20,25-Diazacholesterol as an oral contraceptive for black-tailed prairie dog population management

Black-tailed prairie dog (Cynomys ludovicianus) colonies can become overcrowded, and the colonies, landscape, and people affected by them may benefi t 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®), an inhibitor of cholesterol and reproductive steroid hormone production, could reduce reproductive success of treated black-tailed prairie dogs in a fi eld 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.