Effect of carbohydrate level in the diets of Kholmogor cows on milk productivity and milk quality

Abstract

The effect of the diets with different ratio of easily digestible carbohydrates on milk productivity and milk quality of high-yielding Kholmogor cows during the milking period was studied. The research and production experiment on the cows was conducted in the Arkhangelsk region in 2022. Selection of animals in the control and experimental groups was carried out by the method of pair-analogues under the stall barn system. Two groups of cows participated in the research: experimental and control groups of 10 cows each. The experiment lasted for 100 days. Carbohydrate-protein mixture was used as a carbohydrate supplement to the diets of experimental animals in the amount of 1.5 kg per head per day. Selective milk quality control for mass fraction of fat, protein, lactose, dry matter, milk solids non-fat (MSNF), freezing point, urea and somatic cells were determined on a Bentley Combi 150 high-speed infrared milk analyzer at the Selective Milk Quality Control Laboratory. It was found that the sugar-protein ratio in the experimental group was twice higher (0.58) than in the control group (0.29), due to the presence of carbohydrate supplementation in the diet. The increase in milk productivity of the animals by 4.6 and 0.14% of the protein level in milk at inclusion of carbohydrate-protein mixture in the amount of 1.5 kg per one head per day in the diet was established. A 3.2% decrease in the level of urea in milk was recorded, indicating a more efficient use of amino acids by the animals in the process of metabolism at the same level of absorption of ammonium forms while increasing the level of simple carbohydrates in the diet. The positive effect of this additive on the content of dry skim milk residue, which increased in the milk of the cows of the experimental group by 0.128 absolute % (abs.%), was revealed. Application of the carbohydrate-protein mixture in the amount of 1.5 kg per one head per day and control over the quality of produced products will increase the milk productivity of cows, improve the quality of products, increase the productive longevity of dairy cattle.