Animal Science Department Florida Agricultural
Mimeograph Report AN66-6 Experiment Station
PALATABILITY OF FEED GRADE PHOSPHATES TO RUMINANTS1/
L. R. Arrington, C. B. Ammerman and P. E. Loggins-/
Several different feed grade phosphates are used to provide supple-
mental phosphorus to livestock. These may be added to the ration, mixed
with other minerals in formulating mineral mixtures or they may be
offered free choice to animals. When offered free choice, the voluntary
intake may depend upon phosphorus needs of the animal or upon palatabil-
ity of the phosphate compound. Many of the tests of voluntary phosphate
consumption have been made with salt added (1, 2). When mixtures of
equal portions of salt and phosphates were provided to cattle, the bone
meal-salt mixture was consumed in greater amounts than those containing
dicalcium phosphate, soft phosphate, Curacao phosphate or defluorinated
phosphate. Consumption of phosphates other than bone meal and without
salt were more nearly equal with soft phosphate consumed in the largest
The following study was undertaken to determine the relative vol-
untary intake of four different feed grade phosphate materials without
added salt or other minerals.
Materials and Methods
The four phosphate materials tested for palatability were: (1)
steamed bone meal, (2) defluorinated rock phosphate, (3) dicalcium
phosphate and (4) soft phosphate. They were provided free choice in a
portable covered shed with identical removable compartments. At irreg-
ular intervals, the position of the boxes was shifted so that animals
would not become accustomed to eating from one location within the shed.
The phosphates were not mixed with salt or other minerals, but
offered directly as obtained. Following placement of the initial
weighed amount of each material, boxes were checked twice weekly, and
ample amounts of the phosphates were available continuously. If the
materials became contaminated or had been exposed for about two weeks
with little consumption, the remaining amount was removed, weighed and
a fresh supply added.
1/ Supported in part by grant from Soft Phosphate Research Institute,
2/ Arrington and Ammerman, Associate Animal Nutritionists; Loggins,
Assistant Animal Husbandman.
Experimental animals were mature cattle of beef and dairy type and
dairy calves. They were confined to a small pasture which required
supplemental feeding of hay and concentrate. Frequent exchange or rota-
tion of animals to other experiments was necessary and most of the feed-
ing periods were relatively short with three to eight animals per feeding
period. The phosphates were also offered in a similar manner to sheep on
pasture in two trials.
Following the first series of measurements (table 1) which indicated
that the dicalcium phosphate was consumed in the largest amount, three
additional consecutive measurements (table 2) were conducted in which
dicalcium phosphate was removed and the remaining three phosphates made
available in a similar manner.
A third trial was conducted (table 3) in which different brands of
bone meal and of defluorinated phosphate were used along with the orig-
inal samples of dicalcium phosphate and soft phosphate. These were
offered to eight mature beef steers and to six dairy type yearling
calves in separate periods and weekly intakes were recorded as a measure
of possible change in preference for phosphates with time.
Results and Discussion
Data representing intakes per animal per day of the four phosphates
by calves are shown in table 1. In all of the trials with calves, more
dicalcium phosphate was consumed than any of the other materials. Some
variability, however, was observed between feeding periods with the other
phosphates. An average of the three trials with calves showed that
dicalcium phosphate was consumed in the largest amount and lesser but
more nearly equal amounts of the other three were consumed.
When dicalcium phosphate was omitted from the tests, data shown in
table 2 were obtained. Some variability between trials was observed,
but an average of the three trials indicated a slightly greater intake
of soft phosphate than bone meal with defluorinated phosphate being
Results of trial 3 in which different samples of bone meal and
defluorinated phosphate were used are recorded in table 3. The beef
steers consumed dicalcium phosphate in the largest amount and soft
phosphate least. The dairy type yearlings consumed more soft phosphate
than other phosphates with practically no intake of bone meal.
Some effect of length of time the cattle were exposed to the phos-
phates was suggested by the decrease in consumption of soft phosphate
by beef steers. On the other hand, no change in consumption of this
phosphate by the dairy animals as observed during three weeks. Intakes
of defluorinated and dicalcium phosphate by the dairy animals increased
from the first to third weeks but the increases were not accompanied by
a decrease in the other materials.
