By Daniel J. Meyer
Extension Agricultural Engineer
The Pennsylvania State University
UNIVERSITY PARK - Hot
weather reduces swine per
formance. Lowered feed con
sumption, conception rates, and
higher large hog death losses are
the result.
Pork producers can reduce their
economic losses by adding various
cooling systems. These options
include using:
1. Drip cooling on crated sows.
2. Snout cooling on crated sows.
3. Evaporative cooling cells.
4. Up-to-date summer ven
tilation fan rates.
5. Large sidewall vent doors on
naturally ventilated buildings.
6. A wide ridge opening (24”) on
LIVESTOCK
LATEST
Waiting for your broodmare’s
first foal can make you almost as
nervous as waiting for a baby to be
bom. But knowing how to take care
of the mare prior to foaling as well
as knowing how to recognize
problems during foaling, can
reduce the novice’s stress and the
risks to the mare and foal, says
Nancy Kadwill, County Agent,
Montgomery County Cooperative
Extension Service.
A mare should receive regular,
adequate exercise during
pregnancy. But don’t turn the
mare out on slippery, rough
ground. A fall could hurt the un
bom foal.
Worm the mare during the last
four to six weeks of pregnancy with
a medication approved by your
veterinarian to reduce the danger
of the foal being infected at birth
with worms. The veterinarian may
also recommend administration of
one or more vaccines in late
pregnancy.
During the last 30 days of
pregnancy, keep the mare in a stall
at night. She will have a chance to
get used to both the stall and the
horses in neighboring stalls. She
will be less nervous about her
surroundings when the foaling date
comes.
Mares begin to get ready for
foaling 24 to 48 hours ahead of
time, although they may develop
some udder size four to six weeks
earlier. The foal begins to position
itself inside the mare. The udder
becomes distended and may ooze a
honey-colored fluid or colostrum.
If the mare actually drips milk,
you should save the colostrum and
feed it to the foal.
Birth usually occurs within 24
hours of these signs.
Check the mare at two-hour
intervals around the clock as
foaling time approaches. Leave a
small light on so you can check the
mare without disturbing her.
When foaling time is close, the
mare may be restless. If un
disturbed, she will probably foal
lying down. Once labor begins,
birth should occur in less than an
hour. A normal delivery time is 20
to 30 minutes.
The foal’s nose and feet appear
Cooling hogs
naturally ventilated buildings.
7. Timed sprinkling in open pens.
8. Overhead paddle-type cir
culating fans.
The simplest and lowest cost
cooling idea for sows in crates is
the dripper system. A 0.8 gallon
per hour greenhouse dripper is
forced (needled or drilled) into a
plastic water line over the top of
each sow. The line can be on the
crate if protected or attached to the
ceiling. It should be located 18
inches behind the front of the crate
to reduce wetting the feed. Two
valves are needed - one to shut it
off and one to keep the flow
uniform (adjust only once). About
1-2 drips per second is adequate on
the sow’s shoulders. Ideally the
floor should be totally slotted to
Montgomery extension
offers foaling tips
first. The foal’s membranes should
be broken to allow it to breathe and
clear its nostrils after delivery. Do
not disturb the mare and foal, Once the foal is born, saturate
though. Allow them time to get *he cor( i in 7 percent iodine
acquainted. as soon as possible. Have your
If the feet appear without the veterinarian give the mare and
nose or if the birth is taking too i° a i a complete physical within 24
long, call for professional help, hours.
WASHINGTON, D.C. - A new
blood test for pigs may strip some
of the mystery from trichinosis, a
disease that costs the pork in
dustry millions of dollars in sales
annually.
Animal disease scientists for the
U.S. Department of Agriculture’s
Agricultural Research Service
today said the test the result of
biotechnology research is more
than 90 percent accurate in
detecting trichinosis in live pigs.
Identification of infected pigs
posed problems in the past, said H.
Ray Gamble, developer of the new
test and a parasitologist based at
USDA’s Beltsville, Md., research
center. He said it had been difficult
using earlier tests to separate
trichina parasites and certain
other parasites of pigs.
“The new test specifically
detects trichina infections
nothing else at a higher level of
accuracy than previously achieved
without slaughtering the animal,"
Gamble said.
Pigs are the mam domesticated
food animal to contract trichinosis,
he said, but occurrence among
them is uncommon. Only about one
in a thousand is believed to be
infected.
Even if a pig has trichinosis,
thorough cooking or freezing (at -
10 degrees Fahrenheit for 10 days,
for example) will make the pork
safe to eat, according to USDA
recommendations.
A total of 29 cases of human
trichinosis were reported to the
United States last year. Because
in summer need
Trichinosis blood test
developed of Beltsville
prevent wet floors for the little
pigs. Some companies
manufacture a unit with a ther
mostat to turn it on automatically
when temperatures exceed 80°F.
The greenhouse dripper is about
eight inches long, 1/8 inch in
diameter and sells for about ¥2
cent each.
