Abstract
The study presents an assessment of the quality of feeds (silage and haylage) and biochemical parameters of blood in dairy cows under experimental farm conditions. Four feed samples (two alfalfa haylage samples, a grain haylage, and corn silage) and 12 blood samples from lactating cows were analyzed. All examined feeds met regulatory requirements for fermentation and nutritional characteristics: optimal moisture content, predominance of lactic acid over acetic acid, low butyric acid content (<0,1%), reduced ammonia nitrogen levels, and absence of spoilage signs. The biochemical profile of serum samples was within physiological norms: total protein 75-79 g/L, glucose 2.4-2.8 mmol/L, urea 3.2-3.9 mmol/L, and liver enzyme activity (ALT, AST) slightly exceeded reference values. The obtained data indicate stable metabolic processes and a normal physiological state of cows when fed high-quality silage and haylage. It was concluded that the nutritional value of the prepared feeds fully meets the cows’ requirements without causing metabolic disorders: the rations are balanced, as evidenced by normal blood biochemical constants and high milk productivity.