A:   There are data that suggest that too much added fat to the diet can reduce performance. There are two articles that you can refer to in the 2007 Nebraska Beef Report, page17 and the 2008 Nebraska Beef Reprot page40. Both of these article can be found at our website http://beef.unl.edu then go tho the navagator bar Reports on the left-hand side of the homepage. Both distillers grains with solubles and solubles are good feeds for beef cattle in forage diets, especially when using medium to low quality forages. DDGS typically is between 10% and 12% fat and solubles can be close to 20% fat. In most cow and and backgrounding diets, this is usually not a problem, but that depends on the performance (ADG) projected for the cattle in a backgrounding situation. Currently 4.5% to 5% added fat to the diet, dry matter basis, has been my recommended upper limit. So if you were supplementing 1200 pound cows with 6 lb/hd/da (if solubles were 30% dry mattter and 70% water, that would be 20 lb/hd/da as-fed) solubles with average quality hay and cows were eating 2.2% of their weight on a dry matter basis. Total dry matter intake would be 24 lb/hd/da so 25% of the diet is solubles (6/24=.25). If solubles were 20% fat then fat intake is 1.2 lb/hd/da (6 lb/hd/da dry matter x .20 = 1.2 lb/hd/da fat intake on a dry matter basis) on a dry matter basis and that calculates to 5% added fat to the diet. DDGS at a 1/3 of the diet or less on a dry matter basis will typically be at about 3.8% to 4.1% added fat to the diet on a dry matter basis.