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
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June 30, 2009, 20:14