Coccidiosis In Angora Goat Kids

 

Released: 1 April 2014

Coccidiosis in Angora goat kids

Coccidiosis is one of the most important diseases affecting Angora goat kids and outbreaks can lead to severe losses. Apart from the high mortality that can be caused by coccidiosis, affected kids that do not die, suffer a serious setback, which usually results in stunted growth and also lowers their resistance to other diseases.

At what age is coccidiosis first seen?

Coccidiosis is a disease of young kids with the most common age to be affected is 4 weeks to 5 months.

Nursing kids appear more at risk of acute severe coccidiosis. Occasionally, kids as young as 2 weeks may be affected. Older animals can also be affected if not previously exposed as kids. However, if older animals appear to be suffering from chronic coccidiosis, it may be the lasting effects from an infection from when they were younger.

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. The incidence of the disease is greatly reduced under cold conditions such as when frost occurs.

How is the damage done?

What makes  a Coccidia species more pathogenic is if it infects both the small and large intestine. The small intestine has an amazing ability to recover from damage but not so the large intestine. If only the small intestine is affected, the goat suffers much less.

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, or some times of the year 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.

Stress is the predisposing factor in kids during the post weaning period. Animals may die suddenly during this phase and without any warning. It is easier to consider the factors in three categories:

(i)                  The Parasite

  • What species of coccidia are present and how pathogenic are they?
  • How many oocysts are present in the environment and where are the oocysts?
  •  Are they contaminating places that allow for easier transmission to the kids?

(ii)                The kid

  • How immune is the kid? Younger animals are more susceptible. Are the kids ill with another disease that could weaken their immune systems ( e.g. brown stomach worm, wireworm or orf?)
  •  Have they been stressed by changes in the diet or a poor diet?
  • Have the kids been moved?
  • Have groups been mixed (e.g. younger moved in with older). Has there been  competition at the feeders?
  •  Have they recently been weaned? Although coccidiosis can occur year around, a higher incidence occurs post weaning.

(iii)               The environment

  • Are the conditions crowded? High stocking densities, build-up over the kidding period– all increase the load of oocysts in the environment and thus increase the risk of disease developing.
  •  Bad weather or sudden changes in the weather? (cold , heat, high humidity)
  • Time to sporulation depends on moisture, oxygen (e.g. exposed to the air rather than buried in the bedding pack) and temperature.
  •  Exposure to sunlight will assist killing of the oocysts

How to reduce the predisposing factors?

  • As far as possible, avoid any conditions that will put kids under stress.
  • When kids must be housed in sheds during cold conditions, enough high-energy nutrition must be provided.
  • Provide sufficient dry feed when kids are kept on succulent green pastures in order to ensure adequate intake of roughage.
  • Supply energy supplements from weaning until at least - two months thereafter
  • Supply energy supplements from shearing until at least one month thereafter.
  • 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.
  • If there have been major coccidial parasite problems before the ewes may be given cocciodostats in their feed to reduce the peri-parturient rise in oocyste numbers.
  • Where conditions are favourable for coccidiosis (cultivated pastures, kraal systems coccidiostats can be included in feed.

Clinical signs

The intensity of clinical signs of disease depends on how many intestinal cells are damaged by invading organisms, the susceptibility of the animal, and the body condition.

Acute severe coccidiosis

 Signs may appear fairly suddenly and a kid may be only mildly ill the day before, may be very sick the next day.

  • Diarrhoea is an important feature and may be watery and brown or may have blood in the stool (black and tarry and / or red streaks of fresh appearing blood).
  • The kids may be dehydrated
  • Pale mucous membranes (anaemic).
  • They will invariably be depressed but fever is not always present.
  • Weakness
  •  Some animals may strain from the inflammation of the lower large intestine and pass only watery blood.
  • They sometimes grind their teeth in discomfort
  • They may appear to have stiff hindquarters 

Chronic coccidiosis

Chronic means that the disease affects animals for a long period of time.

The kids may have had acute severe coccidiosis earlier or may not ever have been noticed ill.

  • The kids will be in poor condition and will be growing slowly.
  • The kids are thin, pot-bellied and small – although their heads may continue to grow giving them a runty appearance.
  • The hind end may be dirty due to the soft stools and intermittent diarrhoea.

Kids with chronic coccidiosis may never fully recover from the effects of the disease.

Post Mortem Findings

The inner layer of the intestine may reveal haemorrhaging or ulcerations in the intestinal wall.

The mesenteric lymph nodes (lymph nodes draining the intestinal tract) are enlarged. In chronic cases weight loss, dehydration, diarrhoea  and signs of maldigestion and hypo-proteineamia (oedema resulting in fluid in abdominal cavity ‘swelpens’ or in subcutaneous tissue ‘swelsiekte’.

In acute cases blood in faeces may occur.

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.

