Effect of an Isolated Soy Protein By-Product on Finishing Cattle Performance and Carcass Characteristics

C.R. Krehbiel, R.E. Peterson, L.J. McBeth, J.P. Banta, D.L. Lalman, D.L. Step, H. DePra,
C.E. Markham, D.R. Gill, and R.L. Ball

Story in Brief

The objective was to determine if molasses and soybean meal could be replaced by an isolated soy protein byproduct in diets fed to finishing cattle.  No effects on performance or carcass adjusted performance were observed.  However, the isolated soy protein byproduct did decrease the percentage of cattle grading Choice in this experiment.  Because hot carcass weight, ribeye area, and marbling scores were not affected, we conclude that isolated soy protein by product can be used as a liquid feed in finishing diets.

Introduction

Soybean meal (SBM) is a common source of protein used in diets fed to feedlot cattle.  In the U.S., the majority of soybeans are processed using a solvent-extraction process.  The finished meal from dehulled soybeans contains less than 1.5% crude fat and approximately 48% CP on a DM basis.  In addition to the protein, Drouillard et al. (1999) suggested that the carbohydrate fraction of soybean meal might be of value for stimulating ruminal digestion.  Further isolation of protein from defatted soy flakes results in a liquid (56.7% DM) by-product (NXP25) composed of carbohydrate (62%, DM basis), protein (22%, DM basis), fat (2.4%, DM basis) and minerals (.89% Ca and .84% P, DM basis).  Drouillard et al. (1999) reported that this isolated soy protein by-product appeared to have a feed value similar to or greater than soybean meal when fed in a finishing diet.  We hypothesized that NXP25 could replace molasses and a portion of the SBM in diets fed to finishing steers.  Therefore, our objective was to determine the effect of feeding NXP25 as a liquid feed ingredient on finishing performance and carcass characteristics of feedlot cattle.

Key Words: Carcass Merit, Cattle, Feedlot Performance, Liquid Supplements, Soybean Processing

Materials and Methods 

Seventy one Angus x Hereford steers (523 ± 57 lb) were delivered to the Willard Sparks Beef Research Center on October 30, 2002.  On arrival, calves were individually weighed and ear tagged, vaccinated for Bovine Rhinotracheitis and Bovine Viral Syncytial Virus with 2 mL of Bovishield FP4+L5 (Pfizer, New York, NY), dewormed with 4.5 mL Ivomec Plus, and implanted with Component E-S (Intervet Inc., Millsboro, DE).  On February 7, 2003, steers were re-implanted with Revalor-S (Hoechst Roussel Vet, Clinton, NJ).  Steers were blocked by weight and randomly allocated within block to one of the nine pens (9 pens/treatment, 4 steers/pen).  Pens were randomly allotted to treatments (Table 1).  Steers were fed for 168 (Heavy block) or 189 (Light block) d.   

Treatment diets are shown in Table 1.  Diets were formulated to meet or exceed NRC (1996) nutrient requirements.  Monensin (30 g/ton of diet) and tylosin (10 g/ton of diet) were fed.  Steers were gradually adapted to their final treatment diet by offering 55, 65, 75, and 85% concentrate diets for 13, 8, 7, and 7 days each, respectively.  Feed refused was weighed every 28 d.  In addition, diet samples were collected, and DM content of the diets and dietary ingredients was determined.  Diet and ingredient samples were composited by 28-d periods, dried in a forced-air oven, and ground in a Wiley mill to pass a 1-mm screen.  Interim unshrunk BW was determined at 28-d intervals.  Steers were harvested at a commercial facility.  Hot carcass weight, external fat, internal fat, longissimus muscle area, marbling score, yield grade, and quality grade were determined.

Data for BW, dry matter intake, average daily gain, feed efficiency, hot carcass weight (HCW), carcass-adjusted variables (calculated using carcass-adjusted final weight, which was calculated as HCW/average dressing percent), and normally distributed carcass characteristics were analyzed as a randomized complete block design using the Proc Mixed procedure of SAS Release 8.02 (SAS Institute Inc., Cary, NC).  Non-parametric USDA quality grade data were transformed using Friedman’s test by listing the percentage of Choice and Select for each pen within a block and then analyzed as normally distributed data as above (Elam et al., 2003).  Pen was the experimental unit.  The model statement included treatment, and the random statement included block.

Results and Discussion

Feedlot performance is presented in Table 2.  Across the feeding period, body weight was not affected (P<.42 to P<.91) by treatment.  Similarly, there were no differences (P<.29 to P<.87) in average daily gain.  From d 0 through finish, dry matter intake (P<.61) and feed:gain (P<.70) did not differ among treatments.  Similarly, feeding NXP25 did not influence carcass adjusted performance (Table 2).

Carcass data is shown in Table 3.  No differences in hot carcass weight, dressing percentage, 12th-rib fat thickness, ribeye area, kidney-pelvic-heart fat, yield grade, or marbling score were observed among treatments.  Carcasses from steers fed the control diet had greater (P<.006) percent Choice than steers fed the NXP25.  Reasons for the lower quality grades by steers fed NXP25 are not evident.

Implications

In finishing diets, molasses and soybean meal can be replaced by isolated soy protein by-product with no effects on performance.  Although marbling score was not influenced, NXP25 did decrease the percentage of cattle grading Choice in this experiment.  Because hot carcass weight, ribeye area, and marbling scores were not affected, we conclude that isolated soy protein by product can be used as a liquid feed in finishing diets.

