INFLUENCE OF AGE AND ORIGIN OF SIRE FOR DAIRY COWS EXTERIOR TRAITS

Abstract

The current cattle breeding system is focused not only on registration of productive traits but also on involvement of information, related to the health status and productive longevity of animals. Such approach based on animals’ evaluation based on a large number of traits, including type linear scoring (peculiarity of the exterior). The analysis of the results of the type linear scoring, among other things, allows us to estimate animal's health status and thus may serve as a selection criterion, related to ability for long-term economic use (longevity). Presented study was conducted under the conditions of farm «Kolos Agro Firm» in the Skvyra district of Kyiv region to prove the possibility / efficiency of involvement of different parameters, registered for performing of linear scoring of cows, in breeding programs. The analysis was performed on 490 Holstein cows with an average productivity of 8600 liters of milk per 305 days of lactation. The results obtained were processed using mathematical methods by means of special program for statistical data processing (SPSS 17.0). It was determined, that the number of different genetic and environmental factors are influenced results of linear scoring. Using variance analysis, it was found that factors (traits) like cow age (in lactations) and cow origin affect the development of all evaluated traits with different likelihood and degree of impact. All cows originated from 20 breeding bulls. Also, significant influence of age of the animals on body composition of cows was determined. The biggest changes with age occurred with traits, related to udder quality and fundaments (positioning of the rear legs, angle of the hoof, angle of the rear legs). As a result of the work, it was stated that evaluation of cows using linear scoring method is important to ensure breeding progress in cattle breeding.