MG INFECTIONS
OF POULTRY
Dr. Owen D. Keene
Associate Professor
of Poultry Science,
Penn State University
MG (Mycoplasma gallisepti
cum, the causitive agent) is one ol
the most costly poultry diseases ir
the United States. It is estimated
that about 1/3 of the nation’s table
egg laying flocks and possibly as
many as 90 percent of the backyarc
poultry flocks are infected with
mycoplasma. In Pennsylvania,
approximately 15-20 percent ot
the flocks submitting egg samples'
for avian influenza monitoring
have tested positive for MG. How
ever, some of these positives ma>
be due to the use of killed vaccine.
Regardless, a large number of
Pennsylvania flocks, particular!)
in multi-age complexes, eithei
have or have had the disease.
Most avian species, including
chickens, turkeys, pheasants,
waterfowl, quail and pigeons, are
affected by this disease. Younger
birds are more susceptible than
adults. Infection is more severe
and lasts longer in cold weather
Often the appearance and the sev
erity of the disease depends upon
the amount of stress already
imposed upon the flock. Predis
posed stressors include over
crowding, poor ventilation, exces
sive ammonia and dust, nutritional
imbalances, vaccination and
pathogenic infections that weaken
the birds. In other words, the
organism may be present, but
cause little recognizable disease
until the flock is stressed.
The disease can be transmitted
from the hen through the ovary to
the chick. This is why you should
always buy MG-free replacement
stock. MG can also get into the
poultry house through contami
nated equipment, crates, egg flats,
clothing, shoes, wild birds,
rodents, etc. After being intro
duced into a flock, the organism is
spread through direct bird-to-bird
contact and through minute water
droplets coughed by an infected
bird.
Because MG is a respiratory dis
ease, birds may show symptoms of
coughing, sneezing, nasal dis
charge and watery eyes. In grow
ing birds, feed efficiency and
growth rate are decreased. In adult
laying birds, the most common
findings may be feed consumption
and egg production drop, some
times with a slight increase in mor
tality. Respiratory disease signs
may not be apparent In many
cases, the egg production will be
reduced by as much as 5 to 10 per
centage points.
Once this occurs, it is almost
impossible to return the egg pro
duction graph to normal. This
reduction in egg production is why
prevention is advocated as the best
means of controlling MG
infections.
Prevention starts with obtaining
chicks hatched from eggs of MG
free breeder flocks. The pullets
Lowdown
on Layers
by
Owen Keene
Associate Professor of Poultry Science
Penn State University
must be raised in a clean, sanitary,
isolated facility. The birds should
not be exposed to undue stressors
such as excess dust and ammonia,
nutritional deficiencies, and
uncontrolled exposure to diseases.
This type of low stress manage
ment should continue when the
birds are moved into the layer
house. When possible,
out" (having only one age group on
the farm) management should be
practiced both on pullet grow-out
and layer farms because these
operations are easier to maintain
MG-free. If they do become
infected, the house can easily be
depopulated, cleaned, sanitized
and allowed to stand vacant for a
few weeks prior to housing the
next flock. This methodology will
break the disease cycle and the
next flock stands a good chance of
being MG-free for the entire pro
duction cycle. On the other hand,
when MG invades a layer farm
with several housing units, each
containing a different age bird, it
is almost impossible to get rid of
the disease.
Controlled exposure by immu
nization of flocks has been tried.
To dale there are two different
types of MG vaccine - one is
killed and the other is live (F
-strain). The F-strain is relatively
nonpathogenic (will not produce
severe disease in chickens). The
killed vaccine has been used in
Pennsylvania. Its biggest advan
tage is that there is no danger in
spreading the organism to other
flocks because the organism is
dead. Although the live F-strain
generally would not be transmit
ted from one farm to another via
air, the use of the killed vaccine
eliminates any possibility of this.
In southeast Pennsylvania this
possibility could be important
because there are a lot of poultry
houses in close proximity to each
other.
The disadvantages of killed vac
cine are that it costs more
($.ll/dose vs. $.Ol/dose for the
Uve), each bird needs to be caught
and handled and it may not limit
the colonization of the Held strain
of MG. On the other hand, the live
vaccine tends to replace the field
strain of MG, reducing the overall
levels of disease-producing bac
teria that are present The F-strain
can be administered through the
drinking water or by spray to birds
during the growing period.
However, the live (F-strain) has
the potential to infect other birds,
particularly turkeys. With the high
concentration of birds in south
eastern Pennsylvania, this
becomes a legitimate concern. As
of this writing the Pennsylvania
Department of Agriculture has not
approved the use of live vaccine in
Pennsylvania; however, approval
is imminent The vaccine will be
available only on a limited use
basis and under (hose conditions
approved by the Pennsylvania
Department of Agriculture. When
approved, the vaccine will be
available from Penn State.
