An evaluation of reciprocal levels of hulless oats and barley in diets for growing and finishing steers


V. L. Anderson, M. L. Bauer, J. S. Caton, P. Berg, and D. H. Dhuyvetter

Abstract

Preconditioned steer calves (n=128) were blocked by weight and allotted to treatments of 0, 33, 67 and 100% dry rolled hulless oats with reciprocal amounts of barley. Approximately 10.5 pounds of grain was fed during the 78 day growing period and 18 pounds during the 103 day finishing period. Dry matter intake decreased (P<.05) with increasing level of hulless oats during growing and finishing. Growing gains were similar (P<.05) but finishing gains responded quadratically with the highest ADG recorded at the 67% level (3.88 pounds per day). ADG at 100% were the same as 0% (3.43 and 3.33). Feed efficiency improved with increasing levels of hulless oat during growing but was more pronounced during finishing. No carcass quality traits were affected by diet treatment. Hulless oats appears to be a very useful feed when fed in combination with barley for growing steers but shows more pronounced and positive response in finishing diets.

Key Words: hulless oat, growing, finishing, feedlot, beef

Introduction

North Dakota has been a leader in oat production for many year. Oats typically is high in fiber due to the presence of a largely indigestible hull. A new variety of hulless or naked oats "Paul" developed by Dr. Mike McMullen has been released by NDSU. There is substantial producer interest in this variety as it produces a very energy dense feed, containing nearly 18% protein and 10% fat.

The state is also known for its high quality beef cattle. Feedlots have not developed for a variety of reasons including abundant supplies of energy dense feeds. Barley has been the main feed grain but corn is increasing due to processing plants developing in the area. A high energy, low input crop like naked oats, could stimulate substantial interest in feeding, if results of trials are positive. This paper presents data on the use of naked oats and barley in reciprocal levels in diets for growing and finishing steer calves.

Experimental Procedure

One hundred twenty eight steer calves custom fed for Kerry Dockter and Scott Dockter, Denhoff, ND were weighed, blocked by weight and allotted to one of four treatments on November 19, 1996. Eight steers were assigned to each of sixteen pens. Blocks were used as replicates. Steers were preconditioned together for approximately three weeks prior to the start of the trial. The treatments consisted of grain sources in the growing and finishing diets with hulless oats(HO) at 0, 33, 67, and 100% of the grain. Reciprocal barley (BAR) amounts were 100, 67, 33 and 0%. Diets were balanced to meet or exceed nutrient requirements for growing and finishing beef cattle as described in NRC (1984). Grains were dry rolled just prior to feeding using a Peerless roller mill with worn 10" grooved rolls. Finished particle size was approximately 2500 microns for both hulless oats and barley. Kernels were slightly flattened or broken in no more than two pieces with few fines present.

Steers were fed growing diets for 78 days and finishing diets for 103 days. The higher protein level in hulless oats vs barley reduced the need for a protein supplement (canola meal) in growing diets. At 67% and above, no supplemental protein was needed. The transition from growing to finishing diet was accomplished over a three week period. Table 1 presents average diets for the two periods. The totally mixed ration was fed ad libitum and delivered once per day after bunk reading. Steers were weighed on two consecutive days at the start of the trial and approximately every 28 days during the study. Rumensin/Tylan supplements were manufacture by the Northern Crops Institute Feed Mill, Fargo ND.

Feeding pens were 32 X 80 feet with 20 feet of fenceline bunk. Eight foot wind fences protected the pens from the northwest with bunks on the south-east side of the pens. Steers were bedded with small grain straw during bitter cold temperatures. One of the worst winters on record in terms of snowfall, storm days, and general stress occurred during this feeding study. Steers had to be removed from their replicated pens on two occasions but treatment groups were kept intact. Drifts up to 15 feet deep from extended periods of blowing snow covered fences, feed bunks, and roads. Feed intake data for the partial periods affected was interpolated based on intake during replicated pen feeding.

Steers were marketed at IBP in Laverne, MN with carcass data gathered after a 24 hour chill. Two components of the study to be reported in the future are fatty acid profiles from lean and muscle tissue samples and digestion information from fistulated animal studies.

Data were analyzed for this report by analysis of variance using pen as the experimental unit. Treatment means are reported for the growing and finishing periods separately and overall values for the combined periods.

Results and Discussion

Diets consumed by steers during growing and finishing are reported in Table 1. The as fed values reflect the typical consumption during backgrounding and finishing without regard to the few storm days when only hay was fed.

Steer performance is reported in Table 2. Dry matter intake decreased (P<.05) with increasing percentage of hulless oats in the diet during growing (20.37, 19.36, 19.24, and 18.62). Gains were not affected during growing (avg. 3.12 + .07) resulting in an improvement in feed efficiency as hulless oat level increased (6.61, 6.07, 6.33, and 5.92). During finishing, dry matter intake also decreased (P<.05) with increasing hulless oats in the diet (23.04, 22.34, 21.15, and 20.92). Gains showed a quadratic response during finishing with the 67% treatment greater (P<.05) at 3.88 pounds per day compared to similar gains averaging 3.61 for the 0, 33, and 100% treatments. Feed efficiency improved (P<.05) with increasing level of hulless oats in the diet up to 67% (6.56, 6.13, 5.47 and 5.74). Data for the total feeding period reflects the combination of growing and finishing with decreasing dry matter intake, improved gains and greater feed efficiency with increasing levels of hulless oats in the diet up to 67%.

