Sheep GEMS News Brief 16 – July 2025 In a previous article, we highlighted the need for genetically improving the length of ewe productive life in U.S. sheep based on our studies in Katahdin sheep. Ewe longevity is an example of a trait that will benefit from genomic selection because it is sex limited (only females have records) and measured late in the life of the animals. Therefore, the Sheep GEMS team has conducted genomic studies to support the implementation of genomic selection to improve ewe longevity in U.S. sheep. Using records collected in the National Sheep Improvement Program (NSIP),…

Sheep GEMS News Brief 15 – June 2025 Ewe productive longevity, which is the number of days between a ewe’s first and last lambing, positively impacts flock profitability in at least three ways. It reduces annual ewe replacement costs. It increases ewe output by increasing the proportion of mature ewes in the flock. And lastly, ewes that live longer usually have fewer reproductive and health issues, which are major reasons for early culling. As part of Sheep GEMS, we are investigating ewe longevity using information on ewes in flocks enrolled in the National Sheep Improvement Program (NSIP). Our aim is…

Sheep GEMS News Brief 14 – May 2025 Previously, we introduced the concept of eco-management cluster—groups of flocks that share similar climate and management practices. These clusters are the foundation of our approach in Sheep GEMS for building genetic evaluations that more closely consider production environments. We are still exploring the makeup of eco-management clusters, as they undoubtedly differ among breeds. However, one of their important uses is in our study of genotype-by-environment interactions (G×E). G×E occur when the ranking of animals based on their genetic potential changes depending on the production environment in which they are managed. As an…

Sheep GEMS News Brief 13 – April 2025 Sheep producers across the U.S. operate in a wide range of environments—from humid grasslands to dry, high-elevation rangelands. These environmental differences, along with varied management practices, mean that a “one-size-fits-all” approach to genetic selection often falls short. In other words, the animals that perform best across all environments may not be the same, which could have implications when selecting breeding animals. To help address this challenge, our team in the Sheep GEMS project has developed a tool — coined eco-management clusters —designed to help producers select animals that are best suited to…

Sheep GEMS News Brief 8 – Early December 2024 The genetic diversity available within each sheep breed gives us tremendous opportunity to make genetic improvement. That snapshot of the genetic diversity currently available is extremely valuable since it provides a benchmark for comparing the consequences of selection over time in individual breeds. To establish that starting point, we used both pedigree- and molecular-based information to assess genetic diversity in the four breeds involved in Sheep GEMS. For each of the breeds we evaluated—Katahdin, Polypay, Rambouillet, and Suffolk—we found substantial genetic diversity. That coincides with low inbreeding levels. So, what do…