Assessment of the Productive Qualities of the First Heifers of the Jersey Breed

For the successful development of dairy cattle breeding, it is necessary to have cows with improved milk productivity in combination with an effective herd management system. In the conditions of the North Caucasus, Jersey cattle make up 26% of the total breeding stock of cattle. The article presents the results of research, during which the following tasks were solved: the study of the main parameters of dairy productivity of controlled cows after the first completed lactation (305 days) (milk yield, milk fat and protein content and their percentage in milk, lactose content); the study of live weight indicators at 6 months and after the first calving of the first Jersey breed heifers in combination with the manifestation of productive qualities. As a result of the research work, various reliable correlation coefficients were found between the indicators of dairy productivity of cows (milk yield, milk fat and protein yield, percentage of fat and protein, percentage of lactose) and the live weight of animals at 6 months and after calving. A reliable correlation was established between the average daily gains in the period 0–6 months with the yield of milk fat and the percentage of fat in milk. The percentage of lactose in milk showed a weak but reliable correlation with the mass fraction of fat and protein.