Ultrasonographic studies on the reproductive tract of mares after parturition: effect of involution and uterine fluid on pregnancy rates in mares with normal and delayed first postpartum ovulatory cycles.
Abstract: During breeding of mares, ultrasonographic detection of uterine fluid accumulations in the first postpartum ovulatory period was associated with significantly decreased pregnancy rates, when compared with rates in control mares (P less than 0.005). The previously gravid uterine horn was recognized as the larger horn, when assessed for size by ultrasonography, for a mean of 21 days (range, 15 to 25 days) after parturition. On the basis of similar measurements obtained during 3 ultrasonographic scans (5-day period), uterine involution was determined to be completed in a mean of 23 days (range, 13 to 29 days). Progestin treatment did not affect uterine size, fluid accumulation, or rate of involution after parturition. However, delaying the first postpartum ovulation with 8 days of progestin treatment significantly improved pregnancy rates (P less than 0.05). More (P less than 0.05) mares became pregnant (23 of 28, 82%) when ovulation occurred after day 15 in the first postpartum ovulatory period, compared with those mares that ovulated before day 15 (6 of 12, 50%). We concluded that ultrasonographic detection of uterine fluid and postpartum progestin treatment can be used to manipulate breeding strategies and to improve pregnancy rates in mares bred during the first postpartum ovulatory period.
Publication Date: 1988-02-01 PubMed ID: 3281921
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research article investigates the effect of uterine involution and fluid on pregnancy rates in mares following parturition. The findings suggest that the accumulation of uterine fluid during the first ovulatory period after birth can result in decreased pregnancy rates, and that delaying this first postpartum ovulation using progestin treatment may significantly improve these rates.
Background and Objectives
- The study aimed to investigate the effects of uterine involution and fluid on the rates of pregnancy in mares following parturition.
- The researchers sought to establish whether the detection of uterine fluid using ultrasonography during the first ovulatory period after birth could be a determinant of pregnancy rates.
- Furthermore, it explored the efficacy of progestin treatment in improving the odds of pregnancy by delaying the first postpartum ovulation.
Methodology
- The research employed ultrasonographic studies to examine the reproductive tract of mares after parturition and to detect accumulations of uterine fluid.
- Control mares with low uterine fluid and mares with high amounts were compared in terms of pregnancy rates.
- The research utilized progestin treatment for a period of 8 days, and then compared the pregnancy rates of mares whose first postpartum ovulation was delayed, and those whose ovulation was not.
Findings
- The presence of uterine fluid during the first ovulatory period after parturition was found to be associated with significantly decreased pregnancy rates compared to control mares.
- The previously gravid uterine horn was recognized as the larger one with a mean of 21 days after parturition.
- Uterine involution was determined to be completed in a mean of 23 days.
- Progestin treatment did not affect uterine size, fluid accumulation, or rate of involution, but it did have a significant effect on delaying the first postpartum ovulation, which was found to improve pregnancy rates.
- More mares became pregnant when ovulation occurred after day 15 in the first postpartum ovulatory period.
Conclusion
- Based on the research findings, the authors concluded that ultrasonographic detection of uterine fluid and postpartum progestin treatment could be used to manipulate breeding strategies.
- The results suggest that these could be effective strategies for improving pregnancy rates in mares bred during the first postpartum ovulatory period.
Cite This Article
APA
McKinnon AO, Squires EL, Harrison LA, Blach EL, Shideler RK.
(1988).
Ultrasonographic studies on the reproductive tract of mares after parturition: effect of involution and uterine fluid on pregnancy rates in mares with normal and delayed first postpartum ovulatory cycles.
J Am Vet Med Assoc, 192(3), 350-353.
Publication
Researcher Affiliations
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523.
MeSH Terms
- Animals
- Estrus / drug effects
- Estrus / physiology
- Female
- Fertilization
- Horses / physiology
- Postpartum Period / physiology
- Pregnancy
- Pregnancy, Animal / physiology
- Progesterone Congeners / pharmacology
- Trenbolone Acetate / analogs & derivatives
- Trenbolone Acetate / pharmacology
- Ultrasonography / veterinary
- Uterine Contraction
- Uterus / anatomy & histology
Citations
This article has been cited 4 times.- D'Agostino A, Di Palma T, Cecchini Gualandi S, Boni R. Fluorescence Spectroscopy for the Diagnosis of Endometritis in the Mare.. Animals (Basel) 2022 Apr 29;12(9).
- Falomo ME, Del Re B, Rossi M, Giaretta E, Da Dalt L, Gabai G. Relationship between postpartum uterine involution and biomarkers of inflammation and oxidative stress in clinically healthy mares (Equus caballus).. Heliyon 2020 Apr;6(4):e03691.
- Reilas T, Katila T, Mäkelä O, Huhtinen M, Koskinen E. Intrauterine fluid accumulation in oestrous mares.. Acta Vet Scand 1997;38(1):69-78.
- Huhtinen M, Reilas T, Katila T. Recovery rate and quality of embryos from mares inseminated at the first post-partum oestrus.. Acta Vet Scand 1996;37(3):343-50.
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