Avel för hållbarhet och livslängd hos köttdjur
The purpose of this literature study was to investigate the possibilities to improve longevity and stayability of beef cattle with breeding. The breeding goal for beef breeds is to produce animals with high capacity for growth and good feed efficiency. Longevity and sustainability are two important features to include in the breeding goal. If longevity is increased each cow can produce more calves and the number of female calves used for recruitment can be reduced and only the best heifers need to be selected for breeding. The benefits of longer life is that it lowers the costs of recruitment animals, it increases the number of young animals that become available for slaughter, and it increases the proportion of high producing animals in the herds. Cows that are not producing enough will be culled. It takes some time to obtain a high reliability of a breeding value of a bull for longevity as it is necessary to know how long a large proportion of his daughters lived. Moreover, the heritability is low for longevity, and in the range between 0,03-0,26. Length of life differs in different beef breeds and is also affected by time of year when the cow gets her first calf and calving difficulty. Cows with a higher muscle development and muscularity have a longer life. The sustainability of the high-ranked bulls used for several years is very important for successful breeding activities. Many beef breed bulls suffer from osteochondros; a bull that is lame is mostly useless and can cause great economic losses for farmers.