Effects of replacing soybean meal with canola meal or treated canola meal on ruminal digestion, omasal nutrient flow, and performance in lactating dairy cows

Abstract

Extrusion treated canola meal (TCM) was produced in an attempt to increase the rumen-undegraded protein fraction of canola meal (CM). The objective of this study was to evaluate the effects of replacing soybean meal (SBM) with CM or TCM on ruminal digestion, omasal nutrient flow, and performance in lactating dairy cows. To assess performance, 30 multiparous Holstein cows averaging (mean ± SD) 119 ± 23 d in milk and 44 ± 7 kg of milk/d and 15 primiparous cows averaging 121 ± 19 d in milk and 34 ± 6 kg of milk/d were blocked in a randomized complete block design with a 2-wk covariate period and 12-wk experimental period (experiment 1). Dietary ingredients differed only in protein supplements, which were SBM, CM, or TCM. All diets were formulated to contain (dry matter basis) 30% alfalfa silage, 30% corn silage, 4% soy hulls, 2.4% mineral-vitamin premix, and 16% CP. The SBM diet contained 25% high-moisture shelled corn and 8.6% SBM; the canola diets contained 22% high-moisture shelled corn and either 11.2% CM or 11.4% TCM. To assess ruminal digestion and omasal nutrient flow, 6 rumen-cannulated cows were blocked into 2 squares of 3 cows and randomly assigned within blocks to the same 3 dietary treatments as in experiment 1 in a replicated 3 × 3 Latin square design (experiment 2). Data were analyzed using the MIXED procedure of SAS (SAS Institute, Cary, NC). Orthogonal contrasts were used to compare effects of different protein supplements: SBM versus CM + TCM and CM versus TCM. In experiment 1, compared with SBM, apparent total-tract digestibilities of dry matter and nutrients were greater in cows fed both CM diets, and there was a tendency for nutrient digestibilities to be higher in cows fed CM compared with TCM. Diets did not affect milk yield and milk components; however, both canola diets decreased urinary urea N (% of total urinary N), fecal N (% of total N intake), and milk urea N concentration. In experiment 2, compared with SBM, both canola diets increased N intake and tended to increase rumen-degraded protein supply (kg/d) and N truly digested in the rumen (kg/d). Diets did not affect ruminal digestibility, efficiency of microbial protein synthesis, and rumen-undegraded protein flow among diets. Results from this experiment indicate that replacing SBM with CM or TCM in diets of lactating cows improved digestibility and may reduce environmental impact. Moreover, under the conditions of the present study, treating CM by extrusion did not improve CM utilization.

Effects of replacing soybean meal with canola meal differing in rumen-undegradable protein content on ruminal fermentation and gas production kinetics using 2 in vitro systems

“…Although the high dietary CP might have played a role in ruminal N fermentation, especially with regards to RDP and NH 3 -N levels, previous studies with 16.5 and 15.7% CP, respectively, reported similar results with regards to ruminal N metabolism when comparing SBM and CM Paula et al, 2016a). This suggests that dietary CP levels play a minor role when comparing these 2 protein supplements.…”

Feeding Canola, Camelina, and Carinata Meals to Ruminants

“…On the contrary, Brito et al [49] did not observe differences in total and individual VFA and NH 3 -N concentrations and BCVFA among diets supplemented with CM, SBM, or CSM fed to dairy cows. In addition, other studies evaluating ruminal fermentation parameters in dairy cows fed diets supplements with CM vs. SBM did not observe differences in any VFA traits [25,75]. Comparing CM vs. dried distillers grains, Mulrooney et al [19] did not observe differences in total and individual VFA concentration, except for valerate, which linearly increased when CM was gradually replaced with DDGS.…”

Microbial Inoculum Composition and Pre-weaned Dairy Calf Age Alter the Developing Rumen Microbial Environment

“…Rumen fluid (4 mL) for VFA and NH 3 analyses was thawed, mixed, centrifuged at 30,000 × g at 4°C for 30 min and the supernatant was collected and stored at −20°C. Ruminal VFA and NH 3 were analyzed in-house using previously described gas-liquid chromatography and Lachat methods, respectively (Paula et al, 2018).…”