Effects of bromocriptine and perphenazine on prolactin and progesterone concentrations in pregnant pony mares during late gestation.
Pregnant pony mares in Group A (n = 4) received i.m. injections at 07:00 and 17:00 h of 0.8 mg bromocriptine/kg body weight 0.75 per day beginning on Day 295 of gestation and continuing until parturition. Group B (n = 4) was treated similarly, but perphenazine was administered orally at 0.375 mg/kg body weight twice a day beginning on Day 305 of gestation and continuing until parturition. Mares in Group C (n = 3) received i.m. injections of saline. Mean plasma prolactin and progesterone concentrations were greater (P less than 0.05) for mares in Group C than in Groups A and B from 295 to 309 days of gestation. From 305 days of gestation, plasma prolactin and progesterone concentrations were greater (P less than 0.05) in Group B and C than in Group A mares. Progesterone and prolactin concentrations increased over this period for Group B and Group C mares, but remained constant in Group A mares. From 10 days pre partum through foaling, mares in Group A had lower progesterone (P less than 0.05) and prolactin (P less than 0.01) concentrations than Group B and C mares. All mares in Group A were agalactic at foaling, while all mares in Groups B and C had normal milk secretion. Gestation was longer (P less than 0.05) in Group A than in Group C mares. In Group A, 2 mares retained the placenta for greater than 3 h, 3 mares had dystocia and all 4 mares had thickened, haemorrhagic placentae.(ABSTRACT TRUNCATED AT 250 WORDS)
Ireland
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Department of Animal Sciences, University of Missouri, Columbia 65211.
Loch
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Worthy
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Anthony
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D000818:Animals; D001971:Bromocriptine / Q000633:toxicity*; D004420:Dystocia / Q000139:chemically induced; D005260:Female; D006736:Horses / Q000097:blood*; D007774:Lactation; D010546:Perphenazine / Q000494:pharmacology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood*; D011374:Progesterone / Q000097:blood*; D011388:Prolactin / Q000097:blood*; D013997:Time Factors
D001971:Bromocriptine; D011374:Progesterone; D011388:Prolactin; D010546:Perphenazine