title: The regularity of cycles and ovarian efficiency in a group of Friesland cows.
abstract: Delayed ovulation was recorded in 17,34% and anovulation in 17,66% of 623 oestrus periods in 32 Friesland cows. Cycle length was abnormal in 19,19% of 568 cycles and was associated with an increase in the incidence of defective ovulation. Inseminations failed in 24,6% of cases despite normal ovulatory function at oestrus while in nine out of 134 inseminations sperm retained its fertilizing capacity in the female tract between 24 and 72 hours.
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D003338:Corpus Luteum / Q000502:physiology; D004971:Estrus; D005260:Female; D005306:Fertilization; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D010053:Ovary / Q000502:physiology*; D010060:Ovulation; D011247:Pregnancy