A low FOC does not rule out coccidiosis. As mentioned before, acute disease may be present before the pre-patent period is reached – so the FOC may be very low.

Preventative Treatment

  1. 1.       Reduce the predisposing factors (see above).
  1. 2.       Drugs to control the level of coccidiosis

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. To do that, usually the drug needs to be available from birth to 3 - 4 months of age, usually delivered in palatable creep feed.

 Coccidiosis commonly occurs just after weaning.  As a preventative measure a coccidiostat can be included in a balanced ration for a period of two to four weeks after weaning.  It can be followed by the regular inclusion of the coccidiostats approximately every three weeks for a period of three to five days.

 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.

 Coccidiostats suppresses the full development of the life cycle of the Coccidia and allows immunity to develop.

  1. Lasalocid (Tauratec  premix- Pfizer) as a feed additive - Ionophore

It kills the “free living”(sporozoites) stages of the coccidia as they move from cell to cell in the intestine and so may help control disease after the animal is infected.  To be effective a kids needs to eat 1 mg lasalocid /kg body weight per day. Tauratec dosage advise is 0.1-0.4 per anomal per day. Under-dosing is a big problem in animals that are nursing as they may not be eating enough creep to get that dose level. To determine if they are getting enough, weigh feed consumed daily, weigh the animals and calculate what they are eating.  Too high of a dose may be toxic to goats but fortunately lasalocid is the least toxic of the ionophores.

  1. b.      Monensin  (Rumensin 200)- Ionophore

Monensin is more toxic than lasalocid. 11-22g per ton feed. 11.9 mg/kg bw/day (only slightly more than10 times the therapeutic dose will kill 50% of the kids) . Kids must be introduced to a ration slowly over 2-3 weeks to acclimatise the rumen organisms.

  1. Decoquinate  (Deccox 6%, Pfizer)

The therapeutic dose is 0.5 mg/kg bw daily for sheep and goats although there is strong evidence that 1 mg/kg body weight is much more effective in those species. It is not toxic but is much more expensive than lasalocid or monensin. Decoquinate works very early in the life cycle, killing only the sporozoites as they first infect the kid or lamb, and so is not effective in animals that already have disease. Because it is so effective early in the cycle, for the kid or lamb to develop immunity, it should be treated for a minimum of 3 cycles (e.g. 70 days) and perhaps longer. Decoquinate is non-toxic, it is less dangerous to error on the high side to make sure they receive enough. As with the ionophores, it is difficult to get nursing kids and lambs to eat enough decoquinate in the feed to be effective, particularly when they are very young and very susceptible to coccidiosis. This is because the milk intake as a portion of their body weight is high so feed intake tends to be low.

833g/ton feed (target 0.5mg/kg body weight a day) 

Treating kids

  1. Totrazuril  (Baycox 5% Bayer Animal Health)

Very safe and has high tissue levels for longer periods than Diclazuril (Vecoxan). Do not use in pregnant goats

Dose 0.4ml/kg. There is some evidence in the literature that goats may require a higher dose 0.6ml/kg . Totrazuril kills coccidia in the intracellular stages. All the rest of the coccidiostat drugs only kill the “free-living” stages as they swim to the next cell to infect, but totrazuril kills the coccidia in the cell. This means that they effectively wipe out any infection in the animal when they are treated. Additionally, there is persistency of the drug reducing the need for retreatment.

 It is more suited for pasture-based systems when creep feeding is not used. But there are several factors that must be considered before deciding that this is the method to control coccidiosis.

  • You must drench individual kids – and all must be treated. Even leaving one untreated   lamb or kid can re-infect the remaining animals.
  • If you have had coccidia problems before and want to treat prophylactically prior to the first time you usually see coccidiosis in your kids which on most farms is 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 system, excellent records
  • You must continue to monitor the animals for signs of coccidiosis. In situations where there is still a large environmental load of oocysts, it sometimes is necessary to retreat in 3 to 4 weeks. 
  1. Diclazuril  (Vecoxan- Alanco)

 Dose 2ml/5kg which is repeated after 5 days if diarrhoea continues. Like toltrazuril (Baycox), it works against theintracellular forms of coccidia.  Commonly used at about 6-8 weeks of age, or two administrations beginning at 3 to 4 weeks of age and the second about 3 weeks later. Like toltrazuril, you need to give early in disease to prevent damage. Unlike toltrazuri (baycox)l, it is not persistent.

  1. 3.       Sulfonamides

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

  • Sulphazine 33
  • Sulphamezathine 16%,
  •  Norotrim 24
  •  Amphoprim

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 coccidian. 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.
  • Where creep feeding is provided for kids, a coccidiostat (example an ionophore such as Lasalocid) can be included every two to three weeks for a period of three to five days. This procedure does not, however, do away with the necessity of giving affected kids specific treatment.
  • 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.
  • On 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).

Dr Mackie Hobson

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