View Full Table | Close Full ViewTable 1.

Dietary ingredients and chemical composition of basal finishing diet, DM basis

 
Item Value
Ingredient, %
    Flaked corn 39.45
    Corn silage 7.01
    Cotton seed hulls 2.50
    Sweet Bran Blend1 22.27
    Dried distillers grains 25.18
    Tallow 2.08
    Water 1.60
    Supplement2 0.0003
Chemical compositions3
    DM, % 73.92
    CP, % 16.94
    CF, % 21.14
    Fat, % 8.00
    NEm, Mcal/cwt 100.97
    NEg, Mcal/cwt 65.61
    Calcium, % 0.71
    Phosphorus, % 0.56
1Wet corn gluten feed.
2Rumensin and Tylan (Elanco Animal Health, Greenfield, IN) supplemented at 30.0 and 8.0 g/ton, respectively.
3Diets were formulated to meet or exceed all nutrient requirements of finishing steers (National Research Council, 1996).



View Full Table | Close Full ViewTable 2.

Effect of ractopamine hydrochloride (RH) and zilpaterol hydrochloride (ZH) on carcass characteristics of conventional beef-type steers

 
Item2 Treatment1
SEM P < FTRT3
Control RH 200 RH 300 RH 400 ZH
Initial HCW4 336.8 335.0 334.3 335.7 335.6 1.9 0.9169
Carcass ADG4 1.26d 1.37c 1.54b 1.57b 1.74a 0.04 <0.0001
DMI 9.89 9.60 9.73 9.83 9.63 0.13 0.0575
Carcass G:F4 0.13d 0.14c 0.16b 0.16b 0.18a 0.01 <0.0001
HCW, kg 376.6d 376.0cd 380.5bc 382.9ab 387.7a 1.9 0.0002
Dressing % 63.8bc 63.6c 64.2b 64.2b 65.2a 0.1 <0.0001
Mesenteric Fat, % 1.7 1.6 1.6 1.6 1.5 0.1 0.8429
LM area, cm2 84.7c 84.9c 86.3bc 87.1b 91.4a 0.7 <0.0001
12-rib fat, cm 1.1 1.1 1.1 1.1 1.1 0.1 0.8631
USDA yield grade 3.0a 3.0a 2.9a 2.9a 2.7b 0.1 0.0379
Marbling score5 429a 416ab 412b 420ab 408b 5 0.0422
a–dLeast squares means within a row lacking a common letter superscript differ (P < 0.05).
1Treatments: Control; RH = ractopamine hydrochloride (Elanco Animal Health, Greenfield, IN) fed at 200 or 300 mg ∙ steer–1 ∙ d–1 or 400 mg ∙ steer–1 ∙ d–1 top dress; ZH = zilpaterol hydrochloride (Merck Animal Health, Summit, NJ) fed at 6.8 g/ton.
2Pen used as experimental unit for statistical analysis.
3FTRT = Probability of difference between treatment means occurring when, in fact, no difference existed.
4Initial HCW = 0.2598 × (Initial BW × 0.04)1.1378; Carcass ADG = (Final HCW – Initial HCW)/Days on feed; calculated for final 30 d of finishing period; Carcass G:F = Carcass ADG/DMI; calculated for final 30 d of finishing period (Tatum et al., 2012).
5Marbling score: 400 = Small00.



View Full Table | Close Full ViewTable 3.

Effect of ractopamine hydrochloride (RH) and zilpaterol hydrochloride (ZH) on Quality Grade and Yield Grade distribution of carcasses from conventional beef-type steers

 
Item, %2 Treatment1
SEM P < FTRT3
Control RH 200 RH 300 RH 400 ZH
Prime 0.4 0.1 0.5 0.3 0.1 0.2 0.6762
Upper 2/3 Choice 13.7a 11.5ab 8.7b 11.8ab 3.1c 1.2 <0.0001
Choice 57.6 51.8 48.7 52.6 46.9 2.8 0.0973
Select 40.2 45.6 48.9 45.2 50.4 2.7 0.1076
No roll 1.3 2.0 1.8 1.3 1.8 0.4 0.6890
Hard bone 0.5 0.4 0.1 0.7 0.8 0.3 0.4555
Heavy HCW
        >430.9 kg 0.5 0.3 0.9 1.2 1.3 0.5 0.4448
    >    476.3 kg 0.0 0.0 0.1 0.1 0.1 0.1 0.7283
    Yield Grade 1 6.4b 5.6b 6.3b 6.3b 11.9a 1.6 0.0497
    Yield Grade 2 43.2 44.1 42.7 44.9 52.9 3.5 0.2332
    Yield Grade 3 43.7a 44.6a 46.2a 44.6a 31.9b 3.4 0.0397
    Yield Grade 4 6.6 5.7 4.7 4.2 3.3 1.4 0.4863
    Yield Grade 5 0.1 0.1 0.0 0.0 0.0 0.1 0.5799
a–cLeast squares means within a row lacking a common letter superscript differ (P < 0.05).
1Treatments: Control; RH = ractopamine hydrochloride (Elanco Animal Health, Greenfield, IN) fed at 200 or 300 mg ∙ steer–1 ∙ d–1 or 400 mg ∙ steer–1 ∙ d–1 top dress; ZH = zilpaterol hydrochloride (Merck Animal Health, Summit, NJ) fed at 6.8 g/ton.
2Pen used as experimental unit for statistical analysis.
3FTRT = Probability of difference between treatment means occurring when, in fact, no difference existed.



