Location: Dale Bumpers Small Farms Research CenterTitle: Complete anthelmintic resistance observed in U.S. meat goats
|SCHOENIAN, SUSAN - University Of Maryland|
|FREKING, BRIAN - Oklahoma State University|
|SEMLER, JEFF - University Of Maryland|
|GORDON, DAVID - University Of Maryland|
|BENNETT, MARY - West Virginia University|
|O'BRIEN, DAHLIA - Virginia State University|
|WOODS, EDDIE - Southeastern Oklahoma State University|
Submitted to: Sheep and Goat Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2019
Publication Date: 11/19/2019
Citation: Burke, J.M., Schoenian, S., Freking, B., Semler, J., Gordon, D., Bennett, M.B., O'Brien, D., Woods, E. 2019. Complete anthelmintic resistance observed in U.S. meat goats. Sheep and Goat Research Journal. 34:1-5.
Interpretive Summary: Resistance of worms to dewormers in goats represents a dire situation as many goat farms are plagued by internal parasites that can lead to production losses and death. In response, the University of Maryland and Eastern Oklahoma State College have developed goat tests that evaluate parasite resistance and resilience on pasture. Scientists from the Agricultural Research Service - Booneville, AR, University of Maryland, Oklahoma State University, Eastern Oklahoma State College, and Virginia State University determined that fecal egg count reduction to all classes of dewormers available at the start of the goat test was not adequate for sustainable goat production, including goats from 21 states. This information is important to goat and sheep producers, scientists, veterinarians, and extension specialists with an interest in sustainability of the small ruminant industries in the U.S.
Technical Abstract: The objective was to examine fecal egg count (FEC) reduction in meat goats entered into the University of Maryland (2008 – 2016) or Eastern Oklahoma State College (2014 – 2017) buck test. Weaned buck kids from private farms in 21 U.S. states were entered into the Western Maryland Pasture-Based Meat Goat Performance Test in Keedysville (MD; 2008 – 2016), or the Oklahoma Forage Based Meat Goat Buck test at Eastern Oklahoma State College, Wilburton (OK; 2014 – 2017) in early summer. The buck tests examined growth and response to natural parasite infection on a pasture-based diet in a common environment. In some years or tests, goats were supplemented with up to 225 g/day per goat. Between 18 and 84 goats were enrolled each year. All goats were dewormed upon arrival with moxidectin (0.4 mg/kg), albendazole (20 mg/kg) or fenbendazole (10 mg/kg), and levamisole (12 mg/kg). Feces were collected directly from the rectum to determine FEC on day of arrival (Day 0 or FEC1) and 10 to 12 days later (Day 12 or FEC2). The FECR (1 – (FEC2/FEC1) × 100) was calculated for 300 and 137 observations for the MD and OK tests, respectively, and analyzed using PROC GLM of SAS. The least squares (LS) mean FEC1 was 2069 ± 444 eggs/g (year, P = 0.005), and 342 ± 158 eggs/g (year, P < 0.001) for FEC2 in the MD test. The LS mean for FECR was 82.1 ± 4.7% and ranged between 60 and 96% for states with more than 5 observations. Year was significant, but not linear (P < 0.001). The highest FECR was in 2009 (99.2 ± 4.5%), but the lowest was in 2010 (48.2 ± 5.3%). In the OK test, FEC were 2311 ± 457 (year, P = 0.08) and 426 ± 142 (year, P < 0.001) eggs/g on Days 0 and 12, respectively. The FECR was 73.4 ± 5.8% (year, P < 0.001), and ranged between 47.6 and 98.6% for states with more than 5 observations. The highest FECR was in 2015 (91.4 ± 7.7%) and the lowest was in 2014 (48.9 ± 5.2%). In both buck tests, the FECR was as low as 48% indicating a dire problem for the goat industry.