Annual Report for 2003 Wild Horse Research and Field Activities

Open-File Report 2004-1264

In cooperation with the Bureau of Land Management
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As stated in the Wild Horse Fertility Control Field Trial Plan, the Bureau of Land Management (BLM) has an immediate need for a safe, effective contraceptive agent to assist in the management of the large number of wild horses on western rangelands. The BLM and the U.S. Geological Survey-Biological Resources Discipline (USGS/BRD) are testing the immunecontraceptive agent Porcine Zonae Pellucida (PZP) in field trials with three free-roaming herds of western wild horses. Extensive research has already been conducted on the safety, efficacy, and duration of the PZP applications in both domestic and feral horses on eastern barrier islands and in some select trials with wild horses in Nevada managed by the BLM. However, significant questions remain concerning the effects of PZP application at the population level in the wild, as well as effects at the individual level on behavior, social structure, and harem dynamics of free-ranging animals. These questions are best answered with field trials on wild horse herds under a tight research protocol. The ultimate goal is to provide the BLM with the protocols and information necessary to being using fertility control to regulate population growth rates in wild horse herds on a broader scale. Fertility control is intended to assist the conventional capture, removal, and adoption process as a means of controlling excess numbers of wild horses and burros, and to greatly reduce the adoption costs and numbers of animals handled. Fertility control is not intended to totally replace the removal and adoption processa?|

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USGS Numbered Series
Annual Report for 2003 Wild Horse Research and Field Activities
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Open-File Report
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Geological Survey (U.S.)
Contributing office(s):
Fort Collins Science Center
iii, 22 p.
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