Životna proizvodnja visokomlečnih krava

Lifetime milk production is a key success factor in fulfilling the production potential of high-yielding cows. Lifetime milk production traits are pronouncedly variable. The life expectancy and the length of productive life of dairy cows are repeatedly limiting factors for improving lifetime milk production. Lifetime milk production is greatly depended on age at first calving and the number of lactations during productive life. Previous researches have implied there are real chances for improving the lifetime milk production of high-yielding cows. The goal of this research was to investigate the significance of key systematic factors on the lifetime production of high-yielding Black-and-White cows. The animals included in the sample had different share of Holstein genes. The researchers determined systematic factors that caused some significant phenotypic variations of the investigated trait. The average lifetime milk production was 25,002.66±7,755.39 kg. When observed by cow genotypes, the mean values of the lifetime milk production varied from 27,061.37 kg ( (lt) 58% HF) and 24,761.26 kg (58-73% HF) to 23,185.36 kg (>73% HF). The differences in lifetime milk production determined among the animals were due to a highly significant (p≤0.01) impact of the bulls - the sires of the cows and the year of culling; the impact of the class of HF genes was significant (p≤0.05), whereas the impact of the reason for culling was non-significant (p>0.05).Osobine životne proizvodnje visokomlečnih krava imaju veliki ekonomski značaj. Crno-bela goveda imaju značajan genetski potencijal za proizvodnju mleka. Visokoproizvodne krave crno-bele rase izložene su tokom produktivnog veka velikom broju složenih uticaja koji intenzivno deluju na nivo relizacije njihovog genetskog potencijala. Uslovi sredine često nisu u saglasnosti sa potrebama ove visokomlečne rase goveda. Povećanjem učešća gena holštajn-frizijske rase, tokom procesa oplemenjivanja evropskog tipa crno-belih goveda, došlo je do povećanja prinosa mleka. Dosadašnja istraživanja ukazuju na mogućnost za značajnije povećanje životne produktivnosti crno-belih krava. Poznavanje broja i nivoa uticaja faktora sredine, na životnu proizvodnju visokomlečnih krava, važno je zbog njihovog uključivanja u model. U skladu sa značajem pojedinih sistematskih faktora u okviru istraživanja je obavljena njihova objektivna procena. Cilj rada je bio da se primenom odgovarajuće metodologije ispita značajnost razlika, u ostvarenoj životnoj proizvodnji mleka kod visokoproizvodnih crno-belih krava, preko najvažnijih sistematskih uticaja. Prosečna životna proizvodnja mleka iznosila je 25002.66±7755.39 kg litara. Posmatrano po genotipovima krava prosečne vrednosti životne proizvodnje mleka iznosile su 27061.37 kg ( (lt) 58% HF), 24761.26 kg (58-73% HF) i 23185.36 kg (> 73% HF). Utvrđene razlike između grla u pogledu ostvarenog nivoa životne proizvodnje mleka nastale su kao posledica visoko značajnog uticaja (P≤0.01) bikova-očeva krava i godine izlučenja krava, klasa HF gena krava imala je značajan uticaj (p≤0.05), dok razlog izlučenja nije imao značajan uticaj (P>0.05)