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1999 Beef & Bison Production Field Day


Field peas in diets for

growing and finishing steer calves

V. L. Anderson

Carrington Research Extension Center

North Dakota State University

 

Abstract

Field peas were evaluated in a 2 year growing and finishing study with feedlot steers. Preconditioned steers (n=80) were fed growing diets containing barley, barley and canola meal, or field peas. Corn silage, chopped hay, and supplements were included in the rations during the 50 day trial. Steers fed peas consumed more feed as a % of body weight (P<.10)) and had numerically greater gains than steers fed barley. The barley-canola meal diet was intermediate. Finishing diets based on barley or peas were fed from the end of the growing study until steers reached market weight. Intake tended to be greater (4.7%) for the pea diet compared to barley with corresponding higher (5.5%) gains observed. Carcass traits were similar except marbling scores and the percent choice was greater (P<.10) for steers fed peas. Feed costs are a critical factor in using peas in feedlot diets but peas appear to be a nutrient dense and very palatable feedstuff as the only grain source in growing and finishing diets. Producers should make decisions on feeding peas based on local feed prices and projected cost of gain.

Introduction

Field pea acreage in North Dakota is expected to increase rapidly as producers realize the benefits of including annual legumes in cropping systems. A large proportion of field peas will be marketed as livestock feed although peas qualifying for human food grade usually return more dollars per bushel and per acre. The commercial market for field peas is strong with export potential for very large amounts. Exported peas are generally used in livestock feed, primarily for non-ruminants. The nutritive value of field peas as a feed grain is well documented for non-ruminants but little data is available to compare with conventional feeds in feedlot cattle diets.

The greatest potential market for field peas grown in this region is in beef cattle diets. Peas appear to be very palatable feedgrain as indicated in other studies. Improving the palatability of a receiving ration and therefore increasing intake during the first few days on feed for weaned calves may have significant implications on immune response, and animal performance. Peas will have to compete economically with other feeds such as barley and wheat midds, although the nutrient profiles differ somewhat (Table 1). Depending on the production goals and livestock ration required, peas may be used as a protein supplement or as a major ration ingredient in a variety of diets. Peas are a nutrient dense feedgrain with high levels of carbohydrate and protein that would complement high forage diets. Unless used in balanced diets, the high protein content of peas may contribute to increased nitrogen levels in the feces and urine or volatilized into the atmosphere as ammonia. This is an environmental concern in some parts of the nation, but may be an added source of fertility for integrated crop/livestock operations in the Northern Plains where nutrients can be captured and recycled. This project evaluated field peas in diets for growing and finishing steer calves and was partially funded by USDA Alternative Crops Grant 97-34216-3995, ND0517.


Table 1. Nutrient content of field peas and barley

Item Barley Field peas
Dry Matter, %                   89.59                  89.47               
                                         ---------Dry matter basis---------
Crude protein, % 12.64                   23.01               
Acid detergent fiber, % 7.13 7.50
Neutral detergent fiber, % 24.63 15.16
Fat, % 1.95 1.55
Ash, % 2.64 2.87
Calcium, % .05 .07
Phosphorous, % .39 .46

Materials and Methods
Growing

Crossbred preconditioned steer calves (n=80) were blocked by weight (light and heavy) and allotted to three treatments with two replicates (weight blocks ) per treatment in early October of 1997 and 1998. Dietary treatments (Table 2) were: 1)barley as the primary grain source with protein levels recommended by NRC (Control); 2) barley at the same level as Control but with canola meal added to equalize the crude protein level of the field pea diet (BarCan); and 3) field peas (Peas) as the primary grain source. The protein level in the field pea diet exceeded animal requirements. The BarCan treatment was included to evaluate a diet with barley at protein levels the same as the Pea treatment. Totally mixed rations were fed once daily to appetite. Field peas and barley were dry rolled with a corn setting used for peas to produce minimal fines and barley kernels flattened and broken into two or three pieces. The supplement contained an ionophore (Rumensin at 300

mg/hd/day), vitamins, and mineral supplements to meet requirements and achieve 2:1 calcium-phosphorous ratios. The growing trial included two 25 day feeding periods. Four fecal samples were collected randomly from fresh stools in each of the two pens on each treatment and analyzed for nitrogen content.


Table 2. Growing diets for steer calves fed barley, barley and canola meal, or field peas.

