Immunocontraceptive vaccines are the least invasiveandmost humane fertility control option for free ranging horses, butto be both technically feasible and cost effective, they must consistently have…

Immunocontraceptive vaccines are the least invasiveandmost humane fertility control option for free ranging horses, butto be both technically feasible and cost effective, they must consistently have multi year efficacywith a single dose the main difference between these three studies appears to be theinjectionsite i e , neck in the first two studies, rump in the other thefirstobjective of our research is to assess immune response and contraceptive efficacy usingdifferent injection sites i e , neck and rump we hypothesize that mares vaccinated in the neck will mountasignificantlymore robust immune response with potentially permanent effects on ovarian function compared to mares vaccinated in the rump due to proximity to major lymph nodes additionally, booster doses have never been administered for spayvac, yet amnesticresponses are known to result in increased antibody production for prolonged periods of time our second objective is to examine the effect of a booster dose in a subset of mares vaccinated earlier with spayvac we hypothesizethatthesemares will initiate a robust secondary response resultingin increased efficacy and duration, or possiblypermanent infertility the proposed research will identify improvements to existing contraceptive or sterilization treatments or procedures that could increase their practicality, efficacy or duration , which is the BLM wild horse and burro program s highest priority objective determining optimal administration methods for spayvac will lead tomorereliable fertility control that is conducive to broad scale application by managers of feral horse populations