|PAULA, EDUARDO - University Of Nevada Las Vegas, Las Vegas, Nv|
|BRODERICK, GLEN - Retired ARS Employee|
|DANES, MARINA - Universidade Federal De Lavras|
|LOBOS, NELSON - Kemin Industries, Inc|
|FACIOLA, ANTONIO - University Of Nevada Las Vegas, Las Vegas, Nv|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2017
Publication Date: 11/9/2017
Citation: Paula, E.M., Broderick, G.A., Danes, M.A., Lobos, N.E., Zanton, G.I., Faciola, A.P. 2018. Effects of replacing soybean meal with canola meal or treated canola meal on ruminal digestion, fermentation pattern, omasal nutrient flow, and performance in lactating dairy cows. Journal of Dairy Science. 101:328-339.
Interpretive Summary: Canola meal has improved nitrogen utilization and dairy cow performance when compared to soybean meal. However, studies evaluating the effect of treated canola meal have shown inconsistent results. The objective of this study was to evaluate the effect of feeding extrusion-treated canola meal on omasal nutrient and microbial nitrogen flow and performance. Treated or untreated canola meal or solvent soybean meal treatment diets did not affect omasal nutrient flow or productive performance. However, canola meal diets decreased nitrogen excretion in feces, urine, and milk urea nitrogen, indicating a potential reduction in environmental impact. Nonetheless, treating canola meal by extrusion did not improve performance of dairy cows.
Technical Abstract: Extrusion-treated canola meal (TCM) was produced in an attempt to increase the rumen undegradable protein (RUP) 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, fermentation pattern, omasal nutrient flow, and performance in lactating dairy cows. To assess performance, 30 multiparous Holstein cows averaging (means ± standard deviation) 119 ± 23 days in milk (DIM) and 44.1 ± 7 kg milk/d, and 15 primiparous cows averaging 121 ± 19 DIM and 33.5 ± 6 kg milk/d were blocked in a randomized complete block design with a 2-week covariate period and 12-week 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 (HMSC) and 8.6% SBM; the canola diets contained 22% HMSC and 11.2% CM or 11.4% TCM. To assess ruminal digestion, fermentation pattern, and omasal nutrient flow, 6 rumen-cannulated cows were blocked into 2 blocks of 3 cows and randomly assigned within blocks to the same 3 dietary treatments as in Experiment 1, in a replicated 3x3 Latin square design (Experiment 2). Data were analyzed using the MIXED procedure of SAS. Orthogonal contrasts were used to compare effects of different protein supplements (SBM vs. CM + TCM) and (CM vs. TCM). In Experiment 1, compared to SBM, apparent total tract digestibilities of dry matter, organic matter, crude protein, and neutral detergent fiber were greater on both CM diets; there was a tendency for CM to improve nutrient digestibilities when compared to TCM. Diets did not affect nitrogen (N) intake, 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 to SBM, both canola diets increased N intake and there was a tendency to increase RUP supply (kg/d) and N truly digested in the rumen (kg/d). Diets did not affect ruminal digestibility, efficiency of microbial protein synthesis, flows of RUP and total microbial-non-ammonia-N among diets. Results from this experiment indicated that replacing SBM with CM or TCM in diets of lactating cows improved digestibility and may minimize environmental impact. Moreover, under the conditions of the present study, treating CM by extrusion did not improve CM utilization.