Animal Husbandry and Nutrition Florida Agricultural
Mimeograph Series No. 60-4 Experiment Station
Dried Tomato Pulp-Digestibility by
Steers and Chemical Compositiorn/
C. B. Ammerman, L. R. Arrington, J. T. McCall and G. K. Davis2/
Tomato pulp, a by-product of the tomato industry, was first pre-
pared through efforts to provide an economic means of disposal of cull
tomatoes. The product consists of the whole fruit which has been cut
and pressed with the resulting juice concentrated by evaporation and
remixed with the press cake for further dehydration. As a part of an
over-all program to evaluate this product as a feed for livestock,
Chapman et al.(19$8) reported that, when used to replace citrus pulp,
levels of tomato pulp up to 30 percent of the total concentrate pro-
duced satisfactory gains in yearling steers on pasture. Steers fed
the tomato pulp yielded carcasses equal in grade and acceptability to
those from steers fed citrus pulp.
The present study was conducted to determine the digestibility
by mature steers and to determine the chemical composition of dried
A conventional digestibility trial was conducted which involved
a 21-day preliminary feeding period followed by a 7-day collection
period. Three, 2-year-old Jersey steers averaging 825 pounl's in body
weight were used in the study.
Initially the digestibility of the tomato pulp was determined by
difference using chopped Alyce clover hay fed in a mixture with the
pulp after determining the digestibility of the clover hay. When fed
in combination with the clover hay, tomato pulp composed 30 percent of
the mixture. During the latter part of the experiment it was found
possible to feed tomato pulp alone and its digestibility was determined
directly using the conventional method,
This study was supported in part by funds furnished by the Florida
Tomato Committee, 753 Warner Street, Orlando, Florida.
-Ammerman, Assistant Animal Nutritionist; Arrington, Associate Animal
Nutritionist; McCall, Assistant Chemist; Davis, Animal Nutritioni
Florida Agricultural Experiment Station. The assistance of J.
J. V. Mason and C. W. Burgin is gratefully acknowledged. /
The design of the experiment is shown in table 1. The initial
part was a double reversal design followed by a period in which the
steers consumed only tomato pulp. Six to seven pounds of the ration
were fed twice daily. In addition, 25 grams of defluorinated phosphate
(4.25 grams P, 8.75 grams Ca) and 25 grams of trace mineralized salt1/
were fed daily. Water was provided ad libitum during the preliminary
period but was supplied twice daily when the steers were in the
metabolism stalls. This feeding program was adequate to maintain the
weight of the steers throughout the experiment.
Chemical analyses of the ration
the methods of the A.O.A.C. (1955).
and feces were made according to
Table 1. Design of Experiment
Period 1 2 3
1 Clover hay + Clover hay Clover hay
2 Clover hay Clover hay + Clover hay +
tomato pulp tomato pulp
3 Clover hay + Clover hay Clover hay
4 Tomato pulp Tomato pulp Tomato pulp
Results and Discussion
The chemical composition and digestion coefficients for the hay
and tomato pulp are shown in table 2. Although the determination of
the composition and digestibility of Alyce clover hay was not a pri-
mary objective of this study, it was necessary to make the determin-
ation and the results obtained are recorded in table 2 since little
information is available for this forage. The composition of the
!/The Carey Salt Company, Hutchinson, Kansas, Guaranteed minimum
analysis in percent; Mn 0.25, Fe 0.27, Cu 0.033, Co 0.01, I 0.0007,
Zn 0.005 and NaCl 95.9.
tomato pulp used in this study is considerably different from that of
tomato pomace reported by McCay and Smith (1940) and Edwards et al.
(1952). The percentages of ash, ether extract and crude fiber in
tomato pomace were approximately 3.5, 14 and 30, These may be compared
with values of 9.4, 3.7 and 15.3 obtained for the tomato pulp used in
this experiment. In the preparation of the tomato pulp, the juice was
concentrated by evaporation and remixed with the pomace or press cake.
This difference in method of preparation may explain the major part of
the difference in composition between the two tomato by-products.
The digestibility of each nutrient of the tomato pulp was higher
when determined by difference than when determined by feeding the to-
mato pulp alone. Ether exCbract, however, was the only nutrient which
showed a significant increase in digestibility (P = 5 percent).
Table 2. Chemical Composition and Digestion Coefficients
Dry Ether Crude. rudi Nitrogen-free
Matter Ash Extract Protein Fiber Extract
90o2 9,4 3.7 21.5 15.3 40.3
91.3 5.0 1.4 11.0 33.0 o0.9
Digestion Coefficients, Percent
Ether Crude Crucoe
Extract Protein Fiber
(By difference) 94.6 58.0 50,1 79.5
(Alone) 85.8 54.6 42.2 78.4
Tomato pulp +
Clover hay 72.2 49,0 53.3 66.7
Clover hay 46.8 46.0 57.2 67.9
The percent total digestible nutrients of the tomato pulp was
601l when determined by difference and 56.9 when determined by feeding
the tomato pulp alone.
By gradually increasing the percentage of tomato pulp in the ration
it was possible to feed the steers 100 percent pulp for a period of 17
days which was sufficient time to complete a digestion trial. Although
no signs of digestive disturbances became evident, the steers appeared
rather gaunt during this time presumably from lack of bulk. This con-
dition might have been overcome to some extent had the pulp been offered
free-choice. The feces from the steers consuming tomato pulp alone
contained slightly less water than did the feces from steers receiving
only clover hay (71.6 compared with 73.3 percent) even though the 100
percent tomato ration was fed during warmer weather. This difference
in water content appears in agreement with observations of McCay and
Smith (1.940) and Morrison (1946) that tomato pomace in the diet of dogs,
foxes, mink and humans had an antidiarrheal effect.
The composition of dried tomato pulp was determined by chemical
analysis and its digestibility by mature steers was determined by con-
ventional digestion trials. Digestion coefficients were determined by
differences using Alyce clover hay fed alone and in combination with
the tomato pulp and by feeding tomato pulp alone. Coefficients of
digestibility for ether extract, crude fiber, crude protein and nitrogen-
free extract were 94.6, 58.0, 50.1 and 79.$ when obtained by difference
and 85,8, 54.6, 42.2 and 78.4 when obtained by feeding the tomato pulp
A.O.A.,C Official methods of analysis of the association of official
agricultural chemists. 8th ed. 1955. Washington, D. C. pp. 1008.
Chapman, H. L., C. E. Haines, J. R. Crockett and R. W. Kidder. Dried
tomato pulp for fattening steers on pasture. Everglades Station Mimeo
Report 59-3, 1958.
Edwards, P, W., R. K. Eskew, A. Hoersch, Jr., N, C. Aceto, and C. S.
Redfield. Recovery of tomato processing wastes. Food Technology 6: 383,
McCay, C. M. and S. E. Smith. Tomato pomace in the diet. Science 91: 388,
Morrison, L. M. The control of diarrhea by tomato pomace. J. Digestive
Diseases 13: 196, 1946.