Influence of outbreeding and inbreeding on the productive longevity of dairy cows

Abstract

The data on the indicators of the duration and effectiveness of life-time use of Holstein, Ukrainian Black and Red-and White dairy cows obtained from unrelated and different degrees of related mating are presented. The sample includes information on zootechnical records of 15 farms of different regions of Ukraine (Ivano-Frankivsk, Lviv, Volyn, Rivne, Ternopil, Vinnytsya, Kyiv, Cherkasy, Chernihiv and Kirovograd). To assess the productive longevity of cows for each cow were examined such indicators as life expectancy, economic use and lactation, life expectancy, life expectancy of fat in milk, life expectancy of milk fat, average yields for one day of life, one day of economic use and one day of lactation, lactation coefficient. It was established that among studied livestock of dairy breeds more cows was obtained by outbreeding (Holstein breed – 62.2, Ukrainian Black-and-White dairy – 75.5 and Ukrainian Red-and-White – 76.9%). Among the inbred animals, more cows were obtained from distant and moderate degrees of family ties. At the same time, inbred animals were characterized by higher rates of productive longevity compared with outbreeds. Among the inbred animal life expectancy, lasting productive use, duration of lactation, lifetime milk yield, lifetime number of milk fat and number of lactations for the life cows of all studied species obtained by close and moderate inbreeding were the best (exception – lifetime yield of Ukrainian Black- and Red-and-White and lifelong amount of milk fat of Red-and-White animals. According to inbreeding rate less than 0.78 and more than 12.5%, there was a significant deterioration in both the duration of productive use of cows and their lifelong yields. Inbred depression was detected only in Holstein breed animals, which were obtained by close inbreeding. This indicates a significant decline in most indicators of their productive longevity. Ukrainian Black and Red-and-White dairy breeds, which were obtained through close inbreeding, the indicators of life expectancy and life expectancy, on the contrary, increased compared with outbred animals.