Influence of live weight on milk productivity and longevity of economic use of cows

Abstract

The purpose of the research was to study the influence of the live weight of first-calf heifers on the subsequent milk productivity and productive longevity of high-blood Holstein animals. Research has shown that live weight influence on dairy productivity and productive longevity of cows. From cows with genotype 1/4S+1/4A+1/2RWH with a live weight of 580–600 kg for the first lactation 750 kg more milk was produced than from cows with the live weight 480–500 kg at the first calving. With an increase of the part of Holstein breed blood the differences in milk productivity between cows with different live weight during the first lactation have been increased. First-calf heifers with genotype 1/8S+1/8A+3/4RWH with the live weight of 580–600 kg outperformed their herdmates with the live weight 480–500 kg in milk yield by 1761 kg (P ≥ 0,999), and cows of genotype 1/16S+1/16A+7/8RWH by 2271 kg of milk (P ≥ 0,999). Indicators of productive economic use had certain differences. Thus, cows with the genotype 1/4S+1/4A+1/2RWH with the live weight of 540–560 kg had the highest longevity of economic use – 43,29 months and a lifetime productivity – 24942 kg of milk. In crossbred cows with genotype 1/8S+1/8A+3/4RWH the longevity of economic use and lifetime productivity were higher in cows with the live weight of 580–600 kg, the indicators were 24,73 months and 18294 kg of milk, respectively, in cows with genotype 1/16S+1/16A+7/8RWH the highest longevity of economic use 24,96 months was in cows with the live weight of 560–580 kg, and lifetime productivity – 18131 kg in cows with the live weight 580–600 kg.