Stimulation of Ovulation in Seasonally Anovulatory and Vernal Transitional Mares with Estradiol and Domperidone: Dose and Combination Studies

Mitcham, P.B.; Thompson, Donald L.; Thompson, Tad T.; Bennett, Scott D.; Burns, Patrick; Caltabilota, T.J.

doi:10.1016/j.jevs.2010.03.007

Cited by 11 publications

(4 citation statements)

References 8 publications

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“…Consequently, we do not know whether the same results, in terms of responsiveness to induction of ovulation with hCG, would have been achieved without this pretreatment. The various studies reported in this paper fail to agree on the effectiveness of dopamine antagonist treatments to hasten the first ovulation of the breeding season in mares 11–19 . Nevertheless, the great variability between the different conditions of the already published studies, including the breeding seasons, hemispheres, pretreatments, photostimulations and follicular diameter at the time of the first treatment of the mares 13,35–38 complicates any comparison between studies.…”

Section: Discussionmentioning

confidence: 78%

“… 18 , 19 This is probably due to the differences in the drugs employed, timing of treatments, routes, doses and frequency of administration, body condition scores or pre‐treatments (eg, artificial photoperiod) of the mares in the various studies. 12 , 13 , 14 , 15 , 16 , 17 In previous work, performed under the same conditions as this study, sulpiride treatment hastened the first ovulation of the year without reducing fertility, compared to a control group. 17 …”

Section: Introductionmentioning

confidence: 70%

“…The various studies reported in this paper fail to agree on the effectiveness of dopamine antagonist treatments to hasten the first ovulation of the breeding season in mares. 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 Nevertheless, the great variability between the different conditions of the already published studies, including the breeding seasons, hemispheres, pretreatments, photostimulations and follicular diameter at the time of the first treatment of the mares 13 , 35 , 36 , 37 , 38 complicates any comparison between studies. In our study, the mean number of days of sulpiride treatment before the development of a ≥35 mm follicle was very similar to findings reported in a recent study performed under the same conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Dopamine exerts a tonic inhibition on reproductive activity during the anovulatory season, in mares 10 . Treatments with the dopamine‐2 (D2) antagonists sulpiride, domperidone and pherpenazine hasten the onset of the ovulatory season in mares in some studies, 11–17 but not in others 18,19 . This is probably due to the differences in the drugs employed, timing of treatments, routes, doses and frequency of administration, body condition scores or pre‐treatments (eg, artificial photoperiod) of the mares in the various studies 12–17 .…”

Section: Introductionmentioning

confidence: 99%

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hCG is more effective than the GnRH agonist buserelin for inducing the first ovulation of the breeding season in mares

Fanelli

Tesi

Rota

et al. 2021

Equine Veterinary Journal

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Background Human Chorionic Gonadotropin (hCG) and Gonadotropin Releasing Hormone agonists (GnRHa) are routinely used to induce ovulation in mares. However, GnRHa efficacy in transitional mares has been suggested to be low. Objectives The aims of this study were as follows: (a) to compare the efficacy of hCG and GnRHa in inducing the first ovulation of the breeding season and (b) to evaluate the correlation between ovulatory response, uterine oedema and teasing score at the time of treatment during the early or late transitional phase. Study design Randomised controlled superiority trial. Methods Mares in winter anoestrus were treated with sulpiride when at least two follicles reached a diameter of 25 mm. The day after the follicle reached 35 mm in diameter, mares in oestrus were treated with GnRHa buserelin (N = 29) or hCG (N = 33) and checked daily for ovulation. Results More mares (30/33, 90.1%) ovulated when the first ovulation after winter anoestrus was induced with hCG, than with GnRHa, (11/29, 38.0%) (P = .0001). Ovulation rate was lower in mares that did not show uterine oedema and full acceptance of the teaser stallion for at least three days before the treatment (32/41, 78% vs 9/21, 42.9%) P = .01. Main limitations Plasma LH and oestrogen concentrations were not performed. Conclusions These results demonstrate that hCG was more effective than GnRHa for inducing ovulation in the first cycle after winter anoestrus. Uterine oedema and behavioural signs of oestrus, for at least three days before the treatment, were predictors for a positive response to ovulation induction.

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Section: Discussionmentioning

confidence: 78%