Productive qualities and their interrelation in Holstein cows of black-and-white breed

Abstract

Abstract. Purpose. Evaluation of Holstein cows according to economically useful characteristics and the establishment of indicators of the relationship between productive characteristics. Methods. Milk productivity was assessed by the method of control milking, milk quality indicators – by the instrument method on the Lactan-1M device, reproductive qualities – by conventional methods. We used the data of zootechnical and veterinary records of the IAS “SELEX-Dairy cattle” database, breeding cards of cows. Results. The highest indicator for milk productivity was established for full-age lactation. It was higher than the average by 1611 kg or 23.3 % (P ≤ 0.01) and by 1141 kg or 15.4 % than the maximum lactation (P ≤ 0.01). The duration of productive use of cows on the farm is 1.85 ± 0.07 lactation or 2.39 ± 0.07 calving, but the duration of use of individual animals is 9 lactation. MJ and MDB in milk, depending on the studied indicator, differ slightly and unreliably, but there is a tendency to increase these indicators for full-age lactation. Large coefficients of variability were determined by milk yield, and for lifetime milk yield it is more than 65.0 %, while for individual estimated lactation, the average, maximum and full-age coefficient of variability did not exceed 22.5 %. According to MJ and MDB in milk, the breeding stock is more equalized. Milk yield in cows increases up to 4 lactation, the largest increase in milk yield for 305 days of lactation was recorded in the second lactation – 937 kg or 14.5 %. Then the increase is 79 – 363 kg. Starting from the 5th lactation, there is a gradual decrease in milk yield for 305 days of lactation. There is no positive average and high correlation between milk yield and milk quality indicators, except for some data (6 lactation) and therefore they cannot be used when carrying out measures to improve the herd. Selection and selection for each indicator must be carried out separately. The scientific novelty of the work lies in the fact that new data have been obtained on the dairy productivity of modern Holstein black-and-white cattle with a high proportion of blood in the Holstein breed. The correlation coefficients between productive traits in cows with a share of blood in the Holstein breed over 94.0% were calculated.