U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

March 2007


Published in Human-Wildlife Coinflicts 1(1):60-67, Spring 2007.


Black-tailed prairie dog (Cynomys ludovicionus) colonies can become overcrowded, and the colonies, landscape, and people affected by them may benefit from controlled populations. Contraception is a method that may be useful, particularly where lethal control is inappropriate or illegal. We investigated if oral administration of 20,25-diazacholesterol (DiazaCon®)n, inhibitor of cholesterol and reproductive steroid hormone production, could reduce reproductive success of treated black-tailed prairie dogs in a field trial. Ten treatments of approximately 45-mg DiazaCon per black-tailed prairie dog yielded a 47% reduction of young:adult ratios compared to control sites. Over a 3-month period, desmosterol, a cholesterol precursor used as an indicator of DiazaCon effects, was not detectable in any black-tailed prairie dogs trapped at control sites, whereas elevated levels were detectable in 33 of 35 blood samples from black-tailed prairie dogs trapped at treated sites. Average cholesterol levels were lower in treated animals than in control animals. DiazaCon administration may be a useful tool to control populations of black-tailed prairie dogs, especially in light of the desire for conservation while still managing populations.