Item                     Control Barley Barley Canola     Field Peas         
                                   --------------Pounds/hd/day as fed ------------
Field peas            -                      -                         9.97                 
Barley 8.98 7.07
Corn silage 10.64 11.18 14.45
Chopped hay 3.13 3.04 3.12
Canola meal 1.10 2.90 -
Supplement .45 .48 .49
                                    --------------Percent dry matter basis---------
Field peas            -                      -                         52.66               
Barley 50.25 40.29 -
Corn silage 24.15 24.96 29.70
Chopped hay 16.18 15.37 14.70
Canola meal 6.47 16.54
Supplement 2.96 2.83 2.66

Finishing

Steers from the growing experiment were allotted to two treatments (one pen per treatment) each year to compare the use of field peas or barley as the primary grain source in finishing diets. Steers fed peas during backgrounding were retained in the pea treatment and steers on the control barley diet were retained in the barley group. Steers on the BarCan growing treatment were divided randomly between barley and pea treatments. Steers were fed totally mixed finishing diets to appetite (Table 3) once daily in fenceline bunks. The barley diet was balanced to NRC requirements but the pea diet contained excess protein. The rations were stepped up gradually over approximately 10 days. This trial started in early December and concluded when steers went to market in April. Steers were weighed at the start and end of the trial. Carcass data was collected at slaughter.


Table 3. Finishing diets for steer calves using barley or field peas.

Item                      Barley                    Field peas         
                                   -------Pounds/hd/day, as fed------
Field peas             -                         19.54        
Barley 17.95 -
Corn silage 9.59 10.18
Chopped hay       2.43 2.75
Canola meal .88 -
Supplement .46 .46
                               -------Percent, dry matter basis------
Field peas              -                       76.23         
Barley 73.86 -
Corn silage 11.92 12.81
Chopped hay       8.48 9.01
Canola meal 3.72 -
Supplement 1.98 1.99

Results and Discussion
Backgrounding

Intake tended to be greater (P=.17) for diets containing peas (17.21 lb DM/hd/day) compared to Bar (15.32) with BarCan (16.01) intermediate (Table 4). Gains were numerically greater for Peas (3.05 lb/hd/day) over Bar (2.61) and BarCan (2.78) intermediate but not statistically significant in this trial. Gain per unit feed responded similarly with numerically greater gains from Peas (.180) followed by the higher protein BarCan (.174) and Bar (.170). Growing diets with peas at approximately 50% of dry matter intake appear to be more palatable and tend to improve animal performance.

With barley at $1.50 per 48 lb bushel, equivalent cost per pound of gain will be achieved with peas priced at $2.43 per 60 lb bushel. Or, the breakeven price for a bushel of peas is approximately 162% of the price of a bushel of barley when fed to calves during backgrounding. On a weight basis, equal cost of gain is achieved when peas are $80.99/ton compared to barley at $62.50/ton (equal to $1.50/bu), or one pound of peas is valued at 130% the value of one pound of barley.

Data from steers on the BarCan treatment suggests higher levels of crude protein or protein from other sources may improve performance. The canola meal used in this study was from expeller extraction which increases the proportion of by-pass protein. Barley protein is readily degraded in the rumen and may benefit from this type of supplement. Fecal nitrogen levels suggest improved protein utilization for the BarCon treatment as residual nitrogen was intermediate between the pea and barley treatments. However, nitrogen excretion also occurs in urine and volume of feces and urine would impact concentration.

Expeller meals are also higher in lipid content, containing 8-10% fat which may also have contributed to improved gains. However, cost of gain remains a consideration when purchased proteins are fed at levels above NRC recommendations.

Data from other research indicates that intake in the receiving period plays an important role in calf health during the entire feeding period. Increased feed intake from peas may help enhance immune response, accelerate acclimation to cold stress, and shorten the total time on feed. Additional research is warranted on use of peas in growing rations.


Table 4. Performance of growing steer calves fed diets with barley, barley and canola meal, or field peas (Average of 2 year feeding trial)