The response to increasing amounts of hulless oats may be attributed to the energy density of the grain. The hulless oats used in this study averaged 90.06 % dry matter, 2.47% ash, 17.11% crude protein, 4.94% acid detergent fiber, 15.61% neutral detergent fiber and 9.98% lipid (or fat). Increased lipid in the diet tends to reduce fermentation rate and feed intake in ruminants. The low fiber content provides for increased digestibility of this grain, which is a highly concentrated source of the two major nutrients, energy and protein. Excess protein is metabolized as a carbohydrate after the nitrogen is removed. Energetically, there is little if any advantage to using protein as energy as the deamination and excretion of the excess nitrogen requires some energy. Economically, protein usually is more expensive than energy. Practically, diets higher in protein than animal requirements are often least cost, especially in this region with large amounts of higher protein co-products, grains, and legumes available at often reasonable prices. From a waste perspective, higher nitrogen animal manure and urine could be positive for fertilizer returned to the land or negative if allowed to pollute ground water.

Results of this study and a companion study evaluating hulless oats and corn suggest that processing hulless oats may be a very important component to its successful use. The dry rolling process used in this study resulted in particle size of approximately 2500 microns for both hulless oats and barley. The particle size of hulless oats was smaller (1200 microns) in the corn study. Dry matter intake, and gains decreased (P<.05) rather sharply with increasing levels of hulless oats. It is hypothesized that the smaller particle size in the hulless oat/corn study increased the fermentation rate, possibly leading to an acidic condition in the rumen. The result of which could be reduced intake and gain. Further study is required to precisely determine impact of particle size.

Steer gains during this study were excellent, especially when the severity of the winter is considered. On two occasions, once during the growing period and once during the finishing period, steers had to be removed from their replicated pens for several days due to severe blowing snow. The steers were penned by treatment in much smaller pens with greater protection from the wind. After snow removal, steers were returned to their replicated pens.

Carcass evaluation resulted in no differences (P<.05) in any of the traits measure due to treatment. Table 3 contains carcass data.

Data from this study suggests hulless oats can be a very useful and efficient feed for growing and finishing cattle, especially when used in combination with barley. The economics have not been considered yet, as the commodity market for hulless oats has not been established. With more acres in the state planted to hulless oats in 1997, a greater amount of the grain will be fed resulting in a better understanding of feed costs and cost of gain. Hulless oats may also be useful as a creep feed ingredient or winter supplement for beef cows. More experience with this grain will determine its overall potential.

Literature Cited

NRC. 1984. Nutrient Requirements of Beef Cattle. Sixth Revised Edition. National Academy Press, Washington D.C.

Grant Acknowledgments

This project was funded by a grant from the USDA Alternative Crops Program

Table 1. Rations with reciprocal levels of hulless oats and barley fed to growing and finishing steers.

Treatment

0%

33%

67%

100%

Ingredient

------------------pounds, as fed per head daily------------------

Growing Diets

Rumensin-Tylan suppl

.42

.42

.42

.42

Canola meal

.97

.49

-

-

Hulless Oats, dry rolled

-

3.56

7.18

10.41

Barley, dry rolled

10.88

7.20

3.53

-

Corn silage

17.96

16.77

16.14

15.67

Alfalfa-brome hay, chopped

3.91

3.65

3.62

3.62

Finishing Diets

Rumensin-Tylan suppl

.49

.49

.49

.49

Hulless Oats, dry rolled

-

6.08

11.90

17.56

Barley, dry rolled

18.83

12.40

5.85

-

Corn silage

11.18

9.87

8.95

9.01

Straw, chopped

2.16

2.11

2.03

2.02

Table 2. Feedlot performance of steers fed reciprocal levels of hulless oats and barley during growing and finishing.

Treatment

0%

33%

67%

100%

Std Err

No head

32

32

32

32

-

Initial weight, lb

634

634

635

635

10.47

Final weight, lb

1236

1259

1272

1256

17.16

Growing

Days on feed

78

78

78

78

-

Dry Matter Intake, lb

20.37a

19.36ab

19.24b

18.62b

.47

Average Daily Gain, lb

3.09

3.20

3.05

3.15

.07

Dry Matter per Gain

6.61a

6.07b

6.33ab

5.92b

.19

Finishing

Days on feed

103

103

103

103

-

Dry Matter Intake, lb

23.04a

22.34a

21.15b

20.92b

.71

Average Daily Gain, lb

3.52a

3.65a

3.88b

3.65a

.11

Dry Matter per Gain

6.56a

6.13b

5.47cd

5.74c

.21

Total Feeding Period

Days on feed

181

181

181

181

Dry Matter Intake, lb

21.89a

21.06b

20.11c

19.93c

.40

Average Daily Gain, lb

3.33a

3.45ab

3.51b

3.43ab

.07

Dry Matter per Gain

6.58a

6.10b

5.73c

5.81c

.13

a, b,c ,d Values with different superscripts are significantly different, P<.05)

Table 3. Carcass evaluation of steers fed reciprocal levels of hulless oats and barley during growing and finishing.

Treatment

0%

33%

67%

100%

Std Err

Hot Carcass weight, lb

707.16

705.81

721.94

712.59

23.67

Dressing Percent

.602

.593

.598

.597

.04

Rib eye area, sq in

12.99

12.99

13.23

12.94

.45

Fat thickness, in

.29

.28

.32

.29

.02

KPH fat, %

1.72

1.66

1.75

1.61

.09

Marbling Scorea

382.50

365.48

377.81

371.56

14.27

Yield Gradeb

2.16

2.11

2.21

2.17

.12

a Marbling scores are the basis for USDA Quality grade. Select =300-399, Choice = 400+

b Yield Grade is a score calculated from several factors indicating the lean to fat ratio of the carcass. A low score means less fat.


1997 Beef and Bison Contents