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Acta veterinaria Scandinavica2006; 48(1); 14; doi: 10.1186/1751-0147-48-14

Fertility of frozen-thawed stallion semen cannot be predicted by the currently used laboratory methods.

Abstract: The aim of the project was to use current simple and practical laboratory tests and compare results with the foaling rates of mares inseminated with commercially produced frozen semen. In Exp. 1, semen was tested from 27 and in Exp. 2 from 23 stallions; 19 stallions participated in both experiments. The mean number of mares per stallion in both experiments was 37 (min. 7, max. 121). Sperm morphology was assessed and bacterial culture performed once per stallion. In Exp. 1, progressive motility after 0, 1, 2, 3, and 4 h of incubation using light microscopy, motility characteristics measured with an automatic sperm analyzer, plasma membrane integrity using carboxyfluorescein diacetate/propidium iodide (CFDA/PI) staining and light microscopy, plasma membrane integrity using PI staining and a fluorometer, plasma membrane integrity using a resazurin reduction test, and sperm concentration were evaluated. In Exp. 2, the same tests as in Exp. 1 and a hypo-osmotic swelling test (HOST) using both light microscopy and a fluorometer were performed immediately after thawing and after a 3-h incubation. Statistical analysis was done separately to all stallions and to those having > or = 20 mares; in addition, stallions with foaling rates < 60 or > or = 60% were compared. In Exp. 1, progressive motility for all stallions after a 2-4-h incubation correlated with the foaling rate (correlation coefficients 0.39-0.51), (p < 0.05). In stallions with > 20 mares, the artificial insemination dose showed a correlation coefficient of -0.58 (p < 0.05). In Exp. 2, the HOST immediately after thawing showed a negative correlation with foaling rate (p < 0.05). No single test was consistently reliable for predicting the fertilizing capacity of semen, since the 2 experiments yielded conflicting results, although the same stallions sometimes participated in both. This shows the difficulty of frozen semen quality control in commercially produced stallion semen, and on the other hand, the difficulty of conducting fertility trials in horses.
Publication Date: 2006-08-17 PubMed ID: 16987393PubMed Central: PMC1564023DOI: 10.1186/1751-0147-48-14Google Scholar: Lookup
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  • Comparative Study
  • Journal Article

Summary

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This study examined the predictability of horse fertility using laboratory tests on frozen and thawed stallion semen, and found that current testing methods are inconsistent and unreliable in predicting the semen’s fertility rate.

Research Objectives

This study aimed to examine the accuracy of current laboratory methods used to predict the fertility of frozen-thawed stallion semen through comparative analysis with the actual foaling rates of mares inseminated with commercially produced frozen semen.

  • The small-scale project involved two experiments in which semen from different stallions were tested.
  • The methodology included the assessment of sperm morphology and the bacterial culture from each stallion.
  • In both experiments, a variety of tests were conducted including progressive motility, measured at different intervals using light microscopy and an automatic sperm analyzer, plasma membrane integrity (determining sperm viability), and sperm concentration.
  • In the second experiment, they introduced additional testing known as Hypo-Osmotic Swelling Test (HOST) to measure the structural integrity and functionality of the sperm membrane.
  • They statistically analyzed data for all stallions and for those having over or equal to 20 mares. They also compared the stallions with foaling rates less than 60% or equal to or more than 60%.

Findings

The tests and experiments returned varied and inconsistent results, showing that no single currently used laboratory test method can reliably predict the fertility potential of frozen-thawed stallion semen.

  • In Experiment 1, the progressive motility across a period of 2 to 4 hours showed some correlation with the foaling rate.
  • In stallions with more than 20 mares, there was a negative correlation between the artificial insemination dose and fertility rate.
  • In Experiment 2, the HOST immediately after thawing displayed a negative correlation with the foaling rate.
  • However, the inconsistency between the results of the two experiments proves the unreliability of current laboratory methods in predicting the fertility of frozen-thawed stallion semen.

Implications

  • The study unveils the complexities surrounding the quality control of commercially produced frozen stallion semen and the difficulties in conducting fertility trials in horses.
  • It emphasizes the need for more reliable testing methodologies or controlled breeding trials to accurately estimate the fertilizing capability of frozen-thawed stallion semen.

Cite This Article

APA
Kuisma P, Andersson M, Koskinen E, Katila T. (2006). Fertility of frozen-thawed stallion semen cannot be predicted by the currently used laboratory methods. Acta Vet Scand, 48(1), 14. https://doi.org/10.1186/1751-0147-48-14

Publication

ISSN: 1751-0147
NlmUniqueID: 0370400
Country: England
Language: English
Volume: 48
Issue: 1
Pages: 14

Researcher Affiliations

Kuisma, P
  • Department of Clinical Veterinary Sciences, University of Helsinki, 04920 Saarentaus, Finland. paivi.kuisma@iki.fi
Andersson, M
    Koskinen, E
      Katila, T

        MeSH Terms

        • Animals
        • Cell Membrane / physiology
        • Clinical Laboratory Techniques / standards
        • Clinical Laboratory Techniques / veterinary
        • Female
        • Fertility / physiology
        • Horses / physiology
        • Male
        • Pregnancy
        • Pregnancy Rate
        • Semen / microbiology
        • Semen / physiology
        • Semen Preservation / veterinary
        • Sperm Motility

        References

        This article includes 38 references

        Citations

        This article has been cited 9 times.
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          doi: 10.3390/vetsci12121109pubmed: 41472089google scholar: lookup
        2. Al-Kass Z, Morrell JM, Ntallaris T. Effect of Centrifugation of Stallion Semen Through a Low Density Colloid Prior to Freezing on Sperm Cryosurvival. Animals (Basel) 2025 Jun 25;15(13).
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