Inverkan av den genetiska defekten Complex Vertebral Malformation på fruktsamheten hos SLB

Abstract: Complex Vertebral Malformation (CVM) is an autosomal recessive inherited defect in the Holstein breed. The defect has lead to structurally malformed calves and losses of pregnancies. To determine the effect of CVM on fertility in the Swedish Holstein Breed 375 Holstein bulls used in breeding by Svensk Avel and Skånesemin were assigned to this study. 228 bulls matched the criteria of birth year, 1995-1999, > 75 inseminations and a known CVM-status. Of the total 228 bulls 53 of them were CVM-carriers and 175 were non-carriers. The SAS-programme was used to determine the effects of CVM-status, the bull's father and birth year on Non-return rates (NRR) for 28, 56 and 168 days. Effect of CVM-status on daughter fertility was also investigated. A statistically significant difference was shown for 168 days NRR (p = 0.039) where the difference between CVM-carriers and non-carriers were 101.1 +/- 0.9 vs. 103.1 +/- 0.6. There was no significant difference at 28 days NRR, and an almost significant difference at 56 days NRR. Least-squares means for 28 days NRR were 100.2 +/- 0.4 vs 100.7 +/- 0.3 and the means for 56 days NRR were 100.5 +/- 0.6 vs 101.8 +/- 0.4 for CVM-carriers and non-carriers respectively. The effect of father was highly significant for NRR. The effect of birth year had no significant effect on NRR. The effect of CVM-status on daughter fertility was not significant.