Long term reproductive examination of 3 dogs treated postnatally with deslorelin acetate

M. FAYA; C. MARCHETTI; M. PRIOTTO; M. GRISOLIA; C. LAPUENTE; C. GOBELLO

Savannah

Conferencia; Therio Annual Conference; 2019

American College of Theriogenologists

Long term, detailed reproductive assessment of canine contraceptive treatments is scarce. This kind of evaluation provides additional valuable information about the efficacy and safety of these protocols. The aim of this presentation is to describe the reproductive status of 2 male (Dog 1 and Dog 2) and 1 female, all three dogs 28 months old, body weight 11.1±1.7 kg, crossbred littermate dogs which were treated, within the 24 hours of birth, with 18.8 mg of deslorelin acetate (Suprelorin, Virbac, France) subcutaneously for contraceptive purposes1,2 and had just achieved puberty.The dogs were exposed to other fertile dogs for mating during a whole heat period. Then, they were gonadectomized after blood sampling for hormone determinations and pregnancy diagnosis. The gonads were grossly and histomorphometrically (Image Pro Plus v6.0-Media Cybernetics, Silver Spring, MA, USA) examined. Before surgery, serial physical examinations revealed a small vulva in the female as well as unilateral delayed (6 months old) testicular descend and bilateral inguinal cryptorchidism in Dog 1 and Dog 2, respectively. Seminal samples could not be collected due azoospermia and aspermia in spite of erection in these same males. While the female ovulated (progesterone 15 ng/ml; Elecsys, Roche Diagnostics, Mannheim, Germany) and became pregnant, the males could not achieve mating.Anti-Müllerian hormone (AMH-Gen II, Beckman Coulter, USA) serum concentrations were 21.3 ng/ml and 4.9 ng/ml in Dog 1 and Dog 2, respectively and 0.35 ng/ml in the female. Testosterone (T) was normal in Dog 1 and non-detectable in Dog 2, and estradiol-17β (Elecsys, Roche Diagnostics, Mannheim, Germany) was at normal concentrations in the female.Gonadosomatic index was < 0.02 in the 3 dogs. The ovaries presented 48% of atretic, 44% of primordial, and 8% of primary follicles as well as corpora lutea. The high and low proportions of the 2 former follicles may indicate an enhanced recruitment related to the low AMH concentrations. Dog 2 testes evidenced small seminiferous tubules composed of spermatogonias and Sertoli cells i.e. Sertoli cell-only syndrome. The testes of Dog 1 depicted disorganized spermatogenesis up to the spermatid level, vacuolization and a spermatids-Sertoli cell ratio of 3.07 which was much lower than in the less efficient species. The area of the Leydig nuclei was 40% smaller in Dog 2 than in Dog 1 indicating abnormal steroideogenic function and correlating with the non detectable T serum concentrations found in this dog.It was concluded that this contraceptive protocol caused delayed puberty, abnormalities in both testicular descend and spermatogenesis as well as ovarian and hormonal findings that could be associated with premature reproductive failure in females.