Protected Fats in High-Yielding Cows’ Diet: Effect on Lactation Performance

The amount of fat in the diets of Kholmogory dairy cows is known to affect milk yield and its quality, as well as the economic efficiency of milk sales. In this research, the content of protected fats in the diets of high-yielding dairy cows was raised from 771.9 g to 1,023.9 g (32.6%) during full lactation by adding 300 g calcium salts of fatty acids per day. As a result, the milk yield increased by 8.0% (P = 0.95). The mass fraction of fat increased by 0.05% while that of protein rose by 0.03%, which improved the overall quality of milk. The experimental milk samples demonstrated a slight increase in non-fat milk solids (0.052%). The level of urea rose slightly (2.9 mg/100 mL) and reached 21.1 mg/100 mL, which corresponded to official standards and was a marker of a balanced diet. The study revealed a moderate positive correlation (r = 0.35) between the feed energy and the lactation performance. Protected fats had no significant effect on coagulation time and cottage cheese yield. The experimental diet demonstrated economic efficiency by increasing the potential profits from milk sales by 15.5%.