Megestrol acetate for estrus postponement in the bitch

Area of Science:

• Veterinary Medicine
• Reproductive Endocrinology
• Canine Health

Background:

• Estrus suppression in female dogs is crucial for population control and managing reproductive cycles.
• Megestrol acetate is a progestin with known effects on the estrous cycle.

Purpose of the Study:

• To evaluate the efficacy and safety of megegestrol acetate for estrus suppression in female dogs.
• To assess the impact of megegestrol acetate on reproductive parameters in treated dogs.

Main Methods:

• Oral administration of megegestrol acetate to 389 bitches in early proestrus (2.2 mg/kg/day for 8 days).
• Oral administration of megegestrol acetate to 119 bitches in anestrus (0.55 mg/kg/day for 32 days).
• Monitoring for estrus suppression, adverse effects, and reproductive outcomes in subsequent litters.

Main Results:

• Estrus was suppressed in 92% of bitches treated during proestrus and 98% during anestrus.
• Adverse effects were minimal, with pyometra occurring in 0.8% of bitches treated in proestrus.
• No significant differences were observed in litter size, pup rearing success, or sex ratios compared to untreated controls.

Conclusions:

• Megestrol acetate is a highly effective and generally safe option for estrus suppression in female dogs.
• The drug demonstrates a favorable safety profile with minimal impact on subsequent reproductive success.