Influence of maternal ancestral productivity on offspring's milk yield

The high rates of development of breeding and productive traits in modern populations of dairy cattle breeds in Russia and the Vologda Oblast determine new methods in selection and breeding work. The relevance of the research consists in determining the effective parameters of cow selection for herd reproduction and the selection of breeding bulls according to the level of productivity of maternal ancestors. The purpose of the research is to identify the influence of the level of productivity of maternal ancestors on milk yield of offspring. The scientific novelty consists in determining the direction of the breeding process in herds to obtain a reliable improving effect on the productivity of cows in the next generation. The basic indicator for evaluation remains the productivity of dairy breeds – a breeding trait formed on the basis of genetic and paratypical factors. Weak correlation between the milk yield of mothers in the first lactation (r = 0.21) and the milk yield of offspring in the first lactation was revealed for the selection traits, and the relationship was not reliable. There was no correlation between milk yield of mothers in the highest lactation and mothers of fathers and milk yield of offspring in the first lactation (r = 0.02; 0.06) with a high degree of reliability (P ≥ 0.001). The actual figures indicate that in modern populations the selection of the best breeding material is carried out and the level of productivity of the maternal base is not sufficiently taken into account. During the distribution of paternal mothers by milk yield, it was found that the highest level (13436 kg of milk) was selected on mothers with the lowest milk yield of 9035 kg of milk in the highest lactation. As a result of selection the milk yield of offspring in the first lactation was 7746 kg of milk, which is inferior to the highest indicator of daughters – 729 kg. The highest milk yield of offspring in the first lactation of 8475 kg of milk was obtained with the maximum milk yield of mothers in the highest lactation of 9917 kg of milk and the average productivity of mothers of fathers 10474 kg of milk, that is, the homogeneous improving selection was used. It is recommended to conduct homogeneous and improving selection of bulls taking into account the level of productivity of maternal ancestors to obtain a reliable improving effect on productivity in the next generation.