Milk productivity of Holstein first-calf heifers of different lines depending on the seasons of birth
Автор: Lyashuk R.N., Lyashuk A.R.
Журнал: Биология в сельском хозяйстве @biology-in-agriculture
Рубрика: Актуальные вопросы зоотехнии и ветеринарии
Статья в выпуске: 3 (40), 2023 года.
Бесплатный доступ
Increasing the efficiency of milk production is associated with the study of a variety of paratypical factors. In particular, a number of domestic and foreign researchers have established that cows of different season of birth show reliable differences in milk productivity. On the other hand, successful selection in dairy cattle breeding is very difficult without taking into account reliably established relationships between the most important traits from the economic point of view of productivity. The aim of this study was to establish the relationship between milk productivity of Holstein first calf heifers of different lines and seasons of calving. As a result of this research, it was found that there were no significant differences in milk productivity between Holstein first-calf heifers of different lines of the same seasons of birth. On the other hand, reliable differences were found between some indicators of milk productivity of first-calf heifers of the same line of different seasons of calving. When studying the relationship between milk productivity traits in first-calf heifers of different lines born in the same season, the correlations, with some exceptions, were characterized by unidirectionality and similar level. The correlation between milk yield at 305 days of lactation and the mass fraction of fat in milk of first-calf heifers born in the spring, summer and fall seasons ranged from weak to medium and was usually positive. The relationship between milk yield and the mass fraction of protein in the milk of first-calf heifers was weak and usually characterized by the opposite direction. The obtained data may indicate a complex selection on milk yield and fat-milk yield in the herd, with a one-sided character of selection on milk yield in relation to protein-milk yield.
Selection, holstein breed, productivity of first heifers, correlation, milk productivity traits
Короткий адрес: https://sciup.org/147241996
IDR: 147241996