Sows in the farrowing house and
boars can benefit from snout
cooling. A flexible pipe (four-inch)
is connected to duct work which
provides 50 cubic feet of air per
minute (cfm) per sow or 100
cfm/boar of tempered air (cooled
by earth tubes or an evaporative
cooler). If the air isn’t tempered,
ventilate at the snout with five-inch
tubing and 100 cfm/boar of tem
pered air (cooled by earth tubes or
Foaling difficulties are an absolute
emergency.
the symptoms are flu-like in mild
cases, there probably are far more
undiagnosed cases each year,
Gamble said.
Originally, the new blood test
was developed as a research tool,
but the research agency’s national
swine trichinosis epidemiology
project is using it to determine the
prevalence and distribution of the
disease, said K. Darwin Murrell,
chief of the agency’s Helminthic
Diseases Laboratory at Beltsville.
He said USDA’s Food Safety and
Inspection Service and Animal and
Plant Health Inspection Service,
state regulatory agencies and
agricultural experiment stations,
and industry are cooperating in the
project.
When the geographical
distribution is known, scientists
can concentrate control measures
in the most critical areas, Murrell
said.
Experts are uncertain how pigs
become infected with trichinosis.
Some attributed infection to eating
improperly cooked garbage,
others to pigs eating infected farm
rats or wild animal carcasses, or
directly to hog cannibalism.
If researchers can determine the
method of on-farm infection, then
farmers can develop and use more
effective preventive measures,
Murrell said.
The National Pork Producers
Council is coordinating a task force
of federal, state and industry
researchers that seeks to eliminate
trichinosis in pigs by 1987.
not be expensive
. iping gt Jy
systems is one way to keep sows comfortable throughout the
hot summer months.
an evaporative cooler). If the air
isn’t tempered, ventilate at the
snout with five-inch tubing and 100
cfm/sow and 150 cfm/boar. The air
should be directed as close to their
nose as possible since the lungs do
most of the cooling for the sows. A
suspended 8-10” diameter PVC
pipe with loggers inside and a fan
at the end is a type of commercial
system available which uses the
concept of evaporative cooling in a
pipe. The pipe is placed six to
seven feet above the floor and can
cool sows and boars in rows up to
70 feet long. Four-inch PVC pipes
with 90° elbows extend from the 8-
10 inch pipe down to the sows or
boars.
Evaporative cooling wall pads,
circular drums, and box units are
available commercially. The in
coming air is passed through a
moist pad, where the heat in the air
evaporates moisture into the air.
This raises the relative humidity
while lowering the temperature of
the air. The lower the relative
humidity of the incoming air, the
more effective evaporative cooling
is. A rule of thumb is that
evaporative coolers are effective
when the temperature in degrees
Fahrenheit plus humidity in
percent total less than 120. Most
units use a circulating pump to
distribute water over a fibrous
pad. Air is drawn through the pads
into the animal area. Routine
maintenance is essential to control
algae growth and dirt buildup. Pad
life is 3-5 years.
The pad area needed in square
feet can be approximated by
dividing the ventilation rate in cfm
by 150 for aspen pads and by 250 for
cellulose pads. The water sump
should have a capacity of 0.5
gal/sq ft of aspen pad and 0.8
gal/sq ft for a cellulose pad. The
flow rate in the distribution pipe
over the pads should be 0.3
gal/min. Economics usually
dictate that the breeding and
farrowing buildings are
evaporative cooled.
Recent educational swme in
formation on cooling sows and
boars suggests higher rates than
previous materials. The following
table summarizes their recom
mendations. If your swine facility
is over 2 years old your ventilation
Summer Ventilation Rates
Animal Type cfm
Sow & Litter 500
Boar 300
Gestation Sow 150
Sow in Breeding Bldg. 300
rates may be too low. The rates for
mechanically ventilated buildings
should be checked against the
table.
There are four methods of
cooling naturally ventilated
buildings for growers, finishers,
gestation and breeding animals.
These are summarized as the
previously listed options five, six,
seven, and eight. Ventilation doors
on both sides of the building should
be open one foot for every ten feet
of building width for summer
ventilation.
A recently developed concept for
naturally ventilated buildings is to
open the ridge 24 inches. This
Option is not possible in buildings
with ceilings at 8-10 feet. The ridge
opening size is adjustable with two
2x12 doors for winter. The door
adjustment is controlled by a
thermostat on an automatic door
controller. This helps to maintain a
constant temperature. The suction
at the ridge is directly proportional
to the wind velocity. The wide
ridge aids summer ventilation in
buildings less than 75 feet apart
and in buildings which have
prevailing summer winds blowing
parallel to the ridge rather than
perpendicular to the ridge. On still
days and in wide buildings over 48
feet the wide ridge can drop inside
building temperatures 10-15°F.
The open ridge also reduces am
monia levels in buildings with pits
underneath in winter since am
monia rises.
Sprinklers on tuners (over
slotted floors preferred) are ef
fective in pen type situations. The
timer is needed to allow the
moisture to evaporate off the
wetted skin. Research studies
measuring the performance of
finishing hogs in hot weather
reveal that animals perform as
well with sprinklers as they do with
evaporative cooling of inlet air.
Sprinklers should be designed to
run one to two minutes in every 30-
minute period above 80°F. For a
pen of 20 pigs the water
requirement at 40 psi is 0.4 gal/hr.
An in-line filter is needed to keep
the nozzles from plugging.
A cooling technique that in
creases the sprinkler system ef-
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