Comparative efficacy of BioRelease Deslorelin® injection for induction of ovulation in oestrus mares: a field study

Aust Vet J. 2016 Sep;94(9):338-40. doi: 10.1111/avj.12478.


Objective: To investigate the comparative efficacy of BioRelease Deslorelin® (BRD) and Ovuplant® for induction of ovulation in cyclic mares in Australia.

Methods: Ovarian follicular activity of 60 mares for a total of 95 cycles was monitored by ultrasonography until they developed a follicle ≥30 mm and a uterine oedema pattern of 3. Mares were then randomly allocated to one of three treatment groups: (1) treatment with 1.25 mg BRD, (2) a single Ovuplant pellet or (3) 1 mL compound sodium lactate control. Follicular activity was monitored with ultrasonography every 12 h until ovulation was detected or for at least 5 days post treatment. The injection site on each mare was monitored for reaction for a minimum of 5 days post treatment.

Results: There was no difference in the percentage of mares ovulating within 48 h when treated with BRD (93.75%) compared with Ovuplant (87.09%). Treatment with both ovulating agents significantly decreased the time to ovulation compared with control mares (P < 0.00005). More mares had injection site reactions with Ovuplant (64.5%) treatment compared with BRD (15.6%) or control mares (0%) (P < 0.00005).

Conclusions: Treatment of mares with 1.25 mg BRD when there is a follicle ≥30 mm and uterine oedema pattern of 3 is as effective as treatment with Ovuplant.

Keywords: breeding programs; horses; oestrus; ovulation agents.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Animals
  • Drug Implants
  • Enzyme Inhibitors / administration & dosage
  • Enzyme Inhibitors / pharmacology*
  • Estrus / drug effects
  • Female
  • Horses / physiology*
  • Injections, Intramuscular / veterinary
  • Linear Models
  • Ovulation / drug effects*
  • Ovulation Induction / methods
  • Ovulation Induction / veterinary*
  • Triptorelin Pamoate / administration & dosage
  • Triptorelin Pamoate / analogs & derivatives*
  • Triptorelin Pamoate / pharmacology
  • Ultrasonography / veterinary


  • Drug Implants
  • Enzyme Inhibitors
  • Triptorelin Pamoate
  • deslorelin