Case studies in wildlife immunocontraception: wild and feral equids and white-tailed deer

Abstract

Non-lethal management methods are required for wild equids that are protected by law and for deer inhabiting areas where lethal controls are not legal or safe. Single or multiple inoculations of porcine zona pellucida (PZP) vaccine have been delivered to wild horses and deer by means of darts. Contraceptive efficacy in horses after two inoculations ranged from 90% to 100%, and after a single inoculation ranged from 19% to 28%. Mares given a controlled-release form of the vaccine had foaling rates ranging from 7% to 20%. No detectable changes in social organization or behaviours among treated horses occurred. Contraceptive effects were reversible after 4 consecutive years of treatment but 5-7 years of treatment resulted in ovulation failure and decreased urinary oestrogen concentrations. Among deer, two inoculations were 70-100% effective in preventing fawns, but one inoculation yielded a contraceptive efficacy of < or = 20%, with pregnancies occurring late in the breeding season; a single annual booster inoculation reduced fertility to 20% in the second year. Energy costs of extended breeding seasons were less than those resulting from pregnancy. After two years of treatment, ovaries appeared normal. These studies suggest that PZP immunocontraception can be successfully applied to certain free-roaming populations of wild horses and deer.

Effect of ovariectomy on the social status of brushtail possums(Trichosurus vulpecula)in captivity

“…Similarly, tubal ligation did not affect home range or dominance of free-living foxes (Bubela 1993). Immunocontraceptive control of fertility in feral equids by zona pellucida immunisation of mares did not affect social behaviour (Kirkpatrick et al 1993). We are not aware of studies that have examined the effect of ovariectomy on the behaviour of wildlife.…”

Pedigrees and the Study of the Wild Horse Population of Assateague Island National Seashore

“…For .30 years, this population has contributed to our knowledge of feral horse behavior (Keiper 1977, Keiper and Berger 1982, Keiper and Sambraus 1986, Powell 2008, ecology (Zervanos and Keiper 1979, Rutberg and Keiper 1993, Powell et al 2006, and social structure (Keiper 1978, Rutberg andGreenberg 1990). It has also acted as a natural laboratory for the development and testing of new methods of remote pregnancy testing and immunocontraception (Kirkpatrick et al 1990(Kirkpatrick et al , 1993Kirkpatrick and Turner 1991), as well as for understanding the longer term effects of these technologies on wild mammal populations (Kirkpatrick et al 1997;Powell 1999Powell , 2000Powell and Monfort 2001;Kirkpatrick and Frank 2005).…”

Expression of a Recombinant Porcine Zona Pellucida Glycoprotein ZP1 in Mammalian Cells

“…In the previous studies, some successful applications of native proteins of porcine zona pellucida (pZP) 2 for contraceptive vaccines were reported in various species of wild animals (1). These studies suggest that glycosylated recombinant protein would be a good candidate for the antigen of contraceptive vaccines.…”