Introduction
Corn production in North
Dakota is subject to cool temperatures, variation in
rainfall, and other environmental effects like early frost. During the summer
of 2004, unusually cool temperatures resulted in significant acreages of
immature corn that was disked or rolled down, and in some cases burned. The most common use of immature corn is for
silage but there were not enough choppers or cows in the affected corn-growing
areas to consume all the possible silage.
Combining immature wet corn is possible and there are a few feeders who
can use significant amounts of this grain.
Mature high-moisture corn can be harvested earlier than dry corn,
resulting in reduced dry matter losses and elimination of artificial drying
costs. However, marketing flexibility is
lost and corn will generally not keep for extended periods of time. Immature corn is useful only for feed and can
be harvested with a combine at up to 50% moisture. Processing (rolling or grinding) and packing
(elimination of oxygen) are required for optimum storage with minimal spoilage. Immature corn can be harvested as corn and
cob meal with some modifications to the combine. Wet corn can be piled on the ground and
packed with a tractor. Most feeders
store wet corn in a bunker silo.
Little animal performance information is available on immature or low
test weight, high-moisture corn. Mature high-moisture corn is generally
perceived to have more energy than dry-rolled corn as it is digested more
thoroughly in the ruminant animal. As
the corn kernel dries down, the starch becomes more compact. This compaction
and other physiological developments make the kernel less digestible
(Pritchard, 2005). Dry rolling or grinding increases digestibility of dry corn,
but optimum digestibility is not achieved.
High-moisture corn ferments more rapidly in the rumen compared to
dry-rolled corn, and most of the starch is removed in the rumen. Immature corn,
however, with a higher proportion of fiber from the bran and germ, should not
produce the same acidosis potential as mature corn.
This study was conducted to compare dry-rolled mature corn with immature
high-moisture corn from the harvest of 2004 in finishing feedlot diets.
Ground and packed wet corn stored over
winter.
Experimental Procedures
Ninety-eight crossbred steers (765.4 ± 22.4 lbs.) were allotted by
source and weight to a dry-rolled or high-moisture corn-based diet (6 pens per
treatment, 8 to 9 head per pen) to determine the effect of corn type on
performance and carcass quality. Cattle were blocked into light and heavy
groups. Steers were housed and fed at the Carrington Research
Extension Center
feedlot in open drylot pens. Each pen was equipped with automatic waterers,
windbreaks, and fenceline bunks which allowed for two feet of bunk space per
head. Feed was delivered as a totally-mixed ration once daily to appetite.
Diets were formulated to contain 12.3% CP and 64.7 MCal NEg/cwt (Table
1).
Feed samples were taken every week and composited for analysis of DM and
CP. The high-moisture immature corn was
sourced from a neighboring commercial feedyard with an estimated 150,000
bushels in its pile. At delivery, corn
was tub-ground, piled and packed with a farm tractor and a box scraper. Bushel test weight varied with the many different
loads of immature corn delivered to the feeder.
The range was estimated at 37 to 48 pounds per bushel with an average of
42 to 44 pounds. Moisture content of the
corn was taken as it was removed from the feedyard pile (two loads per
week). The wet corn averaged 72% dry
matter over the trial. Dry, mature corn
averaged 54 pounds per bushel and was 14% moisture.
Cattle were vaccinated for protection against IBR, BVD, BRSV, PI3
(Bovishield-4; Pfizer, Exton, PA),
and clostridia (7-way + somnus; Pfizer, Exton,
PA). Health status of the cattle
was monitored daily. Rectal temperatures were measured in animals that were
visibly anorexic, or had severe nasal mucous drainage and rapid or labored
breathing. Sick animals were treated with one of two antibiotics according to
label instructions (Micotil, Elanco, Indianapolis,
IN; A180, Pfizer, Exton, PA).
Micotil was used on first and second pulls, followed by A180 if cattle were
unresponsive. Antibiotic treatment continued until animals appeared healthy.
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).
All steers were implanted with Component TE-S (120 mg trenbolone
acetate, 24 mg estradiol; provided courtesy of VetLife, Overland Park, KS)
at the initiation of the trial.
Ten out of 12 of the pens were slaughtered at Tyson Foods (Dakota City, NE)
after 118 days on trial. The performance trial ended after 118 days on feed.
Hot carcass weight, fat thickness, percentage kidney, pelvic and heart fat,
longissimus muscle area, and USDA quality and yield grades were determined by
qualified personnel 48 hours after slaughter. Two light pens (one high-moisture
corn and one dry-rolled corn treatment) were not included in the carcass
analysis.
Steers fed immature high-moisture corn.
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).
Pen was the experimental unit.
Results
Cattle fed mature dry-rolled or immature high-moisture corn gained
similarly (3.79 vs. 3.91 lbs. /d, respectively; P > 0.44), and consumed a
similar amount of dry matter (22.4 vs. 21.8 lbs. /d, respectively; P > 0.24)
over the entire trial. Some period to period variation was observed but overall,
cattle fed the immature wet corn exceeded the performance expectations. Owens et al. (1997) reported that cattle fed
mature high-moisture grains tended to gain faster, consume less dry matter, and
convert feed more efficiently. The immature wet corn in this study may not have
contained the starch level to show an advantage over dry corn (Table 2.)
No differences were observed for hot carcass weight, dressing percent,
ribeye area, fat thickness, yield grade, marbling score, or percentage of
carcasses grading choice (P > 0.24). Percent kidney, pelvic, and heart fat
was greater for cattle fed dry-rolled corn (2.43 vs. 2.23%, P < 0.04) (Table
3).
Discussion
Considering the similarity in animal performance in this study, feeders
may have an economic advantage if they can purchase immature corn grain at a
discount from corn farmers with no cattle.
At a minimum, feeders can save corn growers the drying costs and
negotiate an advantage in price. Corn
growers, on the other hand, may want to consider feeding cattle to capture more
value from their grain production.
Insurance regulations may foster this tactic. Feeders who grow their own corn or partner
with corn growers, may consider longer season varieties with increased yield
potential and plan on harvesting immature grain for feed. The net result could be more pounds of beef
per acre and increased profits to the feeding enterprise. The positive outcome of this study is another
reason to consider the opportunities for cattle and feedlots in North Dakota.
References
FASS. 1998. Guide for the Care and Use of
Agricultural Animals in Agricultural Research and Teaching. Consortium for
Developing a Guide for the Care and Use of Agricultural Animals in Agricultural
Research and Teaching. Champaign, IL.
Mader, T., P.
Guyer, and R. Stock. 1983. Feeding high-moisture corn. Extension Circular
G74-100-A. Univ. Nebraska, Lincoln.
Owens, F. N., D.
S. Secrist, W. J. Hill, and D. R. Gill. 1997. The effect of grain source and
grain processing on performance of feedlot cattle: A review. J. Anim. Sci.
75:868-879.
Pritchard,
R. H. 2005. Utilizing dry and high-moisture corn efficiently. Available: http://www.beeflinks.com/DryHMCorn.pdf.
Accessed May 4, 2005.