Optimal timing of seasonal calving of cows in the APC «Druzhba»

Abstract

The choice of the optimal calving time for cows is of urgent importance for the economy. The influence of the calving season on the variability of milk productivity of brown Swiss cows of the APC "Druzhba" (Smolensk region) was studied. It was established that the milk yield of cows calved in the autumn-winter period for 305 days of lactation amounted to 6272 kg of milk, which is 251 kg (4%) higher than the productivity level of cows calved in the spring - summer period. In terms of the amount of milk fat, autumn calving cows exceeded summer cows by 12 kg or 5% (p?0.01), and protein by 10 kg. The range of variation and the coefficient of oscillation in milk yield was lower in animals of summer calving, the highest in cows of spring calving. The coefficient of variation in milk yield, fat and protein is less than 25% and corresponds to the average variability of traits in the groups. In animals calved in winter, the coefficient of lactation stability is 5% higher compared to cows of the spring season, in autumn this indicator is 2% more than in animals calved in summer, 8% in spring and 3% in winter. Revenue from the sale of milk from cows of autumn calving is higher compared to winter by 5.6 thousand rubles, of spring by 11.5 thousand rubles and of summer by 10.3 thousand rubles.