Effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings1

Abstract

To assess the effects of flax addition and flax processing on feedlot performance and carcass characteristics, 128 yearling beef heifers (360 +/- 14 kg of initial BW) were blocked by weight and assigned randomly to feedlot diets that included no flax (control), whole flax (WHL), rolled flax (RLD; 1,300 microm), or ground flax (GRD; 700 microm). Heifers were fed a growth diet (31% corn, 30% corn silage, 18% barley malt pellets, 14% alfalfa, 4% linseed meal, and 3% supplement; DM basis) for 56 d, after which they were adapted to a finishing diet (79% corn, 7% corn silage, 7% alfalfa, 4.75% linseed meal, and 2.25% supplement; DM basis). In WHL, RLD, and GRD, flax replaced all linseed meal and partially replaced corn at 8% of diet DM. All diets provided 0.5 mg of melengestrol acetate, 2,000 IU of vitamin E, and 232 mg of monensin per heifer daily. Cattle were slaughtered by block after 96, 97, and 124 (2 blocks) d on feed. At 24 h postmortem, carcass data were collected, and a portion of the loin was removed, vacuum-packaged, and aged for 14 d. After aging, 2 steaks were removed from each loin for Warner-Bratzler shear force measurement, sensory panel evaluation, and fatty acid analysis (approximately 100 g of muscle was collected). Flax inclusion (WHL, RLD, and GRD vs. control) did not affect DMI (P = 0.79), fat thickness over the 12th rib (P = 0.32), or LM area (P = 0.23). Flax inclusion increased ADG (P = 0.006), G:F (P = 0.006), and USDA yield grade (P = 0.01). Flax processing (RLD and GRD vs. WHL) increased ADG (P = 0.05), G:F (P = 0.08), and apparent dietary NEm and NEg (P = 0.003). Muscle from heifers fed flax had greater phospholipid 18:3n-3 (P < 0.001), 20:5n-3 (P < 0.001), 22:5n-3 (P < 0.001), and 22:6n-3 (P = 0.02) fractions, and greater neutral lipid 18:3n-3 (P < 0.001). Feeding 8% flax to feedlot heifers increased gain and efficiency, and processing flax increased available energy and resulted in increased efficiency of gain. Feeding 8% flax also increased levels of n-3 fatty acids in fresh beef.

Linseed: a valuable feedstuff for ruminants

“…It can also be noted that pasture feeding, which is another source of 18:3 n-3, increases 18:3 n-3 in meat, although generally to a lower extent (Scollan et al, 2005). The increase in muscle 18:3 n-3 concentration is significantly higher with extruded linseeds than with rolled linseeds (Normand et al, 2005), and higher in ground or rolled linseeds than with whole linseeds (Maddock et al, 2006). The increase in 18:3 n-3 was higher in Longissimus thoracis than in Rectus abdominis and Semitendinosus in a trial by Mialon et al (2015), but this difference was not observed in trials by Normand et al (2005) and by Habeanu et al (2014).…”

“…It can be concluded that the incorporation of linseeds for finishing cattle has no effect or a slightly positive effect on performances. Although it has been shown that lipid supply in fattening diets generally increases carcass fat proportion (Clinquart et al, 1995), available data for linseed supply do not fully support this statement: linseeds may increase or not (Maddock et al, 2006;Normand et al, 2005;Razminowicz et al, 2008) carcass fatness. The reality of a difference between linseed and other lipid sources needs further research.…”

“…2). Whole linseeds have been used by Maddock et al (2006) and Corazzin et al (2012). Results suggest that linseed hull does not limit a normal digestion of the seed.…”

“…When linseeds are given as formaldehyde-treated seeds, protecting them from rumen degradation and resulting in high 18:3 n-3 absorption, a fish taste in meat, an increase in rancidity and in a decrease in In experiments by Raes et al (2004) and Normand et al (2005) feed intake was not determined so that additional fat supply is not known. In the experiment by Maddock et al (2006) fat content of diets was not specified. D611, page 6 of 9 M. Doreau and A. Ferlay: OCL 2015, 22(6) D611 overall liking are observed (Scollan et al, 2005).…”

Effects of whole linseed and rumen-protected conjugated linoleic acid enriched diets on beef quality

“…Although the scores for this attribute were over half of the scale in all treatments, tenderness was the greatest in meat from linseed fed animals (6.59), although the addition of CLA together with linseed decreased this perception (5.88) ( Table 4). Also Maddock et al (2006) found that meat from flaxseed fed animals was more tender than meat from steers finished on a corn-based diet without flaxseed. Since fibrousness is negatively related to tenderness (Campo et al, 1999), Mean scores rated from 0 = very low to 10 = very high.…”