Modern dairy farming relies on the use of high producing genotypes capable of achieving milk yields of 8,000–10,000 kg per lactation. However, such high productivity is associated with the risk of profound metabolic shifts, particularly during transition and critical periods of the annual cycle. The Russian Black Pied cattle breed traditionally exhibits high adaptive capacity; nevertheless, seasonal changes in feed composition and the physiological status of animals often lead to an imbalance in metabolic processes. This manifests in reduced protein and glucose levels, as well as the accumulation of intermediate metabolites. Analysis of the obtained results revealed seasonal dynamics in blood biochemical parameters of the studied cows under conditions of technological stress. The most metabolically challenging period was identified as the peak of lactation (days 100–200), which represents the pinnacle of metabolic disorders (winter hepatopathy, critical hyperuremia, autumn ketosis). During the dry period, the most critical state of immunity is observed, while at the peak of lactation the most pronounced hepatic dysfunction is found. Across all periods, spring is characterized by a peak of lipolysis and hyperuremia, autumn by a peak of ketogenesis (except during the early lactation phase) and a deficiency of amino nitrogen, and winter by hepatic dysfunction and immunodeficiency. In all periods and seasons, a chronic metabolic pathology was identified as a total reduction in α2 globulins, serving as a marker of long term hepatocellular dysfunction in high yielding cows
Keywords
Metabolism, season, cattle, blood, biochemical analysis