Changes in maternal hormone concentrations associated with induction of fetal death at day 45 of gestation in mares.
Pregnant Standardbred mares were allocated to 2 groups. On Day 45 of gestation, 20-45 ml saline (240 g NaCl/l) were injected into the fetal sacs of 10 mares, and the other 10 mares were given sham treatment. Post-operative plasma oestrone sulphate concentrations were lower (P less than 0.01) on Days 48-55 in saline-treated mares than in sham-treated mares. Mean plasma progesterone profiles were similar in the two groups of mares, although post-operative luteolysis occurred in 4 saline-treated mares. There was no difference in plasma CG profiles between the 2 groups, except that CG concentrations in saline-treated mares were generally lower than those of sham-treated mares. There was generally a post-operative loss of uterine and cervical tone in saline-treated mares. These results show that the maintenance of maternal plasma oestrone sulphate concentrations requires the presence of a viable embryo and confirm that luteolysis can occur despite high plasma CG concentrations after fetal death.
Jeffcott
L B
LB
Department of Veterinary Clinical Sciences, University of Melbourne, Werribee, Victoria, Australia.
Hyland
J H
JH
MacLean
A A
AA
Dyke
T
T
Robertson-Smith
G
G
D000818:Animals; D004966:Estrogens, Conjugated (USP) / Q000097:blood; D004970:Estrone / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D005313:Fetal Death / Q000662:veterinary*; D006064:Gonadotropins, Equine / Q000097:blood*; D006734:Horse Diseases / Q000097:blood*; D006736:Horses; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*; D013997:Time Factors
D004966:Estrogens, Conjugated (USP); D006064:Gonadotropins, Equine; D004970:Estrone; D011374:Progesterone; C017296:estrone sulfate