Location: Livestock Bio-Systems
Project Number: 3040-31000-105-000-D
Project Type: In-House Appropriated
Start Date: Aug 11, 2022
End Date: Aug 10, 2027
Objective 1: Evaluate and improve genetic resources across diverse production systems and environments. Sub-objective 1.A: Characterize genetics that are fit to different lambing production systems and mating seasons. There are two experimental populations that contribute to this sub-objective, the Composite IV maternal line and the purebred Polypay flock. Sub-objective 1.B: Measuring genetic variation interactions with different production environments and management systems. This sub-objective will be addressed with two experiments. One experiment that estimates interactions at the intra-locus level using genetic variation for a gene that codes for the bone morphogenic protein receptor 1 beta (BMPR-1B) and one experiment that documents interactions at the whole animal performance level across different locations and production systems to estimate levels of GEM interactions. Objective 2: Develop complexes of novel traits to serve as indicator traits associated with improved production efficiencies. Sub-objective 2.A: Characterize behavior traits in rams, ewes, and lambs. Sub-objective 2.B: Characterize feed intake, carcass, health, and longevity traits of ewes and lambs.
Production inefficiencies threaten the ability of U.S. sheep producers to remain competitive with other domestic meat animal species and foreign sheep industries. The American Lamb Industry Roadmap Project identified several goals to overcome these obstacles. High priority was given to increased producer use of quantitative genetic selection tools which highlights the need for continued development of genetic technologies and adoption by the U.S. sheep industry. To support this industry goal, this project plan focuses on evaluating novel traits associated with animal health, behavior, and performance in multiple populations reared in diverse production environments and management systems. Specifically, we will estimate genetic and non-genetic covariation of economically important yet difficult to measure traits alongside more easily measured indicator traits already in use by industry breeders. Trait complexes evaluated will include susceptibility to common periparturient diseases and longevity of ewes; lamb survival, growth, feed intake, and carcass characteristics; ewe reproductive performance and maternal behaviors across mating seasons and lambing environments; and ram behavior and breeding capacity. Results from this work will serve as the foundation for developing new selection criteria for use in national breeding programs. Concurrent genotyping efforts will direct the identification of genomic regions associated with phenotypic variation and advancement of genomic-enhanced selection decisions. A key component of this effort will be to strengthen genetic relationships between flocks across USDA ARS locations at the U.S. Sheep Experiment Station and Dale Bumpers Small Farms Research Center which will, in turn, enable genetic x environment x management systems interactions to be evaluated for the first time in U.S. sheep populations. Germplasm from industry flocks will be routinely sampled thereby accelerating the dissemination of experimental findings. Results will improve our understanding of genetic and non-genetic factors which impact sheep well-being and productivity and provide sheep industry stakeholders with novel genetic selection tools for flock improvement.