Field Pea as a feedstuff for growing lambs.
W. W. Poland(1) and T. C. Faller(2)
Grain producers are beginning to recognize the advantages of adding field pea (Pisum sativum) into their small grain rotations (Endres, 1996). Field pea, while yielding similarly to wheat, has been shown to improve long-term soil quality, increase soil nitrogen content, and provide a break in the cycle of many organisms that can cause problems in wheat production (e.g. orange wheat blossom midge, scab). In part due to these agronomic benefits, acreage seeded to field pea has steadily increased in North Dakota. As the production of field pea increases in the state, producers are looking for alternative markets for their grain.
The chemical composition of field pea (Table 1) suggests that it has an excellent potential to be
used as a livestock feed. A brief summary of Canadian research (Hickling, 1994) indicates that
field pea can be used as a major source of supplemental protein for dairy cattle. Poland and
Landblom (1996) concluded that field pea is a suitable substitute for barley and soybean oil meal
when replacement is made on a equivalent protein basis in growing calf diets. Thus, a lamb
feeding trial was designed to evaluate the feeding potential of field pea in growing lamb diets. The
study involved substituting all or a portion of the barley and soybean oil meal in a control diet with
graded levels of field pea.
Materials and Methods
Two-hundred-forty lambs (wethers and ewes) were used to investigate the feeding potential of field pea in the diets of growing lambs. Lambs (72.3 ± 10.0 lbs initial body weight) were allotted by weight and sex into 8 finishing pens on April 16, 1997. Four dietary treatments were then assigned to pens (2 pens/treatment). A 81% concentrate, self-fed control diet (0%Pea) containing barley , soybean oil meal, alfalfa hay, straw and vitamin and mineral supplements was established (Table 2). Ammonium chloride was also included to prevent urinary calculi (NRC, 1985). The control diet was formulated to meet or exceed the nutritional needs of an early-weaned lamb possessing a moderate to rapid growth potential (NRC, 1985). Three other diets (Table 2) were constructed where field pea replaced one-third (33%Pea), two-thirds (66%Pea) or all (100%Pea) of the soybean oil meal in the control diet. A proportional amount of barley was also displaced by field pea so that diets would be isonitrogenous. Lambs were fed for 90 days. Live weights were recorded at the beginning and conclusion of the study.
Nine lambs died during the course of the trial. Death loss is reported as the average number of
lambs per pen within a treatment that died expressed as a percentage of the total of number of
lambs in that pen. Calculations of death loss and lamb feeding days (total number of days
individual lambs were fed) are based upon all lambs starting the trial. Subsequently, data from
those lambs that died was deleted from the data set before preforming further statistical analyses.
Data were analyzed as a split-plot design, where the whole plot was treated as a completely
random design. Dietary treatment was the only whole plot factor and pen of lambs represented the
experimental unit. Lamb sex was considered the split-plot factor. The sex of 15 lambs was not
recorded in the original data set. These lambs were coded with a separate sex code. Means for
lambs of unknown sex are not reported since proportion of wethers and ewes in this sex class
within a pen was unknown. No interactions were present between sex (wether or ewe) and level of
field pea in the diet.
Feedlot performance is summarized in table 3 and 4. There were no differences due the inclusion of field pea (Table 3) on the percentage of lambs that died during the course of the trial (average = 3.75%) or on the total number of lamb feeding days (average = 88.3 days per lamb). Feeding field pea in a high concentrate diet did not statistically improve final live weight (P = .88), total gain (P = .68), average daily gain (P = .68) or average daily feed intake (P = .54). Feed efficiency (P = .78) was also not affected by the feeding of field pea.
Wether lambs (Table 4) were heavier than female lambs at the beginning (P < .001) and the end
(P < .001) of the trial. Total weight gain (P < .02) and average daily gain (P < .02) also favored
wether lambs. Feed efficiency (P < .05) was improved in wether, over ewe, lambs. However since
daily feed intake was assumed to be the same for all lambs in a pen (sexes combined), this
difference in feed efficiency is computationally a difference in average daily gain.
The results of this study are similar to those previously reported (Poland and Landblom, 1996),
where field pea was fed in barley-based, high concentrate (70%) diets to growing calves. In that
experiment, average daily gain and feed efficiency were not affected by feeding field pea. However
in a second experiment (Poland and Landblom, 1996), calf performance and feed efficiency were
improved by the inclusion of field pea into a lower concentrate (30%) diet. Research in South
Dakota (C. Birkelo, SDSU; personal communication) included field pea in a corn-based, high
concentrate (90%) finishing diet for cattle. While average daily gain was not affected, feed
efficiency was improved (5.1 vs 4.8 feed/gain) when field pea replaced corn and soybean oil meal.
Field pea appears to be an excellent substitute for barley and soybean oil meal for growing lambs and calves. More research is needed to completely characterize the nutritional benefits of using field pea as feedstuff for all types of sheep and cattle.
Endres, G. 1996. Field pea can pay in a wheat rotation. NDSU Extension news release. Carrington
Research Extension Center. November 7th.
Hickling, D. 1994. Canadian peas: Feed industry guide. Canadian Special Crops Association
(Winnipeg, MB) and Western Canadian Pulse Growers Association (Regina, SK).
NRC. 1985. Nutrient Requirements of Sheep. National Academy Press, Washington, DC.
Poland, W.W. and D.G. Landblom. 1996. Feeding value of field pea and hull-less oat in growing calf diets. ND Cow/calf conference and beef cattle and range research report, North Dakota State University, pp3-11.
|Table 1. Chemical composition of field peaa (Hickling, 1994).|
|Ether extract (fat)||1.4|
|Acid detergent fiber (ADF)||9.1|
|Neutral detergent fiber (NDF)||19.8|
|a Composition expressed on a dry matter basis.|
|Table 2. Diet composition and nutrient analysis of growing lamb diets containing field pea.|
|Level of Field Pea|
|Soybean oil meal||8.4||5.6||2.8||0.0|
|ME, Mcal/lb DM||1.28|
|a Analysis was calculated using book values for individual feed ingredients.|
|Table 3. Effects of feeding field pea on feedlot performance of growing lambs.|
|Level of Field Pea|
|Numbera, per pen|
|Daily gainb, lb/hd||0.33||0.40||0.42||0.44||0.067|
|Daily feed intakeb, lb/hd||3.57||3.72||3.70||3.66||0.048|
|a These data are from lambs that started the trial.|
|b These data are for lambs that finished the trial.|
|Table 4. Effects of lamb sex on feedlot performance of growing lambs.|
|Daily gainac, lb/hd||0.44||0.39||0.014|
|Daily feed intakecd, lb/hd||3.66||3.66||-.-|
|a These data are for lambs that finished the trial.|
|b,c Sexes differ (P<.01 and .05, respectively).|
|d Daily feed intake was assumed equal for all lambs in a pen.|
1. Area Livestock Specialist, Dickinson Research Extension Center.
2. Director, Hettinger Research Extension Center.