Lifespan of Ukrainian brown cows of dairy breed depending on the evaluation level of udder linear traits

Abstract

Morphological udder traits of dairy cows occupy a leading place in the system of linear classification of dairy cattle with the highest weighting factor of 40 %. Such a significant attention to the udder evaluation explained by the existence of a correlative relationship between the udder descriptive linear traits and milk productivity, especially with the functional life duration of dairy cows. In this regard, research results presented in this article on the study of influence the evaluation level of udder linear traits on the cows’ lifespan of Ukrainian brown dairy breed are sufficiently motivated and relevant. The evaluation of first-born cows by type was conducted in the advanced farms of Sumy region using the method of linear classification. We took into account the results of evaluation of descriptive traits on a 9-score scale. Five descriptive udder traits included in the linear classification system were studied: front udder attachment, rear udder attachment height, central ligament, udder depth and location of front teats. The research results proved the existence of a reliable correlation between the udder morphological traits and cows’ lifespan of controlled herds. It was established that each of evaluated linear traits exerted its influence on the cows’ lifespan with different correlative variability of scores within each evaluated trait. The front udder attachment evaluation showed a difference of 654 days between cows scored 1 and 9 (P<0.001). The difference between evaluation the trait of rear udder attachment height in 1 and 9 scores was 610 days (Р<0.001). First-born cows (17.3%) with scores for the condition of central udder ligament downward from the average (1–4 scores) had a lifespan of 2436–2156 days, while the same age group with the highest score of 9 differed a high functional life – 2786 days. The advantage was 350-630 days (Р<0.001). In evaluated cows with the udder located the highest relative to the hock, with a score of 8, the difference in lifespan, compared to animals with lowered udder, was 597 days (P<0.001). First-born cows with the trait of front teats location with an average score of 5 had a longer lifespan by 156–484 days (P<0.001) compared to the same age cows with scores from 4 to 1.