Coccidiosis

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Aunt Sally

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Coccidiosis
« on: November 01, 2008, 20:04 »
We appear to have a captive vet on the forums - Welcome Will !

I've copied your posts here so that they dont get lost.

Quote from: "Will2"
Hi everyone,

Firstly an introduction, I am Will, the vet who saw TMG's Polands. I work at Castle Vets in Barnard Castle. I work with all farm animals and am particularly interested in poultry. I also keep an increasing number of broilers and laying hens myself and intend on starting to breed them next year.

I thought it might be useful to add some more information about coccidiosis in poultry to this discussion.

Coccidiosis is caused by an internal protozoal parasite of the intestinal tract. There are many different species of coccidia and each species of coccidia will only affect one species of animal, so a chicken coccidia will not infect a cow or a turkey or a duck or vice versa, although nearly all domestic species are affected by one species of coccidia or another.

There are nine species of coccicdia that can survive in chickens. Of these six (Eimeria tenella, E. necatrix, E. brunetti, E. acervulina, E. maxima and E. praecox) cause obvious disease, E. mivati causes only minor disease and E. hagani and E. mitis may be present but do not cause any harm to the chicken.

Each species of coccidia will live in a specific part of the intestine. In this case the worst affected part was the caeca. This indicates that the most likely species to be present was E. tenella. This is one of the most severe types of coccidia. With this species, one of the first symptoms is often sudden deaths in the flock. Other symptoms of coccidia include anorexia, depression, dullness, reduced weight gain, reduced egg production, diarrhoea and blood or mucous in the faeces.

An infected chicken will have been infected for a considerable time (weeks) before it starts to show any signs of disease. During this time it will be excreting large numbers of oocysts into the environment in its faeces. These can survive well in the environment and are a potential source of infection for other birds in the group, especially where faeces contaminate drinkers and / or feeders. Birds are infected by ingesting (eating) oocysts. For this reason, once one bird has been diagnosed with coccidiosis, it is important to treat the whole group.

Coccidiosis can be diagnosed  most easily by post mortem examination of a dead bird, but also by examination of the faeces for oocysts in a laboratory.

Treatment is usually by medication in the water. I usually opt for Baycox 2.5% solution as I have had alot of good results with this. However, once a bird has had coccidiosis, there may be long lasting gut damage, which may affect its productivity / growth for its entire life.

Prevention of coccidiosis relies upon the principle of ensuring that the resistance of the birds to infection is greater than the challenge they receive from their environment.

The resistance of the birds can be increased directly by using medicated feeds or by vaccination and indirectly by ensuring all management factors are well controlled and that the birds are otherwise in good health, as a bird that is ill with one disease will be more susceptible to other diseases.

The environmental challenge can be reduced by general good hygiene measures, however coccidia oocysts are very tough and are resistant to many disinfectants. However, they are very susceptible to extremes of hot and cold, so steam cleaning is a good way of getting rid of them, ammonia based disinfectants are a second best. Also, keeping groups seperate from each other and not introducing new birds will reduce the chances of introducing an infection to an established group.

I hope this is not too long and boring! and that it is of some help.

Will


Quote from: "Kate and her Ducks"
Will, if it's not too cheeky to take advantage of having a vet here, what is the resting heart rate of a duck? :D


Quote from: "too many girls"
can you elaborate on something Will? i know you explained it to me in the surgery, but i think the folk on here would like to know, i buy my feed from Tallentyre in butterknowle, having heard of coccidiosis from this forum i asked for medicated chick crumbs, Maurice gave me Farmgate, when Pootle first fell ill we researched poultry diseases on the internet, we did not look up coccodiosis believing they were protected from it, i do think that had we been aware they could still get it we would have brought them to you sooner, and maybe Pootle and Popcorn may not have died, i think many people (like me) assume if they feed medicated crumbs their birds are fully protected, can you explain why this isn't the case? thank you, Romney.


Quote from: "Will2"
Duck heart rate is not fully documented, unfortunately this is the case with a lot of poultry data (same for small furry animals) It will vary with breed, size and age. I would usually expect it to be in excess of 150bpm, but less than 200 and would hope to compare this to a similar individual in the same flock kept under the same management conditions, then I would view any differences along side any presenting clinical signs (cyanosis, lethargy etc.) heart disease is reported in most species of domestic birds, but treatment would be difficult.

Will


Quote from: "Kate and her Ducks"
Thanks. I was finding it difficult to find any information. I found an article on Eider ducks which seemed to have resting heart rates of 100-135 but no idea how they compare to domestic ducks.

My duck has sustained trauma during a fox attack and last night was going at about 200-220. has come down with fluids and rest to 160 so hoping we are going the right direction. Don't know how I would assess cyanosis as he's a Cayuga cross and therefore black


Quote from: "Will2"
Medicated chick crumbs contain a coccidistat, several are available. These aid in the prevention (NOT treatment) of coccidiosis. They prevent the replication of coccidia within the intestines. However, as I tried to explain in the essay above, the control of coccidia is a balancing act between the level of environment challenge and the resistance of the chicks to infection. The coccidiostat in the food is only one component of this protection. Imagine a traditional set of scales with the chicks resistance on one side and environmental challenge on the other side, on the side of the chicks resistance there are many factors, such as the natural barrier to infection provided by the lining of the intestines, the chicks own immune system, and in this case, the coccidiostats in the food. On the other side of the scales is the size of the environmental challenge, so, regardless of any medication, it is always possible to see any disease in the chicks if the environmental challenge is large enough. Also, some coccidiostats will reduce the exposure of the chicks immune system to the coccidia, which will reduce the development of the chicks own immunity. In a commercial setting, coccidiostats are sometimes used in pulses (eg one week on, one week off) to allow the chicks immune system a controlled amount of exposure to the coccidia, and therefore a natural immunity to develop, however this can be really complicated to impliment, so I would not advise it without specialist advise on an individual flock basis.

I hope this explains the problem.

Will
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