- 3 -
Considerable variability was observed in the voluntary intake of
the different phosphates indicating no consistent preference. In the
third trial, beef steers consumed very little soft phosphate but dairy
type yearlings consumed more of this phosphate than any of the others
with practically no intake of bone meal which was readily eaten by beef
steers. In trial one, however, with a different brand of bone meal
dairy calves consumed more bone meal than soft phosphate. The differ-
ence in brands of bone meal used might appear to explain this differ-
ence but would not account for the difference observed in trial three.
When all trials were combined in which the four phosphates were fed,
it was observed that dicalcium phosphate was consumed in largest amount
followed by defluorinated phosphate, soft phosphate and bone meal.
Differences in preparation or processing of brands of phosphates within
the classifications used for identification may result in differences
in palatability. The single source of soft phosphate and dicalcium
phosphate and the two sources of bone meal and defluorinated phosphate
which were used may not be representative of all brands within the type
classification used. It may be noted that both bone meals were of
Sheep consumed very little of any of the phosphates, the amounts
being insufficient for accurate measurement.
Four feed grade phosphates were offered free choice to cattle and
sheep in order to measure voluntary intake. Each of the phosphates was
consumed by cattle, but considerable variability in consumption was
observed indicating no specific preference. When all trials were com-
bined, however, the results indicated an order of preference of dicalcium
phosphate, defluorinated phosphate, soft phosphate and bone meal. Shcsp
consumed very little of any of the phosphates, the amounts being insuf-
ficient for accurate measurement.
1. Ammerman, C. B., J. H. Conerty and A. L. Neumann. 1955. Relative
Palatability of Various Inorganic Phosphate Supplements to Beef
Steers. University of Illinois, Cattle Feeders Day Report.
2. Becker, R. B., D. T. DixArnold, W. G. Kirk, G. K. Davis and R. W.
Kidder. 1953. Minerals for Dairy and Beef Cattle. Fla. Agr. Exp.
Sta. Bul. 513.
Daily Consumption of Feed Grade Phosphates and Phosphorus Intakes by Calves
Consumption (Gm. per animal per day)l/
No. No. Bone Meal Defluorinated Dicalcium Soft Phosphate
Animals Days Product Phos. Product Phos. Product Phos. Product Phos.
8 74 5.9 0.71 4.8 0.82 30.3 5.60 1.9 0.18
10 42 6.8 0.82 6.8 1.15 7.6 1.41 3.9 0.37
4 35 1.5 0.18 0.4 0.07 13.6 2.52 0.6 0.06
Average 4.7 0.56 4.0 0.68 17.1 3.16 2.1 0.20
l/ Values expressed as total amount
Daily Consumption of Phosphat
of product or elemental phosphorus consumed.
es when Dicalcium Phosphate Omitted from the Tests
Consumption (Gm. per animal per day):/
Experimental No. No. Bone Meal Defluorinated Soft Phosphate
Animals Animals Days Product Phos. Product Phos. Product Phos.
Mature cattle 4 42 2.5 0.30 0.8 0.14 1.3 0.12
Yearling cattle 6
Calves 8 28 10.2 1.22 2.0 0.34 11.4 1.08
Mature cattle 3 8 0.8 0.10 1.0 0.17 5.1 0.48
Average 4.5 0.54 1.3 0.22 5.9 0.56
Values expressed as total amount of produc-t or eJcnent.l phosphorus ccr:unied.
Consumption of Phosphates by Mature Beef Steers and Dairy Type Yearling Calves./
Consumption (Gm. per animal per day)
Bone Meal Defluorinated Dicalcium Soft Phosphate
Product Phos. Product Phos. Product Phos. Product Phos.
1st Week 17.1 2.05 25-5 4.59 22.8 4.22 7.4 0.70
2nd Week 25.4 3.05 40.1 7.22 42.6 7.88 1.6 0.15
3rd Week 20.3 2.44 10.1 1.82 34.4 6.36 1.1 0.10
4th Week 26.0 3.12 28.4 5.11 38.0 7.03 0.2 0.02
Average 22.2 2.66 26.0 4.68 34.4 6.36 2.5 0.24
Dairy Type Yearling Calves
1st Week 0.14 0.02 2.0 0.36 5.5 1.02 35.8 3.40
2nd Week 0.42 0.05 6.9 1.24 15.1 2.79 32.4 3.08
3rd Week 0.38 0.05 43.6 7.86 51.8 9.58 30.0 2.85
Average 0.31 0.04 17.5 3.15 24.1 4.45 32.7 3.11
phosphate different from those used in trials 1 and 2.
-/ Bone meal and defluorinated