47th Eastern Pennsylvania
4-H Beefy Lamb Sale
ALLENTOWN The grand
champion steer was exhibited by
Amy Jo Keifer, Northampton
County, weighing 1,324 pounds at
the Bucks, Carbon, Lehigh, Mont
gomery, Northampton and Schuy
lkill Eastern Pennsylvania 4-H.,
Beef and Lamb Sale, Saturday,
November 21, 1987, at the Allen
town Fairgrounds. The buyer,
Danny George of George’s Food
liner, Bethlehem, paid $3.40 per
pound.
Jessica Keifer, Northampton
County, showed the reserve grand
champion steer weighing 1,356
pounds and was sold for $1.30 per
pound. The buyer was Danny
George.
The lightweight champion steer
weighing 1,195 pounds sold for
$.95 per pound ami was bought by
Ontelaunee Lions, Kempton. The
steer was exhibited by Lori Rabe
nold, Lehigh County. Todd
Gulick, Northampton County,
showed the reserve lightweight
champion steer, weighing 1,070
pounds and was purchased by
Danny George for $.82 per pound.
The medium-weight champion
steer weighing 1,282 pounds sold
for $.90 per pound and was bought
by Wagner Farms. Easton. The
steer was exhibited by Debra
Krause, Lehigh County. Daniel
Hartman, Lehigh County, showed
the reserve mediumweight champ
ion steer, weighing 1,282 pounds
and was purchased by Berks-
Lehigh Farm Credit Service,
Fogelsville for $.87 per pound.
The grand champion individual
lamb, weighing 123 pounds was
sold at $4.80 per pound to King’s
IGA, Schnecksville. It was owned
by Lori Tyson, Lehigh County.
The grand champion pair of lambs,
exhibited by Scott Lazarus, Lehigh
County, was purchased by Danny
George. The pair of iambs
weighed 211 pounds combined
and was sold at $1.70 per pound.
Deanna Miller, Carbon County,
showed the reserve grand champ
ion and reserve heavy-weight
champion lamb and was sold to
Berks-Lehigh Farm Credit Service
at $1.60 per pound. The lamb
weighed 127 pounds., The reserve
grand champion pair of lambs,
shown by Deanna Miller, Carbon
County weighing 223 pounds
combined was purchased by
Richard Haftl and Help U Sell
Reality, Allentown for $1.20. *
The lightweight champion lamb *
was purchased by Heusseman’s
Farm Equipment, Emmaus for
$1.05 per pound. The lamb
weighed 92 pounds and was exhi
bited by Laura Lazarus, Lehigh
County. The Reserve lightweight
Champion lamb, weighing 93
pounds and was sold at $1.05 per
pound to Mass Mutual Life Insur
ance, Allentown. It was owned by
Tracy Voortman, Lehigh County.
The reserve medium-weight
champion lamb, weighing 115
pounds was sold at $l.OO per
Keep in mind, controlled expo
sure should not be viewed as a
substitute for prevention, but only
as a method to achieve MG-free
status for a given farm. MG-free
flocks will have the best egg pro
duction. While MG vaccines will
never give you the same egg pro
duction as flocks free of the dis
ease, they will give you somewhat
better egg production than flocks
experiencing a frank outbreak of
MG. Prevention is still the best
cure.
Lancaster Farming Saturday, December 12, 1987-D3
Germansvllle, to Danny George, George’s Foodllner,
Harold Aulenbach for King’s IGA, Hamburg, Olay and
-uoyAmy
Danny George, George’s Foodilner, Bethlehem.
pound to Agway, Inc. Ormrod. It
was owned by Grant A. Lazarus
111, Lehigh County.
The sale, as was the show on
Friday, was conducted by the
Agricultural Extension Service,
with the County Agents of the six
counties in charge. The auction
eers were Peter Krall and Ralph
Zettlemoyer.
Other buyers at the sale were
David Schultz, Bailey and Bull,
Todd Gulick, Peters Brothers, Bar
ringer Brothers, Zettlemoyer Auc
tion, Peter Krall, Rodney A. Gram
mes, John Scholl, Albright’s Feed
Mill, William C. Willits, Charles
E. Mertz, Lazarus Farm Market,
William Harris, Realty Center,
Blue Mountain Auto Sales,
Jaindl’s Turkey Farm, Bromm’s
Lullabye Sod Farm, Haring
Brothers, Warren Pennock, Jim
and Ann Bums, Marsteller Meats,
Farm Bureau, Young’s Farms,
Marsteller Grain.
_CE
rcr
LIVESTOCK
LATEST
ENTER
DATA
Average price per pound of the
steers with the grand champion
included was $.96 per pound, with
out the top champions, the averag.
was $.84 per pound. Last year’s
averages were $.96 and $.78.
Average price per pound for the
lambs with the grand champion
included was $l.lO per pound,
without the top champions, the
average was $l.OO per pound. Last
year’s averages were $.95 and
$.87.
The total sales of the 26 steers in
the sale were $30,551.04. The total
sales of the 73 lambs in the sale
were $8,764.16.
LAMB
Grand Champion Lamb
Lori Tyson
Reserve Grand Champion Lamb
Deanna Miller
Champion Pair of Lambs
Scott Lazarus
(Turn to Pago D 4)