Hunting and disease led to the disappearance of Rocky Moutain and California bighorn from Nevada in the 1920-30's. The Nelson desert bighorn survived in harsh desert areas. Between 1968, and 1992, a total of 1,323 bighorns were released in Nevada.
Reflecting the ecological importance of desert sheep to Nevada, reintroduction and augmentation of desert bighorn (792 animals) populations received the most attention, followed by California bighorns (321 animals), and then Rocky Mountain sheep (210 animals).
Outbreaks of disease with high rates of mortality have contributed to declines in native bighorn sheep populations and have limited efforts to repopulate historic range. An understanding of the dynamics that drive these outbreaks remains elusive and an improvement in our understanding of the factors that determine the occurrence of disease outbreaks in bighorn sheep may permit the development of strategies for mitigating such events.
The Nevada Dept. of Wildlife routinely collects biological samples during annual translocation events, as well as at hunter kills and necropsies. These samples will be analyzed for genetic makeup and diversity, evidence of pathogens, trace minerals, and overall health. This data will then be analyzed to better understand the health of the bighorn sheep populations in Nevada.