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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Cell Wall Biology and Utilization Research » Research » Publications at this Location » Publication #327692
Title: Effects of replacing soybean meal with canola meal or treated canola meal on nitrogen metabolism and total tract digestibility in lactating dairy cows

Author
item PAULA, EDUARDO - University Of Nevada School Of Medicine
item DANES, MARINA - Universidade Federal De Lavras
item LOBOS, NELSON - Kemin Industries, Inc
item Zanton, Geoffrey
item BRODERICK, GLEN - Retired ARS Employee
item FACIOLA, ANTONIO - University Of Nevada School Of Medicine

Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2016
Publication Date: 7/8/2016
Citation: Paula, E.M., Danes, M.A., Lobos, N.E., Zanton, G.I., Broderick, G.A., Faciola, A.P. 2016. Effects of replacing soybean meal with canola meal or treated canola meal on nitrogen metabolism and total tract digestibility in lactating dairy cows [abstract]. Annual Meeting of American Dairy Science Association, July 19-23, 2016, Salt Lake City, Utah.

Interpretive Summary:

Technical Abstract: Dietary canola meal (CM) has been shown to improve N efficiency in dairy cows when compared with soybean meal (SBM). Treating CM may increase amino acid (AA) supply from the rumen undegradable protein fraction and improve absorbable AA in the metabolizable protein. The objective of this study was to evaluate the effects of feeding treated CM (TCM) on N metabolism and total tract digestibility of dairy cows. Thirty multiparous Holstein cows, averaging 660 ± 55 kg body weight (BW), 119 ± 23 days in milk (DIM), and 44.1 ± 7 kg milk/d, and 15 primiparous cows, averaging 592 ± 34 kg BW, 121 ± 19 DIM, and 33.5 ± 6 kg of milk/d were blocked in a randomized complete block design. Cows were fed a control diet for a 2-week covariate period and then switched to the experimental diets for a 12-week study. Treatments differed only in crude protein (CP) source, those sources being SBM, CM, and TCM. The CM was treated by extrusion, with molasses added to promote the browning reaction. All diets contained (dry matter [DM] 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 corn (HMC) and 8.6% SBM; the canola diets contained 22% HMC and 11.4% CM or TCM. On the last day of weeks 4, 8, and 12, spot urine and fecal samples were collected at 6 and 18 h after feeding. Data were analyzed using the MIXED procedure of SAS. Orthogonal contrasts were used to compare effects of different protein sources (SBM vs. CM + TCM) and (CM vs. TCM). Compared to SBM, apparent digestibility of DM, organic matter, crude protein, and neutral detergent fiber was greater on both CM and TCM diets. There were no differences for N intake, milk yield, and total N excreted in urine and feces; however, both canola diets decreased urinary urea-N (% of total urinary N) and fecal-N (% of total N intake), and decreased milk urea nitrogen concentration. No differences were observed between CM and TCM. Results from this experiment indicated that replacing SBM with CM or TCM in lactation diets improves digestibility and minimizes environmental impact, but extrusion did not improve CM utilization.