Master of Science (MS)
School of Animal Science
One of the most significant threats to the well-being and performance of grazing livestock are gastrointestinal nematode (GIN) parasitic infections. Allowing a large GIN burden to manifest can cause a significant cost in terms of productivity in grazing cattle. Beef producers commonly rely greatly on the efficacy of broad-spectrum anthelmintics, to not only kill resident worms but to also prevent the establishment of ingested infective stage larvae (L3) for a period following treatment. Eprinomectin (LONGRANGE®, E-LR) is the first extended-release injectable cattle dewormer that claims to provide cattle producers season-long persistent parasite control for 100 to 150 d in a single dose, dependent on parasite species. This in turn, improves nutritional efficiency. The purpose of this study is to evaluate the efficacy of E-LR for controlling long-term GIN infections in nursing calves. E-LR was compared to the traditional anthelmintic fenbendazole (Panacur®, F-P). Four groups of nursing calves (with their dams) grazed separate pastures and pastures were rotated after each sampling date to ensure equal parasitic pasture exposure. Two groups were treated with E-LR and two groups were treated with F-P. Calves were weighed at 28 d intervals and fecal samples were collected on d 0, 14, 28, 56, 84, and 112. Results indicated E-LR was effective in providing long term parasite control. There was no significant (p < 0.05) difference in the FEC between F-P and E-LR treated animals on d 14, showing that both were efficient at initially killing GIN. Significant differences in FEC between treatments started to show by d 56. On d 56, there was an increase in FEC in calves treated with F-P which continued to increase throughout the rest of the study. The E-LR treated animals had only slightly increased FEC for the rest of the study which indicated prolonged GIN control.
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Seibert, Lyndsea D., "The Evaluation of Eprinomectin (LONGRANGE®) on Long-Term Parasitic Infection in Nursing Calves During Summer Grazing®" (2016). LSU Master's Theses. 80.