Postponement of puberty in queens treated with deslorelin

Abstract

Objectives The purpose of this study was to assess efficacy of deslorelin, a gonadotropin-releasing hormone (GnRH) agonist marketed in Europe for the control of male dog reproduction, for the postponement of puberty in queens. Methods Nine prepubertal queens aged 3-9 months were selected for this study; their general and reproductive health was checked through clinical, haematological, vaginal cytology and hormonal tests. Following treatment with a 4.7 mg deslorelin implant, each cat received a monthly clinical examination and blood was collected for hormonal assay every third month. Cats were monitored for 14.1 ± 5.2 (range 7-23) months. Results All cats were in good body condition and normal health prior to treatment. Their health status remained unchanged throughout the study and no significant variation was observed with regard to serum progesterone or oestradiol. Seven days post-treatment, 1/9 queens showed signs of heat, and one other queen showed complete vaginal keratinisation. No other signs of heat were subsequently observed in any other queen. Five queens were lost during the study after 7, 7, 16, 17 and 18 months of observation (during which time they did not show signs of heat). By the end of the study, no sign of puberty was observed in the four remaining queens at 21-36 months of age. Conclusions and relevance A 4.7 mg deslorelin implant was able to suppress the feline pituitary-gonadal axis, leading to postponement of puberty for up to 21-36 months in the four queens that completed the study. Deslorelin can be considered as a safe method to postpone puberty in queens.

Figure 1

Variation of percent keratinised vaginal epithelial cells in nine domestic European shorthair queens from before (day 0) to 580 days following treatment with a 4.7 mg deslorelin implant (Suprelorin; Virbac). Day 0 = day of treatment; period 1 = 1–60 days post-treatment; period 2 = 61–120 days post-treatment; period 3 = 121–180 days post-treatment; period 4 = 181–240 days post-treatment; period 5 = >240 days post-treatment

Figure 2

Average percentage of keratinised cells in nine prepubertal queens treated with a subcutaneous 4.7 mg deslorelin implant. Day 0 = day of treatment; period 1 = 1–60 days post-treatment; period 2 = 61–120 days post-treatment; period 3 =121–180 days post-treatment; period 4 = 181–240 days post-treatment; period 5 = >240 days post-treatment. The insert shows average (± standard deviation) values of keratinised cells (KC), concentration of serum progesterone (P4) and oestradiol (E2) in all animals throughout the study