
Pneumonia outbreaks in bighorn sheep have become a conservation and management issue for wild sheep herds across North America. However, not all pneumonia outbreaks effect sheep populations the same and not all populations carrying pneumonia related pathogens have outbreaks.
We suspect that the susceptibility of a bighorn sheep population to a pneumonia outbreak may be dependent on the nutritional quality of their landscape, and therefore the nutritional condition of the sheep on that landscape. We are studying how disease, habitat, and numerous other factors interact to influence adult and lamb survival.

Main Questions

How do nutrition and disease affect survival and raising offspring?
To investigate the influence of maternal condition and disease status on survival and raising offspring, we pair information on the nutritional condition and disease status of mom with knowing how long lambs survive after birth.

Do moms transmit disease immunity to lambs at birth?
Lamb recruitment can be a limiting factor in population growth, especially after a pneumonia outbreak. Immunities gained from mom could increase their chance at survival, but it is unknown if mom can pass such immunities on to her offspring. We are comparing antibodies–a way to measure immunity–between moms and newborn lambs.

How does habitat quality affect nutritional condition and immunity?
Pneumonia-causing pathogens are present in most bighorn sheep populations in Wyoming, but some populations are more resilient to outbreaks than others. Sheep with access to high quality forage tend to be in better nutritional condition and may be better buffered from the effects of pneumonia-causing pathogens, when compared to sheep with limited access to high quality forage.

Project leads
Rachel Smiley
Brittany Wagler


Collaborators, partners, and funders
This project is conducted in close collaboration with the Wyoming Game and Fish Department and the Wyoming State Veterinary Laboratory. This project is supported by the Wyoming Governor’s Big Game License Coalition, Wild Sheep Foundation, Wyoming Wild Sheep Foundation, Bowhunters of Wyoming, Wyoming Wildlife Livestock Disease Research Partnership, Wyoming Wildlife and Natural Resource Trust, Bureau of Land Management, Wyoming Animal Damage Management Board, United States Forest Service, Teton Conservation District, United States Fish and Wildlife Service, and Mountain View Resort, Lodging, and RV Park.