Estimation of genetic parameters for non‐return rate (NRR) in German herdbook Pietrain and Landrace AI boars |
| |
| Authors: | R Steinheuer H Hamann O Distl |
| |
| Institution: | Institute of Animal Breeding and Genetics, School of Veterinary Medicine Hannover, Germany |
| |
| Abstract: | Between January 1993 and May 2000, 95 136 artificial insemination (AI) records of 445 Bavarian boars were recorded by three Bavarian AI stations. The analysis of the non‐return rate (NRR) was based on AI matings performed by AI technicians. The animal models applied for estimation of variance components for NRR included the fixed effects of AI station, breed of boar, first and subsequent insemination, type of insemination, duration of breeding period of the sow, and AI technician. Herd–year–season and permanent environment of the sow as well as the paternal additive genetic effects were taken into account as random effects. The estimation procedures employed for the described model were both linear and non‐linear. Genetic variances for the NRR (33‐55‐77 days after insemination) were small. Estimates of paternal heritability for NRR were low with  (NRR33),  (NRR55) as well as  (NRR77) using the non‐linear model, and  (NRR33),  (NRR55) as well as  (NRR77) employing the linear model. Due to the low heritabilities genetic progress on mating success for AI boars may be only possible, if sufficiently large numbers of observations are available. |
| |
| Keywords: | |
|
|
