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Division of Agricultural Sciences and Natural Resources • Oklahoma State University
CR-3253
0702
3253.4
How to Estimate the Value
of Supplementing Grazing Stocker Cattle
Donald R. Gill Keith S. Lusby
Extension Animal Nutritionist Extension Beef Cattle Specialist
Table 1. Prices paid for medium-frame number 1 steers at three selected markets, and computed value of gain.
Weight Value/ Value of
Class Amarillo Okla City San Angelo Ave. Head Gain
350 $106.00 $105.00 $111.00 $107.33 $375.67
450 $96.50 $102.00 $101.00 $99.83 $449.25 $73.58
550 $87.50 $94.00 $92.00 $91.17 $501.42 $52.17
650 $85.50 $86.00 $86.00 $85.83 $557.92 $56.50
750 $84.25 $82.50 $80.00 $82.25 $616.88 $58.96
Average Value of 100 lbs of Gain.$60.30
It is easy to estimate the value of supplemental feeding
of grazing stocker cattle in Oklahoma when a few key facts
are known. These facts include the value of gain, the cost of
gain, and the effect the supplement has on forage utilization.
What would the cattle have gained with
no supplement?
This is a critical piece of information that often is not
known. All too frequently, the gains of nonsupplemented
cattle are unknown, and producers and salesmen try to
attribute the total gain of the cattle to the supplemental feed.
We must determine "additional gain due to supplement."
Once this is known, it is then possible to make calculations
to see if it is profitable to supplement.
For example, if steers without supplement would have
gained one pound per day and the steers under exactly the
same conditions plus supplement gain 1.40 pounds per day,
then the additional gain due to supplement would be .4 lbs
(1.4-1.0 lbs).
The next important task is to estimate the value of
additional gain. The classic mistake is to assume that just
because calves of a given weight are selling for $1 per pound,
then each pound of added gain is worth one dollar. Most of the
time the price of cattle rolls back as weight increases as
illustrated in Table 1. Notice that even though cattle sold from
an average of $82.25 to $107.33/cwt, the value of gain only
averaged $60.30/cwt.
The value of gain varies with a number of factors. A major
factor is the cost of grain to feedlots. Cheap grain means
cheap feedlot gains, and the feedlots will not pay more for
added calf weight than the cost of putting on that weight in their
feedlot. The value of added weight has remained remarkably
close to $50-$60 per hundred range in recent years. There is
one very important exception, and that is contract cattle,
where delivery price is agreed upon and premiums or discounts
for weight or lack of weight are defined by these terms.
In this case, the value of gain will be based on the contract
price.
When the gain of nonsupplemented cattle, the added
gain from supplementation, and the value of added gain as a
result of supplementation are known, the returns from supplementation
can be computed as in the following example.
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of feed only costing 14 cents per day boosting gain .18 pound
or (.18 x .60= 10.8 cents) worth of gain is not a good
investment. But 15 cents worth of feed including an ionophore
giving 22.8 cents worth of gain (.38 lb added gain x
$.60/lb) plus fringe benefits is worth considering.
How do we figure the value of ionophores and antibiotics
in these formulas? The key point is to think about these as
being additive with the feed and forage.
The following increases in gain due to the ionophore itself
can be expected with grazing animals when the ionophores
are fed at the recommended levels and frequency and daily
gains are adequate to permit a response:
On summer grasses with base gains over 1#/day.
With daily feeding, .20 lb/day increased gain.
Feeding every other day, .15 lb/day.
With less frequent feeding = little or no value.
The ionophore response on wheat pasture appears to be
less than with the summer grasses. An estimate of 0.15
lb/day increased gain may be used instead of 0.20.
For dry wintering stocker steers gaining less than 0.75
pounds per day, we doubt that there is much growth
response due to an ionophore. Addition of the ionophore
would depend on other concerns such as coccidiosis.
Antibiotic feeding to grazing cattle has not been extensively
studied, but in Kansas and Oklahoma tests with cattle
grazing native range, boosts of 0.20 pound per day have been
observed. Data indicate that 350 mg/day of Aureomycin in
Oklahoma Gold (38% protein) cubes may increase gains 0.20
lb/day.
Feeding examples using supplement and ionophores
Cattle grazing season-long native range.
Base gain (no feed) = 1 lb/day.
Add 1 pound 38% protein supplement + .40 lb/day.
Add Rumensin @200 grams/ton to above + .20 lb/
day.
Gain now is 1.60 lbs/day.
Feed/added gain = 1.66 lbs.
If this feed costs 11 cents per pound, the cost of added
gain will be 18 cents per pound.
Since feeding 1 lb of 38% protein supplement gives such
an efficient increase in gain, what will happen if you feed 3
pounds of Oklahoma Gold per day? (Assume the concentration
of Rumensin or Bovatec is reduced to provide the proper
level per calf.)
Base gain with no supplement = 1.0 lb/day.
