Department of Animal Science
Mimeograph Series No. AN67-1
RESPONSE OF PIGS TO HIGH LEVEL COPPER SUPPLEMENTATION
WHEN FED IN CONCRETE CONFINEMENT OR IN SMALL DIRT LOTS /
H. D. Wallace, R. H. Houser, A. Z, Palmer
J. W. Carpenter and G. E. Combs 2/
This research was part of a continuing effort to learn more about the response
of pigs to high level copper supplementation. It has been rather conclusively estab-
lished that growing pigs will re~pbnd to high level copper supplementation by gain-
ing faster and utilizing feed somewhat more efficiently. Ho..ever, the danger of tox-
icity has been a deterrent to the general acceptance of high level copper feeding.
Several studies have demonstrated that copper levels at or near the effective levels
This experiment was specifically undertaken to study the relative response of
pigs under concrete confinement conditions and outside dirt lot conditions. Feed-
lot performance, parasite infestation and liver damage, carcass measurements and liv-
er copper accumulation served as measurement criteria.
Ninety-six crossbred pigs (Duroc-Landrace x Hampshire), averaging seventy-seven
pounds initially, were divided into outcome groups and randomly assigned to four
treatment groups as shown below:
Treatment group Number of Pigs Diet Confinement
1 15 9 Basal On concrete
2 15 9 Basal + Cu On concrete
3 15 9 Basal Dirt lot
4 15... 9 Basal + Cu Dirt lot
1/ Supported in part by a grant from International Copper Research Association,
Inc., New York.
2/ Wallace, Animal Nutritionist; Houser, Graduate Research Assistant; Palmer,
Meat Scientist; Carpenter, Associate Meat Scientist; and Combs, Associate
Animal Nutritionist, respectively, Animal Science Department.
The formulation of the diets used in the experiment are shown in Table 1. The
diets contained approximately 17% protein, and copper was added to the mixtures for
treatment groups 2 and 4 at a level of 250 ppm. All pigs were self-fed and were
supplied water continuously via automatic waterers. Pigs were slaughtered at a fin-
al weight of approximately 200 pounds.
Table 1. Composition of diets
Ingredient Basal Basal + Cu
Yellow corn meal 77.30 77.30
Soybean oilmeal (50%) 20.00 20.00
Steamed bonemeal 1.50 1.50
Ground limestone 0.50 0.50
Iodized salt 0.50 0.50
B-vitamin premix 1 0.10 0.10
Vitamin B12 premix 2/ 0.05 0.05
Trace mineral premix / 0.05 0.05
Copper sulfate (CuS04) ----- (28.6 gm.)
1/ Contained 8,000 mg. riboflavin, 14,720 mg. d-pantothenic acid,
36,000 mg. niacin and 40,000 mg. choline chloride per pound.
2/ Contained a minimum of 20 mg. B12 per pound.
3/ Contained 11% calcium, 10% manganese, 10% iron, 10% zinc, 1% copper,
0.3% iodine and 0.1% cobalt.
Slaughter procedures and carcass evaluations were as described in Florida Agr.
Exp. Sta. Bul. 706 (1).
Liver samples for analysis were taken from the left lateral lobe at time of
slaughter, dried to a constant weight in an oven at 1000C., then weighed in tared
crucibles and ashed in a furnace for 12 hr. at 6500C. The washed sample was then
put into solution with 1:1 hydrochloric acid and diluted to a volume of 50 ml.
Copper determinations were made on a Perkin-Marlin 303 atomic absorption spectro-
The data were statistically studied using analysis of variance procedures.
- 3 -
Results and Discussion
Results of the experiment are summarized in Table 2.
Animals fed high level copper gained significantly faster (P < .01) than the
non-supplemented pigs in both concrete confinement and in dirt lots. Feed conver-
sion was enhanced considerably by the copper supplementation in concrete confine-
ment. However, in dirt lots the basal pigs utilized feed more efficiently than the
copper-fed pigs. The 48 pigs fed on concrete gained faster (P < .01) than the 48
fed in dirt lots. A more comfortable environment and more restricted movement prob-
ably explain this result. Dressing percent and carcass length were not significant-
ly affected by the experimental treatments. Copper supplementation did not signifi-
cantly affect backfat thickness, but pigs fed on concrete were significantly fatter
(P < .01) than pigs fed in dirt lots. Liver damage scores were not significantly
different for the various groups, but pigs in concrete confinement yielded somewhat
better livers than pigs from dirt lots, and copper supplemented pigs yielded slight-
ly better livers than pigs fed on the basal diet. Mature ascarids were observed in
all groups at time of slaughter, but were more numerous in pigs fed in dirt lots.
Copper treatment did not appear to influence roundworm infestation. Liver copper
analyses showed that copper supplementation increased liver copper concentration
(P < .01) for both environmental regimes. Considerable individual pig variation
was noted, but none of the values were excessively high (48-845 ppm).
Ninety-six pigs were used to study the value of high level copper feeding in
both concrete confinement and dirt lots. The copper (250 ppm) induced significantly
faster gains in both environmental situations. Feed utilization was improved in con-
crete confinement, but not in the dirt lot comparison. Copper supplementation caus-
ed no significant effects on the carcasses as measured by dressing percent, carcass
length and backfat thickness. Liver copper concentrations increased significantly
with the supplementation, but no evidence of toxicity was noted. There was some re-
duction in liver damage observed in the copper supplemented pigs, but this differ-
ence was not statistically significant.
The forty-eight pigs fed in concrete confinement gained significantly faster
and yielded carcasses that were significantly fatter than the forty-eight pigs fed
in dirt lots.
1. Wallace, H. D., A. Z. Palmer, J. W. Carpenter and G. E. Combs. 1966. Feed
restriction of swine during the finishing period. Fla. Agr. Exp. Sta. Bul. 706.
Table 2. Influence of high level copper supplementation on feedlot performance, carcass characteris-
tics, liver damage and liver copper accumulation for pigs fed on concrete as compared to
pigs fed in small dirt lots.
Treatment group 1 2 3 4
Confinement On concrete On concrete Dirt lot Dirt lot
Diet Basal Basal + copper Basal Basal + copper
Number pigs 24 24 24 24
Average initial weight, lb. 77.6 77.6 77.3 77.6
Average final weight, lb. 206.5 207.6 200.5 201.2
Average daily gain, lb. 1.95 2.04 1.61 1.74
Average daily feed per pig, lb. 6.54 6.53 5.24 5.95
Feed per lb. gain, lb. 3.46 3.26 3.32 3.50
Dressing percent 70.35 69.99 70.61 70.58
Carcass length, in. 30.27 30.34 30.57 30.16
Backfat thickness, in. 1.49 1.48 1.29 1.35
Liver damage score- 3.29 2.75 3.46 3.33
Copper in liver, ppm 32.0 169.0 33.0 200.0
Average number days on expt. 66.8 64.3 77.9 72.5
1/ 1 = none, 2 = slight, 3 = average, 4 = bad, and 5 = very severe.