Efficacy of methane fermentor residue as a source of roughage for cattle fed grain based diets

Cattle manure was used as substrate for a methane fermentor and the residue was investigated as a source of roughage ingrain–based feedlot cattle diets. Eighty-eight steers (initial weight, 326 kg) were allotted by weight to 15 pens for a 113 day trial. Dietary treatments were: 1) 85% concentrate + 15% corn silage (control), 2) 95% concentrate + 5% methane fermentor residue, 3) 92.5% concentrate + 7.5% methane fermentor residue, 4) 90% concentrate + 10% methane fermentor residue, and 5) 87.5% concentrate + 12.5% methane fermentor residue. The concentrate was based primarily of whole shelled corn. Daily gains of steers fed the control diet (15% corn silage) were greater (P<0.05) than those of steers fed the 5% methane fermentor diet but did not differ (P>0.10) from steers fed the 7.5, 10 and 12.5% methane fermentor diets. Diet did not affect (P>0.10) feed intake or carcass characteristics. Digestibility of dry matter and organic matter did not differ (p>0.10) between the control diet and diets containing methane fermentor residue. It was concluded that com silage and methane fermentor residue have equal efficacy as a source of roughage within the dietary levels tested in this experiment.