Control of reproduction with anti-progestin and oestrogens in captive bears.
The aim of this study was to establish new methods for controlling reproduction in bears. Anti-progestins were used to interrupt pregnancies. In two consecutive years, the anti-progestin J956 was administered to 11 female bears (nine Ursus arctos, one Ursus tibethanus, one Tremarctos ornatus) living in zoos. The anti-progestin J956 was given orally (n = 4) or parenterally (n = 12). The anti-progestin was administered alone or in combination with ethinyloestradiol, and before or after embryo implantation. The effects of anti-progestin treatment were determined using ultrasonographic examination of the urogenital tract and by monitoring progesterone concentrations in the blood and faeces. Oral administration of anti-progestin was not successful (successful in 0 of 4); however, in contrast, none of the parenteral treated animals remained pregnant (successful in 12 of 12). Parenteral treatment with J956, with or without ethinyloestradiol, was effective in disrupting pregnancy before implantation (successful in 6 of 6) and after implantation (successful in 6 of 6), but administration one month after implantation (n = 2) resulted in incomplete resorption of the fetuses. In conclusion, the administration of anti-progestins may be a useful method for preventing embryo implantation in captive bears.
Göritz
F
F
Institute for Zoo Biology and Wildlife Research, PF 601103, D-10252 Berlin, Germany.
Quest
M
M
Hildebrandt
T
T
Meyer
H H
HH
Kolter
L
L
Elger
W
W
Jewgenow
K
K
D000019:Abortifacient Agents / Q000008:administration & dosage*; D000028:Abortion, Induced / Q000662:veterinary*; D000034:Abortion, Veterinary; D000284:Administration, Oral; D000818:Animals; D000836:Animals, Zoo; D010064:Embryo Implantation / Q000187:drug effects; D010065:Embryo Implantation, Delayed / Q000187:drug effects; D004963:Estrenes; D004997:Ethinyl Estradiol / Q000008:administration & dosage; D005260:Female; D007263:Infusions, Parenteral; D010091:Oximes / Q000008:administration & dosage*; D010120:Oxytocics / Q000008:administration & dosage*; D011247:Pregnancy; D011374:Progesterone / Q000037:antagonists & inhibitors*; D016216:Ultrasonography, Prenatal / Q000662:veterinary; D001503:Ursidae
C446760:4-(17beta-methoxy-17alpha-(methoymethyl)-3-oxoestra-4,9-dien-11beta-yl)benzaldehyd-1-(E)-(O-(ethylamino)carbonyl)oxime; D000019:Abortifacient Agents; D004963:Estrenes; D010091:Oximes; D010120:Oxytocics; D004997:Ethinyl Estradiol; D011374:Progesterone