Sperm morphology in Estonian Holstein dairy bulls having CVM-defect carriers in their pedigree
2001
Padrik, P. | Jaama, Ue. (Estonian Agricultural Univ., Tartu (Estonia). Faculty of Veterinary Medicine)
Breeding success depends on usage efficiency of bulls with high breeding value. One of the most important bull semen quality characteristics that correlates well with NRR of the cows is sperm morphology. The morphological quality of bull semen is affected by several factors: season of semen collection, age of bulls, grade of Holstein genes, inbreeding effects etc. As the pedigrees of the bulls most intensively used for Holstein breeding have become more and more homogenous, the heritable gene defects can accumulate and cause drawbacks in breeding. The results of the study showed that the bulls with the CVM-carries in their pedigree during last four generations had more abnormal spermatozoa in fresh semen that control bulls (P0,0001). The incidence of abnormal sperms was highest in the semen of those bulls who had CVM-carriers both in dam and sire line during four generations (P0,0001). Decrease in the morphological quality of semen was expressed most significantly if the CVM-carrier was in a first generation of the sire line (P0,0001). Based on the results of the current research we can conclude that the morphological quality of semen collected from bulls having CVM-carriers in a pedigree is decreased if compared to the control bulls. We cannot conclude that this is directly influenced by the CVM-gene as the bulls in our study were not analysed for the presence of it. Further studies are necessary to clarify this phenomenon
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