C. A. Tucker
University of Arkansas
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Veterinary Parasitology | 2009
T.A. Yazwinski; C. A. Tucker; J. G. Powell; J. Reynolds; P. Hornsby; Z.B. Johnson
In this study, a single set of naturally infected calves was used for the conduct of a fecal egg count reduction test (FECRT) immediately followed by a control trial; all, to evaluate the efficacies of several commonly used, non-generic anthelmintics. Ten animals were allocated into each of the five treatment groups; untreated control (UTC), injectable 1% moxidectin given at 0.2 mg kg(-1)BW (MXD), injectable 1% ivermectin given at 0.2 mg kg(-1)BW (IVM), 9.06% oxfendazole given orally at 4.5 mg kg(-1)BW (OXF), and 10.0% fenbendazole given orally at 5.0 mg kg(-1)BW (FBZ). Confinement of animals to clean, concrete-floored pens was initiated on day -7 and continued until animal necropsy (2 animals were necropsied per treatment group per day on days 35-39 for nematode collections). All treatments were given on day 0, and the FECRT was conducted on all animals until necropsy. From days 2 to 14, FECR %s for the combined strongyle egg counts were >or=90% for all anthelmintic groups. At the time of necropsy, FECRT %s for the combined strongyle egg counts continued to be >or=90% for all treatments with the exception of IVM (84%). After adjustment of the strongyle egg counts in accordance with coproculture larvae percentages, FECRT %s at the time of necropsy for Haemonchus, Ostertagia and Cooperia were found to be >or=94% for MXD and OXF, but <90% for FBZ (Ostertagia) and IVM (Haemonchus and Cooperia). At necropsy, more than six of the ten untreated animals were infected with Ostertagia ostertagi (adults, EL(4) and LL(4)), and adult Haemonchus placei, Trichostrongylus axei, Cooperia oncophora, C. surnabada and C. punctata. Based on geometric means: all of the above populations were removed by >or=96% by MXD; were removed by >or=90% by IVM except for O. ostertagi LL(4) (81.9%), C. oncophora and C. surnabada adults (77.4%) and C. punctata adults (84.8%); were removed by >or=90% by OXF except for O. ostertagi adults, EL(4) and LL(4) (89.9, 70.2 and 48.1%, respectively); and were removed by >or=90% by FBZ except for O. ostertagi adults, EL(4) and LL(4) (72.5, 0.0 and 21.9%, respectively). Judging from the above data, FECR and control trial results can be extremely similar given the proper experimentation and, despite varied degrees of nematode resistance, targeted nematode burdens commonly carried by Midwestern beef cattle are effectively removed by the parasiticides that are available today.
Veterinary Parasitology | 2013
T.A. Yazwinski; C. A. Tucker; E. Wray; L. Jones; J. Reynolds; P. Hornsby; J. G. Powell
An anthelmintic efficacy study was performed with young, naturally infected beef-type calves obtained at local farms. Presumably, the study calves had been recently weaned and had not been treated with a parasiticide prior to study acquisition. After blocking the 24 study calves in accordance with calculated Cooperia spp EPG counts, the calves were randomly allocated within each block to one of four treatment groups, resulting in 6 animals per treatment group (untreated controls, topical ivermectin at the rate of 500 mcg/kg BW [Noromectin Pour-On(®) Norbrook], topical moxidectin at the rate of 500 mcg/kg BW [Cydectin Pour-On(®) Boehringer Ingelheim Vetmedica (BIVM)] and injectable moxidectin at the rate of 200 mcg/kg BW [Cydectin(®) BIVM]. After treatment, the animals were penned by treatment group until necropsy. Fecal, strongyle egg count reduction percentages at 2 days post-treatment were 13, 52, 81 and 93 for control, topical ivermectin, topical moxidectin and injectable moxidectin treatment groups, respectively. In the same order as above, egg count reduction percentages at necropsy (15-18 days post-treatment) were -14, 91, 94 and 97. Based on geometric means for worm burdens quantified at necropsy, anthelmintic efficacies ranged from 96 to 100% for adult Oesophagostomum radiatum, Ostertagia ostertagi, Haemonchus placei and Trichostrongylus axei. Against adult Nematodirus helvetianus, percent efficacies based on geometric means were 56.7, 98.3 and 82.2 for topical ivermectin, topical moxidectin and injectable moxidectin, respectively; an observation that is guarded, as only 5 control animals were infected with adult N. helvetianus. Respective anthelmintic efficacies (%s) against adult Cooperia oncophora and C. punctata were 93.0 and 73.4 (topical ivermectin), 99.3 and 99.9 (topical moxidectin) and 46.1 and 93.6 (injectable moxidectin). Judging from these data, it appears that treatment of calves soon after weaning with topical moxidectin is effective (>90% efficacy) for all common nematodes in cattle, but injectable moxidectin and topical ivermectin have limited effectiveness against Cooperia spp. With Cooperia spp and H. placei infections, the fecal egg count reduction test and the control trial determinations of anthelmintic effectiveness were in disagreement regarding injectable moxidectin and topical ivermectin.
Veterinary Clinics of North America-food Animal Practice | 2015
T.A. Yazwinski; C. A. Tucker; J. G. Powell; P. A. Beck; Eva Wray; Christine Weingartz
Fly and louse infestations are readily discerned and remedied in feedlot cattle. Tapeworm and fluke infections are accepted as probable but, given the lack of anthelmintics with realistic efficacy against these infections, these helminths are allowed to persist without treatment. Nematode infections are considered ubiquitous with cattle coming from pasture and are targeted with a macrocyclic lactone, usually in combination with a benzimidazole. Populations of nematodes seem to be effectively controlled by a combination of anthelmintic treatment, animal resistance and resilience, lack of reinfection, and diet.
Journal of Applied Poultry Research | 2007
C. A. Tucker; T.A. Yazwinski; L. Reynolds; Z.B. Johnson; M. Keating
Veterinary Clinics of North America-food Animal Practice | 2006
T.A. Yazwinski; C. A. Tucker
Parasitology Research | 2009
T. A. Yazwinski; C. A. Tucker; J. A. Hornsby; J. G. Powell; J. Reynolds; Z.B. Johnson; W. Lindsey; T. K. Silver
Journal of Applied Poultry Research | 2013
T.A. Yazwinski; C. A. Tucker; E. Wray; L. Jones; F. D. Clark
Journal of Applied Poultry Research | 2009
J. Reynolds; C. A. Tucker; T.A. Yazwinski; Z.B. Johnson; D. Clark; S. Clark
Journal of Applied Poultry Research | 2009
T.A. Yazwinski; C. A. Tucker; J. Reynolds; Z.B. Johnson; D. Pyle
Journal of Applied Poultry Research | 2013
T.A. Yazwinski; C. A. Tucker; E. Wray; L. Jones; Z.B. Johnson; S. Steinlage; J. Bridges