FLORIDA AGRICULTURAL EXPERIMENT STATIONS
Dairy Science Mimeo Report DY69-4
Acceptability of Rations Containing Citrus Pulp
Enriched with Phosphorus 1
S. P. Marshall2 and C. B. Browning3
Lime is blended with chopped citrus cannery residue at the rate of about
0.3 to 0.5% to release bound water as a part of the process for drying
citrus pulp. This addition of lime raises the calcium content to about
1.0 to 2.5% in the dried citrus pulp while the phosphorus content remains
low, averaging about 0.15%. To enrich the product in phosphorus, the
equivalent of 40 pounds of phosphoric acid per ton of dried citrus pulp
was added prior to completion of dehydration. This increased the phosphorus
content of the product from 0.19 to 0.63% and reduced the pH from 5.1 to
3.8. Calcium content of the untreated product was 1.61%.<- The influence
of this phosphorus addition on feed intake and milk production was studied
using( a complete ration containing 45% of citrus pulp.
The effect on acceptability of a ration containing the phosphoric acid
treated citrus pulp was tested using lactating cows. Ingredients in the
basal ration, expressed as pounds, were: citrus pulp, 44.7; soybean meal,
11; around corn, 18\;alfalfa pellets, 5; cottonseed hulls, 20; trace min-
eral salt, 1; urea 0.5; and dicalcium phosphate, 0.8. Two thousand I. U.
of vitamin A were added\per pound of feed. The ration containing phosphoric
acid treated citrus pulp was the same except that dicalcium phosphate
was omitted and citrus pulp increased to 45 pounds. The dried citrus pulps
used were from the same source of raw material and differed only in the
addition of phosphoric acid.
Two groups of six lactating cows each were used in a single reversal trial
to compare the two rations when fed ad libitum. The preliminary periods
were 15 days and the experimental periods 10-.days in length. Daily feed
intake of each group of cows was kept and production recorded at each
milking. Milk fat tests were made twice (at weekly intervals) during each
test period. The cows were weighed on two consecutive days at the begin-
ning and end of each period..
-Ci'us pulps and calcium and phosphorus data were furnished through the
co-'tesy of International Minerals and Chemicals Corp.
Nutritionist, Department of Dairy Science
3Animal Nutritionist,aaid Chairman, rDepartment of Dairy Science
To test the acceptability of the citrus pulps when fed alone, separate
groups of six lactating cows were offered an average of four pounds per
cow )f either the treated or untreated product prior to the regular morning
feec allowance. Intake observations were made for a period of five days.
Results and Discussion
Daily feed intake per cow averaged 49.3 pounds on the complete ration con-
taining plain citrus pulp and 52.1 pounds on the one with the phosphoric
acid-treated pulp. Daily intake of feed per one hundred pounds of live
weight averaged 4.1 and 4.3 pounds on the respective rations. Milk pro\-
duction averaged 49.2 pounds daily on the ration containing plain citrus
pulp and 48.4 pounds while on the one containing the phosphoric acid-
treated pulp. Daily production of four percent fat-corrected milk averaged
50.5 and 49.5 pounds on the respective rations. The cows gained weight
throughout the trial. Differences between the comparative values for
these observations were not significant. The results are shown in Table 1.
Both the untreated and treated citrus pulps were platable. The cows readily
consumed an average of four pounds of either plain or phosphoric acid treat-
ed palp when it was offered prior to the regular morning feeding.
These data indicate that the addition of phosphoric acid to citrus pulp
prior to drying to increase the phosphorus content from 0.19 to 0.63%
had no adverse effect on acceptability or milk production. These studies
were not designed to study relative utilization of P between the two rations.
Table 1. Feed intake and milk production by cows fed complete rations con-
taining plain and phosphoric acid-treated citrus pulp.
Average daily feed intake, lbs. 49.3 52.1
Average daily feed intake per cwt., lbs. 4.1 4.3
Average daily milk production, lbs. 49.2 49.4
Average daily production 4% FCM, lbs. 50.5 49.5
Differences between comparative values were not significant.