Table 1. Composition of final diets (DM basis)

 

Ingredient

 

 

 

Control

NXP25

 

Rolled corn

 

 

78.0

79.0

 

Alfalfa hay

 

 

10.0

10.0

 

Molasses

 

 

4.0

 

 

NXP25

 

 

 

4.0

 

Fat

 

 

1.5

1.5

 

Soybean Meal 47.7

 

 

2.6

1.3

 

Urea

 

 

 

.8

.8

 

Limestone 38%

 

 

1.2

1.2

 

Salt

 

 

.25

.25

 

Rumensin 80

 

.019

.019

 

Tylan

 

 

.013

.013

 

Zinc Sulfate

 

 

.004

.003

 

Manganous oxide

 

 

.004

.004

 

Vitamin A-30,000

 

 

.011

.011

 

Availa-Zn 100

 

 

.029

.029

 

Potassium chloride

 

 

 

.12

 

 

Vitamin E-50%

 

 

 

.002

.002

 

Availa-Cu 100

 

 

 

.002

.002

 

Wheat midds

 

 

 

1.446

1.867

Nutrienta

 

 

 

 

 

 

NEm, Mcal/cwt

 

 

95.64

92.90

 

NEg, Mcal/cwt

 

 

61.95

60.14

 

Crude protein, %

 

 

 

12.8

13.0

 

NDF, %

 

 

16.2

18.1

 

ADF, %

 

 

7.70

8.12

 

Potassium, %

 

 

.81

.84

 

Calcium, %

 

 

.68

.67

 

Phosphorus, %

 

 

.29

.32

 

Magnesium, %

 

 

.17

.18

 

Sulfur, %

 

 

 

.18

.15

 

Cobalt, ppm

 

 

.07

.19

 

Copper, ppm

 

 

7.9

7.8

 

Iron, ppm

 

 

 

54.0

46.4

 

Manganese, ppm

 

 

41.2

42.3

 

Selenium, ppm

 

 

.15

.16

 

Zinc, ppm

 

 

 

60.8

61.6

aAll values are calculated except CP, NDF, and ADF, which are actual

 

Table 2. Effect of NXP25 on performance by steers

Item

CON

NXP25

SEM

PR>F

Pens

9

9

 

 

Steers

36

35

 

 

BW, lb

 

 

 

 

Initial

529

530

45

.91

d 27

666

660

52

.62

d 86 (reimplant)

910

897

59

.42

end

1249

1238

30

.57

Adj. end

1247

1241

31

.80

Daily gain, lb/d

 

 

 

 

d 0-27

3.97

3.72

.19

.29

d 28-86

4.12

4.01

.14

.40

d 87-end

3.50

3.52

.11

.87

d 0-end

3.76

3.70

.13

.46

Adj. d 0-end

4.03

4.00

.16

.72

Dry matter intake, lb/d

 

 

 

 

d 0-27

17.53

16.74

.87

.15

d 28-86

19.68

18.72

1.07

.15

d 87-end

21.48

21.99

.34

.25

d 0-end

20.29

20.08

.56

.61

Feed:gain

 

 

 

 

d 0-27

4.48

4.60

.14

.56

d 28-86

4.79

4.69

.12

.45

d 87-end

6.15

6.28

.13

.50

d 0-end

5.39

5.43

.07

.70

Adj. d 0-end

5.02

5.02

.08

.97

aAdjusted final BW was calculated as hot carcass weight/average dress per weight block. Adjusted daily gain was calculated as (adjusted final BW − initial BW)/d on feed. Adjusted gain:feed was the ratio of adjusted daily gain and daily DMI

 

Table 3. Effect of NXP25 on carcass merit of steers

Item

CON

NXP25

SEM

PR>F

Pens

9

9

 

 

Steers

36

35

 

 

Hot carcass wt., kg

762

759

16

.79

Dress, %

61.0

61.3

.31

.51

12th-rib fat, in

.64

.65

.03

.83

Ribeye area, in2

11.84

11.83

.53

.98

KPH, %

2.39

2.32

.11

.64

Yield grade

3.65

3.62

.12

.87

Marblinga

47.4

45.8

3.75

.33

Choice, %

83.3

57.4

5.76

.006

Select, %

16.7

42.6

5.76

.006

a30 = Slight, 4 = Small


Literature Cited

Drouillard, J.S. et al. 1999.  KSU Cattlemen’s Day Report.  http://www.oznet.ksu.edu/library/lvstk2/srp831.pdf.  Accessed 5/28/04.

Elam, N.A. et al. 2003. J. Anim. Sci. 81:2686.

NRC. 1996. Nutrient Requirements of Beef Cattle. (7th Ed.). National Academy Press, Washington D.C.

Copyright 2004 Oklahoma Agricultural Experiment Station

Authors

Clint Krehbiel – Associate Professor

Robert Peterson – Graduate Student

Levi McBeth – Graduate Student

Jason Banta – Graduate Student

David Lalman – Associate Professor

D.L. Step – Associate Professor, Veterinary Teaching Hospital

Heather DePra – Graduate Student

Clint Markham – Graduate Student

Don Gill – Professor Emeritus

Roy Ball – Herdsman