Prospects for improving reproductive performance and longevity of black-and-white cows

Abstract

The article discusses the prospects of improving reproductive performance and longevity of animals in the improvement of commercial herd “Ryazhskaya MTS” Ryazan region through the use of Holstein bulls with genetic evaluation of fertility and longevity indices. A preliminary analysis of the impact of high and low values of bull indices on the number insemination of heifers, age of the first calving, as well as the number of insemination per conception, the interval from calving to conception, the interval between calving cows and their survival to 3 lactation. It was found that the daughters of bulls with a negative value of the HCR index (from -1.5 to -1.3) and the DPR index (from -4.3 to -2.3) had the highest sperm consumption for fruitful conception of 1.9 and 2.0 doses, respectively. With increasing index HCR and DPR bulls the number of insemination for conception heifers decreased. The lowest index (1,2) was observed in heifers whose fathers had the highest index of HCR (from +1,3 to +5,7) and DPR (from +1,0 to +5,0). The daughters of bulls with negative values of HCR indices (from -1.5 to -1.3) and DPR indices (from -4.3 to -2.3) had age of 1 calving of 25.7 and 27.1 months, with positive values of HCR (from +1.3 to +5.7) and DPR (from +1.0 to +5.0) - 23.2 and 23.0 months respectively. Among the bulls (fathers) of imported livestock, carriers of haplotypes affecting reproduction were mainly in groups with negative values of HCR and DPR. Among the daughters of bulls with a high DPR and PL index, 21.8% of cows survived to the third lactation, among the daughters of bulls with low values only 5%. Daughters of bulls with high index values showed a tendency to reduce the number of insemination per conception, the number of days from calving to conception and the interval between calving.