Influence of exogenous adrenocorticotropic hormone on estrous behavior in cattle.
A two-trial experiment was conducted to determine the influence of ACTH on estrous behavior in cattle. In Trial 1, Holstein heifers (n = 20) received an injection of prostaglandin F2 alpha (PGF) during a synchronized diestrus and 30 h later were allotted randomly to receive (i.m.) either 1) 4 mL of gelatin (Veh) or 2) 320 units of ACTH in 4 mL of gelatin (ACTH). Eleven days after the PGF injection, all heifers were again injected with PGF, and they received either Veh or ACTH to complete a cross-over design. Treatment with ACTH decreased (P less than .05) the duration of estrus (12.0 +/- 1.9 vs 18.0 +/- 1.6 h for Veh) and increased (P less than .001) the interval to estrus after PGF injection (62.9 +/- 2.6 vs 43.7 +/- 2.2 h for Veh). Peak serum concentrations of progesterone (P4) and cortisol (C) were elevated (P less than .001) after ACTH compared with Veh. In Trial 2, ovariectomized Holstein cows (n = 12) were injected (i.m.) with .5 mg of estradiol benzoate (EB) and, 10 h later, were allotted randomly to receive (i.m.) either 1) 4 mL of gelatin (Veh) or 2) 320 units of ACTH in 4 mL of gelatin (ACTH). Seven days after the initial EB injection, all cows were again injected with .5 mg of EB and, 10 h later, received either Veh or ACTH to complete a cross-over design. Treatment with ACTH decreased (P less than .01) the proportion of cows in estrus (2/12 vs 11/12 for Veh) and increased (P less than .01) peak serum concentrations of P4 and C.(ABSTRACT TRUNCATED AT 250 WORDS)
Hein
K G
KG
Department of Animal Science, Purdue University, West Lafayette, IN 47907.
Allrich
R D
RD
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D002417:Cattle / Q000502:physiology*; D003008:Cloprostenol / Q000494:pharmacology; D004958:Estradiol / Q000097:blood / Q000494:pharmacology; D004971:Estrus / Q000187:drug effects*; D005260:Female; D005780:Gelatin / Q000494:pharmacology; D011897:Random Allocation
D003008:Cloprostenol; D004958:Estradiol; D005780:Gelatin; D000324:Adrenocorticotropic Hormone