Linear type traits that characterize body development as the predictors of lifetime of Ukrainian Black-and-White dairy and Holstein cows

Abstract

The researches were conducted in the aspect of studying the problem of dairy cows lifetime depending on the linear traits assessment of the conformation type. By the linear classification method were estimated firstborn cows of the Ukrainian Black-and-White dairy (UBWD) and Holstein (H) breeds. Descriptive traits of the conformation that characterize the overall body structure were studied: chest width, body depth, angularity, body condition, rear width and position. According to the research results, the relative variability of the descriptive type traits assessment with cow's lifetime was determined. The relative variability of chest width and cow's lifetime was curvilinear. Cows for chest width assessment of 4–7 score had a higher lifespan with a variability of 2704–2844 (UBWD) and 2688–2789 (H) days. The highest lifetime was in animals with an assessment for body depth development of 6-9 score with an unreliable predominance of Ukrainian Black-and-White dairy breed cows, with the highest grades of both breeds 2824 (UBWD) and 2802 (H) days with an assessment of 9 score. Animals with an optimal angularity estimation of 5 score differed, lived the longest – 2842 (UBWD) and 2828 (H) days, while with increasing and decreasing score for this trait, the number of lifetime days of cows declined. According to the rump width assessment, lifespan was highest in cows with a 9 score – 2766 days (UBWD) and 2832 days (H). Cows of UBWD with the highest assessment for this body part development of 9 score were used on 592 (P <0.001), and Holstein on 708 (P <0.001) days longer compared to animals with 1 score. The maximum lifetime of animals with an average assessment for body condition of 5 score was 2842 (UBWD) and 2774 (H) days. Cows with body condition score below average lived and were used in the herd much longer than with a higher one. The degree of relationship variability between the assessment of these traits and the lifetime of animals depended on the specific body part. Key words: Ukrainian Black-and-White dairy breed, Holstein, linear type traits, lifetime.