Performance profile of cows of ural type at different level of milk productivity

Abstract

One of the tasks of selection and breeding work with dairy cattle is to assess the body type of cows in breeding herds. Body type plays an important role in the effi ciency of the use of animals in dairy cattle breeding only harmoniously developed cows when creating optimal conditions for housing and feeding, can show high milk productivity as well as they are less prone to the risks of premature culling for non-selective reasons. The selection of fi rst-calf heifers of Ural type of Black-and-White breed with milk productivity above 7000 kg of milk in breeding organizations of the Sverdlovsk region has been carried out. Materials on 2150 cows with average milk yield of 8622 kg of milk with the content of fat in milk of 3,90 % and protein – 3,20 % have been presented. With an increase in milk yield in fi rst-calf heifers there is a statistically signifi cant improvement in constitutional and performance features. Heifers have good parameters for the development of the body in height, which vary from 7,7 to 8,5 points, strong enough and deep body (fortress: 4,7–5,3 points; depth: 5,7–7,5 points), with well-defi ned milk forms (5,4–6,8 points). The udder of animals is characterized by a bath-shaped form (attachment density: 5,1–5,3 points; length of the front parts: 5,1–6,3 points) and an expressed escutcheon (width: 5,0–6,0 points; height: 7,8–8,3 points; central ligament: 4,9–5,3 points). For obtaining animals of dairy direction productivity with milk yield 7000 kg milk and more should make selection on the next parts of performance: rump high ≥ 7,0 points (from 145 centimeters); the depth of breast ≥ 6,0 points (not less 83 centimeters), length front share udder ≥ 5,0 points (from 21 centimeters), width rear share udder ≥ 5,0 points (not less 16 centimeters), express of dairy forms, central ligament ≥ 5,0 points.

Ways of improvement of herds, the development and verification of the mate selection method

“…Using the indicators of some genetic parameters (Lim, M ± m, σ, Cv, r, R1/2, R2/1, հ2) and selection intensity (P, u, i) calculated for experimental animals we have predetermined the selection efficiency of milk productivity of crossbred cows (1/4 Brown Caucasian x 3/4 Austrian Swiss), obtained by the breeding of F2 generation in itself, selected in the pedigree kernel during one generational change, having the selection differential (the difference of the average productivity of the selected animals and the herd) which is expressed by sigma (σ), defined by the formula𝑆𝑆𝑆𝑆 = 𝑖𝑖 × 𝜎𝜎, the specific weight (P) of the selected animals (pedigree kernel), the value of the selection intensity (i) which shows the difference of sigma of the minimum limit of productivity (V min) of the selected animals from the arithmetic average [9,11].…”