It depends on the weight and ADG that you wish to target for these cattle. The upper limit of distillers grains is is one-third of the diet on a dry matter basis. For example, if the intake of feeders that weigh 600 pounds is 2.5 percent of their body weight on a dry matter basis, then they will consume 15 pounds per head, per day of dry matter. One-third of the diet would be 5 pounds of hay per day of distillers grains on a dry matter basis. If the distillers is 35 percent dry matter and 65 percent moisture, then the amount of wet distillers grains on an as-fed basis would be about 14 pounds per head, per day. That seems like a lot of distillers but remember distillers is 65 percent water. You will not need to add any protein at this level of distillers as distillers is 30 percent crude protein. You will need to add some calcium to the diet as distillers grains are high in phosphorus. Make sure that you have plenty of bunk space so that all cattle get their share. Sulfur content can vary, and that's another reason for the need for plenty of bunk space. This recommendation assumes that you were not going to add corn to the diet.
Depending on the amount you are planning on feeding, it may take a week to 10 days to work the cattle up on distillers grains.
