The effect of genetic and non-genetic factors on production traits of Simmental cows

Abstract

This study covered 737 controlled first calving Simmental cows with, lactations concluded within one year. All first calving animals were on the farms of individual farmers in the municipalities of Kragujevac and Mladenovac. The research included the influence of bull sires, year and season of calving on milk yield and fertility. Least squares method was used to determine the average duration of lactation of 323.74 days. For a period of 305 days, heifers produced 3701.67 kg of milk, or 3644.58 kg of 4% FCM. The average production of milk fat was 144.26 kg and milk fat content was 3.88%. The interval from calving to first insemination lasted in average 124.19 days, and the animals were first calved at the age of 789.95 days. The bull sires had a highly significant effect (P (lt) 0.01) on the duration of lactation, milk yield and 4% FCM, milk fat yield and content and age of cows at first calving. The duration of service period was not under significant effect (P>0.05) of bull sires. Year of calving had a significant effect (P (lt) 0.01) on the duration of lactation, production of milk, milk fat and 4% FCM. Milk fat content, service period and age at first calving did not show significant variation due to the impact of different years of calving (P>0.05). Season of calving of cows demonstrated highly significant effect (P (lt) 0.01) on the production of milk and 4% FCM, and significant (P>0.05) on the production of milk fat, however it had no effect (P>0.05) on the milk fat content, duration of lactation and service period and age at calving.

Ovim istraživanjem je obuhvaćeno 737 kontrolisanih prvotelki simentalske rase, sa laktacijama zaključenim u toku jedne godine. Sve prvotelke su se nalazile na imanjima individualnih poljoprivrednih proizvođača. Istraživanja su obuhvatila uticaj bikova očeva, godine i sezone telenja na osobine mlečnosti i plodnosti. Metodom najmanjih kvadrata ustanovljeno je prosečno trajanje laktacije od 323,74 dana. Za vremenski period od 305 dana prvotelke su proizvele 3.701,67 kg mleka, odnosno, korigovano na 4%MKM 3.644,58 kg. Prosečna proizvodnja mlečne masti iznosila je 144,26 kg a sadržaj mlečne masti 3,88%. Interval od telenja do prve inseminacije trajao je u proseku 124,19 dana, a grla su se prvi put telila u uzrastu od 789,95 dana. Bikovi-očevi su imali visoko signifikantan uticaj (P (lt) 0,01) na trajanje laktacije, prinos mleka i 4%MKM, proizvodnju i sadržaj mlečne masti i uzrast krava pri prvom telenju. Na dužinu servis perioda bikovi-očevi nisu ispoljili značajnije dejstvo (P>0,05). Godina telenja imala je visoko značajan uticaj (P (lt) 0,01) na trajanje laktacije, proizvodnju mleka, mlečne masti i 4%MKM. Sadržaj mlečne masti, trajanje servis perioda i uzrast pri prvom telenju nisu pokazali značajnija variranja usled uticaja različitih godina telenja (P>0,05). Sezona telenja krava je visoko značajno uticala (P (lt) 0,01) na proizvodnju mleka i 4%MKM, značajno (P>0,05) na proizvodnju mlečne masti, a na sadržaj mlečne masti, trajanje laktacije i servis perioda, uzrast pri telenju nije imala značajnijeg uticaja (P>0,05).