Productive Performance of Yaroslavl Cows and Their Crosses with Holsteins

The surveys were carried out in order to determine the rationale for improving the Yaroslavl cattle breeding stock with Holstein bulls. The cows of the Yaroslavl breed (n = 458) and their peers with percentage of Holstein blood from 38 to 50% (n = 167) at the pedigree enterprise in the Ivanovo oblast were used as the basis to analyze the productivity, welfare, and service interval lengths of cows through the dynamics of the first and two later lactations. The cows were allocated into two groups (of 50 animals each) with the method of analogous pairs to determine the milk composition. In case of the milk yield of 4100 to 5000 kg for the first lactation, the Holsteinized Yaroslavl cows compared to their purebred peers were more efficient in the total milk yield for three lactations by 169 kg. In cases of the milk yields of 5100…6000 and 6100…7000 kg for the first lactation, vice versa, they were inferior to the purebred peers by 556 and 1564 kg, respectively. The service interval length for three lactations in the crossbred specimens compared to their purebred Yaroslavl peers increased by 21…40 days, while the on-farm cow welfare up to the second and third lactations and the fourth lactation reduced, on average, by 10 and 20%, respectively. The daily milk yield of the Holsteinized cows at the first stage through three lactations was 1.6…3.0 kg less than that in their purebred peers. The mass fraction of milk protein at the second stage within the second and third lactations was 0.09 and 0.13% less, respectively. With respect to the amount of lactose at different stages within the second and third lactations, it was 0.08 and 0.20% less, respectively. The fat globule size in the milk of purebred Yaroslavl cows was significantly larger than that for the Holsteinized animals by 0.10…0.11 μm and their number in a winter season was 0.15 billion/mL more, which can indicate the better milk processability for cheese and butter making.