Supplementing corn on alfalfa pasture to alter growth performance, carcass, and quality traits

Supplementing Corn on Alfalfa Pasture to Alter Growth Performance, Carcass, and Quality Traits. Chloe Gresel, Cheryl Campbell, Lisa Duizer, Brian McBride, and Ira Mandell. University of Guelph, Guelph, ON, Canada.

Abstract Text:

Pasture finishing of beef cattle can be used to improve the fatty acid composition of beef (omega 3’s and CLA) but at the possible expense of deleteriously affecting palatability traits.  While pasture finished beef can command a premium in the marketplace, increased time on feed relative to finishing on a high grain diet can lead to production challenges due to much slower rates of gain for grass-fed beef.  Supplementing corn on pasture may increase cattle gains and beef palatability attributes without necessarily deleteriously affecting beef fatty acid composition. The objective of this study was to examine how corn grain supplementation on alfalfa pasture alters carcass, meat quality, and fatty acid traits in an attempt to increase cattle performance and beef palatability. Fifty black Angus and Angus cross steers were randomly assigned to one of four management regimens: 1) 85.4% corn-based concentrate / 14.6% forage diet fed in a drylot as a TMR (n=12); 2) pastured cattle supplemented with corn at 1% BW (n=13); 3) pastured cattle supplemented with corn at 0.5% BW (n=12); 4) pastured cattle with no corn supplementation (n=13). Pastured steers were rotationally grazed through 20 acres of predominantly alfalfa pasture while high concentrate-fed steers were housed in 2 drylot pens equipped with Calan gates to measure individual feed intakes. Cattle were fed for 111 days with BW taken every 14 d to track performance. Steers were harvested at a commercial packing plant where a rib section from each animal was shipped back to the University of Guelph Meat Lab for evaluation. Management regimen effects on performance, carcass, meat quality, trained taste panel and fatty acid data were evaluated using a Proc Mixed procedure in SAS. Average daily gain differed (P< 0.0001) across most management regimens.  While grain feeding decreased (P< 0.01) dissectible lean, backfat and marbling were generally similar (P > 0.14) across management regimens.  Grain feeding decreased (P < 0.0001) n-3 fatty acids without affecting (P > 0.27) CLA concentrations.  Taste panel assessment of tenderness, juiciness, and beef flavour attributes were similar (P > 0.30) between beef from grain-fed cattle and beef from cattle that only consumed alfalfa pasture.

Keywords: Beef cattle, grass-fed, fatty acids