PLEASE NOTE: If you do not have access to a printer and would like a copy of this leaflet , please send an S.A.E  marked Emtryl to: BASC, Marford Mill, Rossett, Wrexham, LL12 OHL

  Emtryl Products - Prohibition of use

Introduction:

The loss of Emtryl emphasises the need for management of gamebirds to be of the highest standard if outbreaks of disease are to be minimised.

Parasitic diseases caused by Hexamita and Trichomonas can kill or seriously incapacitate birds.By looking at conditions in the rearing and release pens that allow the parasites to thrive, we can suggest ways in which these parasitic diseases can be controlled.

Sources of disease:

Obviously the first priority is to try to prevent the parasites being present in the pens to infect the birds.The parasites are not present in newly hatched chicks so are carried to the birds from outside sources.Possible sources of disease include:

1. Sick birds already present on the farm.
2. Wild gamebirds present around the farm.
3. Parasites already present on the farm.
4. Rats, mice, flies, cats and dogs.(spreading disease on their feet etc.)
5. Other farms locally with significant numbers of birds.(particularly at the release pen stage)
6. Staff visiting other sites with game birds present.
7. Visitors (including advisors and Veterinary Surgeons) visiting the farm.

Reducing the effects of parasites present:

Even with strict biosecurity, it is often not possible to totally prevent disease organisms affecting birds.

The most significant difference between naturally reared and artificially reared birds is the stocking density.At higher stocking rates, when gut parasites are excreted, they are more likely to be picked up by another bird than at lower stocking densities and so numbers can multiply rapidly.

In the wild parasitic infections tend to be self-limiting as the birds develop some degree of immunity or tolerance.However, when infections are overwhelming or if a bird’s immune system is depressed then clinical disease due to parasites in the pens a number of strategies are necessary:

1. Avoid overcrowding of the birds in the pens.Reducing bird numbers can significantly reduce the level of parasites present.
2. Improve the immune status of the birds where possible.As stress reduces the effectiveness of the immune system then reducing stress in the birds will improve the immune status and reduce the level of parasitic infection.
3. Reduce the number of parasites present and reduce the birds contact with the parasites.

With so much variation in housing systems for rearing game birds it is difficult to set maximum acceptable stocking rates.However, if birds are to be reared without Emtryl then we may need to consider reducing stocking densities by up to 50% over current levels.Good management enhances the immune status of the birds.Good housing and heating are required to provide steady temperature control in the first few weeks.Also essential is a palatable water supply and high quality feed.Stresses that can adversely affect the bird’s ability to fight parasitic infections include rapid variations in housing temperature, problems with the water or food quality, other disease conditions such as bacterial enteritis and competition from other birds in the pen.

1. There are a number of ways of reducing Hexamita and Trichomonas numbers and of reducing the birds contact with parasites.
2. As already stated above, reduce the number of birds present in a pen and reduce the group size within which birds are reared.
3. Ensure that adult birds are not present on the rearing fields and in release pens, as they are a potential source of infection.
4. As disease is easily transferred on boots and hands ensure both are cleaned well between visiting different batches of birds.If hand wash facilities are not readily available, the use of bactericidal hand wipes is advised.
5. There are feed additives that can improve the immune status of the birds.These should only be regarded as an aid to preventing disease and should not be seen as an alternative to good management.No medication, however good, will prevent disease if the birds are either unacceptably overcrowded or are under excessive stress.
6. Reduce the birds direct contact with the highly contaminated areas around feeders and drinkers by placing feeders and drinkers off the ground on a weld mesh frame so that waste products are collected beneath out of contact with the birds.The frames need to be large enough to cover an area about nine times that of the feeder or drinker.
7. As parasites thrive in warm and damp conditions correct any leaking drinkers as a matter of urgency.Do not empty dirty drinking water onto the ground within the pens but ensure it is disposed of well away from the pens.
8. There are some disinfectant products that can be safely applied whilst the birds are present.These products can be useful in reducing parasite numbers.
9. It is important to remember that the presence of a small number of parasites will not necessarily result in disease. Disease may be prevented if the birds are in conditions that minimise stress, that do not give the parasites their ideal environment of damp and warmth for survival and which reduce the contact between the birds and the parasites.

Dealing with a disease outbreak:

If despite having taken every precaution to protect birds from Hexamitiasis and Trichomoniasis there is illness in the flock, make sure you immediately get a definitive diagnosis from your veterinary surgeon so that the correct treatment can be given. A number of other diseases give very similar clinical signs to those caused by Hexamita and Trichomonas. In rearing birds without Emtryl, a more holistic approach to treatment will be required. Treatment will need to support the birds by the use of appropriate medication, it will need to reduce parasite numbers in the environment to reduce the spread of the disease and will need to ensure that disease is not spread from one pen to another.

Richard T Byas B. Vet.Med, M.R.C.V.S.