Effect of Eprinomectin or Fenbendazole on the Performance of Growing Steers Grazing Tall Fescue

Abstract

Gunter, SA., Beck, PA. and Hubbell III, D.H. 2006. Effect of eprinomectin or fenbendazole on the performance of growing steers grazing tall fescue. J. Appl. Anim. Res., 29: 1–5.

Two experiments were conducted over 98 and 113 days in the fall and spring, respectively, with growing steers grazing tall fescues (Festuca arundinacea Schreb). In both experiments, untreated steers weighed less (P<0.01) than steers treated with eprinomectin or fenbendazole after grazing. The body weight between steers treated with eprinomectin or fenbendazole did not differ (P>0.33). Untreated steers had average daily gains that were less (P<0.01) than steers treated with eprinomectin or fenbendazole. No differences (P=0.49) were noted in average daily gains between eprinomectin and fenbendazole. Untreated steers had higher (P<0.01) strongyle egg counts than the steers treated with eprinomectin or fenbendazole. Steers de-wormed with eprinomectin or fenbendazole responded similarly to treatment in both grazing seasons with de-wormed cattle gaining body weight 67% faster than non-treated control steers. Using eprinomectin did not produce a synergistic effect on body weight gain by cattle grazing tall fescue compared to using fenbendazole which has been suggested to occur when using ivermectin, even though eprinomectin and ivermectin are chemically similar.

Key words:

• Beef cattle
• Tall Fescue
• eprinomectin
• fenbendazole