Recent research at Montana State University, University of Wyoming, and United States Sheep Experiment Station has indicated subclinical mastitis to be much more prevalent than previously thought. These studies have shown that 54% of sampled ewes had diagnosed subclinical mastitis. Additionally, these infected ewes weaned litters that weighed 11 lbs. less at weaning that litters reared by healthy ewes, which represented an economic loss of $26 per ewe. Using somatic cell count to indicate subclinical mastitis, the economic loss was calculated to be up to $31 per ewe if she had a somatic cell count of 500,000 cells/mL (diseased) compared to a ewe with a count of 100,000 cells/mL (healthy). Using somatic cell count to indicate mastitis and assuming a 500 ewe flock (inferring the results of the sampled ewes), 140 ewes would have subclinical mastitis and the producer would be losing nearly 1900 lbs. of lamb at weaning. This is equivalent to an economic loss of $3500 in this flock, which would not have been lost if those lambs were reared by healthy ewes. However, this research only sampled ewes at these three research flocks, with management systems meant to best match commercial sheep production practices. Therefore, mastitis and the bacteria identified within these flocks are likely to be different than bacteria identified in commercial flocks due to environmental, geographical, and management differences. A producer survey of grower-selected ewes would allow the most common bacteria species found in milk and environment (e.g., bedding, soil, gates, etc.) within regions or management systems to be identified. Additionally, the differences in bacterial composition between the environment, teat, milk, and lamb is unknown and will likely influence both the prevalence and severity of mastitis. Another purpose of the producer survey is to evaluate the relationship between these bacterial populations of the environment and milk. After this information is collected, we will have a foundation for understanding the dynamics of subclinical mastitis including the bacterial species infecting the mammary tissue, length of infection, and production impacts. This will lead to further research to mitigate the effects of subclinical mastitis, thus improving animal welfare and health, while increasing productivity and revenue in Western sheep operations.