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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 #318420
Title: Replacing dietary soybean meal with canola meal improves production and efficiency of lactating dairy cows

Author
item BRODERICK, GLEN - Retired ARS Employee
item FACIOLA, ANTONIO - University Of Nevada
item ARMENTANO, LOUIS - University Of Wisconsin

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2015
Publication Date: 6/11/2015
Citation: Broderick, G.A., Faciola, A.P., Armentano, L.E. 2015. Replacing dietary soybean meal with canola meal improves production and efficiency of lactating dairy cows. Journal of Dairy Science. DOI: http:/dx.doi.org/10.3168/jds.2015-9563.

Interpretive Summary: Canola meal is a by-product of producing canola oil, a widely used cooking oil. Canola meal is usually less costly per unit of crude protein than soybean meal, the major protein supplement fed to dairy cows in the U.S. Protein supplements are the most costly feeds that dairy farmers purchase for their cows. We found in a lactation experiment that milk yield was greater when cows were fed supplemental protein as canola meal, rather than soybean meal. Also, cows fed diets supplemented with canola meal rather than soybean meal produced more milk protein and secreted more milk protein per unit of dietary protein consumed. Replacing dietary soybean meal with canola meal reduced urinary nitrogen excretion as well as milk concentration of urea, a compound found in milk that is related to protein efficiency in dairy cows. Improving protein efficiency of milk production reduces nitrogen pollution because less ammonia and nitrous oxide are lost to the atmosphere and into ground water. The dairy feeding handbook published by the National Research Council in 2001 indicated that soybean meal was superior to canola meal as a protein supplement. As a result, dairy nutritionists have generally avoided feeding canola meal to their cows. This research shows that previous information about canola meal was in error and that supplementing high-producing dairy cows with canola meal rather than more costly soybean meal may increase milk and protein yield of dairy cows and improve profitability for U.S. dairy farmers. Moreover, the greater protein efficiency when canola meal is fed will improve the environmental sustainability of U.S. dairy production.

Technical Abstract: Previous research suggested that crude protein (CP) from canola meal (CM) is used more efficiently than CP from solvent soybean meal (SBM) by lactating dairy cows. We tested whether dietary CP content influenced relative effectiveness of equal supplemental CP from either CM or SBM. Fifty lactating Holstein cows were blocked by parity and days in milk (DIM) into ten squares (two squares with ruminal cannulas) in a replicated 5 x 5 Latin square trial. Five squares were fed: 1) low (14.5-14.8%) CP with SBM, 2) low CP with CM, 3) low CP with SBM plus CM, 4) high (16.4-16.7%) CP with SBM, and 5) high CP with CM; the other 5 squares were fed the same diets except with rumen-protected methionine (Met) plus lysine (Lys) (RPML) added as Mepron® and AminoShure-L®, which were assumed to provide 8 g/d of absorbed DL-Met and 12 g/d of absorbed L-Lys. Diets contained (dry matter basis): 40% corn silage, 26% alfalfa silage, 14-23% corn grain, 2.4% mineral-vitamin premixes, and 29-33% neutral detergent fiber (NDF). Feeding periods were 3 weeks each for a total of 15 weeks. Data from the last week of each period were analyzed using the mixed procedures of SAS. The only effects of RPML were increased DM intake, milk urea nitrogen (MUN), and urinary N excretion and trends for reduced milk lactose and SNF concentrations and milk-N/N-intake; no significant RPML-by-protein source interactions were detected. Higher dietary CP increased milk fat yield and tended to increase milk yield, but also elevated MUN, urine volume, urinary N excretion, ruminal concentrations of ammonia and branched-chain volatile fatty acids (VFA). It lowered milk lactose concentration and milk-N/N-intake, while having no affect on milk true protein yield. Feeding of CM instead of SBM increased feed intake, yields of milk, energy-corrected milk and true protein and milk-N/N-intake, tended to increase fat and lactose yields, and reduced MUN, urine volume, and urinary N excretion. At low CP, MUN was lower. Intake tended to be greater on SBM plus CM versus SBM alone, but MUN and N excretion were not reduced to the same degree as on CM alone. Interactions of parity-by-protein source and parity-by-CP concentration indicated that primiparous cows were more responsive than multiparous cows to improved supply of metabolizable protein. Replacing SBM with CM reduced ruminal ammonia and branched-chain VFA concentrations, indicating lower ruminal degradation of CM protein. Replacing SBM with CM improved milk and protein yield and N utilization in lactating cows fed both low- and high-CP diets.