Theriogenology2010; 75(1); 138-143; doi: 10.1016/j.theriogenology.2010.07.019

Clinical use of dopamine antagonist sulpiride to advance first ovulation in transitional mares.

Abstract: Artificial photoperiod treatment is currently the best method to hasten the first ovulation of the breeding season in winter anoestrus mares. However, this is not easy to apply in large herds of mares and, to be effective, has to be planned in the northern hemisphere in December at the latest. Pharmacological treatments have been proposed as alternatives: GnRH agonists, progesterone or its synthetic agonist Altrenogest, and dopamino-antagonists, as pherphenazine, domperidone or sulpiride. Dopamino-antagonists protocols, beginning at a given day of the year, gave controversial results in terms of hastening ovulation. The aim of this study was to evaluate the efficacy of an up-to-21-d long dopamine antagonist (sulpiride) treatment on mares at the beginning of the spring transition for its ability to hasten estrous cyclicity. In Study 1, 49 seasonally-acyclic standardbred mares, maintained in paddocks under natural photoperiod, were treated with 1 mg/kg/d sulpiride at the evidence of the first follicle with of 25 mm in diameter until ovulation for a maximum of 21 d (Group S(1); n = 34) or left untreated (Group C(1); n = 15). Group S(1) and C(1) mares showed a follicle of 35 mm in diameter after 8 and 22 d (median; P < 0.05) and ovulated after 18 and 43 d, respectively (median; P < 0.05). Twenty-two/26 and 6/15 mares of the Group S(1) and C(1) ovulated within 30 d from the beginning of the treatment, respectively (P 0.05) and 50.0% and 61.1% of the remaining became pregnant in the following cycles (P > 0.05), respectively. Beginning with sulpiride treatment when follicles were 25 mm in diameter resulted in a significant advancement of cyclicity in non-photo-stimulated mares. Pregnancy rates after artificial insemination of treated mares were similar to those of untreated animals.
Publication Date: 2010-09-26 PubMed ID: 20875676DOI: 10.1016/j.theriogenology.2010.07.019Google Scholar: Lookup
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The research explored the use of sulpiride, a dopamine antagonist, in advancing the first ovulation in transitional mares, with the study concluding that the treatment shows potential in initiating earlier estrous cyclicity and does not interfere with pregnancy rate.

Research Details

  • The study examined the possibility of using sulpiride to stimulate early ovulation in transitional mares. This came in response to the difficulty of implementing the current best method – artificial photoperiod treatment – in large horse herds.
  • Sulpiride, a dopamine antagonist, was assessed for its efficiency in hastening the return of the breeding season estrous cycle. This matter was underlined by the controversial results obtained from similar treatments using different dopamino-antagonists.

Methodologies and Findings

  • Two studies were conducted. In Study 1, 49 acyclic standardbred mares were given sulpiride after the detection of the first follicle with a diameter of 25mm. The treatment continued until ovulation or for a maximum of 21 days. These mares had considerably faster follicle growth and ovulation compared to untreated mares.
  • In Study 2, the pregnancy rates of 22 acyclic standardbred mares were studied. These mares were kept in natural photoperiod conditions, treated with the same sulpiride regimen as in Study 1, and their pregnancy rates were compared to 47 untreated mares. While the treated and untreated groups showed relatively similar pregnancy rates, it was noted that the sulpiride treatment led to a significant advancement of cyclicity in the mares.


  • From these studies, it can be inferred that sulpiride treatment has potential in advancing the first ovulation cycle in transitional mares when follicles are 25mm in diameter, essentially promoting early cyclicity in such mares without making any impact on their pregnancy rates. This could provide a viable alternative to the artificial photoperiod method in managing large horse herds.

Cite This Article

Panzani D, Zicchino I, Taras A, Marmorini P, Crisci A, Rota A, Camillo F. (2010). Clinical use of dopamine antagonist sulpiride to advance first ovulation in transitional mares. Theriogenology, 75(1), 138-143.


ISSN: 1879-3231
NlmUniqueID: 0421510
Country: United States
Language: English
Volume: 75
Issue: 1
Pages: 138-143

Researcher Affiliations

Panzani, D
  • Dipartimento di Clinica Veterinaria, Universitu00e0 degli Studi di Pisa, Pisa (PI), Italy.
Zicchino, I
    Taras, A
      Marmorini, P
        Crisci, A
          Rota, A
            Camillo, F

              MeSH Terms

              • Animals
              • Dopamine Antagonists / pharmacology
              • Female
              • Horses
              • Ovarian Follicle / drug effects
              • Ovulation / drug effects
              • Ovulation Induction / methods
              • Ovulation Induction / veterinary
              • Pregnancy
              • Pregnancy Rate
              • Sulpiride / pharmacology


              This article has been cited 3 times.
              1. Fanelli D, Tesi M, Rota A, Beltramo M, Conte G, Giorgi M, Barsotti G, Camillo F, Panzani D. hCG is more effective than the GnRH agonist buserelin for inducing the first ovulation of the breeding season in mares.. Equine Vet J 2022 Mar;54(2):306-311.
                doi: 10.1111/evj.13455pubmed: 33884659google scholar: lookup
              2. Satuu00e9 K, Fazio E, Rubio MD, Cravana C, Medica P. Intrafollicular and Systemic Dopamine, Noradrenaline and Adrenaline Concentrations in Cycling Mares.. Animals (Basel) 2020 Oct 16;10(10).
                doi: 10.3390/ani10101896pubmed: 33081160google scholar: lookup
              3. El-Sakkary N, Chen S, Arkin MR, Caffrey CR, Ribeiro P. Octopamine signaling in the metazoan pathogen Schistosoma mansoni: localization, small-molecule screening and opportunities for drug development.. Dis Model Mech 2018 Jul 30;11(7).
                doi: 10.1242/dmm.033563pubmed: 29925529google scholar: lookup