Efficacy and Safety of 4.7 mg Deslorelin Acetate Implants in Suppressing Oestrus Cycle in Prepubertal Female Dogs

SIMPLE SUMMARY: In addition to convenience for owners, controlling female dog reproduction can be necessary to avoid unwanted pregnancy, especially at a young age. Surgical castration in a prepubertal bitch is still a controversial issue regarding the health benefits for the dog. Medical solutions, such as progestagens, often lead to severe side effects for the reproductive tracts. This is why temporary, reversible alternatives are required. Suprelorin(®) (Virbac, Carros, France) is a slow-release implant based on deslorelin, a Gonadotropin-Releasing Hormone agonist. It was first labelled in male dogs for the induction of temporary infertility. This study evaluated the efficacy and safety of this contraceptive implant when administered in female dogs prior to puberty. The results confirmed that this method delays the onset of puberty for at least 5.5 months and, consequently, prevents unwanted and risky pregnancy in young female dogs. ABSTRACT: Our multicentric, masked, controlled and randomised study aimed to assess the efficacy and safety of Suprelorin(®) 4.7 mg (Virbac, Carros, France) regarding oestrus prevention in prepubertal intact bitches. Twelve- to eighteen-week-old females (n = 83) were allocated either a deslorelin implant (n = 62) or 0.9% sodium chloride (n = 21) group. Clinical assessment (heat signs), 17β oestradiol and progesterone assays, and vaginal cytology were performed at day (D)0, D7, D21, month (M)3 and M6 after product administration, and were then performed every other month until reaching puberty. Trained owners assessed heat signs between each veterinary visit. All bitches (n = 83) reached puberty before M30. Deslorelin significantly extended the median time to sexual maturity when compared to the control group (377 days versus 217 days after D0, p < 0.0001). Three females, implanted between 16 and 18 weeks of age, expressed an induced oestrus. Additional descriptive data, collected over a 24 month-period, showed functional reproductive abilities in both deslorelin (n = 52) and control (n = 21) groups once puberty was achieved. In conclusion, Suprelorin(®) 4.7 mg seems to be an effective and safe option for postponing the onset of oestrus when administered to prepubertal female dogs aged from 12 to 16 weeks.