Potential consequences and problems with wildlife contraceptives.

This presentation reviews multiple wildlife health considerations associated with contraception of wildlife, at the level of both the individual animal and wildlife population. Review of the literature demonstrates that many contraceptives studied in the past have had potential adverse effects characterized as follows: harmful effects on pregnant animals, inhibition of parturition or dystocia, changes in ovarian structure or function, changes in sex ratio, changes in lactation or mammary glands, impact on fertility of young, changes in testicular structure or function, changes in secondary sex characteristics, changes in bodyweight, changes in behaviour, changes in annual breeding season, other physiologic and pathologic changes, abscesses or inflammatory reactions, toxicity, interference with diagnostic tests and ecological alterations. Concern is expressed that the use of immunocontraception could create genetic changes in the target population that would influence disease resistance. The use of infectious agents as vectors to deliver immunocontraceptives was not considered wise animal health management because the product will be a new reproductive disease that could be difficult to contain within the target population. Criteria that need to be fulfilled for the safe use of contraceptives in wildlife are offered.