GEMS stands for Genetics, Environment, Management and Society, which are four pillars of our sheep industry. Why so? In the United States, distinct breed-types are spread across climatically diverse regions and management systems. Breeding robust sheep that perform well under these conditions is therefore critical to the industry’s long-term sustainability. Currently, however, traits indicative of robustness and climatic resilience are largely absent in our genetic evaluation. Our ambition in Sheep GEMS is to remedy that shortfall.
Sheep GEMS has been underway for about two years, with exciting results generated. For those findings to be useful to sheep producers, they need to be widely shared. To begin that process, our providing further background into Sheep GEMS seems appropriate. That necessitates defining terms.
Robustness is an animal’s ability to remain healthy and productive – i.e., to survive and reproduce – within a defined environment or set of management conditions. Climatic resilience is an animal’s ability to either be little affected by, or capable of recovering from, changes in climatic conditions – e.g., extremes in temperature or relative humidity. An indicator trait is an on-farm measurement that helps predict an animal’s robustness or climatic resilience. As an illustration, fecal egg count is an indicator trait for resistance to gastrointestinal parasitism and thereby robustness.
The robustness traits incorporated into Sheep GEMS are lamb survival, udder health and gastrointestinal parasitism. Our indicator traits for lamb survival are birth weight and type, early postnatal survival and survival to weaning. For udder health, our indicator traits are udder depth and teat placement near lambing. Lastly, for gastrointestinal parasitism our indicator traits are fecal egg counts and FAMACHA scores collected in lambs and ewes at critical times.
We are assessing climatic resilience focusing on ewe longevity. As its indicator trait, we are recording a ewe’s stayability, defined by her retention in a flock while remaining productive. Additionally, we are collecting body weights and condition scores on ewes at key physiological stages – e.g., breeding and weaning – and monitoring their changes during the production season.
Collecting these additional measurements is an ambitious undertaking. Our success in doing so depends on collaborations. Three U.S. Department of Agriculture Agricultural Research Service facilities are core to our effort: the Dale Bumpers Small Farms Research Center, the U.S. Meat Animal Research Center and the U.S. Sheep Experiment Station. Scientists at these facilities are recording the indicator traits we described – along with others – on their genetically connected Katahdin, Polypay, Rambouillet and Suffolk flocks.
To impact the sheep industry, producers need to collect similar data in their own flocks. In collaboration with the National Sheep Improvement Program, we have recruited 45 NSIP flocks with these same four breeds to join the project.
Another aspect of Sheep GEMS is to incorporate genomic technologies into our genetic evaluations. Those tools allow us to validate pedigrees, provide genetic conditions for simply inherited traits and more reliably predict genetic merit for complex traits such as robustness and climatic resilience.
Sheep GEMS is in its early days. Still, our preliminary outcomes are promising. They set the foundation for providing the American sheep industry with methods to further improve our flocks. We look forward to sharing our discoveries with you in the series of articles that will follow.
The Sheep GEMS scientific team is Project Director Ron Lewis, Project Co-Director Luiz Brito, Joan Burke, Carrie Wilson, Brad Freking, Tom Murphy, Bret Taylor, Luis Pinto, Sara Nilson, Artur Rocha, Hilal Yazar Gunes, and Ali Haider Saleem.
The scientific team would like to thank American sheep associations and breed organizations, NSIP and sheep producers for their contributions to this research. This work is supported by the Agriculture and Food Research Initiative Competitive Grant – grant no. 2022-67015-36073/project accession no. 1027785 – from USDA’s National Institute of Food and Agriculture. USDA is an equal opportunity provider and employer. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the USDA.
Source: Sheep GEMS
