View Full Table | Close Full ViewTable 1.

Composition and chemical analysis of the experimental treatments fed to stocker animals (DM basis)

 
Treatment1
Item SBM CAN SUN
Ingredient, % of DM
    Corn silage 74.0 74.4 74.5
    Ear corn 15.2 9.8 9.8
    Soybean meal 10.8
    Canola meal 15.8
    Sunflower meal 15.7
Chemical analysis2, % of DM
    Dry matter 46.4 46.9 46.9
    Crude protein 13.5 12.9 12.3
    Calcium 0.19 0.23 0.21
    Phosphorus 0.27 0.36 0.34
    TDN 73.3 71.0 70.4
    ME3, Mcal/kg of DM 2.64 2.56 2.54
    Cost, $/t 80.63 75.34 71.76
1SBM: protein supplement was soybean meal; CAN: protein supplement was canola meal; SUN: protein supplement was sunflower meal.
2The University of Georgia Feed and Environmental Water Laboratory, Athens, GA.
3Calculated according to the NRC (2000).



View Full Table | Close Full ViewTable 2.

Performance of stocker animals receiving the experimental treatments

 
Treatment1
Item SBM CAN SUN SE P-value
Number of animals2 89 89 98
Initial BW, kg 285.8 286.1 283.8 1.60 0.56
Final BW, kg 394.3a 393.6a 384.3b 1.58 0.009
ADG, kg 1.29a 1.28a 1.20b 0.018 0.007
DMI, kg/d 6.67 6.82 6.73 0.05 0.167
DMI, g/kg BW 1.96 2.01 2.01 0.02 0.087
G:F, kg 0.195a 0.188ab 0.178b 0.003 0.02
Cost of gain, $/kg of BW gain 1.13 1.09 1.10 0.02 0.31
Daily feed cost, $3 1.44a 1.38b 1.30c 0.01 < 0.001
a–cMeans within a row lacking a common superscript differ (P < 0.05).
1SBM: protein supplement was soybean meal; CAN: protein supplement was canola meal; SUN: protein supplement was sunflower meal.
2Number of animals used in the 3 yr of the experiment.
3Daily Feed Cost: Average daily cost per animal considering prices across the 3 yr.



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Proportions of VFA (mol/100 mol), total VFA concentration (mM), IVDMD, NH3–N, total gas production, and production of CH4 and CO2 for the different treatments incubated for up to 48 h

 
Treatment1
Item SBM CAN SUN SE2 P-value
Acetate 57.5b 58.1a 58.3a 0.14 0.002
Propionate 27.72a 27.24ab 27.16b 0.13 0.02
Isobutyrate 0.75 0.73 0.74 0.006 0.10
Butyrate 10.96 11.01 10.87 0.066 0.35
Isovalerate 1.66a 1.53b 1.53b 0.01 < 0.001
Valerate 1.42a 1.39ab 1.37b 0.01 0.03
Total VFA, mM 81.4 80.2 79.4 0.73 0.185
A:P ratio3 2.09b 2.14a 2.16a 0.014 0.006
IVDMD, % 49.91a 47.47b 45.95b 0.6 < 0.001
NH3–N, mM 4.03 4.10 3.67 0.20 0.308
Total gas production, ml 181.7a 179.8a 171.6b 1.7 0.002
CH4, μmoles/ml of gas 6.2 6.7 6.2 0.2 0.31
CO2, μmoles/ml of gas 21.5 23.3 21.7 0.9 0.43
a,bMeans within a row lacking a common superscript differ (P < 0.05).
1SBM: protein supplement was soybean meal; CAN: protein supplement was canola meal; SUN: protein supplement was sunflower meal. Substrates were incubated for 0, 6, 12, 24, and 48 h. Values are the means for all incubation times.
2Standard error of the main-effect means.
3A:P ratio = acetate:propionate ratio.



View Full Table | Close Full ViewTable 4.

Effect of incubation time on proportions of VFA (mol/100 mol), total VFA concentration (mM), IVDMD, NH3–N, total gas production, and production of CH4 and CO2 for the different treatments incubated for up to 48 h

 
Incubation Period, hours1
P-value2
Item 0 6 12 24 48 SE3 L Q
Acetate 61.7 56.9 56.6 57.0 57.6 0.17 0.006 < 0.001
Propionate 24.7 29.0 29.2 27.7 26.4 0.17 0.62 < 0.001
Isobutyrate 0.66 0.61 0.63 0.79 1.01 0.008 < 0.001 0.001
Butyrate 10.5 10.8 10.8 11.4 11.1 0.086 < 0.001 < 0.001
Isovalerate 1.26 1.27 1.34 1.70 2.29 0.01 < 0.001 0.02
Valerate 1.12 1.40 1.39 1.49 1.58 0.015 < 0.001 < 0.001
Total VFA, mM 28.3 65.1 79.6 102.7 125.8 0.94 < 0.001 < 0.001
A:P ratio4 2.49 1.97 1.94 2.06 2.19 0.018 0.39 < 0.001
IVDMD, % 23.2 39.0 46.0 60.3 70.3 0.7 < 0.001 < 0.001
NH3–N, mM 1.95 0.96 1.11 4.23 11.42 0.26 < 0.001 < 0.001
Total gas production, ml 105.5 169.5 270.5 343.0 2.2 < 0.001 < 0.001
CH4, mmoles/ml of gas 6.1 5.7 6.8 6.8 0.3 0.01 0.43
CO2, mmoles/ml of gas 19.8 22.0 24.9 21.9 1.2 0.26 0.004
1Experimental diets composed of 75% corn silage plus supplements were incubated for 5 different lengths ranging from 0 to 48 h. Values are the means of all treatments.
2Significance of regression coefficients for traits on incubation time. Linear (L) and quadratic (Q) effects.
3Standard error of the main-effect means.
4A:P ratio = acetate:propionate ratio.



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In vitro DM degradation of the experimental treatments after incubation for 48h

 
Treatment1
Item SBM CAN SUN SE2 P-value
Rate of degradation, %/h 1.55a 1.43b 1.40c 0.005 < 0.01
Degradation fraction,3% of DM
    A 22.03 25.21 22.45 0.85 0.10
    B 52.54a 43.54c 45.04b 0.26 < 0.01
    C 25.42c 31.25b 32.50a 0.25 < 0.01
a–cMeans within a row lacking a common superscript differ (P < 0.05).
1SBM: Protein supplement was soybean meal; CAN: Protein supplement was canola meal; SUN: Protein supplement was sunflower meal.
2Standard error of the main-effect means.
3A = fraction immediately degradable; B = fraction degradable at a measurable rate; C = fraction unavailable to ruminal degradation.



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Effect of incubation time on percentage of DE converted into VFA, CH4 and microorganism cells

 
Incubation period, hours1
Item 0 6 12 24 48 SE2 P-value
% of DE converted into VFA 8.94c 49.37b 56.68ab 59.91a 65.61a 2.07 < 0.001
% of DE converted into CH4 5.57b 7.41b 11.14a 11.94a 0.47 < 0.001
% of DE retained as microorganisms 74.95a 46.47b 34.70c 29.13cd 23.34d 1.48 < 0.001
Percentage of DE accounted in vitro3 83.89 101.41 98.79 100.18 100.89
a–dMeans within a row lacking a common superscript differ (P < 0.05).
1Experimental diets composed of 75% corn silage plus supplements were incubated for 5 different lengths ranging from 0 to 48 h. Values are the means of all treatments.
2Standard error of the main-effect means.
3Percentage of DE accounted in vitro = percentage converted into VFA + percentage converted into CH4 + percentage retained as microorganism cells.