|
|
|
Coccidiosis in Goats |
|
What is Coccidiosis?
Coccidiosis in goats can cause acute ill health, severe diarrhea and sometimes death. It can spread very quickly through a herd, hence good husbandry practices are required to minimize occurrence. It is most often seen in kids and stressed animals.
Cause
Coccidiosis is caused by a protozoan parasite of the Order Coccidia. In goats the disease is caused by coccidia of the genus Eimeria which invade the cells of the intestinal wall. Coccidia are highly host specific but sheep and goats may share some species of coccidia.
Signs of Infection:
- The coccidia invade and destroy intestinal cells, resulting in loss of blood and electrolytes and a very poor absorption of nutrients. The most common sign of infection is diarrohea which may be severe. In addition the faeces may contain blood however, if the infection is very severe, goats may die within 24 hours without developing any diarrohea at all.
- Affected goats may also show signs of a rough coat, poor weight gain or even weight loss and a general weakness. Recovered animals may be left with scar tissue in the intestinal lining so they will continue to show signs of ill thrift. In this case their production of milk, meat or fibre will continue to be poor.
Factors that can contribute to Coccidiosis:
- Young or previously unexposed goats are the most susceptible, particularly at times of stress such as at weaning. Goats appear to develop a resistance to coccidian with age, but stressful conditions can cause this resistance to break down.
- Environmental, nutritional and management factors can all act as stressors and predispose goats to the disease. These factors include poor nutrition, lack of shelter, overcrowding and excessive handling.
- Overcrowding of goats in damp conditions, where food and water are liable to faecal contamination can also lead to a build up of ococyst numbers and make a disease outbreak more likely.
How is it spread?
A goat becomes infected by ingesting mature oocysts of coccidia. Each oocyst ingested has the potential to destroy thousands of the host’s intestinal cells. Once inside the intestine, the infective stage of the coccidia emerge from the oocysts and penetrate the cell of the intestinal walls. They then pass through several stages of development during which they multiply rapidly, rupture the host cells and invade new cells. The process is repeated many more times until new oocysts are formed and passed out to the external environment via the infected goat’s faeces.
Kids are the major source of pasture contamination and newly weaned kids often have high oocyst counts.
Once outside the animal, the oocyst mature and are then capable of infecting other goats which pick them up from contaminated feed and water and from licking contaminated hair. A kid can readily pick up infective oocysts from a doe’s udder.
Most temperate or cool conditions favour the maturing process. It can be as short as one day in summer or take a few weeks in winter. Once mature, oocysts are very resistant to environmental fluctuations although they cannot survive hot, dry conditions or direct sunlight. They are resistant to disinfectants and can survive up to two years under favourable conditions.
If exposure to oocysts is stopped, the infection becomes self-limiting. The degree of damage depends on the number of oocysts ingested.
Control:
Control is aimed firstly at preventing access of goats to large numbers of oocysts and secondly at reducing stresses in the goat’s environment. The use of preventative drugs is a third avenue of control that may be necessary in high-risk situations.
Preventing access to oocysts:
- Use feed and water troughs in which goats cannot defecate.
- Ensure that water troughs do not overflow.
- Avoid over-crowding on damp pastures.
Preventing stress:
- Provide good, well drained shelter.
- Avoid yarding goats for long periods
- Avoid mixing young kids and older goats.
- Maintain good health through good nutrition and worm control.
|
|
