Department of Animal Science Florida Agricultural
Mimeograph Series No. AN65-8 Experiment Station
January, 1965 Gainesville, Florida
METHODS OF FEEDING GROWING-FINISHING SWINE
H. D. Wallace and G. E. Combs I/
This study had +hree ot~ectives:
1. To determine the influence of floor feeding on pig performance.
2. To compare the free-choice feeding method with the feeding of a
complete mixed diet.
3. To compare soybean oilmeal and a complex supplemental protein mixture
as sources of supplemental protein.
The advent of automation has stimulated considerable interest in floor feeding.
Equipment can readily be designed to drop measured amounts of feed onto feeding
floors at timed intervals. It is of interest to know if the performance of pigs
is significantly altered by this procedure, as compared to using the conventional
self-feeder. Are there any special problems associated with floor feeding?
The second objective was concerned with free-choice feeding vs. the complete
mixed diet. In three previous experiments at this station (1,2,3) pigs gained
faster when fed complete mixed diets. However, feed costs favored the free-choice
method in one of the three experiments. These results are in general agreement
with other experiments across the country in that the complete mixed diet invar-
iably produces the most rapid gains but is not always the most economical. Al-
though there is a trend toward greater use of complete mixed diets, the free-choice
feeding system remains an important procedure in modern day swine feeding.
Finally, it is always of interest to accumulate data on the relative efficiency
of supplemental protein sources. In this study soybean oilmeal was compared to a
mixture of soybean oilmeal, tankage and alfalfa meal. A previous report (4) demon-
strated that soybean oilmeal, used in combination with corn, generally meets the
protein requirement of the growing pig very adequately. Soybean oilmeal was su-
perior to tankage and was equal to a combination of soybean oilmeal and tankage or
a complex commercial supplement.
The study utilized a total of 100 crossbred pigs fed on concrete in four lots
I/ Wallace, Animal Nutritionist; Combs, Associate Animal Nutritionist, Animal
Science Department. The assistance of Billy Ray Cannon and L. S. Taylor,
Swine Herdsmen, is gratefully acknowledged.
of 25 pigs each. Pigs were allotted at random from outcome groups formed on the
basis of weight, sex and litter. Pigs in Lot 2 were hand-fed twice per day the
amount of feed that they would regularly clean up from one feeding to the next.
The feeding treatments were as follows:
The composition of the complete
are shown in Table I.
The experiment was initiated on
30, 1964. The pigs were weighed off
210 lb. weight per pig.
feed mixtures and the mixed protein supplement
July 21, 1964, and was terminated on October
experiment by lot as the lot approximated a
Results and Discussion
Results of the experiment are summarized in Table 2.
Daily aain During the first four weeks of the experiment lots 1, 2 and 3
gained at approximately the same rate, and all three lots gained significantly
faster (P<.O1) than lot 4. For the entire period, lot I gained significantly
faster than lots 2 and 3 (P<.05) and lot 4 (P<.01). It is interesting to note
that pigs hand fed on the floor (lot 2) did not gain as well during the finishing
phase of the experiment as those fed the same diet by self-feeder (lot I). It is
possible that an element of feed restriction was involved for this lot since an
effort was made to avoid feed wastage. It is also possible that the greater stress
of having to eat from the floor reduced feed intake and hence gains. Then too,
the heavy intake at each morning and evening feeding as opposed to the continuous
ad libitum feeding of lot I may be a factor relative to performance.
The difference in gain for the entire feeding period between lots I and 3 was
significant (P<.05). Apparently the mixed supplement reduced feed intake as
Table I. Composition of diets and mixed protein supplement
Lot Number I 2 3 4
Yellow corn meal 77.20 77.20 74.00 ---
Shelled corn ----- --- ----- free-choice
Mixed protein supple-
ment (41) / --- --- 26.00 free-choice
Soybean oilmeal (50%) 20.00 20.00 ---
Steamed bonemeal I.'50 1.50 -----
Ground limestone 0.50 0.50 ---
lodized salt 0.50 0.50 ---
Trace minerals -/ 0.05 0.05
B-vitamin supplement / 0.10 0.10 ---
812 supplement /A 0.05 0.05 ---
Antibiotic supplement 0.10 0.10 --
100.00 100.00 100.00 ---
I/ The mixed protein was composed of the following: Soybean oilmeal (50%) -
46.80%, meat scraps (50%) 25.00%, dehydrated alfalfa meal (17%) 25.00%,
iodized salt 2.00%, trace minerals 0.20%, B-vitamin supplement 0.40%,
B12 supplement 0.20%, and antibiotic supplement 0.40%.
2/ Adds in p.p.m.: manganese (29.6), iron (36.5), copper (2.5), cobalt (0.83),
zinc (42.0) and potassium (3.9).
3/ Contained 8,000, 14,720, 36,000 and 40,000 mg./lb. respectively of riboflavin,
pantothenic acid, niacin and choline chloride.
4/ Contained a minimum of 20 mg. B12 per lb.
5/ Contained 2 gm. oleandomycin and 8 gm. oxytetracycline per pound.
Table 2. Feedlot performance of pigs as influenced by various methods
Lot Number I 2 3 4
Treatment corn-soybean meal corn-soybean corn-mixed supp. shelled corn
mixture meal mixture self-fed and
self-fed on floor mixed supplement
Number of pigs 25 25 25 25
Initial wt;, Ib. 53.8 53.8 53.6 53.7
Final wt., lb. 210.7 209.4 206.5 211.3
Daily gain, Ib.
