FLORIDA AGRICULTURAL EXPERIMENT STATIONS
Dairy Science Mimeo Report DY69-3
Acceptability of Rations Containing Citrus Pulp
Treated with Diammonium Phosphate 1
S. P. Marshall2 and C. B. Browning3
Dried citrus pulp is a palatable feed ingredient that is high in energy
and a rich source of calcium. It contains a large amount of nitrogen free
extract and its highly digestible fiber adds bulk to the ration. However,
citrus pulp is low in phosphorus and rather low in crude protein content.
In the interest of increasing the phosphorus level and nitrogen content \
of the product, diammonium phosphate was added to citrus pulp prior to
drying at rates equivalent to 0, 2.5, and 4.2 percent of the dried pro-
duct. The effect of these additions of diammonium phosphate on the
acceptability of complete rations containing 45% of citrus pulp was test-
ed using dairy heifers.
Eighteen Holstein and Guernsey heifers, either open or in early gestation;
were fed ad libitum a complete ration containing untreated citrus pulp
during a two-week standardization period. Then they were divided into
three groups on the basis of weight, condition, and breed. One group
was assigned to each of the three rations containin~t citrus pulp treat-
ed with either 0, 2.5, or 4.2% or diammonium phosphate for a 42-day
continuous feeding trial. The diammonium phosphate contained 18.2%
of nitrogen and 20.3% of phosphorus. Composition of the rations are
shcjn in Table 1.
Each group was kept on concrete with shade and water. The complete
rations were fed to each of the groups twice daily in amounts calculated
to leave a 10% refusal. The heifers were weighed on three consecutive
days at the beginning of the trial, at 14-day intervals and at the end.
Three composite samples of citrus pulp were taken from each batch for
nitrogen analysis to determine the effect that diammonium phosphate added
prior toddrying had on the crude protein content of the dried product.
C:.':rus pulps furnished through courtesy of International Minerals and
2Nutritionist, Department of Dairy Science
SAniWal Nutritionist and Chaar.-an, Departmet of -Dairy Science
Results and Discussion
Data on feed intake and body weight gains of the heifers fed the different
rations are shown in Table 0.. Average initial weights of heifers on the
rations containing citrus pulp with 0, 2.5, and 4.2 percent of added
diammonium phosphate weree772, 765, and 765 pounds, respectively. Feed
intakes averaged 29.1, 29.4, and 28.6 pounds daily per heifer on the
respective rations. The daily feed intake per 100 pounds of body weight
averaged 3.5 pounds on all rations. Average body weight gains per heifer
for the 42-day period were 134, 134, and 126 pounds with corresponding
average daily gain being 3.2, 3.2, and 3.0 pounds on the rations con-
taining citrus pulp to which 0, 2.5, and 4.2 percent of diammonium had been
added. The differences in feed intake and body weight gains were not
significantly different indicating no treatment effect on these measurements..
Crude protein content of the untreated citrus pulp calculated from nitrogen
analyses of three samples averaged 6.7%. Samples of citrus treated prior
to drying with the equivalent of 2.5 and 4.2% of diammonium phosphate-on
the air dry basis contained 7.6 and 6.7% of crude protein, respectively.
These data indicate that the additions of diammonium phosphate to citrus
pulp prior to drying had little, if any, influence on the crude protein
content of the dried pulp. Apparently nitrogen from the diammonium was
lose during the drying process.
Table 1. Ration Compositionl
Citrus pulp, Ibs.
Soybean oil meal, 44%, lbs.
Cottonseed hulls, lbs.
Ground yellow corn, lbs.
Trace minerals salt, lbs.
Defluorinated phosphate, lbs.
Vitamin A palmitate, g.
ICitrus pulp in rations of animals in groups 1, 2,
and 3 had been treated prior to drying with ddam-
monium phosphate equivalent to 0, 215, and 4.2%
on the dry basis.
22,000,000 I. U. per g.
Feed intake and body weight gains of dairy heifers fed
complete rations containing citrus pulp treated with
different levels of diammonium phosphate.
Number of heifers per lot
Average initial weight, Ibs.
Average final weight, lbs.
Average gain per heifer
Average Daily gain
Average daily feed intake, lbs.
Average daily feed intake, cwt.
Percent of diammonium
Percent of diammonium
added to citrus
Differences between comparative values were not significant.