Diseases that affect goats: Part One…need for education on diseases

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Caption here (Fortune Moyo, GPJ Zimbabwe)

MY article titled ‘Goat breeding: Reviving an ancient Zimbabwean livestock heritage’ resulted in overwhelming enquiries from readers.

I found it pertinent to re-visit the subject; more so, since over this past week I received several enquiries from distraught goat keepers/farmers with sick stock, and who are astonished to realise that goats, believed to be durable, are susceptible to, and afflicted by, numerous diseases.

In fact, goats and other small ruminants are prey to 28 protozoal and nine rickettsial diseases whose main vectors are ticks, tsetse flies, midges and mosquitoes; 83 diseases caused by viruses and virus-like diseases and 80 diseases caused by bacteria (including mycoplasmas), fungi and algae.   

Imported goat breeds are particularly more vulnerable than the indigenous MaShona, Shangaan or Boer goat that have built some resistance to some diseases over the course of time. 

Some of the major diseases in goats include pneumonia, bloat, diarrhoea and foot rot.

It is unfortunate that ill-informed NGOs operating in most parts of Africa, including Zimbabwe, have for far too long been advocating goat farming as an alternative, quick and low-cost alternative to cattle ranching or crop farming, but neglected to inform the people regarding the diseases goats are predisposed to. 

The current wet spell being experienced in the country this season, following the recent years of unusually low rainfall, has given rise to many diseases and ailments for both free-range and penned livestock, including the sturdy goat.  

As with cattle and other livestock, basic goat and other small ruminants management practices need to be followed judiciously by every goat breeder. 

Knowledge of disease management is also essential for a farmer.  

Goat farmers should pay close attention to their flocks’ behaviour, for this will give the farmer the first indication of illness in his flock.  

It is a good idea to have a pen or two set aside for sick animal quarantine, especially if a disease is contagious.

As a rule, once identified, a sick animal should be separated and quarantined instantly from the rest of the head and treated immediately. 

This is crucial because some diseases are contagious and can rapidly spread to the other healthy animals.  

Since goats are social animals, if one goat gets sick, most of the goats will fall ill too. 

Some of the most common diseases that affect goats are:

  • Respiratory disease, common in goats 

(and sheep), and is usually the result of a series of complicated interactions involving stress inducers, both physical and physiological, and a variety of infectious agents. 

The most common form of respiratory disease is pasteurellosis, which can have a significant impact on the productive value of small stock.

Signs of the acute disease in affected kids (young goats) and lambs (young sheep) include fever, dyspnoea, anorexia, recumbence and sudden death. 

If the animals survive, they can become chronically affected with resultant reduced ability to thrive and survive further infections.

  • Pneumonia is an infection of the lung tissue with multiple causes in goats of all ages.

In younger animals, various bacteria, viruses and parasites of the upper and lower respiratory tract are often responsible for development of pneumonia, while in adult animals, these same disease-causing agents can create pneumonia.

In goats, a systemic virus, the caprine arthritis encephalitis virus, can cause pneumonia and can affect multiple organs, including the lungs, brain, udder and the joints. 

Caprine arthritis encephalitis (CAE) is incurable, contagious and devastating to goat herds.  

CAE can be tested for and only CAE-free goats should be traded/purchased.

Some of the conditions that can predispose goats to pneumonia include overcrowded housing with poor ventilation; poor sanitation which may result in urine and faeces that release gases that harm the goat’s respiratory tract, and wet bedding that can cause the animals to become cold.

Equally harmful are excessive dust and extreme variation in environmental temperatures, such as cold nights followed by hot days; stress during transportation, obstetrics, heavy milk production and weaning.  

Failure to get adequate amounts of colostrum (first milk) may also cause pneumonia in young animals.

The earliest sign of pneumonia is when the affected animal is less active than normal.  

Other symptoms include high temperature/fever, coughing with thick and dark nasal discharge, rapid or laboured breathing and falling behind from the rest of the flock.  

It is necessary to prevent bacteria from causing pneumonia as a complication to a viral infection.

  • Three theileria species infecting small ruminants have been shown to be responsible for heavy mortality.  

Ovine and caprine theileriases in sheep and goats is similar to theileriosis in cattle produced by tannulata, with which it is closely related. 

The disease is transmitted by the ticks theileria lestoquardi, of the genus hyalomma.  

The parasite is transmitted to its vertebrate host by the bite of an infected tick. Depending on the species, they develop into schizonts that release merozoites into the circulation. 

Some species have the ability to transform the host cell so that it can proliferate and disperse throughout the body, 

Affected animals show sustained fever and anemia and mortality can approach 100 percent. 

  • Heartwater, caused by the bont tick, is another disease that afflicts goats. 

Some of the symptoms include a rise in temperature, depression, loss of appetite, increases in pulse and respiration, prostration, convulsion and death.  

Tick control is a vital preventative measure for this disease.

  • Caseous lymphadenitis (CL) is a chronic, contagious disease that is also called ‘abscesses’.  

Pus-filled infections, or abscesses, form around a goats’ lymph nodes. When the abscesses burst, the pus can infect other goats. 

  • Diarrhoea is very common in goats, especially small kids.  

It is important to note that diarrhoea itself is not an illness but rather a symptom of other health problems in goats.  

Before treating goats for diarrhoea, farmers must first determine why the animals are scouring as it may be the body’s way of purging itself of toxicity.   

There are four major causative agents of diarrhoea in goats – namely bacteria, viruses, parasites, and poor management practices such as overcrowding, poor sanitation or over-feeding.  In small kids, diarrhoea could be caused by consuming impure milk, too much milk or colostrum (first milk). 

Changes in the environment may also trigger diarrhoea in goats.

The symptoms for diarrhoea include pain in the belly, loss of appetite and watery faeces.  

Acute diarrhoea may result in dehydration and related problems.  Where the goat is experiencing dehydration, it should be given adequate water and liquids.

  •   Goats can also be affected by enterotoxemia, which is caused by a bacterial imbalance in the animal’s rumen. 

It can result from sudden feed changes, overfeeding, sickness, or anything that causes a digestive upset.  

Farmers should vaccinate their herd against it as enterotoxemia can kill a goat.  

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.

For views and comments, email: tonym.MONDA@gmail.com

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