Field peas in diets for growing heifers, and
backgrounding and finishing steer calves
(Progress report)

V. L. Anderson
Carrington Research Extension Center
North Dakota State University

Introduction
Field pea acreage in North Dakota is expected to increase rapidly as producers realize the benefits of cropping systems with annual legumes. The end use of field peas will be predominantly as livestock feed although peas making human food grade yield a greater return per bushel. 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 the region is in beef cattle diets. 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, peas may be used as a protein supplements or as a major ration ingredient in a variety of diets. Peas will contribute required nutrients to diets high in forage or low in protein. This project evaluates field peas in diets for growing heifer calves, and backgrounding and finishing steers. This report presents data from the first year of a two year study.

Table 1. Nutrient content of field peas, barley, and midds used in feeding trials.

    
Materials and Methods

Experiment 1
In a demonstration trial, weaned heifer calves (n=38) were randomly allotted to two pens and limit fed high forage diets with field peas or wheat midds as the grain source. The diets were formulated for approximately 2 pounds of gain per head per day. The totally mixed diets were fed once daily in fenceline bunks. Ingredients were corn silage, chopped hay, straw and grain (Table 2). The trial started on November 4 and concluded December 30.

Table 2. Diets with field peas or wheat midds for growing replacement heifer calves (Experiment 1).

 
Experiment 2
Growing steer calves (n=46) were blocked by weight and allotted to six pens with three treatments. Dietary treatments (Table 3) 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; and 3) field peas as the primary grain source. The protein level in the field pea diet exceeded animal requirements so the barley with extra protein treatment was included to evaluate equivalent protein levels in diets containing barley or peas. The trial started on October 7 and concluded on December 2.

Experiment 3
Steers from Experiment 2 were allotted to two pens 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 high protein barley treatment were divided randomly between barley and pea treatments. Steers were fed totally mixed finishing diets (Table 4) once daily in fenceline bunks. Changes in amount fed was determined after "reading" feedbunks each morning. This trial started on Dec 2 and concluded at when steers went to market in April. Steers were weighed after 56 and 108 days on feed, and just prior to market.

Results and Discussion
The data reported here should be considered preliminary, nonetheless, it appears field peas are a very useful feed source for growing heifers, or backgrounding and finishing steers calves, given economic competitiveness.

Experiment 1
Heifer start weights averaged 490 pounds on October 7 with final weights on December 20 at 647 for peas and 636 for wheat midds (Table 5). Some period variation was observed in both treatments due to severe weather. Even though intake was controlled in the growing heifer trial, dry matter intake was calculated at 13.69 pounds for field pea heifers and 12.93 for wheat midds calves, a difference of .76 pounds of dry matter intake. Average daily gains were 1.86 for heifers fed peas at 4.95 pounds per day compared to 1.73 pounds from wheat midds at 4.99 pounds. Gain per unit feed was .136 for peas and .134 for midds. Feed costs were 2.5 cents per day greater for pea fed heifers or 2.9 cents per pound of gain.

Table 3. Diets for backgrounding steer calves fed field peas or barley (Experiment 2).

Experiment 2
Starting weights on October 4 averaged 530 pounds with final weights after 56 days on feed averaging 689, 688, and 675 for diets with peas, barley with extra protein, and control barley respectively (Table 6). Backgrounding steers consumed an average of 16.06 pounds dry matter with peas in the diet, 15.34 on high protein barley, and 15.14 on control barley. Gains were 2.88 on peas, 2.79 on high protein barely and 2.58 on control barley. Gain per unit feed averaged .181 for peas, .184 for high protein barley, and .173 for control barley. Feed costs were lowest at $.17 per pound of gain for barley with extra protein.

The backgrounding data suggests higher protein diets produce improved gains and barley supplemented with protein may be more economical to feed.

Experiment 3
Steers on the finishing diets consumed an average of 21.87 pounds of dry matter with peas in the rations compared to 20.57 for barley (Table 7). Average gains were 3.71 for peas and 3.66 for barley with gain per unit feed averaging .170 for peas and .178 for barley. Feed cost favored barley at $.28 per pound of gain vs $.32 for peas at the given prices.

Table 4. Diets with field peas or barley for finishing steer calves
(Experiment 3).

Implications
Additional replicates of these feeding trials are required for valid statistical comparisons but from this preliminary data, field peas appear to be a very useful feed for growing and finishing calves. Feed intake and gains were equal or better than other feeds used in this trial. At this time, the price of peas compared to other feedstuffs needs to be carefully considered before they are used at commodity levels. Peas may be used most economically in high value, high nutrient density diets such as creep feed or as protein sources for calves.

Pea growers that do not make human food quality can be assured that the feed value of peas is competitive with other feedstuffs in these rations. Using peas in the appropriate diet is the key to maximizing profit from this feedstuff. Additional work is needed to determine variation in nutrient content and performance of animals fed different varieties of peas.

Table 5. Performance of growing replacement heifer calves fed wheat midds or field peas during early winter (Experiment 1).

^a Based on feed prices of $320/T for BVT supplement; $400/T for mineral; $200/T for canola meal, $2.00 per bu for barley, $3.00/bu(60 lb) for peas, $50/T for hay, and $20/T for silage.

Table 6. Performance of backgrounding steer calves fed diets with barley, or field peas (Experiment 2).

^a Based on feed prices of $320/T for BVT supplement; $400/T for mineral; $200/T for canola meal, $2.00 per bu for barley, $3.00/bu(60 lb) for peas, $50/T for hay, and $20/T for silage.

Table 7. Performance of finishing steer calves fed field peas or barley
(Experiment 3).

^a Based on feed costs of $3.00/ bu (60 lb) for peas, $2.00 /bu for barley, $200/ton for canola meal, $320/ton for BVT, $400/ton for mineral, $50/ton for chopped hay, and $20/ton for corn silage.

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