Top disinfectants for poultry farms

Group of free-range chicken freely grazing outside

A poultry house is one of the areas with the greatest disease risk. To keep diseases at bay, the units require constant attention which is mostly achieved through a robust hygiene programme involving cleaning and disinfection of the whole unit after cropping and before new flock arrival.

In selecting a good and effective disinfectant, it must be understood that the survival of avian pathogens outside the animal body varies considerably depending on the species, presence of organic matter and protection in cracks and crevices in the farmhouse. Here are the most common disinfectants in poultry farms.

Phenols and cresols

These are by far the most common disinfectants used in the poultry industry to date. Referred to as the 'black fluids', they are very effective against most bacteria and fungi micro-organisms. They are nonetheless poor in killing spores of many pathogens and not effective against viruses. In the presence of organic matter, their effectiveness can be reduced to 10 per cent. Their killing rate increases with rise in temperature of the water solution. Most farmers apply them in the foot baths at the entrance into the units.

Hydrogen peroxide

Hydrogen peroxide and other oxidising agents such as peracetic and propionic acids are becoming more preferred as disinfectants used at very low concentrations. They are good and effective in killing bacteria, spores, viruses and fungi. They are relatively cheap and safe to operators and the environment.

Chlorine

Chlorine is widely used for disinfecting water for human and animal consumption and cleansing equipment. They come as tablets or powder chlorine-releasing compounds containing 60-90 per cent available chlorine. Failure of chlorine disinfection is mostly caused by the presence of organic matter and at higher pH above 7.0. For water disinfection, the aim is to achieve a concentration of three to four parts of available chlorine per million.

Quaternary ammonium compounds (QAC)

These are available as aqueous solutions, powders or pastes. They are widely used against bacteria and moulds and are known to have residual effect hours after the first application. The disinfectants have low toxicity and lack odour or taste and when dissolved in water, they have powerful wetting property. They are mainly combined with such other disinfectants like Glutaraldehyde to give a wide spectrum activity against most poultry pathogens.

Formaldehyde gas

This type of disinfectant has been used widely as a terminal fumigant or aerosol vapour with ability to reach all areas like electrical installations and cracks and crevices. They kill most bacteria even in the presence of organic matter. It is produced by mixing two parts potassium permanganate and three parts of 40 per cent formalin liquid. Great care must be taken when mixing the two as they may explode. The gas can also be produced by heating solid paraformaldehyde on an electrical hot plate at rate of 1kg per 300 metre cube of a building. I have also used a mixture of formalin and water as an aerosol to fumigate buildings at the rate of 30-60ml of 40 per cent formalin with equivalent amount of water for a 6-10 m3 space. It is important that the operator has the right personal protective equipment and nose and eye masks. Formaldehyde is the best disinfectant but has lately been rejected because of its association with health problems to users.

Combined quaternary compound

This is a highly complex compound consisting of formaldehyde + glutaraldehyde + QAC, which is commonly used against stubborn viruses like Gumboro. This complex compound works at low temperature and widely used after encountering a contagious and infectious disease outbreak in your farm and you are preparing to restock.

[The writer is Head Vet at Kenchic]