Epnix® and Liver Abscess Treatment Effects on the Performance, Health, and Carcass Characteristics of Feedlot Steers

A trial was conducted using 3,360 crossbred beef steers in 48 pens to evaluate the effects of feeding EPNIX® products (Alltech Inc.) on the growth performance, carcass characteristics, and health outcomes of feedlot steers. Four treatments were evaluated: 1) Control (CON+MT), standard commercial feedlot ration including monensin and tylosin, 2) EPNIX® without monensin and tylosin (EPNIX), 3) EPNIX® with the inclusion of monensin and tylosin (EPNIX+MT), and 4) EPNIX® 2 without monensin and tylosin (EPNIX 2). The base finishing diet was similar between treatments and included steam-flaked corn, wet corn gluten feed, wet distillers grains with solubles, and chopped corn stalks. Data were analyzed as a randomized complete block design in the GLM procedure of Minitab 17. Dry matter intake and live performance were not different between treatment groups (P ≥ 0.174), although final BW tended to be greatest in the EPNIX+MT and EPNIX 2 treatments compared to CON+MT and EPNIX when dead and removed steers were included (651.0 and 647.9 kg vs. 645.1 and 639.7 kg, respectively, P = 0.059). Additionally, when dead and removed steers were included, feed efficiency was improved in the CON+MT, EPNIX+MT, and EPNIX 2 treatments compared to EPNIX (6.00, 5.97, and 6.10 vs. 6.22, respectively; P = 0.046). Digestive-related deaths were greatest in EPNIX and least in EPNIX+MT (0.95% vs. 0.12%; P = 0.043). Contrasts revealed that inclusion of EPNIX increased HCW (P = 0.031). Dressing percentage was greatest in EPNIX and EPNIX 2 and least in CON+MT and EPNIX+MT (64.7 or 64.8% vs. 64.5 or 64.6%, respectively; P = 0.002). A greater percentage of carcasses graded Choice for CON+MT and EPNIX+MT treatments than EPNIX or EPNIX 2 (74 or 73% vs. 66 or 68%, respectively; P < 0.001). Total liver abscesses were greatest in EPNIX and EPNIX 2 treatments compared to CON+MT or EPNIX+MT (24 or 19% vs. 14 or 10%, respectively; P < 0.001), although EPNIX 2 had tended to have fewer abscesses than EPNIX (P < 0.1). These data indicate that EPNIX® inclusion in finishing diets increased HCW, improved carcass transfer, and had the greatest effect on the prevention of digestive disorders and liver abscesses when fed in combination with monensin and tylosin.