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Farm Practices to Reduce the Incidence of Clostridiums

by 5m Editor
10 October 2008, at 12:00am

By Edgar O. Oviedo-Rondón, DVM, PhD., Dip. ACPV, Assistant Professor and Extension Specialist at the Department of Poultry Science, North Carolina State University, and published in <em>North Carolina Poultry Industry Newsletter</em> in September 2008.

Clostridia are spore-forming bacteria that can be found anywhere. They are present in the soil, litter, feed, intestine and droppings of all animals, but they are more commonly isolated in large numbers in broiler houses from swabs of dirty walls, dirty fans, fly strips, dirt outside of the house entrance, and swabs of farm workers’ boots. They proliferate in carcasses of mortality left inside the house, and especially in sludge of bad compost with anaerobic conditions.

Some specific types of Clostridium involved in diseases that affect broilers are Clostridium perfringens and Clostridium septicum. It is the toxins produced by these bacteria, rather than the bacteria themselves, that cause the diseases. Necrotic enteritis and gangrenous dermatitis are the most common diseases caused by Clostridium in broilers. Necrotic enteritis and/or dysbacteriosis, which are intestinal diseases, can cause from flushing of the gut contents to the death of the broiler. Gangrenous dermatitis can cause from bloody lesions underneath the skin to the death of the broiler. Gangrenous dermatitis is also called gangrenous cellulitis, wing rot or red leg. These diseases are more prevalent in some farms than in others within the same broiler complex, indicating that farm management practices are important to control the disease. The initial step to establish a control strategy is to create understanding among people involved in the corrective actions.

It is important to remember that all animals including broilers are always in contact with Clostridium and other bacteria related to these diseases, such as E. coli and Staphylococcus aureus. Clostridia in low numbers are even normal inhabitants of all animal intestines. However, they can cause these diseases when the immune system of broilers is not working properly due to environmental stress like heat or cold, virus such as infectious bursal disease (IBD) or Marek’s, and mycotoxins in the feed. All these immunosuppressive factors should be avoided to control Clostridium. Review the vaccination programs and the immune status of the flock against IBD and Marek’s disease when trying to control Clostridium-related diseases. Cleaning and sanitation of feed bins and feed lines should be practised to reduce proliferation of mould in the feed. Feed quality and feed consumption should be watched carefully to detect possible contamination of mycotoxins and reported immediately to the technical Service personnel.

Any factor that changes the normal intestinal function of broilers may change the balance of microorganisms in their guts and increase the number of Clostridium and/or the production of their α-toxins. Coccidiosis is one of the most frequent causes of proliferation of Clostridium perfringens and contributor to the necrotic enteritis disease. Although, coccidiosis is normally controlled either by use of ionophores, other feed additives, or by vaccination, it is always important to monitor the efficacy of these control methods. It is important to maintain the litter dry and try to keep relative humidity between 50 and 60%. If the relative humidity is above 70% first thing in the morning, the minimum ventilation setting is probably too low and should be increased. Problems in coccidiosis control detected on time by monitoring can be corrected before they cause significant broiler performance loss.

In the same way, Clostridium and other pathogenic bacteria used to be controlled with some feed additives, but currently the use of these additives is less frequent in poultry feeds, and Clostridium-related diseases more recurrent. Feed and/or water withdrawl, and drastic changes in feed composition or on house temperatures also affect the physiology of the intestines. These failures in management should be avoided even more in farms where Clostridium-related diseases have been observed.

Gangrenous dermatitis incidence may also be increased when broilers have skin cuts and scratches. Avoid sudden loud noises, flashing lights, animals or people entering the house suddenly as these can cause flock hysteria and scratches. Use migration fences to avoid overcrowding in case of flock hysteria. Remove any protruding nails, wires or any sharp objects that can cause scratches. Watch the quality of the litter that you purchase to avoid sharp particles. Observe the normal feathering of your birds; if you detect any abnormalities in feathering, notify technical service personnel. The company could take corrective actions in these cases. Remember that high house temperatures during the second and/or third week of age of the flock may reduce feathering of some broilers.

The previous actions can be taken daily at the farm to prevent Clostridium-related problems. In case of detecting these diseases, there are some practices that have given positive results to reduce its dissemination in the present or future flocks.

For example, to reduce bacteria numbers in the litter, use higher levels of litter acidifiers such as alum, aluminium sulphate, or sodium sulphate than the doses used commonly to control ammonia. Similar effect has been observed with application of salt to the litter. Total clean out of the house is recommended after recurrent outbreaks of Clostridium-related diseases.

Iodine disinfectant can be used in the water to control Clostridium. The formula recommended by some veterinarians is 1 gallon of 1.75 per cent solution of iodine disinfectant mixed with 6 gallons of water to make a stock solution. The stock solution is then given to the birds at a rate of one ounce per gallon of water consumed. The solution is provided to birds every other day for three times. The administration of organic acid blends in drinking water also reduces the numbers of Clostridium and alleviates their negative effects during outbreaks of these diseases. Probiotics in feed or water have shown positive effects to exclude the proliferation of Clostridium in broiler intestines.

Finally, one of the more important aspects on farm management to reduce Clostridium-related diseases is to keep frequent collection of mortality, and in case of using composting for mortality disposal, keep adequate management of compost. Avoid recirculation of materials from the compost pit or bin to the houses through workers’ boots, buckets or other materials used to handle mortality.

In conclusion, learning the factors that favour Clostridium proliferation and increase broiler susceptibility to these bacteria and their toxins can help to create better control strategies.

October 2008