[Influence of undernutrition in the lactating cow on ovulation induction by serum gonadotropins (PMSG) during the post-partum period].
Two experiments were carried out to assess the influence of undernutrition on postpartum ovulation in nursing Charolais cows after PMSG injection. In each experiment, the nursing cows were divided into 2 groups: one fed at a low nutritional level and the other at a normal nutritional level. In the first experiment, 19 animals were injected on post-partum days 15 and 30 with 600 IU of PMSG; in the second experiment, 34 received the same injection on post-partum day 54 after 9 days of priming with a Norgestomet implant. On post-partum day 15, only one cow in each group ovulated. At post-partum day 30, 1 out of 8 cows at the low nutritional plane ovulated vs 5 out of 9 at the normal nutritional plane (P less than 0.05). Likewise, on post-partum day 54, 5 out of 14 cows at the low nutritional plane ovulated vs 17 out of 17 at the normal nutritional level (P less than 0.05). Therefore, there is a time during the post-partum period when the nursing cow ovary does not respond to PMSG by ovulation. The length of this time is increased by undernutrition.
D000818:Animals; D002417:Cattle; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D007774:Lactation; D010053:Ovary / Q000187:drug effects; D010062:Ovulation Induction / Q000662:veterinary*; D049590:Postpartum Period; D011247:Pregnancy; D011502:Protein-Energy Malnutrition / Q000503:physiopathology*; D013997:Time Factors
D006064:Gonadotropins, Equine
Influence d'une sous-alimentation de la vache allaitante sur l'induction de l'ovulation par l'hormone gonadotrope sérique (PMSG) au cours du post-partum.