POSSIBILITIES OF BREEDING VALUE OPTIMATION FOR REPRODUCTION TRAITS INPIGS FOR A PIG BREEDING ASSOCIATION

The selection merit of reproduction traits, their genetic relation amo ng each other and the genetic relation to production performance trait s are analysed. The analysis is based on the sow-management-programme data of 4463 litters and the on-station performance test of 1796 full- sibs of the data pool of the Pig Breeders Association ''Nord-West''. T he heritability for the trait number of piglets born alive ranged from h(2) = 0.09 to h(2) = 0.12. For the trait number of piglets raised, l ower heritabilities (h(2) = 0.05 to h(2) = 0.07) were estimated. The g enetic correlation of different litters were very high for both traits , number of piglets born alive and number of piglets raise (r(g) = 0.8 3 to r(g) = 0.99). For the interval weaning to conception after first litter, a heritability of h(2) = 0.10 and a genetic standard deviation of 5.1 days was calculated. The consideration of this trait in breedi ng value estimations is useful. Between litter size and the interval w eaning to conception after first litter, only low genetic relations we re found. Similar results were found for the genetic relation of produ ction and reproduction traits. Therefore. the breeding value estimatio n for reproduction traits can be carried out independent of the produc tion traits. A breeding value estimation for the trait number of pigle ts born alive and for the trait interval weaning until conception afte r first litter is recommended. Due to the low genetic relations, the e stimation procedure for both traits can be carried out independent of each ether, as well as independent of the breeding value estimation fo r fattening traits.