TECHNOLOGICAL PROPERTIES OF MILK OF COWS WITH DIFFERENT GENOTYPES OF KAPPA-CASEIN AND BETA-LACTOGLOBULIN

The presence of the desirable alleles and genotypes of casein and whey protein genes in the genome of cows affects the milk protein content, quality and technological properties of their milk. Two important properties of milk its producibility is judged on are cheeseability and heat resistance. The present studies aimed at estimating the technological properties of milk of black-motley × Holstein and Kholmogorskaya breeds cows of the Tatarstan type with different kappa-casein (CSN3) and beta-lactoglobulin (BLG) genotypes. The study was carried out using a sampling of the first-calf cows of 5 cattle-breeding farms of the Republic of Tatarstan. In animals, the CSN3 and BLG genotypes have been determined by a PCR-RFLP analysis. The cheeseability, heat resistance and thermostability of milk have been estimated using standard methods. The studies have established that the CSN3 and BLG genotypes of cows affected the condition of a casein clot and duration of milk clotting time. The best cheese-making properties of milk were inherent in the animals with the BB and AB genotypes of the CSN3 and BLG genes. They were superior to the coevals with the AA genotype in terms of the highest yield of the desired dense casein clot and the shortest duration of milk clotting time. The first-calf cows, which are the carriers of an A allele of the CSN3 gene, were superior to the animals with the BB genotype of the CSN3 gene on the thermostability of milk including that on the proportion of animals with this milk characteristic. The BLG genotype of the studied animals did not significantly affect the thermostability of milk. Moreover, the highest thermostability of milk was characteristic of black-motley × Holstein cows with the AA genotype

Identification of relationship of polymorphic variants of lactoferrin gene (LTF) in cows with milk production indicators depending on their lineage

© Published under licence by IOP Publishing Ltd. Dairy farming is striving to achieve positive results both in milk production increase and quality improvement. Unfortunately, the conventional breeding selection system does not consider the genotypic identity that reflects the level and direction of the processes occurring in the organism. The modern breeding selection is based on the selection by a set of features. In breeding, those animals that have more valuable characteristics are considered valuable. Animal husbandry can achieve great success only when analyzing the biology of the animal body and productivity. In order to increase the genetic potential of cows in Russia, it is necessary to take into account genetics and milk productivity. Analysis of milk productivity of cows with different LTF genotype in their pedigrees showed that the maximum milk yield was in cows of the Ayvengo line with the LTFAB genotype. These cows were distinguished from other cows by their high protein content, and these animals had the lactoferrin gene. And the animals of the Ayvengo line differed in the level of fat in milk. The comparative PCR-RFLP analysis of the blood DNA samples of the first-calf Holstein cows showed the benefit virtually by all milk production indicators (milk yield, milk protein and fat), including by somatic cell content in milk of the Ayvengo and Sovereign line cows with the LTFAB genotype. The Aydial line stock with the LTFAB genotype is worthy of notice regarding the selection activity