fOO

Department of Animal Science Florida Agricultural
Research Report AL-1984-3 -11- Experiment Station
May, 1984 Gainesville, FL

EFFECT OF FLOOR SPACE, PIGS PER PEN AND SEASON
ON PERFORMANCE OF WEANLING SWINE1

M. T. Coffey, J. A. Yates and G. E. Conibs2

The practice of early weaning puts added pressure on management skills
and the design of nursery facilities. The amount of floor space required
to optimize performance in the nursery may be affected by weaning weight,
floor type, feeder space and environmental conditions (Kornegay et al.,
1981)3. In modern nursery facilities, attempts are made to maintain
relatively constant environmental conditions. However, seasonal
variations cause temperature extremes that may affect performance.
Experiments were conducted to evaluate the effect of doubling the number
of pigs per pen at a given floor space allowance, and to determine if this
effect is altered by seasonal temperature variation.

Experimental

Experiments were conducted utilizing crossbred pigs weaned at 21 days
of age with an average weight of 7.2 kg. Pigs were allotted to treatments
on the basis of weight, sex and litter origin. All pigs were housed in an
enclosed nursery building equipped with elevated pens having expanded metal
floors and wire mesh sides. In all experiments water and the 18% crude
protein starter diet (table 1) were provided ad libitum. Pig weights and
feed consumption were determined weekly.

Experiment one (Exp. 1) examined pigs/pen (N or 2N), floor space (.24
or .16 m2/pig), and season (Winter, February or Summer, August) over a
28 day period. Treatments 1-4 (pigs/pen, mL) were 12, .16; 24, .16; 8,
.24 and 16, .24, respectively. There were three replicate pens/treatment
in each season. In experiment two (Exp 2) there were N or 2N pigs/pen and
pigs were allowed .16, .19, .24 or .31 m2/pig of floor space.
Treatments 1-6 (pigs/pen, m2) were 12, .16; 24, .16; 10, .19; 20, .19;
8, .24; 16, .24; 6, .31 and 12, .31, respectively, and the 42-day studies
were conducted during the winter (December-January) and summer
(August-September) seasons. There were two replicate
pens/treatment/season.

Data were analyzed by least squares analysis of variance for designs
having 23 (Exp. 1).or 4 x 2 x 2 (Exp 2) factorial arrangements for main

IExperiments 263, 263B, C and D.

2Coffey, Assistant Animal Nutritionist; Yates, Graduate Research
Assistant; and Combs, Animal Nutritionist, Department of Animal
Science, Gainesville.

3Journal of Animal Science 51:285

-12-

effects and interactions. Least squares means procedures were used to
examine significant interactions.

Results and Discussion

The data from Exp. 1 are summarized in table 2. There was a space
allowance x pigs/pen x season interaction on average daily feed intake
(P<.05) and average daily gain (P<.05). During the summer pigs provided
.24 m2 floor space consumed more feed (1.05 and .97 kg/day for .24 and
.16 m2/pig, respectively) and subsequently grew faster (.55 and .48 kg/d
for .24 and .16 m2/pig, respectively) than pigs allowed .16 m2. The
number of pigs/pen did not alter performance regardless of floor space.
During the winter housing fewer pigs/pen (N) resulted in increased (P<.05)
feed intake and faster gains only if pigs were provided .24 m2/pig. The
number of pigs/pen did not affect performance when pigs were provided .16
m2/pig. Season significantly (P<.01) affected Feed:Gain regardless of
space allowance or number of pigs/pen. Pig raised during the winter were
more efficient than pigs raised during the summer months (1.79 vs 1.93).

The data from Exp. 2 are summarized in table 3. There were
significant linear effects of space allowance (P<.01) and season (P<.01)
on growth rate. Increasing floor space resulted in faster gains
regardless of season or pigs/pen. Average daily gains were .39, .41, .42
and .44 kg for pigs allowed .16, .19, .24 and .31 m2/pig of floor space,
respectively. Pigs reared in the summer gained .40 kg/day compared to .42
kg/day during the winter season. There was a space allowance x season
interaction (P<.05) on average daily feed intake. Increasing floor space
during the summer did not affect feed consumption. In contrast, there was
a linear increase (P<.05) in feed intake as space allowance was increased
during the winter trial. The number of pigs/pen had a significant (P<.05)
effect on feed consumption. Doubling the number of pigs in a pen
depressed (P<.01) feed intake (.86 and .83 kg/day for N and 2N pigs/pen,
respectively). As in trial 1, pigs reared during the summer had poorer
feed efficiencies (1.94 and 1.54 for summer and winter, respectively).

These data illustrate that the relationship between pigs/pen and floor
space varied depending on the season of the year. In Exp 1 the maximum
space allowance was .24 m2/pig. During the summer pigs ate more and
grew faster only in response to increased floor space. In contrast,
during the cooler season pigs were able to take advantage of the smaller
group size (N) when space allowance was increased to .24 m2/pig. There
was no benefit from increasing the space allowance to .24 m2/pig in the
winter when more pigs were housed per pen (2N).

In Exp 2 the maximum floor space allowance was increased to .31 m2.
Similar to the results in Exp. 1, floor space allowance was the critical
factor affecting the performance of weanling swine during the summer, and
there was no effect due to the number of pigs/pen. In the winter months
space allowance was also the most critical factor affecting performance.
When the maximum space allowance was increased to .31 m2 in the winter
there was no improvement due to housing fewer pigs/pen. Similarly, pigs
were able to benefit from increased space allowance (.31 m2/pig) even
when more were housed/pen (2N).

