METABOLIC ADAPTATION OF HOLSTEIN COWS IN THE NEW-BIRTH PERIOD UNDER DIFFERENT MILKING SCHEMES

Abstract

The postpartum period in cows is characterized by significant metabolic changes that affect animal performance and health. One of the key technological factors that determines the effectiveness of adaptation during this time is milking frequency, as it directly affects energy balance, calcium metabolism and the risk of postpartum disorders. The aim of the study was to assess the influence of different milking schemes on the course of metabolic adaptation of Holstein cows in the new-birth period, in particular on the indicators of calcium and energy metabolism, the content of β-hydroxybutyrate (BHB), glucose, somatic cells and changes in body condition score (BCS). The study was conducted on 30 cows aged 21 to 49 months during 305 days of lactation. The animals were divided into three groups according to the principle of analogues: two-time milking with transition to three-time with calcium support in the form of boluses; two-time milking with transition to three-time with the use of calcium capsules; constant three-time milking without a transition period (control). The results obtained indicate that the gradual transition from 2× to 3× milking provided a smoother adaptation of the animals to peak lactation, stable blood calcium levels (2.32 ± 0.07 mmol/l) and lower levels of ketone bodies (BHB – 0.73 ± 0.09 mmol/l), which indicates a better energy balance. These cows had higher average productivity during the first 100 days (37.6 ± 11.9 kg/day) and more stable milk composition compared to those milked three times from the first day. Correlation analysis showed a moderate negative relationship between somatic cell count (SCC) and milk yield (r = –0.42, P < 0.05) and a positive relationship between BCS and glucose levels (r = 0.51, P < 0.05). This confirms that somatic cells can act as an indicator of stress load and metabolic imbalance in early lactation. The best results were obtained in the group with a gradual transition to three-time milking and calcium support in the form of boluses. The practical significance of the work lies in proving the feasibility of a differentiated approach to the organization of milking and mineral support of cows during the transition to peak lactation. The use of a phased milking regimen allows you to reduce the risk of metabolic disorders, stabilize physiological indicators and improve milk quality without increasing the load on the animal's body.