Продуктивные качества первотелок красно-пестрой и симментальской пород за период раздоя и взаимосвязь у них селекционируемых признаков в условиях Забайкальского края

Abstract

The results of the study of milk production and morphophysiological properties of the uterus of heifers of the red-and-white breed for 100 days of lactation in comparison with the heifers of the Simmental breed are presented. For 100 days of lactation from heifers of the red-motley breed, 2096 kg of milk each were obtained, with a fat content of 3,9 and a protein of 2,9%, from simmental fat, respectively, 1363,2 kg, with a fat content of 3,7 milk and protein of 2,9% First heifers of the red-motley breed exceeded their peers in milk production by 732,8 kg (34,9%) with a highly reliable statistical difference (B3 ≥ 0.999). Reliability (td=1,6) at zero threshold (Bo> 0,90) was also noted for fat content in milk. The protein content in milk in first-calf cows of both groups was at the same level – 2,9%. It has been established that the morphological features and functional properties of the udder are fairly consistently inherited by the offspring. Therefore, by selection and selection, it is possible to obtain animals with bath-like and cup-shaped forms of the udder, uniform development of quarters, with full milk yield. The shape of the udder is one of the main breeding traits characterizing the suitability of cows for machine milking, which is most closely associated with productivity. In our studies, all the first heifers of the red-and-white breed had a bath-like and cup-shaped udder (65 and 35%). Simmental first heifers were inferior, in them 78% of the animals had a bath-like and bowl shape and 22% were round. When measuring the udder, it was established that the first-hens of the red-and-white breed had a wider, deeper udder with a large girth. Their udder was longer than that of the Simmental ones, by 1,4 cm, wider by 1,5, deeper by 1,7, and more by girth by 3,6 cm. The functional properties of the udder of heifers of the red-and-white breed were significantly better than those of the Simmental. One-time milk yield from them was higher by 5,7 kg and amounted to 10,8 milk. The lactation rate was also higher in the red-and-white first-calfs, and it was 1,794 kg / min. In the red-and-white heifers, a high positive correlation was observed between the milk yield and body weight – 0,76, among the Simmental ones – 0,22, and between the milk yield and the fat and protein content in milk, the negative correlation in both groups of animals. For measurements of the udder (length, width, and girth) and milk yield for 100 days of lactation, a positive correlation was found for both red-and-white and simmental healers.