View Full Table | Close Full ViewTable 4.

Effect of ractopamine hydrochloride (RH) and zilpaterol hydrochloride (ZH) on subprimal yield of carcasses from conventional beef-type steers. Value presented as change from control

 
Item2 Treatment1
SEM P < FTRT3
Control RH 200 RH 300 RH 400 ZH
Chuck roll 0.00 −0.05 −0.05 −0.03 −0.06 0.07 0.9583
Chuck mock tender 0.00 0.02 0.02 0.03 0.04 0.01 0.1001
Chuck flat 0.00 0.00 0.00 −0.02 −0.02 0.01 0.3598
1 piece shoulder clod 0.00 0.07 0.05 0.09 0.14 0.04 0.1093
Teres major 0.00 0.00 0.01 0.01 0.01 0.00 0.1810
Pectoral muscle 0.00 0.03 0.04 0.01 0.02 0.02 0.4023
Bnls chuck short ribs 0.00 0.01 0.00 0.00 0.00 0.01 0.8858
Ribeye roll 0.00 −0.04 −0.06 −0.01 −0.04 0.03 0.5701
Brisket, boneless 0.00 −0.02 −0.02 0.07 0.11 0.05 0.1752
Back ribs 0.00 −0.02 −0.03 −0.02 −0.04 0.01 0.1711
Inside round 0.00d 0.05cd 0.19ab 0.15bc 0.28a 0.05 0.0012
Eye of round 0.00c 0.03bc 0.10ab 0.08a 0.12a 0.02 0.0005
Shank meat 0.00b 0.02ab 0.04a 0.01ab 0.04a 0.01 0.0145
Knuckle, peeled 0.00b 0.01b 0.13a 0.08ab 0.10a 0.03 0.0474
Outside (flat) round 0.00c 0.04bc 0.17a 0.10ab 0.17a 0.03 0.0001
Tenderloin 0.00 0.01 0.03 0.06 0.06 0.02 0.0526
Strip loin 0.00b 0.10a 0.06ab 0.07a 0.10a 0.03 0.0495
Top butt 0.00 −0.01 0.02 0.01 0.03 0.03 0.8017
Short rib 0.00 −0.01 0.01 −0.02 −0.02 0.01 0.2543
Flank 0.00 0.01 0.01 0.01 0.02 0.01 0.5559
Inside skirt 0.00 0.00 0.00 0.01 0.01 0.01 0.9578
Outside skirt 0.00 0.01 0.00 0.00 −0.01 0.01 0.3430
Sirloin flap 0.00 0.04 0.02 0.04 0.02 0.02 0.4038
Tri-tip 0.00b 0.02a 0.03a 0.02ab 0.05a 0.01 0.0221
Ball-tip 0.00 0.00 −0.02 0.01 0.04 0.03 0.6262
Blade meat 0.00b 0.00b 0.02b 0.04ab 0.08a 0.02 0.0255
Quadriceps 0.00c 0.01bc 0.11abc 0.08ab 0.14a 0.03 0.0021
50’s trim 0.00 −0.11 −0.10 −0.09 −0.13 0.05 0.3838
65’s trim 0.00 0.04 −0.02 0.06 0.01 0.05 0.8100
81’s trim 0.00 0.18 0.05 0.08 0.11 0.06 0.2938
86’s trim 0.00 0.04 0.10 0.05 0.10 0.03 0.0543
91’s trim 0.00a −0.06ab −0.02a −0.14b −0.10ab 0.03 0.0174
Trim 0.00 0.10 0.02 −0.03 −0.01 0.14 0.8618
Fat 0.00 −0.16 −0.42 −0.55 −0.53 0.24 0.4175
100% lean trim4 0.00 0.37 0.30 0.31 0.36 0.01 0.6243
Bone 0.00a −0.30ab −0.17a −0.23a −0.65b 0.12 0.0091
Whole muscle yield 0.00c 0.32bc 0.53abc 0.73ab 1.18a 0.46 0.0341
a–dLeast squares means within a row lacking a common letter superscript differ (P < 0.05).
1Treatments: Control; RH = ractopamine hydrochloride (Elanco Animal Health, Greenfield, IN) fed at 200 or 300 mg ∙ steer–1 ∙ d–1 or 400 mg ∙ steer–1 ∙ d–1 top dress; ZH = zilpaterol hydrochloride (Merck Animal Health, Summit, NJ) fed at 6.8 g/ton.
2Weight expressed as a percentage of chilled side weight; subprimals cut to plant specification. Pen used as the experimental unit for statistical analysis.
3FTRT = Probability of difference between treatment means occurring when, in fact, no difference existed.
4100% lean trim = (individual trim and fat components × % lean)/chilled side weight. Percentage lean calculated on individual trim and fat components based on output from a MeatMaster (FOSS, Hilleroed, Denmark).