Investigation of the genetic correlation between milk and fertility traits of first calving cows of Simmental breed

Abstract

Investigation of the production capacity of cattle for the purpose of increase of milk and milk fat production, as well as number of calves, greatly depends on phenotypic and genetic variability, heritability and correlation between desired traits, and on production level in the population. This research included 3.461 first calving cows of Simmental breed under control and reared on farms of individual agricultural producers on the territory of Republic of Serbia. Genetic correlations were calculated using equation of mixed model which included the effect of bull-sire, breeding region, year and season of calving: Yijklm = μ + Bi + Rj + Gk + Sl + eijklm. Coefficients of genetic correlation between service period and milk traits were following: duration of lactation 0,239, milk yield 0,089, percentage of milk fat 0,095, quantity of milk fat 0,105 and yield of 4%FCM 0,099. Correlation between service period and age at calving was 0,535. Genetic correlation between age at calving and milk traits was following: duration of lactation 0,245, production of milk 0,003, percentage of milk fat 0,531, quantity of milk fat 0,082 and production of 4%FCM 0,050.

Ispitivanje proizvodnih kapaciteta goveda u cilju povećanja proizvodnje mleka, mlečne masti i broja teladi, u velikoj meri zavisi od fenotipske i genetske varijabilnosti, heritabiliteta i povezanosti poželjnih osobina, kao i nivoa proizvodnje u populaciji. Ovim istraživanjem je obuhvaćena 3.461 kontrolisana prvotelka simentalske rase na imanjima individualnih poljoprivrednih proizvođača na području Republike Srbije. Genetske korelacije izračunate su jednačinom mešovitog modela koja uključuje uticaj bika-oca, odgajivačkog područja odnosno regiona, godine i sezone teljenja: Yijklm = μ + Bi + Rj + Gk + Sl + eijklm. Koeficijenti genetske povezanosti između servis perioda i osobina mlečnosti su sledeći: trajanje laktacije 0,239, prinos mleka 0,089, procenat mlečne masti 0,095, količina mlečne masti 0,105 i prinos 4%MKM 0,099. Povezanost servis perioda i uzrasta pri telenju iznosila je 0,535. Genetska povezanost uzrasta pri telenju sa osobinama mlečnosti iznosila je: trajanje laktacije 0,245, proizvodnja mleka 0,003, procenat mlečne masti 0,531, količina mlečne masti 0,082 i proizvodnja 4%MKM 0,050.