The use of straw in dairy cattle diets has increased greatly in recent years. Nutritionists recommend including wheat straw in the lactating cow total mixed rations for the following reasons: need to increase the effective fiber in the ration for improved rumination, desire to increase rumen fill and (or) or slow the rate of passage of digesta from the rumen when only finely chopped and (or) very highly digestible forages are available on the farm, and the need to extend farm forage inventories.

Potential benefits of straw for dry cows in addition to dietary energy restriction include reduced dietary potassium and cation-anion difference to reduce the incidence of milk fever and increased rumen fill to reduce the incidence of digestive disorders including displaced abomasum.

Whenever straw is included in the diet of a lactating dairy cow particle sorting should be carefully monitored. It is well documented that lactating dairy cows and heifers preferentially sort against the longest feed particles in a total mixed rations.