A National Survey of the Gastrointestinal Nematode Control Practices Used by Goat Producers in the United States

Authors: AVERY, RYAN - Us Agency For International Development (USAID); URIE, NATALIE - Animal And Plant Health Inspection Service (APHIS); BRANAN, MATTHEW - Animal And Plant Health Inspection Service (APHIS); WIEDENHEFT, ALYSON - Animal And Plant Health Inspection Service (APHIS); DENNIS, ELLIOT - University Of Nebraska; MARSHALL, KATHERINE - Animal And Plant Health Inspection Service (APHIS); Burke, Joan; MILLER, JAMES - Louisiana State University

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: A 2019 nationwide survey of U.S. goat and goat farm gastrointestinal nematode management practices was conducted by the USDA National Animal Health Monitoring System. The study uncovered practices used by farmers to control worm parasites between autumn and spring (the peak summer period could not be included). The average fecal egg count for goats was 651 eggs/g, and for farm was 658 eggs/g, primarily from 25% of animals surveyed. Classes of goats that had the highest fecal egg counts were does around the time of kidding, thin animals, and those that grazed or browsed compared with those confined. The collaborators on this study from USDA-APHIS, USDA-ARS, University of Nebraska, and Louisiana State University found the value in this study in assessing practices and risks of worm parasites at a regional level that allow for a more comprehensive understanding of challenges facing producers. These results are important to the U.S. goat industry, the producers, veterinarians and consultants, and other scientists involved in understanding and managing goat parasites.

Technical Abstract: Gastrointestinal nematode (GIN) parasites are a major constraint to goat production. Control has relied primarily on using anthelmintic drugs. GIN populations have developed widespread resistance to anthelmintics which has become a major problem in goat operations globally, including in the United States (U.S.). U.S. goat producers are highly concerned with GIN infections, but there remains limited information on what practices are used nationally to combat infections and prevent anthelmintic resistance. As part of the 2019 National Animal Health Monitoring System (NAHMS) study, conducted by the U.S. Department of Agriculture, the practices used by goat producers to control GIN parasites and reduce anthelmintic resistance on their operations were evaluated. The study aims were to determine GIN parasite burden at both the individual animal- and operation-level, investigate geographic patterns of GIN parasitism, and identify risk factors associated with infection prevalence and intensity. The study covered 24 U.S. states, representing 80.4% of U.S. goats on operations with =5 goats and 75.8% of operations with =5 goats. Data from fecal samples submitted for fecal egg count (FEC) analysis and individual goat- and operation-level questionnaires were collected from 9,879 goats across 623 operations. The estimated, weighted mean operation- and animal-level FEC for goats was 658 and 651 eggs per gram , respectively. Across all goats tested, egg-shedding was found to be over-dispersed, with the top 24.1% of animals contributing to 80% of the total FEC. Univariate analysis revealed that primary operation production type, primary land/facility management type, primary grazing/browsing management, FAMACHA© card usage, body condition categorization, and month of sample collection were significant factors impacting mean FEC at both the operation- and animal-level. U.S. regionality, goat type, breed, FAMACHA© score, and browsing schedule were found to be significant at the animal-level. Multiple regression analysis at the operation-level revealed that deworming frequency in the previous 12 months, pasture housing practices, and the interaction between region and sample collection date were significant factors that impacted the mean FEC. Multiple regression analysis at the animal-level revealed that goat type, FAMACHA© score, body condition categorization, primary grazing/browsing management, primary operation production type, the interaction between region and multiple species grazing, and the interaction between region and sample collection date, were significant factors that impacted mean FEC. This study provides valuable information to help guide future GIN research and regionally specific control practices.