Selection for Parasite Resistance
Joan M. Burke, Ph.D.
Research Animal Scientist
USDA, Agricultural Research Service
Dale Bumpers Small Farms Research Center
Dr. Jay Parsons, Department of Agricultural Economics
University of Nebraska-Lincoln
Time: 1 hour 30 minutes
Gastrointestinal parasite infection of sheep and goats is a major health issue that can cause anemia, reduced weight gains, poor performance, mortality and discouragement to farmers. Dewormer resistance limits the ability to control these parasites using available dewormers. Because of moderate heritability, opportunities exist to improve parasite resistance through genetic selection programs. This will be discussed along with scientific background, what to expect, and limitations. Climate, rainfall, management, sex of animal, rear type and age will influence parasite infection. Genetic resistance to parasite infection is arguably the best means of gastrointestinal parasite control. It can be achieved through selection of sires with favorable estimated breeding values in programs such as the National Sheep Improvement Program (NSIP), which will be reflected by lower parasite infection measures in offspring.