Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2001
Publication Date: 8/1/2001
Citation: N/A Interpretive Summary:
Technical Abstract: The effect of dietary ethoxyquin on antioxidant status, VFA status, ADG, and volatile N losses from manure were determined. Eighty steers (219 kg) were housed in 16 pens in Arkansas during a 42-d backgrounding period, and fed either a control diet or 150 ppm ethoxyquin, (Agrado; Solutia Inc., St. Louis, MO). Pre-transit blood and ruminal fluid samples were obtained and steers were transported to Bushland, TX. On arrival, steers were allotted to 6 pens equipped with pin-pointer feeders or 2 bunk pens (10 hd/pen) and fed either a control or 150-ppm ethoxyquin diet in a 2 X 2 factorial arrangement. Blood was drawn on d 0, 28, and 87 post-transit. Weights were obtained at 28-d intervals, and rumenocentesis was performed on d 5 and 28 to determine ruminal fluid VFA. Samples of excreta were collected from pen surfaces to determine NH3 volatilization using an in vitro gas emission chamber. Steers fed ethoxyquin in Arkansas, had lower (P < .05) serum vitamin E concentrations pre-transit than controls steers (1.93 vs. 2.23 microg/ml). Post-transit, steers that received ethoxyquin in Arkansas had higher (P < .04) vitamin E concentrations than control steers. Steers receiving ethoxyquin post-transit had greater vitamin A concentrations (P < .03) than control steers on d 28 and 87. Steers fed ethoxyquin consumed more (P < .001) feed (8.58 vs 7.25 kg/d) for d 1 to 182, and subsequently had greater (P < .05) ADG (1.61 vs 1.45 kg/d). Butyrate and iso-valerate were the only VFA affected by treatment. The excreta harvested from pens housing steers fed ethoxyquin had greater (P < .03) NH3 volatilization than control pens. These results suggest that adding ethoxyquin to a feedlot diet may increase ADG of feedlot steers, and may effect certain antioxidant concentrations.