Effect of dried distillers' grain, soybean meal and grain or canola meal and grain-based supplements on forage intake and digestibility

Abstract

Four ruminally cannulated beef heifers (72 wk of age) were individually fed a basal ration of 75% ground barley straw and 25% ground bromegrass hay [total digestible nutrients =46.3, crude protein (CP) =7.5 (% dry matter (DM))]. Heifers were supplemented with either (1) no supplement (CONT); (2) dried distillers' grains plus solubles [70:30 wheatcorn blend; dried distillers' grains plus solubles (DDGS)]; (3) commercial range pellet (COMM); or (4) barley grain and canola meal (BAR + CM). Forage intake, apparent total tract digestibility, passage rate, rate and extent of forage degradation, rumen pH and rumen ammonia nitrogen were measured. Forage intake, passage rate, and apparent total tract digestibility of DM, neutral detergent fiber, and acid detergent fiber were unaffected (P>0.41) by treatment. Apparent total tract digestibility of CP was increased (P = 0.02) with supplements as compared with CONT, but did not differ (P>0.05) among DDGS, COMM, and BAR + CM. Ruminal pH was not affected (P=0.20) by treatment, but rumen ammonia-N was increased (P B0.01) with all three supplements. Potentially degradable and undegradable forage fractions were decreased (P B0.02) and there was a tendency (P =0.06) for the rate of forage DM degradation to increase with supplementation. Supplementing forage diets with either DDGS, grain-soybean-canola- or grain-canola-based supplements did not increase the intake or digestibility of a forage-based diet. More research, however, is required to study the feasibility of feeding these supplements at greater levels with forage-based beef cattle diets.