Assessment of the biological value of forages according to the control tests of milk and its use in the organization of feeding of dairy cattle

Abstract

The article presents the results of the assessment of the biological usefulness of feed according to the control tests of milk. Scientific research was carried out in LLC "Minskoye" of the Kostroma district of the Kostroma region on a population of 369 cows of the Kostroma and Black-and-White breeds according to the seasons of the year. The authors found that in terms of the level of digestible protein in lactating cows, there is an imbalance in almost all seasons of the year, so most animals are prone to diseases associated with metabolic disorders. The level of rumen acidity in animals of the Koroma breed was more stable (pH = 6.2-6.4) in all seasons of the year, which indicates a lower likelihood of developing acidosis, in contrast to Black-and-White breed cows. Based on the indicators of milk control tests, insufficient supply of raw protein to cows of the Kostroma and Black-and-White breeds during the milking period was established. The highest daily milk yields (more than 30 kg of milk) were obtained from cows in the first and second periods of lactation in all seasons of the year. In animals with a level of availability of digestible protein of 10.3-10.9 g/MJ, there is a normal ratio of fat: protein (1.26:1), with a profitability level of 66.11%, while animals with an insufficient level availability of digestible protein of 10.2 g/MJ and less, had the level of profitability of milk production 73.93 and 86.44%, respectively. When the level of availability of digestible protein is more than 11.0 g/MJ in animals, the likelihood of acidosis increases. Evaluation of the biological value of feeds according to control tests of milk during the period of control milkings will allow monitoring the energy and protein nutrition of animals.