The ultimate goal of the Mexican gray wolf Canis lupus baileyi captive management program is reintroduction of healthy individuals into wild habitats. To this end, zoo population managers work to provide not only for the physical well‐being but also for the genetic health of these animals. However, the very limited genetic founder base, exacerbated by breeding within three distinct lineages, resulted in very high coefficients of inbreeding. Because support for measurable levels of inbreeding depression in the captive wolf population, as defined by reductions in common fitness measures such as juvenile survival or reproductive success, has been weak, we investigated the potential effects on male reproductive capacity. We analyzed semen samples from wolves from all three lineages and compared them with samples from subsequent lineage crosses and from generic gray wolves. We not only found a significant effect of inbreeding on sperm quality but we related both inbreeding and sperm quality to reproductive success. Samples from male offspring of lineage crosses, with inbreeding coefficients of zero were similar in quality to those from generic gray wolves. However, samples from a limited number of offspring from back‐crosses were of extremely poor quality. Although it is reassuring that sperm quality was so much improved in male offspring of lineage crosses, the concomitant reduction in inbreeding coefficient does not eliminate the potentially deleterious alleles. Our results demonstrate that sperm quality is an important indicator of fertility and reproductive success in Mexican wolves. In addition, our data lend further support to the presence of inbreeding depression in this taxon.

Contents: North American zoos began using melengestrol acetate (MGA) implants to control reproduction in wild felids in the mid‐1970s. Research linking MGA and other progestin‐based contraceptives to uterine and mammary pathology in canids as well as felids resulted in a shift to GnRH agonist implants (Suprelorin^®: deslorelin, Peptech Animal Health, Australia). However, a recent study revealed an association between Suprelorin^® and uterine pathology in canids, but that pathology was not found in canids treated with oral megestrol acetate (MA) for 2 weeks around the time of implant insertion to prevent the initial agonist stimulation phase. Thus, the AZA Wildlife Contraception Center (WCC) currently recommends Suprelorin^® plus the 2‐week MA regimen for wild canids and felids. WCC research is now focusing on factors affecting Suprelorin^® reversibility.