Induction of fertile oestrus in bitches by an intranasal spray of gonadotrophin-releasing hormone agonist.

摘要

Twenty Beagle bitches were divided into 3 groups which were treated with 3.6 micro g of an intranasal spray of a sustained-release formulation of leuprolide acetate (n=7), 0.3 mg/kg estradiol-17 beta orally once daily for 3 days and a daily intranasal spray of leuprolide acetate (n=7) and untreated controls (n=6). The dogs were observed daily for vulval swelling and oestrus behaviour. Blood progesterone levels were measured to determine whether ovulation had occurred. They were allowed to breed on the first day of oestrus and undergo pregnancy and parturition. Behavioural signs of oestrus were induced in 3 bitches treated with leuprolide acetate alone and in 5 bitches treated with leuprolide acetate and oestrogen. In the 3 bitches treated with leuprolide acetate, plasma progesterone levels rose above 2 ng/ml during normal oestrus. All the bitches with induced oestrus became pregnant and delivered normal litters, those that were not induced returned to normal oestrus within 3 months. The interoestrus interval of the induced dogs was significantly shorter compared to control dogs. However, litter sizes did not significantly differ between the induced and control groups. This is the first report of the successful induction of oestrus in bitches by treatment with an intranasal spray of a GnRH agonist. This is a useful method for controlling the induction of oestrus in anoestrus bitches..