First 4 weeks 1.52 1.54 1.47 1.20
Entire period 1.74 1.64 1.61 1.56
Feed per lb. gain, Ib.
First 4 weeks 2.71 3.04 2.64 2.60 /
Entire period 3.41 3.56 3.11 3.24 /
Feed cost per ton of feed 2/ $70.32 $70.32 $68.74 $65.34
Feed cost per 100 lb. gain $11.97 $12.50 $10.67 $10.59
II The feed consumed during the first 4
shelled corn. For the entire period
week period consisted of 27.98% supplement and 72.02%
the feed consumed consisted of 26.78% supplement and 73.22%
2/ Based on the following ingredient prices: Ground corn $60.00 per ton, Shelled corn $55.00
per ton, Meat scrap $105.00 per ton, Soybean meal $95.00 per ton, Dehydrated alfalfa meal -
$72.00 per ton. Cost of fortification estimated at $5.00 per ton of feed.
compared to soybean oilmeal. There is little reason to believe that a nutritional
inadequacy was involved. The fiber content of the alfalfa meal and the high ash
content of the meat and bone scrap probably were responsible for the reduced con-
sumption of this diet.
During the first 4 weeks the pigs in lot 4 which were fed shelled corn and
the mixed supplement gained significantly slower (P<.O1) than pigs in lot 3
which were fed the same ingredients in a ground mixed form. However, during the
finishing period lot 4 pigs gained faster than lot 3 pigs and the overall gains
for the entire experimental period were not significantly different.
Feed per Ib. gain Pigs fed the corn-soybean mixture by self feeder (lot I)
not only gained faster but were more efficient than pigs fed the same diet on the
floor (lot 2). The respective feed conversions were 3.41 and 3.56. The most ef-
ficient group of pigs was that in lot 3, self-fed the corn and mixed supplement
diet. These pigs required only 3.11 lb. feed per lb. gain. Lot 4 pigs, fed
shelled corn and mixed supplement free-choice, were also relatively efficient, re-
quiring only 3.24 pounds of total feed per lb. gain. These pigs voluntarily con-
sumed a combination of corn and supplement containing approximately 17.6% crude
protein during the first 4 weeks and 17.1% crude protein during the finishing phase
of the experiment. It would appear that the pigs did a fairly good job of balanc-
ing out their protein requirements early in the feeding period but may have been
overeating some on protein supplement during the finishing period. The calculated
protein content of the complete diets consumed by the other three lots was 16.5%.
This level of protein was fed during the entire experimental period.
Feed costs Based on prices actually'paid for the major feed ingredients and
feed conversion data, the feed costs per 100 pounds gain were $11.97, $12.50, $10.67
and $10.59, respectively, for lots I, 2, 3, and 4. The main difference in costs
other than the influence of feed conversion was the cheaper price for the mixed
supplement as compared to soybean meal. The price of shelled corn compared to
ground corn also exerted a significant influence on relative feed costs.
Comparison of gains of barrows and gilts Each lot of pigs in the experiment
contained. 13 barrows and 12 gilts. The 52 barrows gained 1.69 pounds per day com-
pared to 1.58 pounds per day for the gilts. This difference.was highly significant
(P<.01) and is fairly typical of the difference expected in performance between the
I. One hundred growing-finishing pigs were used to study various methods of
feeding swine in concrete confinement.
2. Pigs fed by self-feeder gained faster and more efficiently than pigs fed
on the floor.
3. Pigs fed shelled corn and supplement free choice gained significantly
slower than pigs fed a complete mixed diet for the first 4 weeks of the feeding
period. However, during the finishing phase, the free-choice pigs outgained pigs
fed a complete mixed diet and thus gains for the entire period were not significant-
ly different. Pigs fed the complete mixed diet were superior in feed conversion.
4. Soybean oilmeal, used in combination with corn, induced greater feed con-
sumption and more rapid gains, while feed conversion was less efficient than for
a mixed supplement consisting of soybean oilmeal, meat scraps and alfalfa meal.
5. Under the conditions of this experiment feed costs favored the use of
the mixed supplement, fed either as a complete mixed feed in combination with corn
meal or free-choice with shelled corn. It must be pointed out, however, that 7-10
days more time was required to finish the hogs when the mixed supplement was used.
6. The 52 barrows in the experiment gained an average of 1.69 pounds per
day compared to 1.58 pounds per day for the 48 gilts.
I. Wallace, H. D., G. E. Combs, Jr., and C. E. Haines. 1957. Free choice
feeding vs. a complete mixed ration for finishing market swine. Fla. An.
Husb. Mimeo. Series No. 58-1.
2. Hunt, J. W., H. D. Wallace and G. E. Combs, Jr. 1958. Free-choice feeding
vs. a complete mixed ration for finishing market swine. Fla. An. Husb. and
Nutr. Mimeo. Series No. 58-8.
3. Wallace, H. D., G. E. Combs, Jr., R. B. Christmas and L. E. Swanson. 1958.
SWINE FEEDING STUDIES. A. Free-choice vs. complete mixed rations. B. Effect
of low level continuous piperazine phosphate supplementation. Fla. An. Husb.
and Nutr. Mimeo. Series No. 59-1.
4. Combs, G. E., H. D. Wallace, R. B. Christmas and G. E. McCabe. 1959. Com-
parison of protein supplements for growing-finishing swine. Fla. An. Husb.
and Nutr. Mimeo. Series No. 59-5.