Introduction
Field peas contain high levels of protein (approximately 24% CP) and
energy (~88% TDN, 48% starch), and are increasingly available as livestock
feed. Significant amounts of pulse grains are produced annually in the northern
Great Plains of the United States
and the prairie provinces of Canada. North Dakota leads the United States in field pea
production, giving producers in the region a high quality option for protein in
beef cattle rations. Peas may make an excellent winter supplement for beef cows
grazing native range or fed low quality forages. This study was undertaken to determine the
effects of processing peas on cow performance during the winter feeding period.
Gestating cows fed peas in their winter
ration.
Experimental Procedures
One hundred-two Red Angus-cross cows (1301.2 ± 2.3 lbs.) were allotted
by weight, breed composition, and age to one of three pea-supplemented diets (2
pens per treatment) to determine the optimum level of pea processing needed to
maximize cow performance. All cows were determined to be pregnant prior to
initiation of the trial. Cows were housed and fed at the Carrington Research
Extension Center
feedlot in open drylot pens. Each pen was equipped with automatic waterers and
fenceline bunks for cows. Cows were fed 35 lbs. per head (as-fed basis) of a
totally-mixed ration once daily. Straw bales, fed in round bale feeders, were
offered free choice. The gestation diet
consisted of corn silage and wheat straw, with peas added as protein source at
20% of the diet DM (Table 1). Diets contained 9.7% crude protein. Cows were
weighed and condition scored at the start of the study (Dec 6) and at the end
of the study (March 3) just prior to calving, with intermediate weights taken
at 28 day intervals. Additional observations of calving date, calf growth, and
rebreeding performance will be reported in the future.
Research protocols regarding animal care followed guidelines recommended
in the Guide for the Care and Use of Agricultural Animals in Agricultural
Research and Teaching (FASS, 1998).
Data were subjected to a one-way analysis of variance as a completely
randomized design using the GLM procedures of SAS (Version 8.0; SAS Inst. Inc.,
Cary, NC).
The model included effects due to diet and pen was the experimental unit.
Results and Discussion
Particle size of ground, rolled, and whole peas was 701, 3100, and 9250
microns, respectively.
Cow weight did not differ among treatments (P > 0.85) over the
three-month study. Average gain showed
some response during the second period with improved gains (1.50 lbs. per hd
per day) for rolled peas (P<.02) over ground (1.30 lbs.) and whole (.92
lbs.). During the last period, gains
from whole peas (.33 lbs. per hd per day) were greatest (P<.03), followed by
rolled (-.07 lbs.) and ground (-.20 lbs.).
This pattern is not consistent.
Similarly, Birkelo et al. (2000) observed no effect of processing
(dry-rolled vs. whole peas) on performance when peas were included in the diet
at 10%. However, Bock (2000) reported that when fed at 40% of the diet DM in a
forage-based ration, cattle fed rolled peas gained the least compared to cattle
fed ground and whole peas. Cows do not require as much protein and energy as
growing cattle, thus the benefit of grain processing may not be realized. Overall, cows appear to be able to utilize field
peas whether they are processed or not.
Beef cow producers needing to purchase an energy or protein source for
their cows should consider growing field peas or seeking peas on the market.
Literature Cited
Birkelo, C. P., B.
J. Johnson, and B. D. Rops. 2000. Field peas in finishing cattle diets and the
effect of processing. SDAES Cattle 00-4. South Dakota State Univ. Extension
Service, Brookings.
Bock, E. J. 2000.
Effects of processing field peas in steer grower diets. Pages 29 – 31 in Carrington Research Extension
Center Beef Production Field Day Report. Vol. 23. North Dakota State Univ.,
Fargo.
This
material is based upon work supported by the U.S. Department of Agriculture. Any
opinions, findings, conclusion, or recommendations expressed in this publication
are those of the author(s) and do not necessarily reflect the view of the U.S. Department
of Agriculture.