Using flax as a feedstuff for beef cattle

Three trials investigated if flax in beef cattle diets affects performance or carcass composition. The first trial examined level and duration of inclusion. Cattle were fed diets that included 3 or 6% (dry matter; DM) flax for 28 or 56 d prior to harvest. Steers fed flax had greater (P = 0.03) marbling than steers fed no flax. Feeding flax for 56 d increased ( P < 0.001) muscle alpha-linolenic acid (ALA) compared to 28 d. Feeding 6% flax increased (P = 0.04) ALA compared to 3%. Steaks from steers fed flax were less tender (P ≥ 0.001) than steaks from steers fed no flax. The second trial offered calves creep feed that contained 0, 12.5, or 25% (DM) flax. Flax did not affect ( P ≥ 0.36) performance. Calves offered creep feed containing flax had lower (P = 0.06) marbling than calves offered no flax. Calves offered 25% flax had greater (P = 0.08) marbling than those offered 12.5%. The third trial investigated flax processing. Beef heifers were fed corn- and silage-based diets that contained 0 or 8% (DM) flax that was whole, rolled, or ground. Heifers fed flax had greater (P ≤ 0.006) average daily gains (ADG) and gain efficiency (G:F) compared to heifers fed no flax. Processing (rolled or ground) increased (P ≤ 0.05) ADG and G:F compared to whole flax and increased (P < 0.001) muscle phospholipid and neutral-lipid proportions of ALA. Flax-fed heifers had greater (P ≤ 0.02) muscle proportions of phospholipid eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). Processing increased the proportion of muscle phospholipid and neutral lipid ALA (P < 0.001) and increased (P ≤ 0.01) EPA and DHA. Sensory panelists noted that flax-fed beef was less juicy (P = 0.05). Flax can be included in beef cattle diets to improve G:F and to manipulate beef fatty acid profiles. Changes in fatty acid profiles are dependent on flax inclusion level, time of feeding, and processing. Processing is necessary when feeding flax to maximize G:F. Including flax in creep feeds will not affect performance or carcass composition.