Observations on the oestrous cycle of the Friesian heifer.
D000818:Animals; D002417:Cattle / Q000502:physiology*; D004724:Endoscopy; D004971:Estrus; D005260:Female; D010060:Ovulation; D010173:Palpation; D011247:Pregnancy; D012007:Rectum; D012621:Seasons; D013997:Time Factors