Effects on the oestrous cycle of dairy cows of the administration of colostrum in the mid-luteal phase.
A group of 13 cows were dosed orally nine or 10 days after a normal oestrous cycle; six animals received colostrum, five animals received milk containing varying amounts of oestrone sulphate, and two cows were given milk containing a low level of oestrone sulphate. Measurements of milk progesterone levels after dosing showed that colostrum had an apparent luteolytic effect, milk containing oestrone sulphate at a level of 2000 pg/ml had a less marked effect on milk progesterone and those animals receiving milk showed no reduction in milk progesterone. These results show that there is a physiological basis for the practice of inducing overt oestrus in cows showing no visible oestrus, by dosing them with colostrum.
D000818:Animals; D002417:Cattle / Q000502:physiology*; D003126:Colostrum / Q000032:analysis; D003338:Corpus Luteum / Q000187:drug effects; D003612:Dairying; D004970:Estrone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D004971:Estrus / Q000187:drug effects*; D005260:Female; D008892:Milk / Q000032:analysis; D011247:Pregnancy; D011374:Progesterone / Q000032:analysis
D004970:Estrone; D011374:Progesterone; C017296:estrone sulfate