Effect of a contraceptive compound (EP-1) on fertility of female Brandt's voles, gray hamsters and mid-day gerbils

Abstract

We tested the effect of contraceptive compound of levonorgestrel and quinestrol (coded as EP 1) on the fertility of female Brandts voles, gray hamster and mid day gerbils. Although less palatable (61% intake of control baits),reproduction of female Brandts voles in the laboratory was significantly prohibited by this contraceptive; the time of littering was delayed about 3 days longer and the proportion of littering females was reduced to 40%-50%. Two dose baiting was better than one dose baiting in reducing fertility of voles. The proportions of littering females and the numbers of littering of gray hamsters and mid day gerbils were also significantly reduced by this contraceptive within 3 months after animals were given two dose baiting in laboratory. The effect of this contraceptive on gray hamsters was better than on mid day gerbils. The contraceptive caused some mortality in mid day gerbils. This contraceptive showed promise for fertility control of wild rodents. Two dose baiting or one-dose satiation baiting are recommended for further tests in the field.