Comparison of barley, hull-less barley, and corn in the concentrate of dairy cows

Twelve multiparous and 12 primiparous lactating Holstein cows were used to compare the effects of hull-less barley with barley and corn on dry matter intake (DMI), digestibility, and milk production. Three concentrates were formulated using steam-rolled grains: barley, hull-less barley, or corn. During three 21-d periods, cows received a total mixed diet consisting of 60% concentrate, 30% barley silage, and 10% cubed alfalfa hay [dry matter (DM) basis]. Milk production and DMI were higher for cows fed the corn diet than for cows fed the barley or hull-less barley diets; no interaction with parity was detected. The DMI of cows fed the hull-less barley and barley diets were similar. Despite the higher estimated energy density of the hull-less barley diet, milk production was similar for cows fed the hull-less barley and barley diets because of the lower digestibility of the hull-less barley. Results of an in situ study showed that, for steam-rolled grains, DM and starch from hull-less barley were less degradable than were DM and starch from barley, although the opposite result was observed for ground grains. For steam-rolled hull-less barley, low ruminal degradabilities of DM and starch were apparently not compensated by high intestinal digestibility because total tract digestibility and milk production were lower than expected. Although the net energy for lactation value of hull-less barley is higher than that for barley, milk production by cows might be limited unless hull-less barley is adequately processed to ensure high ruminal and total tract digestibilities.