EVALUATION OF CANOLA MEAL VERSUS SOYBEAN MEAL AS A PROTEIN SUPPLEMENT FOR BEEF CATTLE: EFFECTS ON GROWTH PERFORMANCE, CARCASS CHARACTERISTICS, RUMEN FERMENTATION, AND NUTRIENT DIGESTION.

Abstract

The objective of this research was to determine the effect of canola meal (CM) as a protein supplement for beef cattle on growth performance, rumen fermentation, and nutrient digestion compared to soybean meal (SBM) and wheat dried distillers’ grains with solubles (WDDGS). A 95-d backgrounding trial (Trial 1) and a 61-d backgrounding, 147-d finishing trial (Trial 2) were used to evaluate performance and carcass characteristics of feedlot cattle fed CM vs. SBM with or without WDDGS. In Trial 1, cattle fed SBM had greater ADG (P < 0.05) relative to cattle fed SBM+WDDGS but also numerically the highest feed cost of gain compared to the other three treatments. No other treatment differences were noted in Trial 1. In Trial 2, no treatment differences (P > 0.05) were detected for overall ADG, DMI, or gain : feed. Numerically, cattle fed SBM had the highest feed cost of gain with cattle fed WDDGS the lowest. Cattle fed SBM+WDDGS had the poorest fat deposition (P < 0.05) compared to cattle fed CM+WDDGS and WDDGS. However, no treatment differences were noted in final carcass value. A third trial using omasal, rumen, and fecal collections in heifers fed CM or SBM with or without WDDGS in a 4 x 4 Latin square was carried out to determine the effect of protein supplement on rumen fermentation, apparent and true ruminal nutrient digestibility, and total tract nutrient digestibility. Heifers fed WDDGS had lower (P < 0.05) DM, OM, and N intake than those not fed WDDGS. Heifers fed CM had the highest (P < 0.05) DM, OM, and N apparently and truly digested in the rumen compared to heifers fed SBM, and inclusion of WDDGS tended (P < 0.10) to decrease N truly digested in the rumen. There were no treatment differences (P > 0.05) noted in DM, OM, CP, ADF, or NDF digestibility. The results of all three trials indicate that CM is not different than SBM as protein supplement for feedlot cattle and that the inclusion of WDDGS did not improve feedlot performance, rumen fermentation, or nutrient digestibility.