Effects of Complex Vertebral Malformation on Fertility in Swedish Holstein Cattle |
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Authors: | Britt Berglund Anna Persson Hans Stålhammar |
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Institution: | (1) Department of Animal Breeding and Genetics, Centre for Reproductive Biology in Uppsala, Swedish University of Agricultural Sciences, Uppsala;(2) Svensk Avel, Skara, Sweden; |
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Abstract: | Complex vertebral malformation (CVM) is an autosomal recessive inherited defect in the Holstein breed. It causes intra-uterine
mortality through the entire gestation period leading to repeat breeding and involuntary culling of cows and thereby economic
losses. The defect was first reported in Denmark in 1999 and a direct DNA test for the defect has been available since February
2001. The aim of this study was to investigate if Holstein bulls heterozygous for the CVM gene had reduced reproductive performance,
measured as non-return rate (NRR) and in a daughter fertility index. All genotyped Swedish Holstein bulls born between 1995
and 1999 were included. Altogether 228 bulls were analysed, of which 53 bulls, i.e. 23%, were confirmed CVM carriers. A statistically
significant difference between carriers and non-carriers in the relative breeding value for NRR was observed for 168 days
NRR (101.1 ± 0.9 vs. 103.1 ± 0.6, p < 0.05). There was no difference for 28 days NRR whereas the difference approached significance
for 56 days NRR. No significant effect of the paternal CVM genotype on the daughter fertility index was shown probably due
to the complexity of traits this index is composed of. In conclusion, the study showed that carriers of the CVM defect have
an inferior NRR compared with non-carriers. |
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