In the Republic of Kazakhstan over the past decade positive changes have been observed in increasing the number of farm animals, increasing their productivity, and increasing the gross production of milk, meat and other products. At the same time the development of dairy cattle breeding is mainly due to the breeding of Black-and-White, Red Steppe, Simmental breeds and their intra-breed types as well as imported from abroad Holstein breed. The purpose of the research was to analyze ways to improve the intra-breed type Karatomar of Black-and-White breed in Northern Kazakhstan. Research work has been carried out on breeding animals such as Karatomar type cattle of Black-and-White breed in LLP “Experimental farm Zarechnoe” in the Kostanay district in the Kostanay region. The dynamics of growth and development indicators, reproductive traits of heifers of a new intra-breed type Karatomar of Black-and-White cattle have been studied. A comprehensive assessment of their economically useful traits in the first lactation, determined by the resistance of animals to climatic and forage conditions, the efficiency of breeding of animals of different genotypes has been conducted. It has been found that the replacement heifers – daughters of American breeding sires inherited precocity and showed higher growth energy after 6 months of age and continued to grow rapidly until 18 months. The advantage in metabolism was in the daughters of Holstein sires of the American selection Orbit 4078, and the increased immune status of the organism in the daughters of the sire of the domestic selection Yamal 975 as the most adapted to the conditions of Northern Kazakhstan. The best ability to increasing the milk yield, stable lactation activity, high milk productivity, gross content of dry matter and nonfat milk solids have been characterized by the daughters of sires of the American selection Orbit 4078 and Lowrider 4129. Analysis of economic indicators of milk production has been shown that from cows – daughters of sires Orbit 4078 and Lowrider 4129 for 305 days of lactation received 15,8 and 15,2 % more milk of base fat, the expenditures of EFU per 1 kg of production was lower by 10,2 and 5,9 %. A higher level of profitability has been observed in the group of daughters of the sires Orbit 4078 – 35,5 % and Lowrider 4129 – 33,1 %, which was 8,5 and 10,8 % higher than in the group of daughters of the sire Yamal 975.
ASSOCIAÇÕES GENÉTICAS ENTRE O PERÍMETRO ESCROTAL E AS CARACTERÍSTICAS PRODUTIVAS E REPRODUTIVAS EMREBANHO NELORE CRIADO NA REGIÃO NORTE DO TOCANTINS Genetic associations between scrotal circumference and productive and reproductive traits in herd Nellore raised in northern Tocantins State, Brazil
