Continuing last week's post, we will go through further health conditions that can affect your birds.
Duck virus enteritis (or duck plague)
This is a contagious viral disease, affecting adult waterfowl.
It is characterised by marked seasonality (commonly between April and June) and exposure to wild/feral waterfowl, which may be carriers. Muscovy and Indian Runner ducks have an increased susceptibility. Mallards have shown to be more resistant to this.
Clinical signs include: increased mortality, ataxia, loss of appetite and watery, blood stained diarrhoea.
Diagnosed by PME and histopathology.
Goose parvovirus
This is a highly contagious and fatal (up to 100% mortality) disease of young goslings and muscovy ducklings. It is characterised by a rapid course of disease with anorexia, prostration and death.
Diagnosed by PME, histopathology, virus isolation and serology.
Blackhead (histomonosis)
This is a protozoal disease caused by histomonas meleagridis. It usually affects turkeys but can be also found in chickens.
Clinical signs include sulphur yellow droppings and mortality. PME is characterised by multiple, necrotising target-like liver lesions (circular depressed area of necrosis circumscribed by a raised ring) and typhlitis (severe ulceration and necrotic ceacal cores).
Diagnosed by PME and histopathology.
Parasites coccidiosis
It is a protozoan disease associated with enteritis, ill-thrift and mortality. The severity of the disease is related to the weight of the coccidial oocyst challenge and immunity of the birds.
Typical gross lesions at PME may include thickening and/or dilatation of the intestinal tract, haemorrhagic intestinal or caecal contents or causeous caecal cores.
Diagnosis by PME, microscopy and histopathology.
Ectoparasites
Red mite and northern fowl mite infestations cause lethargy, egg drop, anaemia and can cause death. Othe common ectoparasites include yellow body louse. Burrowing mites like Knemidocoptes can cause feather loss or excessive scaliness of the skin, leading to thickening and even deformity of the legs (scaly legs).
Endoparasites
It can cause enteritis and ill-thrift in backyard poultry. Internal nematodes include:
- Ascaridia galli - causes ill-thrift, enteritis and intestinal impaction;
- Heterakis gallinarum - has an important role in the transmission of blackhead and is commonly located in the caecum;
- Capillaria spp - pathogenic when present in large numbers and required microscopical examination of mucosa smears.
- Cestodes and trematodes are not usually pathogenic except in young birds, if inhigh numbers.
Toxicities
As backyard flocks are usually kept outdoors and owners may have fewer stock husbandry skills, there may be opportunities for birds o gain access to toxins, including plants and other materials. Exposure to any toxin should be regarded as a potential food safety incident and, where necessary, risk management measures should be taken and advice provided to flock owners to protect the food chain.
Lead intoxication may cause non-specific signs, gizzard impaction, egg drop and mortality. It is due to occasional exposure of backyard chickens and ducks to lead, often from clay pigeon shooting. Waterfowl can sometimes ingest lead from the bottom of ponds and lakes. Exposure should be regarded as a potential food safety incident and measures should be taken to protect the food chain as appropriate, with relevant advice to owner.
Rodenticide intoxication caused anaemia with fluttering, gasping and haemorrhage in the eyes, mouth and other tissues, with death typically occurring within 72 hours. Occasional, backyard chickens may ingest anticoagulant rodenticides by accident due to careless bait placement.
Ionophore intoxication may occur in backyard turkeys if they get access to chicken feed supplemented with ionophore-based coccidiostats (broiler mix). Clinical signs inlcude reluctance to walk, gait abnormalities, lameness, dyspnoea and death.
General management
Incorrect supply of grit or fibrous feeds may lead to gizzard impaction, and poor hygiene to sour crop. Inadequate nutrition may have devastating consequences with vitamin and mineral deficiencies such as rickets, deficiency in calcium, phosphorus or insufficient vitamin D, which presents as poor chick performance, lameness and an increase in bone deformities. The bones in limbs and beak will be pliable. Also, inadequate housing can make birds vulnerable to predation, cannibalism as well as infectious diseases.
That is all for today. Hope you have found this helpful.
From our team, with love,
FL Poulty
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