Everglades Station Mimeo 62-25
ADDITIONAL INFORMATION CONCERNING THE VALUE OF COBALT "BULLETS"
TO YEARLING STEERS ON MUCK SOIL
C. E. Haines
Numerous studies on the use of cobalt "bullets" for cattle have been re-
ported from many sections of the country. Recently, the results of three trials,
conducted in south Florida, were reported by H. L. Chapman, Jr. (EES Mimeo Report
61-4 and the Florida Cattleman, May, 1961). The trials were conducted in three
different locations and nutritional conditions and results indicated that cattle
having access to a mineral mixture containing cobalt, showed little response to
the cobalt "bullet". However, an additional study was conducted to determine
the repeatability of the results with steers, on muck soil, under adequate
Present day information recognizes the fact that cobalt is considered an
essential mineral element for cattle but that only a very small intake is needed
to meet normal requirements. Recommended mineral mixtures usually include
amounts of cobalt sufficient to provide the daily needs of this element. How-
ever, cases of cobalt deficiency have appeared occasionally in some herds in
certain locations. This fact.caused the development of a cobalt "bullet" which
is administered orally once a year. The "bullet" contains 90 percent cobalt
oxide and is supposed to be retained in the stomach where it releases the cobalt
over a prolonged period of time.
The study reported herein was conducted with these "bullets" given to
yearling steers on Roselawn St. Augustinegrass pasture. The steers were pro-
vided with a salt-trace mineral mixture free choice throughout the trial which
contained 0.03 percent cobalt. The animals were weighed at quarterly intervals
during an 11 months period which began in November, when the steers were approxi-
mately one year old, and terminated the following October.
The 80 Angus steers involved had been divided into four groups of 20 animals
each for a management study and the cobalt treatments were superimposed on this
experiment. One-half, or 10 of the steers on each management treatment were
given a cobalt "bullet". The data from the steers on the two cobalt treatments
were combined from the four management treatments. One animal was removed from
the trial for reasons not connected with experimental treatments so that the
data presented included only 79 steers.
A summary of the data collected during the study is shown in the following
table. The average weight changes will illustrate the lack of seasonal fluctu-
ations in gains that could have occurred between the two cobalt treatments.
I/ Assistant Animal Husbandman, Everglades Experiment Station, Be l ade,
Florida. The cobalt "bullets" were furnished by Nicholas Ameridajtd.,
Chicago, Illinois. 2/ .a
Treatments and Weigh Periods No "bullet" Cobalt "bullet"
Number of Steers 39 40
Average Initial Weight (Nov. 8, 1960) 369.0 354.5
Average Period Gains (Ibs.)
Jan. 31, 1961 94.9 101.6
Apr. 25, 1961 88.8 92.5
July 18, 1961 88.1 85.3
Oct. 10, 1961 39.6 40.7
Total Weight Increase (lbs.) 311.4 320.1
Average Final Weight (Ibs.) 680.4 674.6
Initial Condition Grade* 5.68 5.23
Final Condition Grade* 6.82 6.88
*Grade: 5 = High Utility; 6 and 7 = Low and Medium Standard.
Although the average weight of the steers not given the cobalt "bullet"
remained slightly higher than the "bulleted" group, their weight advantage
decreased from 14.5 pounds at the beginning of the trial to 5.8 pounds at the
termination. During the first half of the study, steers receiving the bullets
gained an average of 10.4 pounds more than those not provided the bullets.
However, in the second half of the test period, the "bulleted" steers gained
an average of 1.7 pounds less than the control steers. Thus, the cobalt treated
group gained an average of 8.7 pounds more per steer over the 11 months period
than the control steers. This difference in gains was not statistically signi-
On the basis of present cattle prices and the latest local cost of a cobalt
"bullet" ($0.75*) the practice proved of slight economic value with this group
of steers. It amounted to an investment of $0.75, plus labor, for an additional
gain of almost nine pounds over an 11 months period. The market grade changes
also suggest that the "bullets" may have improved the condition of the steers
slightly. This improvement amounted to increasing the market grade, during the
study, by approximately 1/6 of a grade more for the cobalt treated group. This
occurred since their initial grades were lower than those of the control group.
* Cost $0.75 per bullet when purchased in quantities of 1,000 or more.
EES Mimeo 62-25