Travis Maddock, Vern Anderson, Rob
Maddock, Marc Bauer and Greg Lardy
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his study was designed to investigate if processing flax would affect how cattle responded to flax inclusion in the diet. These data suggest flax addition increases gain and feed efficiency, and that processing flax is necessary to optimize feedlot performance.
A randomized complete block design
was used to evaluate the effects of processing flax in beef feedlot diets. One
hundred twenty-eight beef heifers (792.8 ± 31.0 lbs initial BW) were blocked by
weight and assigned randomly to 16 pens (8 heifers/pen).
Pens were then assigned to one of four diets. Heifers were fed a growing diet
for the first 56 days after which they were stepped up to a finishing ration
(Table 1). The control growing diet consisted of corn, corn silage, alfalfa,
barley malt pellets and linseed meal, and the finishing diet consisted of corn,
corn silage, alfalfa, and linseed meal. Flax diets added whole, rolled, or
ground flax to rations at eight percent of DM, replacing linseed meal and
partially replacing corn. Supplements were formulated to provide 0.5 mg MGA,
2000 IU vitamin E, and 232 mg monensin daily. Heifers
were harvested by block on days 96, 97, and 124 (two blocks) with carcass data
and m. longissimus lumborum
samples for shear force and sensory panel analysis collected. Dry matter intake
(25.2 ± 0.4 lbs/d) was not affected (P = 0.79) by treatment. Flax addition
increased (P ≤ 0.01) ADG
(lbs/d), feed efficiency (feed:gain), and hot carcass
weight (lb; HCW), and increased KPH fat percent, and calculated yield grade.
Processing (grinding or rolling) increased (P
≤ 0.001) ADG, feed efficiency, and HCW. No treatment effects (P ≥ 0.23) were noted for dressing
percent, external fat, or ribeye area. Marbling score
tended to increase with flax addition (P
= 0.14). Steaks from cattle fed flax were less juicy (P = 0.06) than those from control diets, and steaks from cattle fed
rolled flax were juicier (P = 0.09)
than those fed ground flax. Treatment did not affect (P ≥ 0.16) sensory tenderness or flavor ratings. Warner-Bratzler shear force tenderness was affected (P = 0.06) by treatment, with steaks from
cattle fed flax rated more tender (P =
0.04) than the control cattle, and steaks from cattle fed processed flax were
more tender (P = 0.05) than steaks from
cattle fed whole flax. These data indicate including flax at eight percent of
diet DM improves growth and efficiency of feedlot heifers, but may increase
internal fat deposition and negatively affect yield grade. Additionally,
processing flax is necessary to optimize these effects. Feeding flax reduced
sensory panel ratings of beef juiciness, however flax did increase mechanical
measurements of tenderness in the resultant beef.
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Table 1. Diet composition of control and
flax diets. |
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Growing Dietsa |
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Finishing Dietsa |
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Ingredient |
Control |
Flax |
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Control |
Flax |
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------- 100% DM Basis ------ |
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Flax |
-- |
8.00 |
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-- |
8.00 |
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Corn |
31.00 |
27.00 |
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79.00 |
75.75 |
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Corn Silage |
30.00 |
30.00 |
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7.00 |
7.00 |
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Alfalfa |
14.00 |
14.00 |
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7.00 |
7.00 |
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Barley Malt Pellets |
18.00 |
18.00 |
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-- |
-- |
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Linseed Meal |
4.00 |
-- |
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4.75 |
-- |
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Supplementb |
3.00 |
3.00 |
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2.25 |
2.25 |
a Composition of flax diets was the same regardless of
degree of processing.
b Supplements were formulated to provide 0.5 mg melengesterol acetate (MGA),
2000 IU vitamin E, and 232
mg monensin daily.
