THE LIFETIME OF COWS UKRAINIAN RED-AND-WHITE DAIRY BREED DEPENDING ON THE LINEAR TRAITS ESTIMATION

Abstract

Studies conducted in the herd for breeding Ukrainian Red-and-White Dairy breed (n=250). Evaluation of exterior-type heifers were conducted by the method of linear classification according to the latest recommendations of the ICAR at the age of 2-4 months after calving. Such descriptive traits, that characterize the body structure of cows – chest width, body depth, angularity, the fatness, the position and rump width had been studied. The results of studies showed reliable influence of the score level of exterior descriptive traits on the lifetime of cows. The degree of variability of relationship between these traits depended on the score level and specific point of the body structure. The effect of the chest width on the lifetime of cows has curvilinear variability. Longer lifespan have been identified in animals in 3-5 scores for the development of this trait and was 2452-2505 days. With the increase from the average value in 5 scores, the lifetime of cows decreased from 2351 (6 scores), to 2041 days (9 scores). Comparing group of animals valued in 5 score with groups in 6-9 scores revealed a reliable variance in favor of the former, which ranged from 184 (P<0,05), to 464 days (P<0,001). Studies of the effect of body depth on lifetime showed that the longest periods of longevity inherent in animals evaluated the development of trait in 6-9 scores, with the highest value of 2531 days estimated in 8 scores. Cows with excessive angularity and maximum lifespan (2455-2503 days) had higher scores (7-9). A significant decrease is observed when reducing the score for this trait starting from 6 scores (-193 days; P<0,001) to 1 score (-648 days; P<0,001) in comparison with the best result in 8 scores. The relationship between the assessment for condition of rump angle and lifespan of cows has a curvilinear nature. Animals with an optimal rating of the trait in 5 scores had a high lifetime in 2517 days, whereas with the increase and decrease of scores, the number of cows days of life decreased. The difference in life expectancy between cows valued at 5 scores with groups of animals assessed in 6-9 scores ranges from 12 to 284 days with a reliable variance only compared with 8 and 9 scores (P<0,05). Compared with groups of animals estimated by 1-4 scores, the variability of variance was 100-509 days with reliability compared with 1 and 2 scores (P<0,01). The lifetime of cows is in straight dependence on the score level for trait chest width. Cows with the highest estimate for the development of trait in 9 scores was used for 462 days longer compared to animals with 1 score (P<0,01). Among the evaluated population, the greatest number of cows (n=88) estimated in 7 scores, next (n=56) in 6. In general, the vast number of cows (n=189), or 75,6% are for the development of this trait above the average, i.e. is characterized by a rather wide rump. The highest average lifetime of animals in 5 scores for fatness is on average – 2523 days. A sufficient lifetime of cows valued 1 to 4 scores with variability 2276-2459 days inferior for animals in 5 scores on 64-247 days with a significant difference between the groups estimated in 1 and 3 scores (P<0,05). A significant reduction in lifetime observed in cows with body condition score in 7-9. They are significantly worse in comparison with groups of animals with 5 scores, for a high reliable difference 282-566 days (P<0,001). A significant effect on the development of linear type traits was installed on longevity of cows Ukrainian Red-and-White Dairy breed. Each of the estimated descriptive traits influence on life expectancy of cows with different variability within grading scores in accordance with desirable development. Selection of Dairy cattle for desirable development of exterior type traits by results of linear classification will enhance the duration use of cows.