24
The Physiological Impact of
Co-mingling Pigs
Every day across the United States,
thousands of pigs are relocated. The
average time a group of pigs spends
on the trailer might be as short as
15 minutes and as long as 20 hours.
Regardless of the weight class of
pigs, it is imperative that a maximum
level of swine comfort and welfare
be maintained. Both producers and
packers have been motivated to
minimize death loss, bruising, and the
percentage of non-ambulatory pigs
during transport. An area that has not
previously been examined is how pigs
interact on the trailer during transport.
Are behavioral aspects, such as
fighting to establish dominance of
co-mingled pigs, interrupted during
transport, and, if not, what impact
does this have on the hauling
experience?
Two different weight classes of pigs
were used in the study. Pigs weighing
between 40 and 60 pounds were
classified as feeder pigs, and pigs
weighing between 265 and 300
pounds were classified as market
hogs. The trailer was divided into four
compartments of equal size for the
data collection. Within each of the
four replications, there were two pens
of control pigs (pigs that originated
from the same pen) and two pens of
test pigs (pigs that originated from
different pens). Pigs were allocated
to one of two designated travel
times. The duration of travel time
was either one hour or four hours.
Each pig was individually weighed
before and after transportation to
determine the percentage of body
weight loss. Additionally, each pig
was subjectively scored on comfort
level and skin abrasions during the
weighing process before and after
transportation.
Results indicate that time of
transportation had minimal influence
on the percentage of weight loss
in market hogs. Pigs that were
transported for one hour averaged
2.41% weight loss, whereas pigs
transported for four hours averaged
2.93% weight loss. In contrast,
feeder pigs that were transported
for one hour averaged 5.37% weight
loss, whereas pigs transported for
four hours averaged 8.46%. These
results indicate that the feeder pigs
experienced more stress than market
hogs during transportation and that
duration of transportation had a
significant impact on feeder pigs in
terms of weight loss. There was not
a significant difference between the
control and test groups. Feeder pigs
that were co-mingled did experience
a greater increase in scores for
comfort level and abrasions after
transportation when compared to
market hogs that were co-mingled
with an average score increase of
1.23 and 1.85 versus .8 and 1.0,
respectively.
WIU Internal Program
Mark D. Hoge – Agriculture
Western Illinois University
