Poultry production, slaughter and inspection - Gracey's Meat Hygiene - page 240

diarrhoea, BWD or pullorum disease, in chicks under 3
weeks of age. The disease is now eradicated from devel-
oped countries and because of the age of the bird affected
would not be seen in a poultry meat plant.
Salmonella gallinarum causes fowl typhoid, an acute,
subacute or chronic infectious disease of poultry, ducks,
turkeys (notably in the United States), pheasants, guinea
fowl, pea fowl, grouse and quail. The disease differs from
other avian Salmonella infections in that clinical disease
is usually seen in growers or adult birds, although chicks
can be affected. In acute outbreaks, the first sign will be
an increase in mortality, accompanied by a drop in food
consumption. Depression, with affected birds standing
still with ruffled feathers and their eyes closed, is seen
clinically. As with most poultry diseases, the signs of ill
health are mainly non-specific. In the chronic phase,
there is progressive loss of condition, and an intense
anaemia develops which produces shrunken, pale combs
and wattles.
Lesions. Carcases of birds dying in the acute phase
have a septicaemic, jaundiced appearance, with the sub-
cutaneous blood vessels injected and prominent and the
skeletal muscles congested and dark in colour. A consist-
ent finding is a swollen friable liver that is dark red or
almost black, and the surface has a distinctive copper-
bronze sheen. The spleen may be enlarged and there is
catarrhal enteritis.
In chronic cases (those most likely to be seen on
inspection), greyish areas of necrosis may be seen in the
myocardium, pancreas and intestine.
Judgement. Condemnation.

birds. The main causes of rejection were birds DOA
(0.24%), disease (1.57%) and miscellaneous conditions
(0.28%). The most common cause of carcase rejection
due to disease was colisepticaemia (42.8%). Septicaemia/
toxaemia/fevered accounted for 29.63%, emaciation for
19.45% and ascites for 5.91%. Hydropericardium/peri-
carditis (1.01%), skin lesions (0.62%), joint lesions
(0.31%), jaundice (0.16%) and tumours (0.01%) were also
seen. The birds from units with high rejection rates had
lower average slaughter weights than birds from units
with normal rejection rates.
The productivity of intensively reared poultry falls as a
result of disease problems as the size of the flock increases
and as the number of rearing houses on one site increases.

Coliform infections
E. coli is the most commonly isolated organism from
condemned carcases. E. coli is a normal inhabitant of the
digestive tract of poultry, and large numbers are often
found in the lower part of the small intestine and caeca.
The serotypes most frequently causing colisepticaemia
(01, 02, 08 and 078) are also likely to be found in the
throat and upper trachea. These pathogenic E. coli prob-
ably invade the bird's body from the respiratory tract to
produce the characteristic condition.
The best method of controlling colisepticaemia is to
maintain the highest standards of flock management and
obtain chicks only from disease-free well-managed breed-
ing flocks and hatcheries. Pathogenic E. coli serotypes can
be transmitted via the hatchery following faecal contami-
nation of hatching eggs. Chicks should be the progeny of
mycoplasma-free stock which have been vaccinated
against IBD, infectious bronchitis and any other disease
that is a local threat. The production birds, if necessary,
need to be vaccinated against infectious bronchitis and
IBD and provided with a coccidiostat in the feed. There is
an increasing use of coccidial vaccination in speciality birds
which avoids the need for a coccidiostat in the feed. The birds
should be fed a well-balanced diet to avoid the consequences
of mineral/vitamin deficiencies and malnutrition. Good litter
management and properly ventilated houses are also vital
control measures. The litter should be dry, but not dusty, and
the airflow should be such that there are no pockets of
stagnant air or build-up of ammonia fumes.
Lesions. The main lesions found in colisepticaemia of
broilers, turkeys and ducks are congested muscles,
enlarged liver and spleen with pericarditis, perihepatitis
and airsacculitis.

Incidence and control
In the United States, over 150 different salmonellas have
been isolated from poultry. Evidence of disease in birds
is most common in chicks, poultry or ducklings under 2
weeks of age. The main significance of Salmonella infec-
tion is as a zoonosis. The Zoonoses Directive (2003/99EC)
contains provisions for community-wide controls for
Salmonella in domestic fowl, and the Poultry Breeding
Flocks and Hatcheries (England) Order 2007 reflects
monitoring requirements of the directive. Defra has
codes of practice for the prevention and control of
Salmonella in breeding flocks and hatcheries and in
chickens reared for meat on farms.
There are approximately 2500 different types (sero-
types) of Salmonella . Most do not normally cause clinical
disease in poultry. However, virulent strains such as
Salmonella typhimurium DT104 have been associated
with illness and mortality in chicks although cases in
chickens reared for meat have been falling.
A survey carried out in the EU in 2008 showed 15.6% of
broiler carcases to be contaminated with Salmonella ,

Salmonellosis
There are two specific Salmonella organisms which affect
only poultry. Salmonella pullorum causes bacillary white