Impact of Major Non-Genetic Factors on Phenotypic Variability of Milk Production Traits in the Black And White Cattle Population

Abstract

Modern beef production in intensive rearing conditions imposes a need for constant improvement of production traits of individuals. Meeting the growing requirements that accompany this type of production means the provision of optimal rearing conditions, not only in terms of cattle nutrition, care and housing but also in terms of health. Milk yield, milk fat and protein are properties of primary importance in dairy cattle breeding. These properties express a pronounced variability that occurs due to a large number of factors. The paper presents the average values and phenotypic variability of major milk production traits in the black-and-white cattle population raised on the farm "PK Beograd". In the first three standard lactations the average milk yield was 7.241 kg with 3.56% fat. The impact of major non-genetic factors (farm, year, season of calving) on the expression of milk production traits was also observed. The impact of the examined factors on the variability of the production traits was highly significant (P lt 0.01).

Savremena govedarska proizvodnja u intenzivnim uslovima odgajivanja nameće potrebu konstantnog unapređenja proizvodnih osobina jedinki. Realizacija sve većih zahteva koji prate ovu proizvodnju podrazumeva obezbeđenje optimalnih uslova gajenja, kako u pogledu ishrane, nege i smeštaja, tako i zdravstvenog stanja goveda. Prinosi mleka, mlečne masti i proteina su osobine od primarnog značaja u selekciji i oplemenjivanju mlečnih rasa goveda. Ove osobine pokazuju izraženu varijabilnost koja se javlja usled delovanja velikog broja činilaca na njihovu ispoljenost. U radu su prikazane prosečne vrednosti i fenotipska varijabilnost važnijih osobina mlečnosti u populaciji crno belih goveda gajenih na farmi PK “Beograd”. U prve tri standardne laktacije ostvaren je prosečan prinos od 7241 kg mleka sa 3,56% mlečne masti. Posmatran je i uticaj važnijih negenetskih faktora (farme, godine, sezone teljenja) na ispoljenost osobina mlečnosti. Ustanovljen je visoko značajan uticaj ispitivanih faktora na varijabilnost posmatranih proizvodnih svojstava (P lt 0.01).