Intensive / Internal
Parasites
There are two main worms that may cause
problems in cage birds:
-
Roundworms (Ascaridia
galli).
These are the biggest and
most common. They are white, up to 2 inches long and may be visible in
droppings in heavy infections.
-
Hairworms
(Capillaria).
These are much smaller
(hair-like) and are barely visible with the naked eye but can cause
significant damage even in only moderate
infestations.
Worm burdens can be identified by
examination of faeces, culled birds or worm egg counts on bulk faeces.
Routine worm counts on droppings samples are recommended to monitor
infection levels.
Effective control is aimed at breaking the
cycle of infection. Strategic use of in feed worming (starting in the
rearing phase and during lay) will help to reduce a challenge.
The only licensed wormer for laying birds
is Flubenvet, (Janssen Animal Health). This product has a nil withdrawal
period which means that it can be given in the feed during lay without the
need to discard eggs, except in organic diets where eggs may need to be
with held.
Coccidiosis
This parasitic infection of the intestines
can lead to gut damage and, in severe infestations, death of birds. More
commonly, poor control of subclinical infection reduces feed conversion,
or leaves pullets with chronic irreversible gut damage. Such flocks may be
uneven or underweight at grading, and may not perform to their full
potential in lay.
Currently, effective control is achieved
with drug treatments in feed that suppress oocyst output. These may
involve the use of ionophores or chemicals on a step-down programme to
ensure a good build up of immunity in pullets. To avoid problems with drug
resistance and continuous drug treatment, and help ensure even and target
weight pullets, a live attenuated oral vaccine (Paracox: Schering Plough)
is available. This vaccine is currently administered in the drinking water
as a single dose between five and nine days of age. Alternative
application methods for the vaccine are being developed for ease of
use.
All treatment/vaccination strategies should
be supported with effective biosecurity. The use of a disinfectant with
proven efficacy against coccidial oocysts will reduce challenge pressure.
Maintenance of good friable litter when floor rearing will reduce oocyst
build up.
Internal Parasites
Worm infections cause damage to the
birds’ gut. This may result in a variety of problems
including:
-
Loss of shell colour and strength, yolk
colour and egg size.
-
Poor body weight gain leading to
unevenness or sick birds. Affected birds may be dull and show pale
combs.
-
Increased cannibalism through vent
pecking due to straining.
-
Death: in very heavy
infestations.