Progesterone and equine chorionic gonadotropin concentrations around the time of pregnancy loss in mares impregnated by donkeys or stallions

Boeta, Myriam; Zarco, L.

doi:10.1016/j.jevs.2005.10.007

Cited by 18 publications

(38 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This indicates that minimal concentrations of progesterone may be sufficient to maintain pregnancy in the mare (Allen, 1984). Thus, the low progesterone levels observed in mares carrying mule embryos, in most cases, is sufficient to reach the minimal for the maintenance of pregnancy, as well as for normal embryonic development (Boeta and Zarco, 2005).…”

Section: Resultsmentioning

confidence: 99%

“…It should be pointed out that a higher number of mares was used in the present experiment to characterize the losses compared to other similar studies. Boeta and Zarco (2005) used a total of 47 pregnant mares, being 28 horse embryos and only 19 mule embryos, compared to the 208 mares carrying a mule embryo, evaluated in this experiment.…”

Section: Resultsmentioning

confidence: 99%

“…Boeta and Zarco (2005) evaluated mares until 150 days of pregnancy resulting from inseminations with jackass semen and found a high pregnancy loss incidence (36.8%), being all losses observed after 40 days of ovulation and thus, classified as fetal losses. They found higher pregnancy losses in mares carrying hybrid mule than for mares impregnated by a stallion (21.4% of pregnancy loss).…”

Section: Resultsmentioning

confidence: 99%

“…Mares pregnant with mule embryos exhibit serum eCG six to ten times lower than mares carrying horse embryos. Moreover, the eCG secretion period is shorter and becomes undetectable in the bloodstream before 80 days of gestation (Boeta and Zarco, 2005;Boeta, 2008). These authors reported lower (P<0.05) eCG circulating in mares inseminated with jackass semen, when compared to mares inseminated with semen from stallions.…”

Section: Resultsmentioning

confidence: 99%

“…According to Boeta and Zarco (2005), the low eCG and progesterone concentrations in mares carrying mule embryos did not affect embryo survival, since there were no differences in the concentrations of these hormones between mares that had normal pregnancies and births and those that lost. This finding is in agreement with Allen (1984Allen ( , 2001 who concluded that eCG is not essential for the maintenance of pregnancy in mares.…”

Section: Resultsmentioning

confidence: 99%

See 4 more Smart Citations

Effect of month of conception on fertility of mares inseminated with jackass semen

Rossi

Gonczarowska

Palhares

et al. 2016

Arq. Bras. Med. Vet. Zootec.

View full text Add to dashboard Cite

Fertility obtained by cross-breeding mares (Equus caballus) with jackasses (Equus asinus) was evaluated. Two extenders, containing skim milk-glucose or egg yolk-glycine were used to study the fertility of mares inseminated with diluted jackass semen (T1 and T2) or diluted and cooled semen at 5°C for 12 hours (T3 and T4). A total of 272 cycles of 208 mares of undefined breeds were evaluated, being uniformly distributed between groups. The cycles were controlled by transrectal palpation and teasing, and mares were inseminated every Tuesday, Thursday and Saturday (three times/week), from the detection of a follicle with 3.0 to 3.5cm diameter in one of the ovaries until ovulation. Pregnancy was detected using transrectal palpation, teasing and ultrasound exams every 14 days. The extenders had no effect on fertility (P>0.05). Pregnancy rates for the first cycle were 64.52%, 61.11%, 50.72% and 54.17% and pregnancy rates/cycle were 63.64%, 54.55%, 52.69% and 47.06%, respectively, for T1, T2, T3 and T4. Differences in pregnancy loss rates between groups and effect of month of conception on fertility were found. Pregnancy loss rates were significantly higher (P<0.05) in January (38.46%) and in February and March (52.38%), with an average of 33.09%. The results indicate that mares conceiving at the end of the physiological reproduction time, carrying a mule embryo, are more susceptible to pregnancy loss.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%