Dear Mohair producer

Getting back to work after a period away it is not surprising that one of the first cases will be an Angora Post Mortem!

A diagnosis of chronic coccidiosis was made in young kapaters in the first week of September.

We usually associate coccidiosis with young kids where the disease is usually acute but underestimate the loss in growth, production and deaths with the chronic form of coccidiosis.

 Mortality can be high in young kids but in older kids it results in a serious setback, which usually results in stunted growth and lowered resistance to other diseases.

The chronic coccidiosis picture is usually that of kids in poor condition with slow growth rates resulting in thin, small and sometimes potbellied young goats. Their heads may continue to grow giving them a runty appearance and their hind ends may be dirty due to the soft stools and intermittent diarrhoea.

Chronic coccidiosis may be the lasting effects from an infection from when they were younger and affected kids may never fully recover from the effects of the disease.

 

The intensity of clinical signs of disease depends on how many intestinal cells are damaged by the invading organisms, the susceptibility and the condition of the goat at the time of infection.

 

Clinical signs in chronic cases include:

• weight loss,
• signs of maldigestion and hypo-proteineamia (oedema resulting in fluid in the abdominal cavity ‘swelpens’ or in subcutaneous tissue ‘swelsiekte’)
• Diarrhoea is not always a significant finding but bouts of diarrhoea or soft faeces may occur.

How is the damage done?

There are many stages in the development of the coccidia, and at each stage intestinal cells are invaded and then destroyed – causing repeated damage to the intestine. The intestinal damage can release blood and cause inflammation of the lining of the gut. The animal loses blood, water and protein and cannot absorb nutrients as efficiently. If enough damage is done, it becomes extremely ill and may die.

 

Why does one herd have a problem with coccidiosis and another does not? Why are some years worse than others?

It is important to realise that presence of the disease agent alone is often not sufficient for a coccidiosis problem to occur, but that different factors all play a role which vary between flocks and between years.

• Stress is the major predisposing factor.
• The number of oocysts present in the environment (contamination) and the environment theses oocytes occur (moist lands, around feeding and water troughs).
• How immune is the goat? Younger animals are more susceptible. Are the kids affected by another disease that could weaken their immune systems such as brown stomach worm, wireworm or orf?
• Bad weather or sudden changes in the weather?

 

How do kids get infected?

The infection occurs by ingesting the sporulated oocyst through pasture or water. Oocysts can be transferred by wind and flies. Kids sucking ewes contaminated teats can potentially pick up the infection. After infection, oocysts will be passed through the faeces to the environment in about 2 to 3 weeks. However, they must undergo a period of sporulation in order to be contagious to another host. This sporulation period occurs when there is adequate moisture and warm temperatures.

 

Diagnosis

The best way to diagnose coccidiosis is based on the clinical signs shown in the group of animals and evidence of infection based on post mortem if any animals have died. Taking a faecal sample and having a quantitative count of the number of oocysts (faecal oocyst count or FOC) in the ‘mismonster’ can also be helpful.

Remember that shedding of the coccidia eggs – oocysts – is not evidence of disease, but only evidence of infection.

In acute cases low FOC does not rule out coccidiosis as disease may be present before the pre-patent period is reached – so the FOC may be very low.

 

Treatment- Options

The goal of using medications is to control the level of infection so as to prevent the disease but to still allow enough infection so that the young animal develops immunity.

Drugs are an expense and to decide to use them, there should be a benefit to the animal higher than their cost.  Even the best drug cannot protect stressed animals or those in a heavy contaminated environment. Few farmers understand the differences between the commonly used drugs Totrazuril (Baycox) and Diclazuril (Vecoxan).

 

1. Totrazuril (Baycox) is expensive but very safe and has high tissue levels for longer periods than Diclazuril (Vecoxan). Do not use in pregnant goats.

Baycox is dosed 0.4ml/kg as a single treatment. There is some evidence in the literature that goats may require a higher dose 0.6ml/kg (6ml/10kg)

Totrazuril kills coccidia in the intracellular stages. Additionally, there is persistency of the drug reducing the need for repeated retreatment as in the case of Dicazuril (Vecoxan)

 

2. Diclazuril (Vecoxan)

 Dose 2ml/5kg (4ml/10kg) which is repeated after 5 days if diarrhoea continues. Like Toltrazuril, you need to dose early in disease to prevent damage. Unlike Toltrazuril (Baycox), it is not persistent. It can be used in pregnant goats.

Diclazuril has efficacy against the asexual or sexual stages and only a limited effect on the intestinal lesions caused by the parasitic stagesolder than 16 weeks.

Treatment causes interruption of the life cycle for about 2 weeks after treatment.

 Commonly used at about 6-8 weeks of age, or two administrations beginning at about 4 weeks of age and the second about 3 weeks later when problems have occurred on the farm before.

 

3. Sulfonamides

These are old drugs and are to be used for treatment only. There are several types with efficacy against coccidian.  Treatment must be continued for at least 4 days to be effective.

 

If you have had coccidiosis before and want to treat prophylactically. The first time you usually see coccidiosis in your kids is about 4 to 5 weeks of age. This often means treating each animal when it reaches 3 to 4 weeks of age. This means you can’t treat the group at one time but rather when the individual animal reaches that age.  To do this, you must have a very good identification and record keeping system.

In situations where there is still a large environmental load of oocysts, it sometimes is necessary to retreat in 3 to 4 weeks.

 

Practical procedure and suggestions on problem farms

During the period prior to weaning, very good results are obtained by dosing only those kids that show signs of coccidiosis. Follow manufacturer's dosing instructions. In this way all affected kids will be treated regularly, while healthy kids (which are usually in the majority) are not treated unnecessarily.

 

Prevention and control

• Although adult animals are not as susceptible to the disease, they can serve as a source of infection to younger animals.
• Under conditions, which are favourable to coccidiosis such as irrigated lands where problems have occurred in the past a coccidiostat can be included in the supplement or lick given to the goats at regular intervals (e g monthly for three to five days)
• As far as possible, avoid any conditions that will put kids under stress.
• Provide sufficient dry feed when kids are kept on succulent green pastures in order to ensure adequate intake of roughage.
• Supply additional nutrition during periods of stress such as weaning, after shearing.
• Ensure the kids do not defecate into the feed troughs
• Supplement vitamin E and selenium and other mineral deficiencies
• Vaccinate against clostridial disease and pasteurella. Ensure the kids’ immunity against other diseases.
• Monitor internal parasites closely.

 

Coccidiosis is a disease of young kids with the most common age to be affected is 4 weeks to 5 months. For more information on coccidiosis and acute coccidiosis in kids see our website http://www.angoras.co.za/page/coccidiosis

 

Regards

Dr Mackie Hobson