For better breeding values for rams and conservation of genetic variation in Gotland sheep
The goal of this work is better breeding values for rams and conservation of genetic variation in Gotland sheep
The population size for Gotland sheep is rather large, but split over many herds. Since use of semen is low, some herds are isolated islands in the relationship matrix. When only one ram is used in a herd and this ram is the father of all the lambs in the herd, it is difficult to distinguish between the genetic effect and the herd effect. Even so, the estimated accuracy of the ram's breeding value can be high if the ram is father of many lambs. Today, such a ‘single herd-ram’ is not allowed to be included in the list of the best rams even if it has a high breeding value, and it is questioned whether it should be selected for AI or not. On the other hand, AI rams with low relationship to the population are positive for genetic diversity in the population.
Historical data in the database Elitelamm is used for genetic evaluation. Rams’ breeding values are estimated based on data from one year's offspring at a time. The breeding value for the first and second year as sire is compared. Does the breeding value between first and second year differ more on average for ‘single herd-rams’ than for rams that have been used in herds with several rams?
Suitable for: Animal science.