Investigation of methods to enhance the efficiency of canola meal use in pelleted calf starter mixtures and comparisons with other high-protein by-products

Abstract It was hypothesized that the efficiency of canola meal ( CM ; also known as 00 rapeseed meal) utilization in pelleted starter mixtures for calves can be increased with the use of feed additives and additional processing. Additionally, it was hypothesized that CM would yield greater feed intake, growth, and improved fecal scores compared to wheat bran and DDGS when included as a high-protein by-product in a pelleted starter mixture. In order to verify the hypotheses, four studies were conducted to determine whether lysine ( Lys ) inclusion, feed enzyme inclusion, and CM extrusion improve the efficiency of CM utilization in pelleted calf starter mixtures, and to compare effects of CM to that when other high-protein by-products are fed. In study 1, 45 female Holstein calves (44.7 ± 4.2 kg, 24.2 ± 2.8 days of age) were allocated to one of three treatments and fed a pelleted starter mixture containing: 1) soybean meal ( SBM ) as the main source of protein ( TSBM ); 2) CM as the main source of protein ( TCM ); or 3) CM as the main source of protein with supplemental rumen-unprotected Lys ( TCML ). Final body weight ( BW ), average daily gain ( ADG ), starter intake, and fecal score did not differ among treatments ( P ≥ 0.20) but the gain to feed ratio was greater for TSBM than for TCM and TCML ( P < 0.01). No differences between TCM and TCML were found. In study 2, 100 female Holstein calves (44.3 ± 4.8 kg, 17.7 ± 2.1 days of age) were assigned to one of four treatments and fed pelleted starter mixtures with: 1) low CM inclusion (10%; LOW ); 2) low CM inclusion supplemented with feed enzymes (xylanase, glucanase, invertase, protease, cellulase, amylase, and mannanase; LOW+ ); 3) high CM inclusion (32%; HIGH ); and 4) high CM inclusion supplemented with the same feed enzymes ( HIGH+ ) as for LOW+. In treatments that included feed enzymes, final BW, ADG, and starter intake were greater while the number of days with diarrhea was lower ( P ≤ 0.05). The number of days with diarrhea was also lower for high CM treatments ( P < 0.01). In study 3, 120 female Holstein calves (42.6 ± 4.4 kg, 17.2 ± 2.1 days of age) were allocated to one of four treatments and fed a pelleted starter mixture: 1) containing SBM as a main source of protein ( CTRL ), or diets where: 2) SBM was partially replaced by wheat bran and corn DDGS ( TRBP ); 3) SBM was partially replaced by CM ( TRCM ); and 4) SBM was partially replaced by CM with feed enzymes (the same used in study 2; TRCM+ ). Feed intake and the gain to feed ratio did not differ among treatments. Final BW tended ( P = 0.10) to be heavier for CTRL than for TRBP and TRCM, but the CTRL group had a higher fecal score, a greater number of days with diarrhea, and more episodes of diarrhea compared to TRBP and TRCM ( P ≤ 0.05). No differences between TRCM and TRCM+ were detected. In study 4, 120 female Holstein calves (44.1 ± 4.9 kg, 18.3 ± 1.9 days of age) were allocated to one of four treatments and fed a pelleted starter mixture with: 1) moderate CM inclusion (24%; MC ); 2) high CM inclusion (34%; HC ); 3) moderate inclusion of extruded CM ( MEC ); and 4) high inclusion of extruded CM ( HEC ). Fecal score tended to be ( P = 0.10) and the number of days with diarrhea was ( P < 0.01) reduced when extruded CM was used in the starter mixture but BW, ADG, and the gain to feed ratio were not different among treatments. In conclusion, rumen-unprotected lysine supplementation in a pelleted starter mixture containing CM as the main source of protein does not improve the performance of calves although inclusion of enzymes may improve feed intake and ADG of calves. Extrusion of CM improves fecal score of calves but does not affect feed intake or growth. Canola meal should be considered at least as valuable source of protein as wheat bran and DDGS.