Reproductive parameters of Mangalarga Marchador mares in a commercial embryo transfer programme.
Abstract: The objective of this study is to evaluate the reproductive efficiency in donors and recipient Mangalarga Marchador mares in commercial programmes of embryo transfer (ET) and the effects of some reproductive characteristics and ET methodology on conception rates in the recipient mares. A total of 1140 flushing procedures were performed and 830 embryos (72.8%) were recovered. There were no differences between the rates of embryonic recovery in the different breeding seasons (p > 0.05) and 92.8% of the recovered embryos were 8-9 days old. There was no difference in the embryonic recovery regarding the collection order from the first to the ninth embryo collection along the breeding season, as well as among mares inseminated during the foal heat or subsequent cycles (p > 0.05). Pregnancy rates observed in the total period of all reproductive seasons at 15, 30, 45 and 60 days of pregnancy were 73.4, 69.9, 66.7 and 64.5%, respectively. Differences in pregnancy rate and early embryonic loss rates were not observed between embryos transferred immediately after collection (66.8% and 13.5%) and embryos transported at room temperature for periods of < 1 h (62.9% and 14.4%; p > 0.05). Pregnancy rates were higher when the interval between ovulations of donor and recipient mares remained between -3 and -2 days (p < 0.05), and the lowest rates were observed for intervals of -6 days (p < 0.05) with intermediary values for intervals of -1, 0 and +1 (p > 0.05). Embryonic loss rates, however, did not differ between intervals of ovulation's synchronism between donor and recipient mares (p > 0.05). This flexibilization in the ovulatory synchronism between donor and recipient mares optimizes the use of recipient mares, thus reducing costs and facilitating management of horse breeding farms.
© 2010 Blackwell Verlag GmbH.
Publication Date: 2010-06-23 PubMed ID: 20565699DOI: 10.1111/j.1439-0531.2010.01656.xGoogle Scholar: Lookup
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Summary
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The research evaluated the reproductive efficiency of Mangalarga Marchador at different stages of their embryo transfer programs, as well as the effects of specific reproductive factors and transfer methods on their conception rates.
Study Overview
- The study primarily focused on understanding the reproductive efficiency of Mangalarga Marchador mares, a horse breed from Brazil, in commercial embryo transfer programs which are usually aimed at enhancing the production rate of high-quality animals.
- The researchers conducted 1140 flushing procedures (the process of retrieving the embryo from the mare) and managed to recover 830 embryos, which equates to a recovery rate of approximately 72.8%.
Breeding Seasons and Embryo Age
- The research also probed into the seasonality of breeding and its direct correlation with the rate of embryonic recovery, but the data indicated that there was no significant difference between different breeding seasons.
- Most of the recovered embryos (92.8%) were 8-9 days old, which implies that this could be the optimal age for embryo transfer, although the study didn’t directly point out this conclusion.
Collection Order and Insemination Cycle
- The collected data also confirmed that there was no significant variation in the rate of embryonic recovery, regardless of the order of collection throughout the breeding season or the insemination cycle, such as during the foal heat or subsequent heat cycles.
Pregnancy Rate and Early Embryonic Loss
- The researchers then moved on to analyze the pregnancy rates which were recorded at 15, 30, 45, and 60 days of pregnancy with rates of 73.4%, 69.9%, 66.7% and 64.5%, respectively. This decreasing trend over time is a normal observation in reproductive studies.
- The authors also estimated the early embryonic loss rates between embryos that were transferred immediately after collection (13.5%) and those that were transported at room temperature for less than an hour (14.4%). No significant difference was noted here either.
Interval Between Ovulations of Donor and Recipient Mares
- By studying the effect of different intervals between the ovulations of donor and recipient mares, the researchers concluded that the highest pregnancy rates occurred when the interval was between -3 and -2 days. Meanwhile, the lowest rates were recorded for intervals of -6 days.
- However, the rate of embryonic loss, in relation to the synchronism of ovulation between donor and recipient mares, revealed no significant difference regardless of the considered interval.
Concluding Remarks
- The study concluded that adjusting the ovulatory synchronism between donor and recipient mares could help in optimizing the use of recipient mares, thereby reducing the overall costs and facilitating the management of horse breeding farms.
Cite This Article
APA
Lopes Ede P, Siqueira JB, Pinho RO, Guimarães JD, Rocha AN, de Carvalho GR, Torres CA.
(2010).
Reproductive parameters of Mangalarga Marchador mares in a commercial embryo transfer programme.
Reprod Domest Anim, 46(2), 261-267.
https://doi.org/10.1111/j.1439-0531.2010.01656.x Publication
Researcher Affiliations
- Ms Autonomous Veterinary, Zootecnia/UNESP - Botucatu, SP, Brasil.
MeSH Terms
- Animals
- Embryo Transfer / veterinary
- Female
- Horses / embryology
- Horses / physiology
- Pregnancy
- Pregnancy Rate
- Pregnancy, Animal
- Time Factors
Citations
This article has been cited 1 times.- Alonso MA, Silva LA, Affonso FJ, Lemes KM, Celeghini ECC, Lançoni R, Carvalho HF, de Arruda RP. Effect of hCG application at different moments of the estrous cycle on corpus luteum and uterine vascularization and serum progesterone concentration in mares. Anim Reprod 2019 Oct 24;16(2):317-327.
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