title: Effect of storage time on the fertility of bull semen frozen in straws.
abstract: Fertility rates were analysed of more than 190000 first inseminations with frozen semen stored for up to six years in liquid nitrogen. Semen was used of 158 different bulls and frozen in 0.25 ml French straws. Fertility rates ranged from 69.1 to 75.9% non-return after 56 days. An influence of the storage time on the fertility could not be demonstrated.
mesh_terms: D000818:Animals; D002417:Cattle; D002470:Cell Survival; D005260:Female; D005298:Fertility; D005615:Freezing; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D011247:Pregnancy; D011309:Preservation, Biological; D013094:Spermatozoa / Q000032:analysis*; D013997:Time Factors