-13-

These data indicated a relationship between pig number/pen, floor
space and season. Decisions regarding the number of pigs to house per
pen should consider environmental conditions and available floor space.

Summary

Experiments were conducted to examine the effect of pig/pen, floor
space and season on the performance of weanling pigs. Crossbred pigs
weaned at 21 days of age with an average weight of 7.2 kg were
utilized. All pigs were housed in an enclosed nursery building equipped
with elevated pens having expanded metal floors and wire mesh sides.
Experiment one (Exp. 1) examined pigs/pen (N or 2N), floo- space (.24
or .16 m2/pig), and season (Winter, February or Summer, August) over
a 28 day period. Treatments 1-4 (pigs/pen, m2) were 12, .16; 24,
.16; 8, .24 and 16, .24, respectively. There were three replicate
pens/treatment in each season. In experiment two (Exp 2) there were N
or 2N pigs/pen and pigs were allowed .16, .19, .24 or .31 m2/pig of
floor space. Treatments 1-6 (pigs/pen, m2) were 12, .16; 24, .16;
10, .19; 20, .19; 8, .24; 16, .24; 6, .31 and 12, .31, respectively,
and the 42-day studies were conducted during the winter
(December-January) and summer (August-September) seasons. There were
two replicate pens/treatment/season. In Exp. 1 there was a space
allowance x pigs/pen x season interaction on average daily feed intake
(P<.05) and average daily gain (P<.05). During the summer pigs
provided .24 m2 floor space consumed more feed (1.05 and .97 kg/day
for .24 and .16 m2/pig, respectively) and subsequently grew faster
(.55 and .48 kg/d for .24 and .16 m /pig, respectively) than pigs
allowed .16 m2. The number of pigs/pen did not alter performance
regardless of floor space. During the winter housing fewer pigs/pen
(N) resulted in increased (P<.05) feed intake and faster gains only if
pigs were provided .24 m2/pig. In Exp. 2 there were significant
linear effects of space allowance (P<.01) and season (P<.01) on growth
rate. Increasing floor space resulted in faster gains regardless of
season or pigs/pen. Average daily gains were .39, .41, .42 and .44
kg/d for pigs allowed .16, .19, .24 and .31 m2/plg of floor space,
respectively. These data illustrate that the relationship between
pigs/pen and floor space varied depending on the season of the year.
In Exp. 1 during the summer pigs ate more and grew faster only in
response to increased floor space. In contrast, during the cooler
season pigs were able to take advantage of the smaller group size (N)
when space allowance was increased to .24 m2/pig. When the maximum
floor space allowance was increased to .31 m2 (Exp. 2), floor space
allowance was the critical factor affecting the performance of weanling
swine during the summer and winter months and there was no improvement
due to housing fewer pigs/pen.

-14-

TABLE 1. COMPOSITION STARTER DIET, %.

Ingredient

Ground yellow corn 71.80
Soybean meal 25.00
lodized salt 0.25
Dynafos 1.70
Ground limestone 0.80
Trace minerals 0.10
Vitamin mix (UF)b 0.10
Aureo SP-250 0.25

aSupplied by Calcium Carbonate Company, Quincy, Illinois. Contained
20% zinc, 10% iron, 5.5% manganese, 1.1% copper, 0.15% iodine, 12%
calcium.

bProvided 13,200 mg riboflavin, 44,000 mg niacin, 26,400 mg
pantothenic acid, 176,000 mg choline chloride, 22,000 ug vitamin
B12, 5,500,000 IU vitamin A, 880,000 ICU vitamin D3 and 22,000 IU
vitamin E per kg of premix.

-15-

TABLE 2. EFFECT OF PIGS/PEN, FLOOR SPACE AND SEASON ON
WEANLING SWINE (Exp. 1)

THE PERFORMANCE OF

Pigs/Pena N 2N N 2N
Floor Space, m2/pig .16 .16 .24 .24

Item Seasonb

Average Daily Gain, kgc S .47 .48 .53 .54
W .54 .53 .56 .52

Average Daily Feed, kgc S .94 .88 1.02 1.08
W .98 .94 1.05 .94

Feed:Gaind S 2.01 1.87 1.91 1.94
W 1.80 1.78 1.80 1.78

aFor .16 m2 N=12 and 2N=24. For .24 m2 N=8 and 2N=16.

b S = summer, W = winter.

CSignificant Floor Space x pigs/pen x season interaction

dSignificant season effect (P<.01).

(P<.05).

TABLE 3. EFFECT OF PIGS/PEN, FLOOR

Pigs/Pena
Floor Space, m2/pig

Item Seasonb

SPACE AND SEASON ON THE PERFORMANCE OF WEANLING SWINE (Exp. 2)

N 2N N 2N N 2N
.16 .16 .19 .19 .24 .24

N 2N
.31. .31

Average Daily Gain, kgc,d S .38 .39 .39 .40 .39 .41 .44 .42
W .39 .39 .41 .42 .46 .43 .44 .44

Average Daily Feed, kgef S .67 .72 .65 .71 .68 .70 .73 .72
W .79 .77 .88 .79 .97 .85 .96 .91

Feed:Gainc S 1.89 1.95 1.78 1.90 1.84 1.80 1.68 1.74
W 1.90 1.95 1.93 1.85 1.92 1.91 1.92 1.90

aFor .16 m2 N=12 and 2N=24, for .19 m2 N=10 and 2N=20, for .24 m2 N=8 and 2N=16, for .31 m2 N=6 and 2N=12.

b S = summer, W = winter.

CSignificant season effect (P<.01).

dSignificant floor space effect (P<.01).

eSignificant floor space x season interaction (P<.01).

fSlgniflcant pigs/pen effect (P<.05).