Comparison of pregnancy outcome in mares among methods used to evaluate and select spermatozoa for insemination.
Abstract: An artificial insemination dose for mares consisting of 500 million progressively motile spermatozoa is considered "standard" by most clinicians. However, little information is available directly comparing pregnancy outcome among methods of evaluating and selecting spermatozoa for insemination. The objective of this study was to determine if the method of spermatozoal evaluation and selection influences fertility as measured by pregnancy outcome. Mares were inseminated with 100 or 500 million spermatozoa that were selected for progressive motility, normal morphology, hypoosmotic swelling or absolute number regardless for evaluation method or quality. Thirty-two breeding cycles were tested for each treatment group and at each spermatozoal dose. Pregnancy outcomes were 44 and 41%, 55 and 41%, 39 and 31%, and 45 and 41%, for the 100 and 500 million progressively motile, morphologically normal, hypoosmotic swelling positive and absolute number treatment groups, respectively. Pregnancy outcome did not differ among methods of spermatozoal evaluation and selection for artificial insemination in the 100 (P=0.52) or 500 (P=0.78) million spermatozoa groups. Also the total number of spermatozoa and the absolute number of progressively motile, morphologically normal or hypoosmotic swelling positive spermatozoa inseminated, were not closely associated with pregnancy outcome in the 100 (P=0.24, 0.29, 0.33 and 0.38, respectively) or 500 (P=0.20, 0.84, 0.50 and 0.74, respectively) million spermatozoa groups. In this study, we found that the method of spermatozoal evaluation did not offer an advantage for pregnancy when used to select spermatozoa for insemination at the doses tested. These results were surprising, as we expected there would be differences among the evaluation methods. Instead, we found that evaluating spermatozoa offered no advantage for pregnancy over simply inseminating with a specified number of spermatozoa not selected for any particular characteristic under the conditions of our experiment.
Publication Date: 2002-01-29 PubMed ID: 11812631DOI: 10.1016/s0378-4320(01)00180-4Google Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research study investigates whether the method of selecting and evaluating sperm for horse artificial insemination impacts the outcome of pregnancy. The key finding is that no particular method of sperm evaluation provided a distinct advantage for pregnancy, challenging the currently prevailing clinical standards.
Research Objectives and Methodology
- The research aimed at comparing pregnancy outcomes in mares among different methods used to evaluate and select sperm for artificial insemination. The study looked at whether the selection produced higher fertility rates.
- Spermatozoa were selected and evaluated based on progressive motility, normal morphology, hypoosmotic swelling, or total number without stressing the evaluation method or quality. The selected spermatozoa were used in two different doses – 100 million and 500 million.
- For each method of sperm evaluation and each sperm dose, 32 breeding cycles were examined, resulting in a comprehensive sample size.
Research Findings
- The different methods of sperm evaluation did not result in significantly different pregnancy rates. Regardless of the spermatozoa selection process used, the pregnancy outcomes ranged from 31% to 55% for the two separate doses under observation.
- The study found that the total number of spermatozoa, the absolute number of progressively motile, morphologically normal, or hypoosmotic swelling positive spermatozoa, were not significantly associated with pregnancy outcome.
- This finding held consistency regardless of whether 100 million or 500 million spermatozoa were utilized.
Conclusion and Implication
- The results of this research suggest that no particular method of spermatozoa evaluation provides a distinct advantage for successful pregnancy in horse artificial insemination.
- This result is surprising because the researchers expected to find differences in pregnancy outcomes based on the evaluation methods used. However, the data showed that merely inseminating with a specific number of spermatozoa, without selection for any particular attribute, did not compromise the pregnancy outcome.
- In conclusion, the study challenges the prevalent clinical assumption claiming a strong correlation between specific spermatozoa characteristics and successful pregnancies. The results here propose that there may be no advantage in intricate spermatozoa evaluations over simply selecting a specific quantity for insemination.
Cite This Article
APA
Nie GJ, Wenzel JG, Johnson KE.
(2002).
Comparison of pregnancy outcome in mares among methods used to evaluate and select spermatozoa for insemination.
Anim Reprod Sci, 69(3-4), 211-222.
https://doi.org/10.1016/s0378-4320(01)00180-4 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, 146 McAdory Hall, AL 36849-5522, USA. gnie@roodanddriddle.com
MeSH Terms
- Animals
- Female
- Horses / physiology
- Insemination, Artificial / methods
- Insemination, Artificial / veterinary
- Male
- Pregnancy
- Pregnancy Outcome
- Pregnancy Rate
- Semen / cytology
- Sperm Count
- Sperm Motility
- Spermatozoa / physiology
Citations
This article has been cited 2 times.- Strassner FM, Demattio L, Siuda M, Malama E, Muffels G, Bollwein H. Relationships Between Metabolism of Cryopreserved Equine Sperm Determined by the Seahorse Analyzer and Sperm Characteristics Measured by Flow Cytometry and Computer-Assisted Analysis of Motility. Vet Sci 2025 Nov 21;12(12).
- Kuisma P, Andersson M, Koskinen E, Katila T. Fertility of frozen-thawed stallion semen cannot be predicted by the currently used laboratory methods. Acta Vet Scand 2006 Aug 17;48(1):14.
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