M. Fisher, G. Asher, L. Meikle
Mar 1, 1994
Citations
1
Influential Citations
13
Citations
Quality indicators
Journal
Animal Reproduction Science
Abstract
Abstract The luteolytic effectiveness of the prostaglandin F 2α analogue, cloprostenol, was investigated by monitoring plasma progesterone concentrations. In Experiment 1, pubertal ( n =20) and adult ( n =20) hinds had their oestrus synchronised by intravaginal delivery of exogenous progesterone for 14 days. Fourteen days after progesterone withdrawal 0, 100, 250 or 500 μg of cloprostenol was administered intramuscularly and blood samples were collected by jugular venepuncture. All cloprostenol treatments were equally effective in lowering progesterone concentrations in both age groups. Twelve hours after administration, progesterone concentrations averaged 41% of pretreatment values for the three treated groups and at 24 h were 26% of pretreatment values. However, in some hinds (eight pubertal and four adult) luteal regression was incomplete and progesterone concentrations increased within 24–48 h of the onset of treatment. In Experiment 2, adult hinds ( n =28) were treated to induce synchronised oestrus with either mono-ovulation or superovulation induced with combinations of pregnant mare's serum gonadotrophin (PMSG), follicle stimulating hormone (FSH) and gonadotrophin releasing hormone (GnRH). Hinds were then allocated to receive 750 μg of cloprostenol intramuscularly at either 11 or 15 days after progesterone withdrawal (9–10 or 13–14 days after oestrus). Plasma progesterone concentrations in hinds with single and multiple corpora lutea, were reduced within 6 h of cloprostenol administration, and continued to decline thereafter. Cloprostenol induced complete luteolysis in all 13 hinds treated on Day 15 but in only six out of the 12 hinds treated on Day 11. The six hinds (four mono-ovulation, two superovulation) in which luteolysis appeared incomplete were characterised by short-lived reductions in progesterone concentrations. These results indicate that cloprostenol is luteolytic in both young and adult red deer hinds and in hinds with multiple corpora lutea. However, its effectiveness may be incomplete in some animals.