A DISEASE that affects mostly sheep and goats, but rarely affects cattle, is blue tongue, caused by several species of virus brought about by midges.
Although not contagious, it is an acute infectious disease, characterised by high fever, eye and nasal discharge, inflammation and ulceration of the lips, mouth and tongue.
Hooves become affected and the animal becomes recumbent and dies.
A few may recover, but recovery is usually very slow.
Abortion in pregnant females is also a result of blue tongue.
It is thus important for farmers to control midges and move animals to high ground in rain seasons.
- Mineral stones, known as urinary calculi, sometimes form in the goat’s urethra.
It can occur in both males and females, but is mostly a problem in male goats.
These stones can result from an imbalanced diet, so consult your vet if you experience these in your herd.
- Bloat is a life-threatening condition in goats.
It is the result of gas, a natural by-product of digestive fermentation, being trapped in the rumen instead of being expelled by the goat’s belching.
Besides loss of appetite, symptoms for bloat include bulging on left side of the belly, which, when tapped, sounds like a loose-skinned drum.
Other signs of pain include grinding of teeth, bleating, difficulty in breathing, depression and trembling limbs.
The most common causes of bloat in goats include over-eating, damp and very old fodder, leguminous crops and over-feeding on manufactured feed concentrate.
- Footrot, a contagious disease in goats, is caused by bacterial infection that thrive in moist soils.
Infected goats’ hooves become painful, resulting in kids not growing properly and bucks having difficulties in mating.
Infected goats may also start limping and experience inflammation of the hooves.
Goats with footrot usually struggle to stand up properly and should be quarantined from rest of the flock.
To prevent footrot, attention must be paid to maintaining good hygiene in the housing.
Goats’ hooves should be trimmed when they get long or infected, especially where pen feeding is used as opposed to free-range grazing.
- The disease peste-des-petits ruminants (PPR), caused by moribillivirus of paramyxoviridae family, is an acute, highly contagious viral disease of small ruminants characterised by fever, loss of appetite, stomatitis, gastroenteritis and pneumonitis.
The disease is markedly evident in goats as sheep are less susceptible.
Natural transmission occurs primarily through direct contact with infected goats.
Transmission may take place through contaminated food, water and beddings, among others.
Although ingestion of infected material is the main mode of transmission, it can also take place through inhalation and contact with ocular (eye) secretions.
Faeces are the main spreading agent and through it, the disease may occur in epidemic proportion.
Wild ruminants have also been suspected to play a role in the spreading of this disease.
Clinical symptoms include high temperature, dull coat, dry muzzle and inappetence; heavy nasal discharge accompanied by sneezing and coughing; lesions on lips, mouth, gums, dental palate and tongue, with halitosis (bad breath).
Sick animals should be separated from the rest of the herd.
Death may occur in a few animals but most should recover. Pregnant goats may abort.
- Contagious ecthyma, sore mouth, also
known as orf, is another contagious viral infection where blisters form in the goat’s mouth and nose.
Sore mouth heals in a few weeks, but the scabs from the blisters can be contagious for years.
Orf can be transmitted to humans, so care and cleanliness are essential when handling infected animals
Clinical symptoms include appearance of nodular eruptions on the lips, mouth and nostrils; the lesions are followed by papules, vesicles, pustules and ulcers in three-to-four days as well as profuse salivation, lacrymation (crying), accompanied by nasal discharge.
Extensive lesions on the feet lead to lameness.
Ewes (female goats), nursing infected lambs may develop lesions on the udder which can result in mastitis in ewes. Affected animal should be isolated from the rest of the herd and strict hygienic and sanitary measures are to be adopted.
- Gas gangrene is caused by the organism clostridium chauvoei entering wounds, often after shearing or late dehorning.
There is no cure and it usually results in sudden death. Symptoms in live animals is severe lameness with gas crepitation under the skin.
- Like gas gangrene, tetanus is the result of deep puncture wounds – often after castration.
Clinical signs of tetanus are muscle stiffness followed by spasm.
Eventually, an animal becomes recumbent with legs and neck held out and stiffly.
Jaw muscles become rigid, locking the jaw.
If caught early, antibiotics, tranquilisers and tetanus toxoid vaccine may help, but most animals die.
Vaccination in areas where tetanus and gas gangrene is known is essential.
- Another disease for which regular vaccination is essential, especially in areas where it is prevalent, is anthrax.
Here, spores of bacillis anthracis in soil and environment affect the animals resulting in sudden death – usually within 48 hours of illness.
Animals are rarely seen alive, but symptoms include increase in temperature, muscle tremors, convulsions and death.
Following death there is oozing of blood from the natural orifices, and bloat may develop.
Oedema may be noticed predominantly under the neck, brisket region, thorax, abdomen and flank.
The disease is notifiable and should be brought to the notice of the authorities in case of an outbreak.
The dead animal body should not be opened and care must be taken to destroy it by deep burial with quick lime.
Strict quarantine measures should be adopted in anthrax-prone areas to prevent the introduction of infected animals into disease-free areas.
Meat from infected animals should never be consumed or sold.
- Lumpy wool (dermatophilis congolensis) is a fungus found in the environment, possibly caused by the bont tick that causes breaks in the skin where the fungus attacks the skin, causing lesions which become hard, thickened crusts which damages the wool hide while young animals may die.
Farmers must ensure sheep/goats do not get shearing or other wounds, as culling may be called for in severe cases.
Tick control is essential for the prevention of this disease.
Farmers should be cognisant of goat diseases when buying goats so they avoid buying sick animals.
If possible, farmers should always inspect records and the rest of the herd for tell-tale signs and symptoms of any diseases.
They should have a clear understanding of the role of the causative conditions in the development of diseases and always inspect the animals’ environment for any conditions that might cause an outbreak and correct these, including making sure that goats have a clean environment, dry bedding, good feed, clean water and fresh air.
Prevention is better than cure.
Since there is no treatment for some diseases, prevention is always key.
Preventing goat diseases by keeping goats healthy is the first line of defence.
Prevention relies on good quarantine and biosecurity procedures and regular vaccination.
Dr Tony Monda is Zimbabwean socio-economic analyst and scholar. He is currently conducting veterinary epidemiology, agronomy and food security and agro-economic research in Zimbabwe and southern Africa.
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