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ARS Home » Southeast Area » Booneville, Arkansas » Dale Bumpers Small Farms Research Center » Research » Research Project #432086

Research Project: Understanding Parasite Resistance in Organic Livestock and Using a Systems Approach for Control

Location: Dale Bumpers Small Farms Research Center

Project Number: 6020-21310-010-17-A
Project Type: Cooperative Agreement

Start Date: Oct 1, 2016
End Date: May 31, 2020

Objective:
One of the greatest barriers to organic production of ruminant livestock is the control of gastrointestinal nematodes (GIN) or parasites. The goals of this project are to 1) understand host mechanisms involved in GIN resistance/resilience by examining differences in immune response among susceptible, resilient, and resistant individuals and breed types, 2) identify genetic loci associated with resistance/resilience, 3) further examine successful systems approaches of GIN control, including fall lambing to minimize summer exposure of GIN to lambs, diverse forage and grazing systems to minimize GIN exposure and use secondary plant compounds for control, and finally, 4) work with farmers enrolled in the National Sheep Improvement Program (NSIP) to understand tools for selection for GIN resistance. Participating farmers will be involved by providing 5000 DNA samples and phenotypes on GIN resistance of lambs in NSIP to use in our objectives. We will educate organic farmers on the importance of NSIP’s breeding values and elite resistant sires to improve flock genetics for GIN resistance.

Approach:
We will determine effect of Katahdin sire Estimated Breeding Values (EBV) on Haemonchus (H.) contortus infection in Katahdin lambs using genotype data and gene expression studies to identify genes and gene networks contributing to these traits from which genetics variant markers can be incorporated to improve genetic prediction. At ARS, we will use industry data and identification of genetic loci associated with resistance to gastrointestinal nematodes (GIN) to improve the accuracy of Fecal Egg Count (FEC) EBV calculations. Genome wide association studies will be used to identify genetic loci associated with resistance to GIN with genotypic information obtained from industry, ARS and institutional animals. Integration of resistant genetics, grazing and forage systems, and season of lambing to control GIN will be employed to develop farm systems that minimize the need for deworming. The Texel breed will be examined as a GIN resistant terminal sire.