Abstract
The article presents the results of studying the effect of neutral-detergent fiber level in dry cow rations on physiological status and prevention of metabolic disorders during the transition period, i.e., three weeks before and three weeks after calving. The study was conducted on Holstein cows under commercial dairy farm conditions in the Northern region of Kazakhstan (Olzha-Sadchikovskoye LLP, Kostanay region,). Feed analysis was performed using the Van Soest detergent fiber system with an ANKOM analyzer in accordance with AOAC, ISO, and GOST standards. Rations for early and late dry periods were formulated with controlled NDF levels and balanced energy-protein supply. Ration structure, nutrient intake, indirect indicators of rumen metabolism based on dietary structural characteristics, mineral balance and zootechnical indicators were evaluated. It was established that excessive structural fiber content in traditional rations reduced metabolizable energy concentration, disrupted the calcium-to-phosphorus ratio, increased cation-anion difference (DCAD) values, and elevated the risk of metabolic disorders. Optimization of NDF content contributed to stabilization of rumen microflora, improved feed intake, reduced feeding stress, and enhanced physiological adaptation of cows to calving and the onset of lactation.