Effects of tempered barley on milk yield, intake, and digestion kinetics of lactating Holstein cows

The effects on milk yield and digestion kinetics were compared when tempered (10% water added 24 h prior to processing and feeding), rolled barley and dry, rolled barley were fed in trial 1, or tempered, whale barley, and dry, rolled barley were fed in trial 2. In trial 1, the diet based on tempered, rolled barley resulted in increased milk yield (5%), efficiency (10%), and apparent digestibility of dietary DM (6%), NDF (15%), ADF (12%), CP (10%), and starch (4%). Mean fractional rate of passage was slower for tempered (7.8%/h) than for dry (8.6%/h) barley particles. Mean fractional rate of passage of forage particles and rates of digestion of forage and concentrate did not differ. The percentage of particle washout from an in situ bag (pore size, 53 mu) was 21% for dry barley and 6% for tempered barley, indicating that tempering reduced the pool size of small particles in rolled barley. In trial 2, the diet based on tempered, whole barley resulted in decreased daily milk yield (5%), efficiency (11%), and apparent digestibility of dietary DM (16%), CP (10%), and starch (8%). The results indicated that tempered, rolled barley can be effectively used in diets for high yielding dairy cows to increase yield and efficiency; however, tempered barley must be rolled to achieve these effects.