Factors affecting pregnancy rates and early embryonic death after equine embryo transfer

Carnevale, E.M.; Ramirez, Raymund; Squires, E.L.; Alvarenga, Marco Antônio; Vanderwall, Dirk K.; McCue, Patrick M.

doi:10.1016/s0093-691x(00)00405-2

Cited by 116 publications

(124 citation statements)

References 22 publications

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“…When the incidence of embryonic loss was evaluated by CARNEVALE et al (2000) in cyclic recipient mares, the authors found a 16% loss between 12 and 40 days of gestation, with the highest incidence detected between 17 and 25 days, as observed in the present study. Therefore, the embryonic loss rates in non-cyclic recipient mares found in this study are similar to those of cyclic recipients and mated or inseminated pregnant mares.…”

Section: Discussionsupporting

confidence: 83%

“…The use of non-cyclic recipient mares in ET programs and their pregnancy rates have been described in the literature (CARNEVALE et al, 2000;GRECO et al, 2012;. However, there are no reports on the developmental pattern of conceptuses transferred to these recipients during early pregnancy.…”

Section: Discussionmentioning

confidence: 99%

“…Most of the studies demonstrate that pregnancy and early embryonic death rates of non-cyclic recipient mares are similar to those of cyclic recipients, and thus can be successfully used in ET programs (CARNEVALE et al, 2000;ROCHA FILHO et al, 2004;GRECO et al, 2012;. In addition, the use of non-cyclic recipient mares is an advantageous alternative to horse owners and veterinarians, since it enables the anticipation and/or prolongation of the breeding season (GRECO et al, 2012), eliminates the need for synchrony of ovulation between donor and recipient and reduces the number of recipients per donor (MCKINNON et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

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Ultrasonography of the conceptus development from days 15 to 60 of pregnancy in non-cyclic recipient mares

et al. 2015

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The present study evaluated the development of equine conceptus transferred to non-cyclic recipient mares treated with altrenogest. Twenty four mares were used as embryo recipients during the ovulatory phase (Control group; n=8) or anestrus/transitional phases (Altrenogest group; n=16) and were evaluated by transrectal ultrasonography, at five day intervals, to monitor the development of embryonic vesicles from 15 to 45 days of pregnancy and embryo proper/fetus from 20 to 60 days. Embryonic vesicle's features such as shape, embryo location within the vesicle and umbilical cord development were similar between cyclic and non-cyclic recipient mares. The embryonic vesicle and embryo proper/fetus growth was significant (P<0.05) between 15 and 60 days of gestation in Altrenogest and Control groups, except for days 20 to 30, where embryonic vesicle growth decrease was observed (P>0.05). The embryonic vesicle and embryo proper/fetus growth was similar (P>0.05) when gestational days were compared between groups. The similarity in conceptus growth between cyclic and non-cyclic recipient mares during early pregnancy indicates that the uterine environment of non-cyclic recipient mares treated with progestins provides similar conditions for the development of transferred embryos

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Section: Discussionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultrasonography of the conceptus development from days 15 to 60 of pregnancy in non-cyclic recipient mares

et al. 2015

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“…Thus, Thoroughbred mares have proven low reproductive efficiency despite their high pregnancy rates. Furthermore, high embryonic mortality is cited as the main reason for low reproduction [7,32].Reproductive dysfunction in mares is closely linked to low fertility caused by improper care and maintenance, artificial control of breeding season, and hormonal and genital disorders [5,7]. In addition, the morphology and diameter of the fetus are important factors for pregnancy and embryonic death rate of mares [5,7].…”

mentioning

confidence: 99%

“…In addition, the morphology and diameter of the fetus are important factors for pregnancy and embryonic death rate of mares [5,7]. Embryonic death in mares is primarily associated with genetic and environmental factors [3,21,29,32].…”

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confidence: 99%

Factors Concerning Early Embryonic Death in Thoroughbred Mares in South Korea

Yang¹,

Cho

2007

The Journal of Veterinary Medical Science

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ABSTRACT. A total of 384 Thoroughbred mares were investigated to determine and evaluate the features of early embryonic death at nine equine farms on Jeju Island, South Korea, from 2001 to 2003. Overall, 771 matings for 384 mares resulted in 376 pregnancies 15 days after ovulation. Subsequently, 12.2% (46/376) of these early conceptuses were lost within 45 days after ovulation. Furthermore, about three quarters of the 46 embryonic deaths occurred between 16 and 25 days after ovulation. The incidence of embryonic death was highest in the barren (17.2%), more than 15 years old (15.4%), and more than 10 parities (18.2%) groups compared with the other groups (9.1-16.9%). Mares mated in March, April, and during the first estrus postpartum had higher embryonic death rates, (19.6%, 17.2%, and 24.6%, respectively). Mares with abnormal fluid and cysts in the uterus (18.0%) or multiple embryonic vesicles (23.1%) had higher embryonic death rates than those with normal uterine conditions (9.8%) or single embryonic vesicles (10.5%). The condition of mares, such as breeding condition and the environment of the embryo or fetus, are the major factors in relation to occurrence of early embryonic death. KEY WORDS: breeding condition, embryonic death, Thoroughbred, uterine environment.J. Vet. Med. Sci. 69(8): 787-792, 2007 Horses are long-day breeders and have lower reproductive efficiency compared with sheep and cows [32]. The fertility of mares depends on their individual fertility status. Some mares show total fertility rates of 90% if they are highly fertile, while ordinary mares have total fertility rates ranging from 81% to 92%, which are still higher than those of other animals [2,3]. Sullivan et al. [31] reported a fouryear cumulative pregnancy rate of 74% for Thoroughbred breeding, which was lower than the 85% rate for Quarter horses. Bruck et al. [4] stated that 85% of Thoroughbred mares achieve pregnancy and 69.3% of them give birth to live foals. Rose and Hodgson [25] reported that Thoroughbred mares worldwide have a foaling rate ranging from 60% to 70% on average. Davies Morel [7] suggested that the foaling rates of Thoroughbred mares range from 50% to 80%. Thus, Thoroughbred mares have proven low reproductive efficiency despite their high pregnancy rates. Furthermore, high embryonic mortality is cited as the main reason for low reproduction [7,32].Reproductive dysfunction in mares is closely linked to low fertility caused by improper care and maintenance, artificial control of breeding season, and hormonal and genital disorders [5,7]. In addition, the morphology and diameter of the fetus are important factors for pregnancy and embryonic death rate of mares [5,7]. Embryonic death in mares is primarily associated with genetic and environmental factors [3,21,29,32]. Vaginal infections and other uterine abnormalities have a particularly significant impact on premature loss of the fetus by failing to meet the metabolic needs of pregnancy [3,21,29,32]. At the same time, irregular and unbalanced nutrition and psycholog...

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Embryo Transfer andin vitroFertilization

Hasler¹

2007

Comparative Reproductive Biology

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Factors affecting pregnancy rates and early embryonic death after equine embryo transfer

Cited by 116 publications

References 22 publications

Ultrasonography of the conceptus development from days 15 to 60 of pregnancy in non-cyclic recipient mares

Ultrasonography of the conceptus development from days 15 to 60 of pregnancy in non-cyclic recipient mares

Factors Concerning Early Embryonic Death in Thoroughbred Mares in South Korea

Embryo Transfer andin vitroFertilization

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