Department of Animal Science Florida Agricultural
Research Report AL-1984-4 -17- Experiment Station
May, 1984 Gainesville, FL
COMPARISON OF THE VALUE OF FEEDING "TROPICAL CORN"
WITH COMMERICAL YELLOW CORN IN GROWER-FINISHER DIETS1
A. C. Williams, M. T. Coffey and G. E. Combs2
Florida is recognized as a grain deficient area which dictates that
swine producers purchase shipped in corn to ensure an adequate feed
supply. Consequently, transportation costs result in high corn prices and
narrow profit margins. Corn varieties that are better suited to Florida's
climate are becoming available. The term "tropical corn" is applied to
several varieties being used to follow vegetable planting in Central and
South Florida. A study was conducted to compare the feeding value of
"tropical corn" with that of standard commercial yellow corn for
A trial was conducted using 36 crossbred pigs (26 kg). Six pigs were
allotted to each pen on the basis of weight, litter and sex. There were
three replicate pens per treatment. Treatments consisted of corn-soy
grower and finisher diets using either standard commerical yellow corn (1)
or Pioneer 304-C "tropical corn" (2). Pigs were fed a 16% crude protein
grower diet (table 1) to 56.5 kg body weight, followed by the finisher
diet containing 15% crude protein. Laboratory analysis of the corn
sources are presented in table 2. All pigs were housed in a semi-enclosed
grower-finisher barn with concrete floored pens. Feed and water were
provided ad libitum. Weight gains and feed consumption were determined on
a biweekly basis. Data were analyzed by analysis of variance. Least
squares means were used to examine significant interactions.
Results and Discussion
There was a significant (P<.05) treatment x sex effect on average
daily gain (table 3). In treatment 1 males grew faster (P<.05) than
females (.83 vs .74 kg/day). In contrast, there was no difference in the
growth of males and females fed treatment 2 ("tropical corn"). Females
fed treatment 2 gained faster than females fed treatment 1 (.85 vs .74
kg/day). Feeding "tropical corn" resulted in increased (P<.05) feed
intake and decreased (P<.05) feed efficiency (table 3).
The increase in feed intake and decreased efficiency may have been due
to a lower energy content of diets formulated with "tropical corn" as
2Williams, Graduate Research Assistant; Coffey, Assistant Animal
Nutritionist and Combs, Animal Nutritionist, Animal Science Department,
shown by laboratory analysis (3.03% in tropical vs 3.91% in control).
Analysis indicated similar protein and~amino acid content of diets
formulated with tropical and commercial yellow corn (table 2). The
increased feed consumption resulted in increased protein intake by pigs
fed "tropical corn". It is well known that female pigs have a higher
dietary protein requirement than males. The increased consumption of
feed and therefore, protein may account for the faster gains of females
fed treatment 2. There was no increase in the growth of males fed
"tropical corn" indicating that dietary protein was adequate.
The data indicated that "tropical corn" supported gains that were
similar to those of pigs consuming commerical yellow corn. Feed intake
was increased by 15% and 12% more feed was required per unit of gain.
This suggested a lower energy content of diets formulated with
"tropical corn". These results indicated that diets formulated using
"tropical corn" have a feeding value of slightly less than diets
formulated with commerical yellow corn.
Thirty-six crossbred pigs were used to examine the feeding value of
"tropical corn" (Pioneer 304-C) in growing-finishing diets of pigs.
Six pigs (26 kg) were allotted to each pen on the basis of weight, sex
and litter origin. Substitution of commercial yellow corn with
"tropical corn" resulted in a significant (P<.05) treatment x sex
effect on average daily gains. Female pigs fed "tropical corn" grew
faster than females fed commercial yellow corn. Feeding "tropical
corn" resulted in increased feed intake (P<.05) and decreased (P<.05)
feed efficiency. The increase in feed intake and decreased efficiency
may have been due to a lower energy content of diets formulated with
TABLE 1. DIET COMPOSITION, %
Grain source 74.80
Soybean meal (48%) 22.00
)ynafos (IMCC) 1.70
lodized salt 0.25
Trace minerals (CCC)b 0.10
Vitamin premix (UF)c 0.10
aTreatment 1 utilized ground yellow corn (IFN 4-02-935). Treatment
2 utilized "tropical corn" (Pioneer 304-C).
bSupplied by Calcium Carbonate Company, Quincy, Illinois. Contained
20% zinc, 10% iron, 5.5% manganese, 1.1% copper, 0.15% iodine, and
cContained 13,200 mg riboflavin, 44,000 mg niacin, 26,400 mg panto-
thenic acid, 176,000 mg choline chloride, 22,000 mcg vitamin B12,
5,500,000 IU vitamin A, 880,000 IU vitamin D3 and 22,000 IU vitamin
E per kilogram of premix.
TABLE 2. ANALYSIS OF AMINO ACID CONTENT IN DIETS, %
Amino Acid 1 2
Aspartic 1.39 1.32
Glutamic Acid 2.78 2.93
Histidine 0.44 0.46
Serine 0.83 0.83
Arginine 1.07 1.05
Glycine 0.66 0.62
Threonine 0.67 0.63
Alanine 0.93 0.99
Tyrosine 0.58 0.60
Methionine 0.29 0.26
Valine 0.49 0.78
Phenylalanine 0.80 0.84
Isoleucine 0.65 0.69
Leucine 1.45 1.54
Lysine 0.83 0.80
aTreatment 1 utilized commercial yellow corn. Treatment 2 utilized
"tropical corn" (Pioneer 304-C).
TABLE 3. EFFECT OF CORN TYPE ON THE PERFORMANCE OF GROWING-FINISHING
Item 1 2
Initial weight, kg 25.75 26.00
Final weight, kg 91.90 95.35
Daily gain, kgc 0.79 0.82
Daily feed, kgd 2.36 2.71
Feed/gain, kgd 2.99 3.34
aLeast squares means.
bTreatment 1 utilized commerical yellow corn. Treatment 2 utilized
"tropical corn" (Pioneer 304-C).
CTreatment x sex effect (P<.05).
dTreatment effect (P<.05).