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Ingredient composition of experimental diets

 
Ingredient, % diet DM RDP level 11 RDP level 2 RDP level 3
Cool season grass hay 20.00 20.00 20.00
Switchgrass hay 20.00 20.00 20.00
Cracked corn 29.90 29.90 29.90
High-moisture corn 12.82 12.82 12.82
AminoPlus2 14.30 4.84 5.53
Soybean meal 0.00 9.38 8.15
Urea 0.00 0.08 0.62
Limestone 1.30 1.30 1.30
Potassium chloride 0.50 0.50 0.50
Trace mineral salt3 0.75 0.75 0.75
Vitamin ADE Premix4 0.05 0.05 0.05
Choice white grease 0.38 0.38 0.38
1Levels refer to the amount of RDP in the diet, nominally described as 75% (level 1), 105% (level 2), and 120% (level 3) of NRC (2000) RDP requirements.
2AminoPlus is a product of Ag Processing Inc. (AGP, Omaha, NE)
3Trace mineralized salt provided 92.9% salt, 68 mg/kg Co, 1,838 mg/kg Cu, 120 mg/kg I, 9,290 mg/kg Mn, 19 mg/kg Se, and 5,520 mg/kg Zn.
4Vitamin premix supplied 1,820 IU/kg vitamin A, 363 IU/kg vitamin D, and 227 IU/kg vitamin E.



View Full Table | Close Full ViewTable 2.

Effect of RDP treatments on ADG, DMI, and G:F conversion1

 
RDP level2
Item 1 2 3 SEM3 P-value
Initial wt, kg 244 244 242 1.2
ADG, kg/d
    d 0 to 29 1.02 1.03 0.96 0.045 0.57
    D 29 to 58 1.54 1.53 1.55 0.051 0.97
    d 0 to 58 1.27 1.28 1.26 0.032 0.85
DMI, kg/d
    d 0 to 29 6.70 6.94 6.65 0.146 0.34
    D 29 to 58 7.93 8.16 7.73 0.156 0.18
    d 0 to 58 7.32 7.55 7.19 0.131 0.17
DMI, % BW
    d 0 to 29 2.60 2.70 2.61 0.053 0.38
    D 29 to 58 2.70 2.79 2.67 0.045 0.20
    d 0 to 58 2.62 2.71 2.60 0.039 0.15
G:F
    d 0 to 29 0.150 0.148 0.143 0.0055 0.61
    D 29 to 58 0.199 0.191 0.199 0.0056 0.51
    d 0 to 58 0.177 0.171 0.173 0.0035 0.50
1There were no 2- or 3-way interactions involving RDP level (P ≥ 0.12).
2Levels refer to the amount of RDP in the diet, nominally described as 75% (level 1), 105% (level 2), and 120% (level 3) of NRC (2000) RDP requirements.
3Here n = 16 for initial weight and ADG; n = 14, 13, and 13 for RDP levels 1, 2, and 3 for intake and efficiency variables. With unequal n among treatments, SEM is the average of the values for the 3 treatments.



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Effect of behavioral treatments on ADG, DMI, and feed conversion efficiency

 
EV1
WSD2
P-value
Item Slow Fast Low High SEM3 EV × WSD EV WSD
EV,4 m/s 1.74 3.56 0.081
WSD,4 % 1.17 2.79 0.001
Initial wt, kg 245 241 240 245 1.0
ADG, kg/d
    d 0 to 29 1.09 0.91 0.97 1.04 0.035 0.89 <0.01 0.13
    D 29 to 58 1.54 1.54 1.53 1.54 0.039 0.34 0.91 0.86
    d 0 to 58 1.31 1.23 1.25 1.29 0.025 0.40 0.02 0.23
DMI, kg/d
    d 0 to 29 7.0 6.5 6.6 6.9 0.12 0.14 0.01 0.06
    D 29 to 58 8.2 7.6 7.7 8.2 0.12 0.30 <0.01 0.01
    d 0 to 58 7.6 7.1 7.1 7.5 0.11 0.15 <0.01 0.01
DMI, % BW
    d 0 to 29 2.68 2.58 2.60 2.66 0.043 0.11 0.09 0.34
    D 29 to 58 2.78 2.65 2.67 2.76 0.034 0.27 0.01 0.08
    d 0 to 58 2.70 2.58 2.60 2.68 0.032 0.11 0.01 0.09
G:F
    d 0 to 29 0.153 0.143 0.148 0.148 0.0046 0.64 0.14 1.00
    D 29 to 58 0.193 0.201 0.203 0.191 0.0041 0.95 0.16 0.05
    d 0 to 58 0.175 0.175 0.178 0.171 0.0028 0.61 0.99 0.11
1Exit velocity (EV) is the time taken for steers to travel 1.68 m on exiting the chute; assignment to slow and fast treatments is described in text.
2Weight standard deviation (WSD) is the SD of 50 recorded weight values across a 10-s interval while the animal was restrained by the head in a chute; assignment to low and high treatments is described in text.
3Here n = 24 for initial weight and ADG; n = 18, 22, 21, and 19 for slow EV, fast EV, low WSD, and high WSD for intake and efficiency variables. With unequal n among treatments, SEM is the average of the values for the 4 treatments.
4Average initial (d 0) measures of EV and WSD by treatment.



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Effect of behavioral treatments on morbidity

 
EV1
WSD2
P-value
Item Slow Fast Low High EV × WSD EV WSD
Respiratory3 13 19 17 15 0.47 0.25 0.70
Pulls, not treated4 5 3 1 7 0.56 0.49 0.06
Weight loss5 6 0 1 5 0.72 0.12 0.13
Other6 5 1 4 2 0.28 0.14 0.39
1Exit velocity (EV) is the time taken for steers to travel 1.68 m on exiting the chute; assignment to slow and fast treatments is described in the text.
2Weight standard deviation (WSD) is the SD of 50 recorded weight values across a 10-s interval while the animal is restrained by the head in a chute; assignment to low and high treatments is described in the text.
3Number of animals displaying respiratory illness as described in the Materials and Methods section.
4Number of animals that were displaying clinical signs of illness without a corresponding increase in rectal temperature and thus were not treated.
5Number of animals that were observed to be losing weight but were not displaying clinical signs of illness.
6Number of animals that were treated for illness other than respiratory (leg injury, coccidiosis, etc.).