Possible negative effects of inbreeding on semen quality in Shetland pony stallions.
Abstract: Inbreeding is widely believed to negatively affect reproductive performance. Indeed, in some species, high levels of inbreeding are thought to be the major cause of poor semen quality. It is, however, not clear whether inbreeding affects fertility in horses. In this study, the relationship between inbreeding and semen quality was examined in 285 immature Shetland pony stallions submitted for breeding soundness examination in March-April of the years 1992-1997. The majority of stallions examined were 3 years old (85%) and their coefficients of inbreeding ranged from 0 to 25% (mean+/-S.D.: 3+/-4.6%). For the purpose of analysis, stallions were divided into six inbreeding classes (0-1, 1-2, 2-5, 5-8, 8-12 and >12%) containing 132, 40, 42, 27, 25 and 19 animals, respectively. The degree of inbreeding significantly affected many aspects of sperm production and quality, based on a standard examination of two ejaculates collected at a 1.5-3h interval. In particular, coefficients of inbreeding above 2% were associated with lower percentages of motile (p<0.01) and morphologically normal sperm (p<0.001). When the data set was used to estimate heritability of semen characteristics, the high values calculated for sperm progressive motility (0.46) and concentration (0.24) suggested that these traits could be improved by phenotypic selection. These findings support the hypothesis that inbreeding has a detrimental effect on semen quality in Shetland ponies, although examination of multiple ejaculates after repeated semen collection to bring the animals to daily sperm output is needed to confirm this conclusion. Nevertheless, the results support previous suggestions that inbreeding is an important cause of reduced semen quality.
Publication Date: 2005-09-13 PubMed ID: 16165199DOI: 10.1016/j.theriogenology.2005.08.001Google Scholar: Lookup
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- Journal Article
Summary
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This research investigates the potential negative impact of inbreeding on the semen quality of Shetland pony stallions. The study concludes that higher levels of inbreeding may result in lower sperm motility and morphology, suggesting that inbreeding could indeed be a cause of reduced semen quality in these animals.
Research Context
- The research is premised on the widespread belief that inbreeding negatively impacts reproductive performance across species, potentially leading to poor semen quality.
- Yet, it’s not clear whether this effect extends to horses, hence sparking the need for this study.
Methodology
- The researchers examined the relationship between inbreeding and semen quality in 285 immature Shetland pony stallions submitted for breeding soundness examination between 1992 and 1997.
- Most of the stallions examined were three years old, with their inbreeding coefficients ranging from 0 to 25%.
- To facilitate the analysis, the stallions were grouped into six distinct inbreeding classes based on their inbreeding coefficients.
- The researchers then examined aspects of sperm production and quality, focusing on two ejaculates collected at a 1.5 to 3-hour interval.
Findings
- Inbreeding degrees significantly affected various aspects of sperm production and quality.
- Specifically, inbreeding coefficients above 2% were associated with lower percentages of motile and morphologically normal sperm.
- When the data set was used to estimate heritability of semen characteristics, high values were calculated for sperm progressive motility and concentration, suggesting potential room for improvement via phenotypic selection.
Conclusion
- The findings of the research bolster the hypothesis that inbreeding can negatively impact semen quality in Shetland ponies.
- However, the researchers acknowledge the need for further studies involving examination of multiple ejaculates after repeated semen collection to affirm their findings.
- Despite this, the results still lend support to previous suggestions implicating inbreeding as a significant factor in reducing semen quality.
Cite This Article
APA
van Eldik P, van der Waaij EH, Ducro B, Kooper AW, Stout TA, Colenbrander B.
(2005).
Possible negative effects of inbreeding on semen quality in Shetland pony stallions.
Theriogenology, 65(6), 1159-1170.
https://doi.org/10.1016/j.theriogenology.2005.08.001 Publication
Researcher Affiliations
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL Utrecht, The Netherlands. p.vaneldik@vet.uu.nl
MeSH Terms
- Animals
- Horses / genetics
- Horses / physiology
- Inbreeding
- Male
- Reproduction
- Sperm Count
- Sperm Motility / genetics
- Spermatogenesis / genetics
- Spermatozoa / abnormalities
- Spermatozoa / physiology
Citations
This article has been cited 12 times.- Ghoreishifar M, Vahedi SM, Salek Ardestani S, Khansefid M, Pryce JE. Genome-wide assessment and mapping of inbreeding depression identifies candidate genes associated with semen traits in Holstein bulls. BMC Genomics 2023 May 3;24(1):230.
- Harris IT, Maddock C, Farnworth M, Nankervis K, Perrett J, Pyatt AZ, Blanchard RN. Temporal trends in equine sperm progressive motility: a systematic review and meta-regression. Reproduction 2023 Jun 1;165(6):M1-M10.
- Vostry L, Vostra-Vydrova H, Citek J, Gorjanc G, Curik I. Association of inbreeding and regional equine leucocyte antigen homozygosity with the prevalence of insect bite hypersensitivity in Old Kladruber horse. Anim Genet 2021 Aug;52(4):422-430.
- Próchniak T, Kasperek K, Knaga S, Rozempolska-Rucińska I, Batkowska J, Drabik K, Ziȩba G. Pedigree Analysis of Warmblood Horses Participating in Competitions for Young Horses. Front Genet 2021;12:658403.
- Müller-Unterberg M, Wallmann S, Distl O. Effects of inbreeding and other systematic effects on fertility of Black Forest Draught horses in Germany. Acta Vet Scand 2017 Oct 18;59(1):70.
- Joseph PN, Sasson DA, Allen PE, Somjee U, Miller CW. Adult nutrition, but not inbreeding, affects male primary sexual traits in the leaf-footed cactus bug Narnia femorata (Hemiptera: Coreidae). Ecol Evol 2016 Jul;6(14):4792-9.
- Opatová P, Ihle M, Albrechtová J, Tomášek O, Kempenaers B, Forstmeier W, Albrecht T. Inbreeding depression of sperm traits in the zebra finch Taeniopygia guttata. Ecol Evol 2016 Jan;6(1):295-304.
- Takasu M, Hiramatsu N, Tozaki T, Kakoi H, Hasegawa T, Maeda M, Kusuda S, Doi O, Murase T, Mukoyama H. Population statistics and biological traits of endangered kiso horse. J Equine Sci 2011;22(4):67-72.
- Ala-Honkola O, Hosken DJ, Manier MK, Lüpold S, Droge-Young EM, Berben KS, Collins WF, Belote JM, Pitnick S. Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster. Ecol Evol 2013 Jul;3(7):2089-102.
- Brosnahan MM, Brooks SA, Antczak DF. Equine clinical genomics: A clinician's primer. Equine Vet J 2010 Oct;42(7):658-70.
- Fitzpatrick JL, Evans JP. Reduced heterozygosity impairs sperm quality in endangered mammals. Biol Lett 2009 Jun 23;5(3):320-3.
- Madeddu M, Berlinguer F, Ledda M, Leoni GG, Satta V, Succu S, Rotta A, Pasciu V, Zinellu A, Muzzeddu M, Carru C, Naitana S. Ejaculate collection efficiency and post-thaw semen quality in wild-caught Griffon vultures from the Sardinian population. Reprod Biol Endocrinol 2009 Feb 19;7:18.
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