Effects of Feeding Crab Processing Waste and Other Protein Supplements on Growth and Ruminal Characteristics of Steers Fed High-Roughage Diets1

A 126-d growth trial was conducted with 48 Angus × Hereford and Angus × Simmental steers (average BW 223 kg). Steers were blocked by body weight andbreeding into 8 blocks and randomly allotted within blocks to 6 supplements (8 steers/treatment). Diets were formulated to contain 10.5% CP and 63% TDN, DM basis. The supplements were 1) soybean meal (SBM), control; 2) supplement based on industrial by-products ofboth plant and animal origin (IPA); 3) experimental supplement based on byproducts of animal origin; 4) hydrolyzed supplement No. 3 (HESA); 5) commercial supplement based on animal protein, Pro-Lak; and 6) crab meal. In each diet, onethird of the N was supplied by the protein supplement. Steers were full fed in individual stalls during a 16-h period daily. Lower (P < 0.05) weight gain was recorded for the cattle fed the HESA and IPA supplements compared with other supplements. Feed efficiency was lowest (P < 0.05) for cattle fed the HESA supplement. At 126 d, ruminal NH3 N was higher (P < 0.05) for steers fed SBM than for those fed the IPA and HESA supplements. When included in the diet on a N equivalent basis, crab meal was comparabl to SBM or other products as a protein supplement for growing steers.