Table 2. Effects of processing flax on feedlot
performance and carcass characteristics. |
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Dietsa |
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P-valuesb |
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Item |
Control |
Whole |
Rolled |
Ground |
SE |
Treatment |
Control vs. Flax |
Whole vs. Processed |
Rolled vs. Ground |
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DMI, lbs/d |
25.6 |
25.0 |
25.1 |
25.1 |
0.4 |
0.79 |
0.34 |
0.90 |
0.96 |
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ADG, lbs/d |
3.08 |
3.18 |
3.42 |
3.41 |
0.08 |
0.01 |
0.008 |
0.01 |
0.64 |
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Feed Efficiency |
8.25 |
7.84 |
7.33 |
7.34 |
0.31 |
<0.001 |
0.001 |
0.008 |
0.68 |
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HCW, lbs |
702.2 |
716.2 |
729.5 |
726.8 |
5.4 |
0.001 |
<0.001 |
0.008 |
0.38 |
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Dressing % |
60.4 |
60.8 |
60.6 |
60.8 |
0.5 |
0.85 |
0.48 |
0.79 |
0.70 |
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Backfat, in |
0.49 |
0.52 |
0.55 |
0.53 |
0.03 |
0.33 |
0.14 |
0.42 |
0.45 |
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REA, in2 |
12.2 |
11.9 |
11.7 |
12.1 |
0.2 |
0.23 |
0.26 |
0.79 |
0.09 |
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KPH, % |
2.20 |
2.55 |
2.54 |
2.58 |
0.10 |
0.07 |
0.01 |
0.92 |
0.79 |
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Yield Grade |
2.93 |
3.20 |
3.40 |
3.21 |
0.09 |
0.03 |
0.01 |
0.38 |
0.17 |
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Marblingc |
431.6 |
477.5 |
469.8 |
456.2 |
13.1 |
0.14 |
0.04 |
0.39 |
0.48 |
a Control
treatment was a basal, no-flax diet; whole, rolled, and ground treatments
included flax in the diet at 8% of DM.
b P-values
are associated with F-test for treatment and contrasts of control diets vs.
diets that include flax, whole flax diet vs. treatments where flax was
processed, and the rolled flax diet vs. the ground flax diet.
c Marbling
scores are reported as 300 = slight 0 or low select, 400 = small 0 or low
choice, and 500 = modest 0 or average choice.
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Table 3. Effect of processing flax on sensory panel
evaluations and Warner-Braetzler shear force
determination of tenderness. |
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Dietsa |
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P-valuesb |
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Item |
Control |
Whole |
Rolled |
Ground |
SE |
Treatment |
Control vs Flax |
Whole vs
Processed |
Rolled vs
Ground |
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Tendernessc |
5.08 |
5.21 |
5.46 |
5.24 |
0.12 |
0.16 |
0.11 |
0.31 |
0.18 |
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Juicinessc |
5.54 |
5.19 |
5.50 |
5.27 |
0.10 |
0.02 |
0.06 |
0.09 |
0.09 |
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Flavorc |
5.29 |
5.23 |
5.44 |
5.41 |
0.09 |
0.30 |
0.54 |
0.07 |
0.82 |
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Shear, lbs |
8.15 |
7.91 |
7.01 |
7.29 |
0.33 |
0.06 |
0.04 |
0.05 |
0.49 |
a Control
treatment was a basal, no-flax diet; whole, rolled, and ground treatments
included flax in the diet at 8% of DM.
b P-values
are associated with F-test for treatment and contrasts of control diets vs.
diets that include flax, whole flax diet vs. treatments where flax was
processed, and the rolled flax diet vs. the ground flax diet.
c
Tenderness, juiciness, and flavor
were evaluated on a scale of 1 to 8 with anchors of 1 = not at all tender, not
at all juicy, no flavor at all and 8 =
extremely tender, extremely juicy, and an extreme amount of flavor.
Implications
These results suggest that flax incorporated into the diet at eight percent of dry matter will increase average daily gain and feed efficiency and that processing of the flax is necessary to optimize these effects. Additionally, adding flax to feedlot diets can increase internal fat deposition and increase yield grades while tending to increase carcass quality grades. Palatability of beef may be affected by flax, as trained sensory panelists reported lower juiciness scores from flax-fed beef, however mechanical determination of beef tenderness indicated that feeding flax may increase tenderness.