lmmunocontraception in White-Tailed Deer

Authors

John W. Turner Jr.
Jay F. Kirkpatrick
Irwin K.M. Liu

Date of this Version

October 1993

Comments

Contraception in wildlife management. APHIS Technical Bulletin No. 1853. USDA, Animal and Plant Health Inspection Service, Washington, D.C., USA.

Abstract

lmmunocontraception may have management application for white-tailed deer populations in parks and preserves. where hunting 1s illegal or impractical. This study examines physiological aspects of immunocontraception with porcine zonae pellucidae in 53 fertile white-tailed does. In separate studies, we employed protocols of three and two porcine zonae pellucidae (PZP) injections as well as two different protocols using one injection. Each one-injection vaccination consisted of one dose of porcine zonae pellucidae as in other protocols plus a second controlled-release dose of the material delivered via an osmotic minipump implant or injected, biodegradable polymer microspheres. We monitored fawn production for 1 to 3 years in all does and measured serum PZP antibody titers at various times after treatment in 15 randomly selected PZP does and in 2 control does. All three-injection PZP does were give a single PZP booster inoculation after 1 year. None of the two- or three-injection does and none of the one-injection does with a minipump produced fawns the first year after treatment, whereas two of seven does given a single injection with controlled-release microspheres produced fawns. In 49 control-doe breeding seasons, the pooled incidence of fawn production was 93.8 percent. Regarding reversibility of infertility, the incidence of fawn production was 75 % within 2 years after treatment was discontinued. Serum anti-PZP antibody titers were present only after PZP treatment, and highest titers occurred in does given two or three separate PZP injections. PZP-treated does showing >50% of maximal antibody titers at the onset of a breeding season did not produce fawns; those showing <33% of maximal titers did. These data demonstrate in white-tailed does that (1)multiple-injection PZP vaccination can produce complete contraception for at least one breeding season, (2) the contraceptive effect is reversible within 2 years in most does, (3) an elevated anti-PZP antibody titer occurs after PZP vaccination, and (4) multiple-injection PZP vaccination produces a sustained antibody response through at least one breeding season.

In separate field studies of wild, free-roaming deer in three locations, we successfully lured does to within darting range using bait stations. In two locations, we attempted and achieved remote delivery PZP vaccination of 60-9- percent of does. In the one location for which we have data on fawn production, the fawning incidence was 0/10, 6/9, and 8/9 for two- and one-injection porcine zonae pellucidae and untreated controls, respectively. In the same location, we monitored seasonal aspects of activity, behavior, and physical condition. We also determined that there is a good potential for remote assessment of pregnancy in does using measurement of pregnancy-specific elevations of steroid metabolites in fecal samples.