Results and Discussion
Dry matter intake increased linearly from 23.5 to 27.7 kg/day (Table 2) with increasing brewers grains substitution for forage. Despite the lower formulated NEL concentrations, though, DMI appeared to amply compensate the increasing concentration of wet brewers grains. However, lactation performance was not affected by the substitution of brewers grains for forage.
The DMI by cows fed cottonseed diets were similar to that of cows fed the control but were lower than that of cows fed high brewers grains, which had a similar forage NDF concentration. The coating of the Easiflo cottonseed could have reduced the effectiveness of the fiber, decreasing milk fat percentage. However, milk fat yield was not affected, so this could be a dilution response to a slightly (but not significant) higher milk production.
This study documented that effective fiber and nonfiber carbohydrates should be considered simultaneously when nonforage fiber sources replace forage. More work is needed to characterize long-term feeding characteristics of these types of diets for associative effects so that ration formulators can better evaluate how and when to use these feed sources to improve flexibility and profitability.