Diagnosis and correction of twin pregnancy in the mare.
Abstract: Reproductive Physiology 1. Twin pregnancies result in high rates of abortion, stillbirth, and neonatal mortality. 2. Twins develop subsequent to multiple ovulations. Multiple ovulations are related to breed, parity, and mare history. Multiple ovulations are most frequently seen in Thoroughbred and Draft mares. Multiple ovulations are more common in barren and perhaps maiden mares than in lactating mares, and they are more common in certain individual mares. 3. Equine embryos are motile in the uterus from the time of first detection (Days 9 to 10) until fixation (Day 16). They are frequently located in the uterine body on Days 9 and 10. 4. Twin embryos have a pattern of motility and fixation similar to that of single embryos, and fixation is more frequently unilateral than bilateral (70 per cent versus 30 per cent, respectively). 5. Mares have an efficient natural embryo-reduction mechanism to eliminate excess (greater than 1) embryos resulting from multiple ovulations. Natural embryo reduction is more successful in unilateral than bilateral twin pregnancies (89 per cent versus 11 per cent successful reduction, respectively). 6. After the establishment of endometrial cups (Days 35 to 40), mares that are aborted will frequently not cycle for several months. Management of Twin Pregnancy 1. Breed all mares regardless of the number of preovulatory follicles. Withholding mares with preovulatory follicles from breeding does not decrease the incidence of twin pregnancy, but it decreases the overall pregnancy rate and results in a loss of breeding time. 2. Check all mares for twins, regardless of the number of detected ovulations.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1988-08-01 PubMed ID: 3044536DOI: 10.1016/s0749-0739(17)30637-5Google Scholar: Lookup
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Summary
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This study provides an in-depth understanding of twin pregnancies among mares, detailing the complications associated with such pregnancies including high rates of abortion, stillbirth, and neonatal mortality. Furthermore, it discusses effective management strategies to deal with twin pregnancies in horses, emphasizing the need for check-ups despite the number of detected ovulations.
Understanding Twin Pregnancy in Mares
- According to the research, twin pregnancies in mares often result in complications like abortion, stillbirth, and neonatal mortality.
- These twin pregnancies occur after multiple ovulations, with the propensity for such ovulations varying according to breed, parity, and the mare’s ovulation history.
- Mares which belong to the Thoroughbred and Draft breeds are more likely to exhibit multiple ovulations. The study further reveals that barren and maiden mares are more prone to multiple ovulations as compared to lactating mares. However, this propensity is more pronounced in some mares than in others.
- The study also highlighted the motility of equine embryos within the uterus from the first detection (Days 9-10) till fixation (Day 16). On the 9th and 10th days, these embryos are usually located within the uterine body.
Twin Embryos and Natural Embryo-Reduction Mechanism
- Like single embryos, twin embryos also exhibit a pattern of motility and fixation. However, the rate of unilateral fixation is higher than bilateral (70% vs 30%)
- Mares possess a natural embryo-reduction mechanism that successfully eliminates any extra embryos resulting from multiple ovulations. This mechanism is more effective in reducing embryos from unilateral twin pregnancies than from bilateral ones. (89% vs 11%)
- After endometrial cups are established (Days 35 to 40), mares that have aborted often do not cycle for several months.
Effective Management of Twin Pregnancy
- Irrespective of the number of preovulatory follicles, the research recommends breeding all mares.
- Refraining from breeding mares having preovulatory follicles does not reduce twin pregnancy incidence. Rather, it lowers the overall pregnancy rate and leads to loss of breeding time.
- It is essential to check all mares for twins, regardless of the number of detected ovulations.
Cite This Article
APA
Miller A, Woods GL.
(1988).
Diagnosis and correction of twin pregnancy in the mare.
Vet Clin North Am Equine Pract, 4(2), 215-220.
https://doi.org/10.1016/s0749-0739(17)30637-5 Publication
Researcher Affiliations
- Washington State University College of Veterinary Medicine, Pullman.
MeSH Terms
- Abortion, Veterinary
- Animals
- Female
- Fetal Death / veterinary
- Horse Diseases
- Horses
- Pregnancy
- Pregnancy Complications / veterinary
- Twins
Citations
This article has been cited 1 times.- Alamaary M, Ali A. Abortion and uterine prolapse in a Thoroughbred mare with twin pregnancy: Clinical and laboratory findings and treatment approach. J Equine Sci 2020;31(4):95-99.
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