Anim Biosci > Volume 29(12); 2016 > Article |
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Item | Treatments1 | |||
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U4 | U+SRU3 | U+SRU4 | U+SRU5 | |
Ingredient composition (% DMB) | ||||
Steam flaked corn | 60.00 | 55.00 | 60.00 | 65.00 |
DDGS | 8.00 | 6.00 | 8.00 | 13.00 |
Soybean meal | 5.00 | 5.00 | 4.00 | 0.00 |
Wheat straw | 12.00 | 18.00 | 12.00 | 6.00 |
Urea | 0.80 | 0.80 | 0.80 | 1.00 |
Optigen 12002 | - | 1.00 | 0.80 | 0.80 |
Cane molasses | 9.70 | 9.50 | 9.60 | 9.40 |
Yellow grease | 2.20 | 2.50 | 2.50 | 2.50 |
Trace mineral salt3 | 0.50 | 0.50 | 0.50 | 0.50 |
Limestone | 1.80 | 1.70 | 1.80 | 1.80 |
NE concentration4 (Mcal/kg of DM basis) | ||||
Maintenance | 2.00 | 1.89 | 1.99 | 2.10 |
Gain | 1.34 | 1.26 | 1.34 | 1.43 |
Nutrient composition (% of DM)5 | ||||
Crude protein | 14.01 | 15.70 | 15.40 | 15.84 |
Starch | 42.62 | 38.77 | 42.10 | 45.12 |
ADF | 10.71 | 13.07 | 10.52 | 8.53 |
Calcium | 0.78 | 0.76 | 0.80 | 0.79 |
Phosphorus | 0.35 | 0.32 | 0.35 | 0.41 |
U, urea; SRU, slow-release urea; DMB, dry matter basis; DDGS, dried distillers grain with solubles; NE, net energy; DM, dry matter; ADF, acid detergent fibre; NEm, net energy of maintenance; NEg, net energy of gain.
3 Trace mineral salt contained: CoSO4, 0.068%; CuSO4, 1.04%; FeSO4, 3.57%; ZnO, 1.24%; MnSO4, 1.07%; KI, 0.052%; NaCl, 92.96%.
4 Based on tabular NE values for individual feed ingredients (NRC, 2007) with the exception of supplemental fat, which was assigned NEm and NEg values of 6.03 and 4.79, respectively (Zinn, 1988).
Item | Treatments1 | SEM | S:F ratio2 | |||||
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U4 | U+SRU3 | U+SRU4 | U+SRU5 | U4 vs U+USR4 | Linear | Quadratic | ||
Pen replicates | 5 | 5 | 5 | 5 | ||||
Days on feed | 56 | 56 | 56 | 56 | ||||
Weight (kg)3 | ||||||||
Initial | 36.61 | 36.49 | 36.75 | 36.73 | 0.21 | 0.66 | 0.42 | 0.60 |
Final | 49.89 | 49.30 | 52.34 | 52.42 | 0.64 | 0.02 | <0.01 | 0.09 |
Average daily gain (kg) | 0.235 | 0.229 | 0.278 | 0.280 | 0.013 | 0.04 | 0.02 | 0.15 |
Dry matter intake (kg) | 1.237 | 1.257 | 1.335 | 1.295 | 0.046 | 0.16 | 0.57 | 0.31 |
Gain for feed (kg/kg) | 0.190 | 0.180 | 0.208 | 0.216 | 0.006 | <0.01 | <0.01 | 0.03 |
Dietary net energy (Mcal/kg)4 | ||||||||
Maintenance | 2.03 | 1.98 | 2.15 | 2.21 | 0.02 | 0.01 | <0.01 | 0.03 |
Gain | 1.37 | 1.33 | 1.48 | 1.53 | 0.02 | 0.01 | <0.01 | 0.03 |
Observed to expected dietary ratio5 | ||||||||
Maintenance | 1.02 | 1.04 | 1.08 | 1.05 | 0.01 | <0.01 | 0.42 | 0.03 |
Gain | 1.02 | 1.05 | 1.10 | 1.06 | 0.01 | <0.01 | 0.60 | 0.02 |
Apparent energy retention per unit DMI6 | 0.98 | 0.94 | 0.90 | 0.94 | 0.01 | <0.01 | 0.57 | 0.01 |
U, urea; SRU, slow-release urea; SEM, standard error of the mean; DMI, dry matter intake; BW, body weight; NE, net energy; ADG, average daily gain; DMI, dry matter intake; NEm, net energy of maintenance; NEg, net energy of gain.
1 U4 = 0.80% U for 4 S:F ratio; U+SRU3 = 0.80 U and 1.00% SRU for 3 S:F ratio; U+SRU4 = 0.80 U: 0.80% SRU for 4 S:F ratio; U+SRU5 = 1.00 U and 0.80% SRU for 5 S:F ratio.
3 The initial BW was reduced by 4% to adjust for the gastrointestinal fill, and all lambs were fasted (food but not drinking water was withdrawing) for 18 h before recording the final BW.
4 The estimation of dietary NE was performed based on observed ADG, DMI and average shrunk weight (SBW) and was estimated by means of the quadratic formula:
5 Observed to expected dietary NE ratio was computed by dividing NE observed between expected diet NE, which was estimated based on tabular values for individual dietary ingredients (NRC, 2007).
6 Expected DMI was performed based on observed ADG, average shrunk weight (SBW) and the calculated NE diet and was computed as follows: DMI, kg/d = (EM/NEm)+(EG/ENg), where EM = maintenance coefficient of 0.056 Mcal/BW0.75 (NRC, 1985) and EG is the daily energy deposited (Mcal/d) estimated by equation: EG = ([0.276×ADG]×SBW 0.75, NRC, 1985). The divisors NEm and NEg are the NE of diet (Table 1, calculated from tables of composition of feed [NRC, 2007]).
Item | Treatments1 | SEM2 | S:F ratio2 | |||||
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U4 | U+SRU3 | U+SRU4 | U+SRU5 | U4 vs U+SRU4 | Linear | Quadratic | ||
Hot carcass weight (kg) | 29.79 | 28.45 | 30.97 | 31.16 | 0.43 | 0.08 | <0.01 | 0.05 |
Cold carcass weight (kg) | 29.44 | 28.13 | 30.68 | 30.83 | 0.42 | 0.06 | <0.01 | 0.04 |
Drip loss (%) | 1.18 | 1.03 | 0.95 | 1.09 | 0.16 | 0.34 | 0.80 | 0.59 |
Dressing percent | 59.66 | 57.66 | 59.17 | 59.44 | 0.45 | 0.46 | 0.02 | 0.28 |
Longissimus muscle area (cm2) | 15.21 | 14.63 | 14.88 | 16.82 | 0.51 | 0.65 | 0.02 | 0.20 |
Backfat thickness (mm) | 2.52 | 2.53 | 2.66 | 2.61 | 0.25 | 0.69 | 0.82 | 0.78 |
Kidney-pelvic fat (%) | 2.84 | 2.56 | 2.90 | 3.08 | 0.21 | 0.85 | 0.09 | 0.73 |
Body wall thickness (mm) | 13.81 | 13.42 | 13.43 | 13.81 | 0.50 | 0.61 | 0.59 | 0.77 |