Add 1 pound 38% protein Gold Cube = .60 lb/day.
Add 2 more pounds (2 lbs x .09 lb/day) = .18 lb/day.
Total gain = 1.78 lbs/day.
Supplement/added gain
(3 lbs feed / .78 lb gain) = 3.85 lbs
Summary
When evaluating the potential for feeding on grass,
remember the potential gain from correcting protein deficiencies
is large with most summer forages. However, after
protein requirements are met, additional protein is no more
efficient than additional energy (grains). High protein feeds
have about the same value as grains on wheat pasture, again
because protein is already high. Following the advantages of
protein is the large potential for increasing gain with ionophores
(Rumensin or Bovatec fed at a rate of 100-200 mg per
head per day). One hundred milligrams of either of these two
ionophores (one cent/head) may increase gain 0.15-0.20 lb
per day when used properly. Antibiotics are used to both
stimulate gain and to prevent disease problems. Energy feeds
are often the carriers for ionophores or antibiotics when
additional protein is not needed. Energy feeds alone have a
small potential margin for profitability and must be calculated
carefully.
Energy feeds give about .09 pound of gain per pound of
feed fed, or stated the other way, require about 10-15 pounds
of feed per pound of added weight gain.
The first pound of protein supplement is both a protein
and an energy supplement. If you are mathematical and like
to derive your own formulas, assign the first pound of protein
supplement a one time value of 0.31 lb of added gain for
protein. Then each pound of protein including the first should
result in 0.09 pound of added gain per pound fed.
3253.2 0000.3
Table 2. The average protein content of native range
grass West of Stillwater, Oklahoma (three years average).
Date Protein (dry matter basis)
May 15th 13.10
June 15th 10.03
July 15th 7.50
August 15th 7.33
September 20th 7.25
Table 3. Protein requirements for large frame steer
calves assuming that dry matter intake is equal to 2.8
percent of body weight.
Expected Gain in pounds / day.
Animal
Weight 0.50 1.00 1.50 2.00
300 9.17% 11.79% 14.17% 16.31%
400 7.95% 9.82% 11.61% 13.13%
500 7.14% 8.64% 10.71% 11.21%
600 6.61% 7.80% 8.93% 9.88%
Steers will gain one pound per day during the summer
season without supplement. Feeding one pound per day of
Oklahoma Gold cubes (38% protein supplement containing
200 grams per ton of either monensin or lasalocid) will
increase gain to 1.60 pounds per day. If the supplement cost
12 cents per day and the resulting 0.60 pound per day of
weight gain was worth 36 cents (0.60 pound per day times
60 cents per pound of gain), the practice would net the
cattleman 24 cents per day (36 cents minus 12 cent feed
cost).
Predicting the gain response due
to supplementation
Supplementation of standing forage is most advantageous
if the supplement can correct a nutritional deficiency
that is seriously interfering with forage utilization. This is
often the case when warm-season forages are deficient in
protein. The first symptom of protein deficient diets is a
reduction of forage intake. Reduced intake severely restricts
potential energy intake and thus, restricts potential
animal performance.
Tables 2 and 3 show a high probability of protein
deficiency in any of these months when high rates of gain
are expected with light weight cattle. By the first of July,
most Oklahoma forages will be too low in protein to support
gains of over 1.0 pound per day even on cattle over 500 pounds.
At this time the forage will be too low in protein to support
maintenance in light weight cattle. Because protein limits the
utilization of energy, the protein deficiency must be corrected
first. Correction for low protein will allow a significant increase
in forage intake and cause a slight increase in forage digestibility.
For example, supplementing one pound of cottonseed meal
(41% protein) to stocker cattle in July will likely increase rate of
gain about 0.40 pound per day. Up to the point where protein
is adequate it appears that there is a 1 to 1 increase in gain per
unit of protein fed (0.41 pound of protein equals 0.40 pound of
additional weight gain). Adding low-protein, high energy feed
(12-20% CP feeds) to a diet already deficient in protein will not
improve animal performance. The protein deficiency is made
worse and the added starch can further impede forage digestion.
Getting ready to determine if feeding
is feasible
The following are a series of thoughts that you may want to
consider before attempting to calculate the economics of supplemental
feeding.
1. Does supplemental feeding add value in addition to
feed induced gain?
Reduced shrink at sale time (easy gathering).
Tame wild cattle.
Reduce the risk of theft.
Reduce death loss (easier observation).
Increases ease of management (antibiotics for foot-rot).
Include additives such as antibiotics, ionophores etc.
2. Do I have an adequate supply of forage?
Feeding high protein supplements will increase forage
digestibility and intake.
3. What is the gain without supplementation?
How much gain do I really need?
If the difference between what is needed and the gain
without supplement is more than 50% or 0.70 pound, then
look for an alternative to forage.
4. What is the best time to supplement forage?
(See tables 2 and 3.)
5. Will the supplement increase forage intake or will
supplement replace the forage? A mistake on this
question is the most serious error that cattlemen
make.
