Semen Quality and Onset of Sterility Following Administration of a 4.7‐mg Deslorelin Implant in Adult Male Dogs

Abstract

ContentsThe purpose of this study was to define (i) the interval between treatment and sterility, and (ii) semen quality in male dogs administered a 4.7-mg deslorelin implant. Six healthy, adult dogs of various breeds and body weights were implanted with deslorelin (Suprelorin, Virbac) and followed every 2 weeks with semen and blood collections. Semen quality remained stable or even improved during the first month following treatment and then showed a progressive decline until the end of the study, except for sperm morphology, which was unaffected by the treatment. Complete sterility was achieved on post-treatment days 70, 84, 60, 23, 51 and 40 for dogs 1 to 6, respectively. The 4.7 mg deslorelin implant caused a significant (p < 0.05) decrease in serum testosterone as well as sperm motility. Our results (i) confirm the efficacy of deslorelin in causing reversible sterility in male dogs, (ii) confirm and provide details about endocrine and seminal parameters involved in this process and (iii) contribute to define the interval between treatment and achievement of complete sterility. Practitioners should be aware that such interval may be longer than 2 months in some cases, and that fertility may actually be increased during the first 2-4 weeks post-treatment.

Suppression of Fertility in Adult Dogs

“…The recovery of fertility followed the same steps with normal plasma levels of LH and testosterone after 198–474 days and 487–800 days, respectively (Romagnoli et al. ). Complete return of semen quality to pre‐treatment values was observed by 62 (3 mg) to 102 (12 mg) weeks post‐implantation (Junaidi et al.…”

“…; Romagnoli et al. ). The effect of the implant in suppressing fertility is also affected by the dose of deslorelin in the implant and by the size of the animal (Trigg et al.…”

“…) and after 3 months when using a 4.7 mg deslorelin implant (Romagnoli et al. ). The recovery of fertility followed the same steps with normal plasma levels of LH and testosterone after 198–474 days and 487–800 days, respectively (Romagnoli et al.…”

“…The duration of the effect is unpredictable due to a significant individual variability. Sterilization has been observed in the majority of male dogs treated with deslorelin implants Junaidi et al 2009;Ludwig et al 2009;Romagnoli et al 2012). The effect of the implant in suppressing fertility is also affected by the dose of deslorelin in the implant and by the size of the animal .…”

The effects of a slow release GnRH agonist implant on male rabbits

“…As a consequence of reduced testosterone concentrations, testis and prostate volumes are reduced and semen quality is significantly affected with an arrest of spermatogenesis with development not occurring beyond the spermatogonia/spermatocyte stages. Although the available product containing deslorelin is licensed for the temporary suppression of fertility in adult and intact male dogs and male ferrets only (Ema, 2012) and all above described effects are well-known to occur (Trigg et al, 2001;Junaidi et al, 2003Junaidi et al, , 2007Junaidi et al, , 2009aSchoemaker et al, 2008;Romagnoli et al, 2012;Van Zeeland et al, 2014). Offlabel use of sustained released GnRH agonist implants has been effective for temporary hormonal castration in tom cats (Goericke-Pesch et al, 2011a, 2013b, 2014Novotny et al, 2012), boars (Kauffold et al, 2010), and also in model animals such as rats (Grosset et al, 2012;Edwards et al, 2013) or (captive) wildlife animals such as coyotes (Mac Gregor et al, 2013), red pandas (Koeppel et al, 2014), sea otters (Larson et al, 2013) and cheetahs (Bertschinger et al, 2006).…”