Effect of Rumen-Protected Lysine Supplementation of Corn-Protein Based Diets Fed to Lactating Dairy Cows

Tuesday, July 22, 2014: 2:00 PM
2103C (Kansas City Convention Center)
Nelson E Lobos , Department of Dairy Science, University of Wisconsin-Madison, Madison, WI
Glen A. Broderick , Broderick Nutrition & Research, LLC, Madison, WI
Michel A. Wattiaux , University of Wisconsin-Madison, Madison, WI
Abstract Text:

This trial tested whether rumen-protected Lys (RPL) supplementation would improve the nutritive value of RUP from corn protein. Thirty-two lactating Holstein cows were blocked by DIM and parity into 8 squares of 4 cows in replicated 4 x 4 Latin squares. Treatments were all supplemental CP from: 1) Soy [67% expeller soybean meal (ESBM) plus 33% solvent soybean meal (SSBM)]; 2) Soy/Corn [33% ESBM, 17% SSBM, 25% corn gluten meal (CGM) plus 25% distillers dried grains plus solubles (DDGS)]; 3) Corn (50% CGM plus 50% DDGS); or 4) Corn/RPL [diet 3 top-dressed with RPL (125 g Ajipro®/d, an estimated 20 g absorbed Lys/d)]. Diets contained (DM basis) 22% alfalfa silage, 43% corn silage, 18% ground high moisture and dry corn, 2.4% mineral-vitamin premix, 1.5-3.9% soyhulls, 15% CP, 30-32% NDF and, as predicted by NRC (2001), equal RDP, RUP and metabolizable protein. Cows within squares were randomly assigned to treatment sequences and fed diets for 4-week periods before switching; data from the last 2-week were analyzed using the mixed procedures of SAS. The table reports LS-means. Intake was highest on diet 1, intermediate on diets 2 and 3, and lowest on diet 4; BW change was highest on diet 3, intermediate on diets 1 and 2 and lowest on diet 4. Intakes and BW changes were reflected by differences in Milk/DMI, which was highest on diets 2 and 4 and lowest on diet 3. Milk yield was lower on diet 3 than on diets 1, 2 and 4 and protein yield was highest on diets 1 and 2, intermediate on diet 4 and lowest on diet 3. These results indicated that dilution of soybean meal RUP with that from corn protein did not reduce milk yield and adding RPL to the corn-protein based diet increased milk and protein yields.

Table. Effect of Dietary CP Source and Rumen-Protected Lys on Production
Item Soy Soy/Corn Corn Corn/RPL  SE P > F
DMI, kg/d 27.7a 27.4ab 26.9bc 26.8c 0.40 < 0.01
BW change, kg/d 0.03bc 0.59ab 0.70a -0.07c 0.23 0.04
Milk, kg/d 45.8a 46.1a 44.3b 45.4a 1.17 0.01
Milk/DMI 1.66ab 1.69a 1.65b 1.69a 0.038 0.04
Fat, kg/d 1.87 1.87 1.83 1.83 0.060 0.37
True protein, kg/d 1.36a 1.34a 1.25c 1.30b 0.029 < 0.01
MUN, mg/dL 10.6 10.6 10.8 11.1 0.25 0.06

abc(P < 0.05)


Soybean meal

Corn gluten meal

Corn distillers dried grains

Rumen-protected Lys