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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #198840
Title: EFFECT OF DIETARY CRUDE PROTEIN, RUMEN-UNDEGRADED PROTEIN AND RUMEN-PROTECTED METHIONINE ON MILK PRODUCTION OF LACTATING DAIRY COWS

Author
item Broderick, Glen
item STEVENSON, M - DEGUSSA CORP.
item PATTON, R - NITTANY DAIRY NUTRITION I

Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/10/2006
Publication Date: 7/10/2006
Citation: Broderick, G.A., Stevenson, M.J., Patton, R.A. 2006. Effect of dietary crude protein, rumen-undegraded protein and rumen-protected methionine on milk production of lactating dairy cows [abstract]. Journal of Dairy Science. 89(suppl. 1):402.

Interpretive Summary:

Technical Abstract: When crude protein (CP) is fed above that needed to meet requirements for metabolizable AA, excess urinary N contributes to environmental pollution. Rumen-undegraded protein (RUP) or rumen-protected Met (RPMet) may permit reduction of dietary CP without loss of production. A lactation trial was conducted using diets formulated to contain 28% NDF and 16.8 or 15.5% CP [dry matter (DM) basis], with or without RUP added as expeller soybean meal (ESBM). Diets were fed as TMR and contained (DM basis) 20% alfalfa silage, 35% corn silage, 4% soyhulls, 2% ground shelled corn, 2% rumen-inert fat, 0.5% sodium bicarbonate and 0.5% vitamins and minerals. Diets with 16.8% CP contained about 23% high moisture corn and 13% soybean meal; diets with 15.5% CP contained about 26% high moisture corn and 10% soybean meal. The RPMet was fed as Mepron. Forty-eight Holstein cows were blocked by DIM into 6 groups of 8, randomly assigned to incomplete 8x8 Latin squares and fed the TMR for three 4-wk periods. Data were summarized from the last 2-wk of each period. The statistical model included square, period, cow(square), diet, and diet*period. Probability was set at 0.05; LS means are reported below. Contrasts indicated that higher dietary CP increased intake and yield of milk, FCM, fat and protein but RUP reduced (P Š 0.05) fat and protein yield. Feeding RPMet increased intake and yield of FCM, fat and protein. Feeding RUP increased milk/DM intake. Milk urea was increased by both CP and RUP. While supplementing RPMet at 15.5% CP gave production comparable to 16.8% CP without RPMet, RPMet gave similar responses at both CP levels. CP, % 15.5 16.8 P > F ESBM, % 0.0 5.0 P > F Mepron, g/d 0 15 P > F Variable DM intake, kg/d 24.3 25.4<0.01 25.1 24.7 0.13 24.6 25.2 0.04 BW gain, kg/d 0.37 0.38 0.96 0.42 0.33 0.50 0.35 0.40 0.67 Milk, kg/d 40.0 41.6 0.01 40.8 40.9 0.88 40.5 41.2 0.26 Milk/DMI 1.65 1.64 0.62 1.63 1.67 0.03 1.65 1.64 0.60 3.5% FCM, kg/d 44.9 47.2 0.01 45.4 46.6 0.16 45.1 46.9 0.04 Fat, kg/d 1.43 1.52 0.01 1.44 1.51 0.07 1.44 1.51 0.02 Protein, kg/d 1.28 1.32 0.04 1.31 1.29 0.24 1.28 1.32 0.05 Lactose, kg/d 1.93 1.99 0.10 1.96 1.96 0.98 1.94 1.98 0.25 SNF, kg/d 3.58 3.68 0.07 3.64 3.62 0.72 3.59 3.67 0.17 MUN, mg/dl 9.8 11.5 <0.01 10.4 11.0 <0.01 10.6 0.8 0.36