Effect of periovulatory prostaglandin F2α on pregnancy rates and luteal function in the mare

M. H.T. Troedsson, M. M. Ababneh, A. F. Ohlgren, S. Madill, N. Vetscher, M. Gregas

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

The objective of this study was to determine whether periovulatory treatments with PGF2α affects the development of the CL, and whether the treatment was detrimental to the establishment of pregnancy. Reproductively sound mares were assigned randomly to one of the following treatment groups during consecutive estrus cycles: 1. 3,000 IU hCG within 24 hours before artificial insemination and 500 μg cloprostenol (PGF2α analogue) on Days 0, 1, and 2 after ovulation (n=8); 2. 2 mL sterile water injection within 24 hours before artificial insemination and 500 μg cloprostenol on Days 0, 1, and 2 after ovulation (n=8); 3. 3,000 IU hCG within 24 hours before artificial insemination and 500 μg cloprostenol on Day 2 after ovulation (n=8); or 4. 3,000 IU hCG within 24 hours before artificial insemination and 2 mL of sterile water on Days 0, 1, and 2 after ovulation (controls; n=8). Blood samples were collected from the jugular vein on Days 0, 1, 2, 5, 8, 11, and 14 after ovulation. Plasma progesterone concentrations were determined by the use of a solid phase 125I radioimmunoassay. All mares were examined for pregnancy by the use of transrectal ultrasonography at 14 days after ovulation. Mares in Group 1 and 2 had lower plasma progesterone concentrations at Day 2 and 5, compared to mares in the control group (P < 0.001). No difference was detected between group I and 2. Plasma progesterone concentrations in group 3 were similar to the control group until the day of treatment, but decreased after treatment and were significantly lower than the control group at Day 5 (P < 0.001). Plasma progesterone concentrations increased in all treatment groups after Day 5, and were comparable among all groups at Day 14 after ovulation. Cloprostenol treatment had a significant effect on pregnancy rates (P < 0.01). The pregnancy rate was 12.5% in Group 1, 25% in Group 2, 38% in Group 3, and 62.5% in Group 4. It was concluded that periovulatory treatment with PGF2α has a detrimental effect on early luteal function and pregnancy.

Original languageEnglish (US)
Pages (from-to)1891-1899
Number of pages9
JournalTheriogenology
Volume55
Issue number9
DOIs
StatePublished - Jun 1 2001

Keywords

  • Corpus luteum
  • Equine
  • Fertility
  • Prostaglandin Fα

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