Faecal oestrogens and progesterone metabolites in mares of different breeds during the last trimester of pregnancy.
Abstract: Non-invasive pregnancy diagnosis in mares by measuring faecal oestrogens has been performed over years with great accuracy. However, results have indicated breed-related differences in the amount of excreted steroids during late pregnancy. Therefore faecal samples were collected during the last 4 months of pregnancy of Thoroughbred (n = 10), New Forest pony (n = 9), Shetland pony (n = 10) and Iceland pony mares (n = 11). Concentrations of oestrogens, 20alpha-hydroxy- and 20-oxopregnanes were measured using enzyme immunoassays. Breed differences concerning both levels (though significant only in case of oestrogens) and time course of measured steroids were observed. There was a highly significant time effect (p < 0.00001) and an interaction between time and breeds (p < 0.02) for all steroids measured, suggesting that the time effect differs for different breeds. Oestrogen concentrations showed a decrease towards parturition, whereas in 20alpha-hydroxy- and 20-oxopregnane levels a pronounced increase was found 2 and I months, respectively, before parturition. A breed effect was only significant (p = 0.001) when comparing oestrogen concentrations and was mainly due to Iceland ponies, which had the lowest concentrations especially during the last 2 months of pregnancy. An almost significant (p = 0.06) breed effect was found for 20-oxopregnanes. In Iceland mares an additional increase in faecal pregnane content was already observed earlier, reaching maximum levels before the 60th day ante-partum (a.p.), followed by a decrease until the 30th day a.p. The ratio of 20-oxopregnanes to oestrogens in the samples was significantly higher (p < 0.006) in Iceland ponies in comparison with any other breed throughout all months before parturition. The breed differences observed in the amounts of oestrogens and/or progestagens present during late pregnancy may demonstrate micro-evolutionary changes in the endocrine system of a species.
Publication Date: 2002-03-12 PubMed ID: 11885746DOI: 10.1046/j.1439-0531.2001.00302.xGoogle Scholar: Lookup
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- Journal Article
Summary
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The study details an investigation into the variances in levels of faecal oestrogens and progesterone metabolites in different breeds of horses during the last trimester of pregnancy. Findings highlighted breed-related differences in the excreted steroid hormones related to pregnancy.
Methodology
- The study assessed faecal samples from four different breeds of mares, including Thoroughbred, New Forest pony, Shetland pony, and Iceland pony, over the last 4 months of their pregnancy.
- The researchers quantified the concentrations of oestrogens, 20alpha-hydroxy-, and 20-oxopregnanes in the faecal samples using enzyme immunoassays.
Findings
- The research unveiled differences in hormone levels among different breeds.
- The differences were significant particularly for the oestrogen levels.
- There was a time effect on the levels of all steroids in that their levels varied significantly in different times of the pregnancy, different for different breeds.
- Oestrogen levels showed a decline towards parturition while the levels of 20alpha-hydroxy- and 20-oxopregnanes saw a considerable growth, especially within the 1-2 months preceding parturition.
- The breed-specific difference was at its most conclusive when comparing oestrogen concentrations, with Iceland ponies showing notably lower concentrations, especially during the final two months of pregnancy.
- An almost significant breed-specific effect was noticed for 20-oxopregnanes.
- In contrast to other breeds, Iceland mares showed an earlier increase in faecal pregnane content, peaking prior to 60 days ante-partum, followed by a decrease until 30 days ante-partum.
- Notably, the ratio of 20-oxopregnanes to oestrogens in the samples was significantly higher in Iceland ponies than in any other breed throughout all months before parturition.
Conclusion
- The differences in the oestrogen and progestagen levels could highlight micro-evolutionary changes in the endocrine system of the species.
Cite This Article
APA
Palme R, Entenfellner U, Hoi H, Möstl E.
(2002).
Faecal oestrogens and progesterone metabolites in mares of different breeds during the last trimester of pregnancy.
Reprod Domest Anim, 36(5), 273-277.
https://doi.org/10.1046/j.1439-0531.2001.00302.x Publication
Researcher Affiliations
- Ludwig Boltzmann Institut für Veterinärmed, Endokrinologie und Institut für Biochemie, Veterinärmedizinische Universität Wien, Austria. Rupert.Palme@vu-wien.ac.at
MeSH Terms
- Animals
- Breeding
- Estrogens / metabolism
- Feces / chemistry
- Female
- Gestational Age
- Horses
- Pregnancy
- Pregnancy, Animal / metabolism
- Pregnanes / metabolism
Citations
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