Endocrine alterations around the time of abortion in mares impregnated with donkey or horse semen

Boeta, Myriam; Zarco, L.

doi:10.1016/j.anireprosci.2010.05.015

Cited by 12 publications

(13 citation statements)

References 14 publications

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“…41 In hybrids between donkey and horse (mules), the gestation period is closer to the father's species than to that of the mother. 42 Similarly, regarding the gestations of hybrids between bighorn and domestic sheep, the paternal component of the bighorn sheep that has a gestation period of approximately 175 days 21 significantly increases the normal gestation period of domestic sheep, from 146 days to 152 days (on average), like the results obtained in these two experiments and in a previous work. 23 From a physiological perspective, an inadequate placental vascularization and size throughout pregnancy causes reduced intrauterine foetal growth and the birth of small offspring.…”

Section: Experiments IIsupporting

confidence: 79%

Progesterone promotes fetal growth in a restricted interspecies gestation (Ovis canadensis x Ovis aries)

Villanueva¹,

Cazadero²,

Mejía³

et al. 2018

Vet Méx OA

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Gestations between bighorn (Ovis canadensis) and domestic sheep (O. aries) can be considered for ex situ conservation of bighorn. In the first experiment, domestic sheep were inseminated with bighorn or domestic semen. Bighorn inseminated sheep showed lower fertility than domestic inseminated sheep (40% vs. 65%, p = 0.11). Bighorn inseminated sheep had longer gestation periods (152.13 days vs. 146.54 days, p < 0.001) and lower progesterone levels during the last third. Hybrid lambs weighed less than domestic lambs (2.46 kg vs. 5.10 kg, p < 0.001). Their placentas were not as long (48.67 cm vs. 72.17 cm, p < 0.001), were less wide (17.83 cm vs. 23.83 cm, p < 0.001), and the weight of cotyledons was lower (1.50 g vs. 3.20 g, p < 0.001). In the second experiment, hybrid embryos (O. canadensis × O. aries) were transferred into domestic recipients, and pregnant ewes were divided into the treated group, which had a progesterone daily dose of 25 mg from weeks 7 to 20, and the non treated group. Gestation in domestic sheep that received one hybrid embryo and progesterone reached 152.60 days, which was similar to the 153.33 days (p = 0.51) in the non treated sheep. Hybrid offspring of the group treated with progesterone were heavier, 3.41 kg, than the control, 2.21 kg (p < 0.001), and their placentas were longer (71.20 vs. 50.83 cm, p = 0.002). Although progesterone levels were lower in domestic females inseminated with bighorn and in the recipients of hybrid embryos, it is possible to establish pregnancies between both species and the birth of viable offspring. The administration of progesterone during gestation increases the length of the placenta and promotes higher birth weights of hybrids. promotes foetal growth in a restricted interspecies gestation (Ovis canadensis × Ovis aries). Veterinaria México OA. 2018;5(3).

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Section: Experiments IIsupporting

confidence: 79%

Progesterone promotes fetal growth in a restricted interspecies gestation (Ovis canadensis x Ovis aries)

Villanueva¹,

Cazadero²,

Mejía³

et al. 2018

Vet Méx OA

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“…As expected from previous reports (Allen ; Boeta and Zarco , ), in this study, the concentrations of eCG were much lower in mule pregnancies than in horse pregnancies (Fig. ).…”

Section: Discussionsupporting

confidence: 91%

“…Ultrasonographic observations of the foetus were conducted immediately before the first injection and every 12 h thereafter until the product was expelled. Foetal death was considered to have occurred when no cardiac beat or foetal movements were found during an examination, and abortion was considered complete upon foetal expulsion (Boeta and Zarco , ).…”

Section: Methodsmentioning

confidence: 99%

“…; Allen ), which could protect the CL of the pregnant mare in a manner similar to the way in which exogenous hCG has been shown to protect the ovine CL against PGF2α administration (Bolt ). This concept is supported by the observation that mares that produce very little or no eCG, such as mares carrying mule pregnancies or xenogeneic donkey pregnancies, appear to be more vulnerable to endogenous PGF2α, as suggested by the high incidence of abortions in which foetal death is immediately preceded by an abrupt fall in progesterone concentrations in mule pregnancies (Boeta and Zarco , ) and in donkey‐in‐horse pregnancies (Allen ).…”

Section: Introductionmentioning

confidence: 91%

“…However, these effects of eCG are not indispensable for pregnancy success, as a large proportion of mares impregnated by donkeys carry their mule foetuses to term even though they produce very little or no eCG (Allen ; Boeta and Zarco ) and have progesterone concentrations significantly lower than those of mares impregnated by horses (Boeta and Zarco ). Thus, it has been suggested that pituitary LH could generally suffice to maintain luteal function during pregnancy in the mare and that the role of eCG might be to protect pregnancy in cases of special need (Boeta and Zarco , ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Luteoprotective Role of Equine Chorionic Gonadotropin (eCG) During Pregnancy in the Mare

Flores-Flores

Velázquez-Cantón

Boeta

et al. 2014

Reprod Domestic Animals

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The effects of repeated cloprostenol administration were compared in mares impregnated by horses and mares impregnated by donkeys in order to assess the role of eCG on the development of pregnancy-associated resistance to the luteolytic and abortifacient effects of PGF2α. Eleven mares impregnated by donkey (mule pregnancy) and 9 mares impregnated by horse (horse pregnancy) were used. Six mares with mule pregnancy and four with horse pregnancy were injected with cloprostenol (0.25 mg) when they were between day 65 and day 75 of pregnancy, and the treatment was repeated 48, 72 and 96 h latter. The rest of the mares remained as controls. Concentrations of eCG were 10 times higher (p < 0.001) in mares impregnated by horses than in mares impregnated by donkeys, and they were not affected by cloprostenol treatment. Luteolysis was completed 30 h after the first cloprostenol injection in mule pregnancies, while mares with horse pregnancies required 96 h and three cloprostenol injections to complete luteolysis. Regression analysis revealed significant associations between eCG concentrations at time 0 and the time required for completion of luteolysis (p < 0.001), foetal death (p < 0.01) and foetal expulsion (p < 0.05). It is concluded that high eCG concentrations in mares impregnated by horses protect the corpora lutea of pregnancy against the luteolytic effects of PGF2α. Low eCG concentrations in mares carrying mule foetuses afford them less protection against the luteolytic effect of PGF2α, and this may be a cause of the increased foetal mortality that occurs between days 60 and 90 of pregnancy in these mares.

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Luteogenic and luteotropic effects of eCG during pregnancy in the mare

Boeta

Zarco

2012

Animal Reproduction Science

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Endocrine alterations around the time of abortion in mares impregnated with donkey or horse semen

Cited by 12 publications

References 14 publications

Progesterone promotes fetal growth in a restricted interspecies gestation (Ovis canadensis x Ovis aries)

Progesterone promotes fetal growth in a restricted interspecies gestation (Ovis canadensis x Ovis aries)

Luteoprotective Role of Equine Chorionic Gonadotropin (eCG) During Pregnancy in the Mare

Luteogenic and luteotropic effects of eCG during pregnancy in the mare

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