You have now asked some of the important questions. The
following discussion should help answer some of these questions.
Predicting response due to supplement
The higher the forage quality (higher protein, higher energy
digestibility, lower fiber content) the greater the intake of the
forage without supplementation, assuming there is enough
forage. You now must estimate what the supplement will do
to forage intake. There are good reasons for increasing
forage intake, but there are also times when you might not
be able to afford to increase intake such as when forage is
short.
If you remember two numbers, and if you know which
direction forage intake is moving, then you can make good
estimates of probable feed required per unit of additional
gain. The two numbers are 4 and 9.
When the forage is slightly deficient in protein, you can
expect about 0.4 pound of added weight gain from the first
pound of high protein supplement fed.
When protein in the diet is adequate, you can expect
about 0.09 pound of added weight gain from each pound
of supplemental "energy" feed added.
For example, if you correct a minor protein deficiency,
1 pound of a protein supplement such as cottonseed meal
should increase gain about 0.4 pound per day. If the protein
level in the diet (forage or forage plus supplement) is
adequate, the addition of 1 pound of corn will likely increase
gain by 0.09 pound per day.
Further explanation of the "9" rule. This rule will apply
only if supplemental feed is limited to 0.75 percent of body
weight.
For example, if 500 pound calves were fed 3.75 pounds
per day of corn (500 x 0.75%), you can expect about .09
pound gain for each pound of supplemental corn. At lower
feeding rates, i.e., one pound of corn per day, the prospect
of a slightly more efficient response is a possibility. However,
at higher feeding rates, reduced response is a
certainty. Cattlemen always want to know how much they
can bend these rules with regard to energy (lower protein,
grain-based) feeds. The answer is not very much. The
important point is the direction of change. Even with only
one pound of energy feed, there is little evidence suggesting
that added gain due to supplement could exceed 0.15
pound per pound of feed. If the feeding rate is over 1 percent
of body weight, the response will be less than .09.
Energy feed must be fed daily to maintain the indicated
response. Feeding large amounts of grain supplement
on a given day must be avoided.
For the purpose of these rules, what is an energy feed?
Corn has been the example used thus far, but corn, milo,
wheat midds, soybean hulls and a number of low protein
commercial formulations would be similar. Remember that
the rules have already limited these feed to a feeding rate
of no more than 0.75 percent of body weight. There may be
a large difference in the safety of the above feeds with the
grains having the most potential of killing cattle with acidosis
if too much is consumed too rapidly by unadapted animals.
The protein response can be maintained even with extended
feeding intervals such as every other day, or three days
per week. Our definition of a "protein" feed would be one which
was an all natural protein containing at least 38 percent crude
protein. Oklahoma experience would limit these to cottonseed
meal, soybean meal, sunflower meal, peanut meal, or combinations
made up primarily of the previously mentioned protein
concentrates. Lower protein mixtures may be useful but should
be calculated as "protein-energy mixtures" as illustrated below
in the following examples.
With many younger cattle, or with high growth potential
cattle, the response due to additional protein may go beyond
that supplied by 0.40 pound of supplemental protein. With the
"SUPERGOLD" with monensin, fed at a rate of 2.5 pounds per
day additional gains of up to 0.90 pounds have been observed.
Summer stocker example:
Base gain without supplement = 1.0 lb/day.
Feed 1 pound of cottonseed meal, add 0.4 lb/day
total is now 1.4 lbs/day.
Add 1 pound of "energy feed" to the 1 lb of CSM.
base 1.0 + 0.4a + 0.09b = 1.49 lbs/day.
a Gain from the first pound of protein supplement.
b Gain from each pound of "energy" feed.
Wheat pasture example (assuming adequate forage):
Base gain is 1.75 lbs day (no supplement).
Feed grain @ 1% of body weight to 450-pound
steers.
4.5 lbs grain x 0.09 = .41 lb added weight gain.
1.75 lbs + 0.41 = 2.16 lbs / Day.
Feed per pound of added weight gain = 11.1 lbs.
Supplementation with feed only is unlikely to ever increase
daily gain sufficiently to be profitable when calves have access
to adequate supplies of high quality, high protein forages such
as wheat pasture or clovers. When forage supply is adequate,
forage intake will be near maximal and the cattle will have a very
good rate of gain (often exceeding 2.0 lb/day) from forage alone.
When supplements are fed, especially at rates close to 1.0 % of
body weight, the cattle respond by reducing forage intake. As
a result, daily gain is increased very little and available forage
was replaced with purchased supplement. In fact, valuable
forage may be wasted by increased trampling.
How about ionophores?
Ionophores and other feed additives have tilted the advantage
of feeding to the point where many grazed cattle should
never spend a day on pasture without some supplemental feed.
With energy feed such as wheat midds, 2 pounds per day would
be expected to increase gain .18 pound per day. An additive
may easily add another .20 pound of gain per day. Two pounds