PRODUCTIVE AND GENETIC PARAMETERS OF SAANEN DAIRY GOATS WITH PROLONGED LACTATION

Abstract

The research was conducted in order to evaluate the productive and genetic parameters of the Saanen nanny goats with prolonged lactation in the conditions of industrial technology of keeping. The work was performed on the basis of the pedigree breeding unit of LLC “Goat dairy unit “Nadezhdinsky” in the Stavropol Territory in 2019-2025. Methods of zootechnical estimation, measurement, comparison, and statistical analysis were used. It was established that young animals were characterized by high growing capacity. Live weight increased from birth to 7 months by 8,7-9,6 times, reaching 61,2-66,3% of the weight of adult animals. Goats with prolonged lactation (on average 637,5 days) showed the highest milk yield per lactation – 1870,9 kg, which was 85,4 and 144,7% higher than in animals with shorter lactation. The superiority of this group in the amount of milk fat was 1.8 and 2,3 times, and milk protein – by 1.9 and 2.4 times. The genetic and statistical analysis revealed an average and high variability of productive (Cv up to 27,5%) and external (Cv up to 23,5%) traits. The coefficients of heritability (h²) of productive traits were 0,29–0,48, the coefficients of repeatability of daily milk yield and protein content were 0,42–0,43, which made it possible to predict the productivity of an animal in subsequent lactations with moderate accuracy and provided the basis for early selection of nanny goats by the first lactation. A positive correlation was found between economically useful traits, and the highest was between the fat and protein content in milk (r = +0,52; P <0,05). High variability and moderate characteristics of heritability indicate the effectiveness of selection in the formation of a herd of goats with prolonged lactation.