FIELD-TEST OF ACTIVITY OF THE LOW-DOSE RATE (2.64 MG KG) OF PYRANTEL TARTRATE ON ANOPLOCEPHALA-PERFOLIATA IN THOROUGHBREDS ON A FARM IN CENTRAL KENTUCKY/

A field test was done to evaluate activity on Anoplocephala perfoliata for the low dose rate (2.64 mg/kg) of pyrantel tartrate fed once dail y for 30 consecutive days to Thoroughbred mares (n = 83) and yearlings (n = 58) on a farm in central Kentucky. Tapeworm eggs were found pret reatment in feces of 35% of the mares and 33% of the yearlings. Posttr eat-ment fecal samples for the mares were negative for tapeworm eggs a t 35 days and 153-167 days postinitial treatment day (PIT) but positiv e (2%) at 72-86 days PIT. For the yearlings, post-treatment fecal samp les were positive for tapeworm eggs at 2 days (71%), 7 days (33%), 14 days (13%), 21 days (7%), 35 days (2%), and 75 days (2%) but negative at 28 days PIT. Also, for the yearlings, about two-thirds of the feces was collected during the first 2 days PIT for examination for A. prof oliata specimens; 401 with scolices were found in 74% of these animals . Prevalence of A. perfoliata in the yearlings was 96%, as determined by findings eggs in feces pretreatment and 48 hr PIT in addition to sp ecimens passed in feces.