                                                              -----------Treatments-------                                           
Item Control Barley  Barley Canola  Field Peas  Std Err   P value 
Number of steers 27 27 26
Number of replicates 4 4 4
Initial wt, lb (early Oct) 579 581 578 20.7 .81
Final wt, lb (early Dec) 707 717 727 21.8 .48
Pd 1 DM intake/hd/day, lb 14.58 15.14 15.89 .44 .20
Pd 2 DM intake/hd/day, lb 16.06 16.87 18.52 .68 .15
Overall DM intake/hd/day, 15.32 16.01 17.21 .56 .17
Pd 1 Average daily gain, lb 2.74 2.92 2.94 .21 .81
Pd 2 Average daily gain, lb 2.48 2.63 3.17 .22 .25
Overall Average daily gain, lb 2.61 2.78 3.05 .22 .40
Pd 1 Gain/unit feed .188 .193 .188 .014 .96
Pd 2 Gain/unit feed .155 .156 .173 .017 .65
Overall Gain/unit feed .170 .174 .180 .016 .90
Pd 1 DM intake, % Body Wt. 2.39 2.48 2.60 .12 .11
Pd 2 DM intake, % Body Wt. 2.38 2.47 2.69 .12 .26
Overall DM intake, % Body Wt. 2.39a 2.47ab 2.65b .09 .07
Fecal nitrogen, % 12.38a 15.12b 18.89c 1.76
Feed cost/day, $d .581 .642 .641
Feed cost/lb gain, $d .223 .231 .210

a, b, c Values with different superscript are significantly different P<.10).
d Based on feed costs of $2.20/ bu (60 lb) for peas, $1.50/bu for barley,
$125/ton for canola meal, $280/ton for supplement, $40/ton for chopped forage,
and $20/ton for corn silage.


Finishing

As in the growing period, feed intake was numerically greater for the field pea diet (Table 5). Steers consumed 1.05 lb more dry matter per head per day with peas in the finishing diet compared to barley. Daily gain follows the dry matter intake pattern with a 5.5% (.20 lb/hd/d) improvement observed with peas over barley. Gain per unit feed was nearly identical. While feed costs per day were greater for steers fed peas, gains tended to be greater and the higher feed costs. The cost of gain for steers fed barley was $.230/lb at $1.50 per bushel compared to peas at $.210 when a bushel cost $2.20. Feed cost per pound of gain would be equal with peas at $2.02 per 60 lb bushel compared to barley at $1.50. Therefore, breakeven price for a bushel of peas is approximately 135% of the price of a bushel of barley in finishing rations. On a weight basis, equal cost of gain would occur when peas are valued at approximately 108% of a ton of barley.


Table 5. Performance of finishing steer calves fed diets with barley or field peas. (Average of 2 year feeding trial)

                                       -----------Treatments---------                
Item Barley     Field Peas    Std Err    P value 
Number of steers 41 42
Initial wt, lb 711 716 14.5 .88
Final wt, lb 1158 1177 21.2 .67
DM intake, lb/hd/d     21.54 22.59 .45 .64
Avg Daily Gain, lb 3.63 3.83 .13 .40
Gain/unit feed .170 .171 .01 .92
Feed cost/day, $a .836 .938 -
Feed cost/lb gain, $a .230 .245 -

aBased on feed costs of $2.20/ bu (60 lb) for peas, $1.50/bu for barley, $125/ton for canola meal, $280/ton for supplement, $40/ton for chopped forage, and $20/ton for corn silage.


Carcass

No differences were observed for carcass traits with the exception of marbling score and percent choice (Table 6). Marbling scores were greater for steers fed field pea diets (395 vs 369) and the percent choice higher (43.9 vs 24.8) for the field pea steers even though other indicators of carcass condition were similar. This result may be due to the tendency for increased feed intake and resulting gain advantage.

Future Studies

Additional research is needed to evaluate the impact of increasing field peas in receiving rations. Some variation due to year was observed in both the growing and finishing trials suggesting additional studies with more replicates for greater confidence in the results. Studies to determine animal performance from different varieties of peas would also be appropriate.

Implications

Biologically, peas have proven to be a useful feedgrain for growing and finishing steers. The amount of peas in a ration appears to be an economic issue as intake tended to improve with peas in the diet during both growing and finishing. Peas appear to be a very palatable feed grain and may offer unique advantages over other grains in growing and finishing steer diets.


Table 6. Carcass traits of steers finished on diets using field peas or barley

                                               -----------Treatments---------                    
Item Barley      Field Peas      Std Err      P value 
Number of steers 42 41
Hot Carcass Weight, lb     685 705 10.85 .34
Dressing Percent 62.1 62.3 .01 .53
Rib Eye Area, sq in. 12.62 12.35 .15 .83
Fat Thickness, in .38 .43 .02 .63
Kidney, Pelvic, Heart fat 2.51 2.45 .05 .47
Yield Grade 2.14 2.35 .13 .32
Marbling Scorea 369b 395c 7.12 .07
Percent Choice 24.8 43.9

a based on Low Select =301-350, high select = 351-400,
low choice = 401+
b,c Values with different superscripts are significantly different (P<.10).


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