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Grand Teton National Park Report

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Brucellosis is a bacterial disease of cattle that has become established in elk and bison of the Greater Yellowstone Area. It causes elk and bison to abort and has the potential to be transmitted back to domestic cattle, which are now free of the disease. In this study we examined how long healthy bovine fetuses, as surrogates for aborted bison or elk fetuses, remained in the environment and could be available for contact by elk, bison, and cattle. Healthy bovine fetus carcasses were placed on state elk feedgrounds, the National Elk Refuge, and Grand Teton National Park to simulate an elk or bison aborted fetus. Fetuses were monitored until they disappeared due to scavenging. Fetuses took 26 hr on average to disappear from the National Elk Refuge, 46 hr at state elk feedgrounds, and 61 hr at Grand Teton National Park. Ninety percent of the fetuses could be expected to disappear from the National Elk Refuge within 60 hr (2.5 days); from state elk feedgrounds within 105 hr (4.4 days); and from Grand Teton National Park within 140 hr (5.8 days). Analysis of covariance showed that there was a significant difference in fetal disappearance rates depending on habitat type and site of placement. The dominant scavengers at all locations were coyotes (Canis latrans), but ravens (Corvus corax), magpies (Pica pica), bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) also frequently participated in scavenging. We found that aborted fetuses could potentially serve as a source of bacterial infection for several days. This study will be expanded to include greater numbers in the coming season.