NORTH FLORIDA EXPERIMENT STATION
December 13, 1957
NFES Mimeo Rpt. 58-2
STEER FATTENING TRIAL AT THE NORTH FLORIDA EXPERIMENT STATION
By F. S. Baker, Jr. and Elwyn S. Holmes
In one summer fattening trial, a group of steers in a well-ventilated barn
with a fan ate slightly more feed, yielded slightly heavier carcasses, and returned
$3.32 per head more than the control group without the fan.
In the first fattening trial with Dynafac, groups of steers receiving levels
of 1.5 and 2.0 grams per head daily in the feed graded slightly higher and returned
approximately $9 per head more than the control steers. This experiment must be
repeated before results are conclusive.
Dynafac tetraa alkylammonium stearate) is a compound derived from animal fat.
When added to cattle rations in small amounts, Dynafac has been reported to increase
feedlot gains and improve feed efficiency. In a Washington State study, adding 2.0
grams Dynafac to a fattening ration for yearling steers resulted in 0.3 pound more
gain per head daily (with or without stilbestrol) and an improvement in feed
utilization.1 A number of field trials have also indicated a marked response to
levels of 1.0, 1.5, and 2.0 grams of this feed additive per head daily.2 Because
of these reports, Dynafac was tried in a steer fattening ration commonly fed in
In North Florida, cattle are being fed more year-round rather than seasonally
in the cooler months as was formerly done. Although shade is provided, the question
has arisen as to the value of air movement by an electric fan with fattening steers
during the summer months. A marked response to the use of fans has occurred in
feedlots in the Imperial Valley of California.3 Although summer temperatures in
North Florida are not as extreme as those in Southern California, the heat together
with the high humidity probably exert a stress on fattening cattle in this area
during the summer. This prompted the trial of a fan with a group of steers during
the June-September period of 1957.
Thirty-two yearling Hereford steers weighing approximately 775 B wre
selected from a large group on improved pasture in Gadsden County. 'Zi-e
were divided as equally as possible into four uniform groups and ed on fee
in dry lot in a well-ventilated barn. Following were the treatm o:2
1 li ii \'~R %O l n js~ '"
1 Dyer, I. A. and J. McGregor. 1957. Some Effects of Tetra Al inonium Se
(Dynafac) and Diethylstilbestrol on Performance of Fattening S s. J. An/S/
2 Armour's Analysis, Armour Livestock Bureau, Chicago, Illinois, Ma~hZ.r
3 Ittner, N. R., C. F. Kelly and T. E. Bond. 1957. Cooling Cattle by Mechanicall
Increasing Air Movement. J. An. Sci. 16:732.
Mimeo Rpt. 58-2 cont'd.
Lot 13.--1.5 grams Dynafac per head daily.
Lot 14.-2.0 grams Dynafac per head daily.
Lot 15.--Artificial air.
All groups were fed the following ration:
Ground snapped corn according to appetite.
Citrus molasses 4.0 lbs. per head daily.
41% cottonseed meal 2.5 lbs. per head daily.
Coastal Bermuda hay self-fed.
Salt and bonemeal self-fed separately.
Dynafac was added to the cottonseed meal fed to Lots 13 and 14. Details of
the fan installation, and recording of temperatures and wind velocity are given
in a separate report by the junior author.
Estimated costs of the use of the fan were based on the assumption that the
fan could have been used as effectively for 32 cattle as for the 8 head actually
used in this trial. The costs include the cost of electrical current and a charge
for depreciation of the fan. Cost of feed per 100 pounds gain for Lot 15 (Table
2-580) includes the cost of operating the fan.
At the beginning; of the trial, the cattle were individually weighed on three
consecutive days, and the average of the three weights was used as the initial
weight. When the test was completed, the cattle were trucked three miles to
Quincy, weighed and a three percent shrink deducted from the Quincy weight to
obtain the final weight. Thus the initial weight was not shrunk while the final
weight was shrunk about four or five percent (one or two percent actual shrink
plus three percent calculated shrink) from the final weight at the feedlot.
The one final weight was used in calculating both gain and carcass yield. This
procedure was followed to approximate weighing conditions customarily used by
steer feeders in this area.
RESULTS AND DISCUSSION
Table 1-580 gives the results of the trial with Dynafac. The group of steers
fed 1.5 grams Dynafac (Lot 13) ate slightly less feed and made a slower and more
expensive gain than the control group (Lot 16). Because of a higher carcass yield,
the 1.5 gram Dynafac steers yielded heavier carcasses than the controls, indicating
that the difference in average daily gain was largely due to a difference in fill
at the end of the feeding period. The slightly higher carcass grading and market
prices resulted in approximately $9 per head more net return from the Dynafac
groups. It should be noted, however, that this is the result of only one trial
which must be repeated before definite recommendations can be made.
Mimeo Rpt. 58-2 cont'd.
Results of the air movement test are shown in Table 2-580. The group of
steers under the fan (Lot 15) ate slightly more feed but made very little more
gain than the control steers (Lot 16). Cost of feed per 100 pounds gain was
somewhat higher for the fan steers, partially because of the cost of the fan and
partially because of the higher feed consumption. The slightly heavier carcasses
and slightly higher carcass grading resulted in a $3.32 per head higher net return
for the steers under the fan. It should be pointed out, however, that these are
the results of only one trial and therefore not conclusive. The study will be
repeated in succeeding summers.
Appreciation is expressed to Mr. W. M. Inman, Quincy, Florida for furnishing
the cattle for the experiment.
Mr. Ray F. Cook, McKesson and Robbins, Inc., New York City, furnished the
Dynafac and Dr. M. A. Schooley, Armour Laboratories, Chicago, Illinois, gave
valuable suggestions concerning the conduct of the feed trial.
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