carried out to establish the factors affecting milk, butterfat and protein yields in Zimbabwean Jersey cattle. A total of 10,986 unedited 305-day lactation records were obtained from Zimbabwe Livestock Identification Trust containing 25 herds, with cows calving in the period 1996-2008. The general linear model procedure of the Statistical Analysis Systems version 9.1.3 was used to determine the environmental factors. Herd-year-season, calving interval, days dry and both the linear and quadratic effects of age at calving fitted as covariates significantly (P<0.0001) affected the milk, fat and protein yields. Herd-year-season accounted for 36%, 36% and 35% to the total variation in milk, fat and protein yields, respectively. Milk, fat and protein yields increased with an increase in calving interval. The optimum dry period for milk, fat and protein yields obtained was 60-75 days dry. The relationship between the production traits and age at calving was both linear and quadratic, implying that milk, fat and protein yields increase with the age of the animal. It is thus necessary to preadjust data for these environmental factors when carrying out genetic evaluations of production traits in dairy cattle.

Comparative evaluation of non-genetic factors affecting milk yield and composition of Red Dane and Jersey cattle in Zimbabwe

“…The Red Dane cattle produced milk yield of an average of 8300 kgs whilst the Jersey cattle produced 4200 kgs. These results are in agreement with those reported by (Hatungumukana et al 2007 ), (Missanjo et al 2011 ) and (Nyamushamba et al 2013 ) that calving interval significantly affect milk yield and composition of dairy cattle. The ideal calving interval is 365 days for both breeds in milk production whereby the producer is assured of one calf from each cow annually.…”

“…Environmental factors tend to obscure the animal’s true genetic ability. (Missanjo et al 2011 ) observed that selection within the best environment allowed better gene expression and selection response were therefore improved. Environmental variance, which by definition embraces all variation of non-genetic origin, is a source of error that reduces precision in genetic studies.…”

Jersey ve Holstein İneklerinde Buzağılama Yılının Süt Verimi ve Bileşenleri Üzerine Olan Etkisi

“…Similar conclusions were reached by Gurses et al 10 and Teke and Akdag 11 , who documented that the effect of calving year was significant on 305 DMY in Jersey cow. Missanjo et al 12 found similar results and concluded that calving year had a significant effect on milk, fat and protein yields of Jersey cattle. The results found in this study are also consistent with literature.…”

Estimation of Non-Genetic Parameters for Reproduction and Production Traits of Holstein Friesian Dairy Herd at Elfora Cheffa Dairy Farm, Amhara Region, Ethiopia

“…Environmental factors tend to obscure the animal's true genetic ability. In this regard, Missanjo et al (2011) observed that selection within the best environment allowed better gene expression and selection response were therefore improved. Hence, environmental variance, which by de nition embraces all variation of non-genetic origin, is a source of error that reduces precision in genetic studies.…”