Digestion and Utilization of High Moisture Barley by Lactating Dairy Cows

Two experiments were conducted to study digestion and utilization of dry and high moisture barley.Dry matter yield of dry barley was 2.99 tonnes/ha in contrast to 3.58 tonnes/ha for high moisture barley.In Experiment 1, 38 cows in early to midlactation were assigned to two diets (40% alfalfa hay; 9.4% supplement and 50.6% barley, DM basis) that differed only in the type of barley fed: diet 1, roiled dry barley, and diet 2, rolled high moisture barley.Although DM intake, milk yield, and 4% FCM were not significantly influenced by diet, cows fed diet 2 had higher milk persistency than those fed diet 1.In Experiment 2, three lactating cows fitted with ruminal and duodenal cannulae were assigned to three dietary treatments in a Latin square design.Diets 1 and 2 were as in Experiment 1, whereas diet 3 contained ground high moisture barley.Digestibility coefficients tended to be lower and duodenal starch percent higher for cows fed diet 3 than those fed diets 1 or 2. No significant dietary differences were observed in ruminal pH, VFA, or ammonia concentrations.Although ensiling and processing influenced the rate and extent of DM and CP degradation in situ, treatment did not influence effective degradability.Results suggest that the feeding value of high moisture barley for lactating cows is equivalent to dry barley on a DM basis.sorghum can improve performance and feed efficiency compared with those for cattle fed dry grain (9, 14, 18).Although there is considerable data available on the feeding value of HM grains such as corn and sorghum, data on the feeding value of HM barley (HMB) is limited, especially for dairy cattle.Advantages for HMB include an earlier harvest with less dependency on the weather during harvest and DM yield increases ranging from 1 to 17% (8,12,13,14).Starch and protein in barley tend to have higher digestibility and be less responsive to processing than sorghum or corn (15,16,20).Replacement of dry barley (DB) by HMB in the diet of feedlot or dairy cattle does not result in the improved animal performance, which would have been predicted on the basis of results obtained with corn and sorghum.In many experiments, replacement of DB by HMB has resulted in either reduced, or at best marginal improvement in animal performance (3,6,7,11).In experiments where HMB has improved performance, its superiority has often been related to improvements in feed efficiency rather than improvements in gain (7, 9).Interpretation of feed efficiency data is complicated by the fact that oven drying of fermented products, such as HMG, can result in significant losses of fermentation products (5), and therefore, underestimation of DM intake.The objectives of the studies reported herein were to determine the relative feeding value of DB and HMB for lactating dairy cows and to evaluate the effect of processing on the site, rate, and extent of digestion of HMB.