Common deficiencies seen with water sanitation in the poultry industry

Despite the importance of effective sanitation of surface water in the Australian poultry industry, deficiencies can occur that may increase the risk of incursion of a disease such as AI. Given that effective sanitation of surface water is not achieved under all circumstances, poultry flocks in Australia may be exposed to surface water that has been ineffectively treated. Epidemiological links have been made between contaminated drinking water and a number of past HPAI outbreaks in Australia and overseas.

Some producers may not recognise the importance of water sanitation in their overall biosecurity program, or may lack the necessary combination of available technical skills and knowledge to ensure an effective surface water sanitation system in their poultry operation. Deficiencies which may be seen within the poultry industry include:

• no intention to sanitise surface water due to either
  
  • noncompliance due to various motivations
  • some organic farms wishing to avoid chemical use
  
  
• use of equipment, sanitisers and systems that fail to ensure the reliable and sustainable
  effective sanitation of water through any of the following
  
  • ineffective products
  • inadequate contact time
  • open storage systems
  • mixing of unsanitised rainwater or recycled water
  • incorrect dosing
  • no maintenance program
  • problematic equipment
  • inability to accommodate for changed demands in water quality
  • inadequate pretreatment
  
  
• insufficient monitoring through
  
  • absence of, or inadequate, testing programs
  • inability to test system operational status in real time (alarms)
  • inadequate frequency of monitoring
  • use of only microbiological testing
    
    
• intermittent use of sanitation systems due to
  
  • avoiding sanitation during vaccination or with young stock
  • modification of facilities
  • insufficient stocks of chemicals.
  
  

4.5.1 No sanitation of surface water

The failure to sanitise surface water is relatively uncommon in the Australian poultry industry.Vertically integrated companies are generally comprehensively audited and supply sanitisedwater to poultry. Industry- and company-based quality assurance programs and state regulatoryauthorities encourage water biosecurity in all poultry industry sectors.

Organic farming organisations state that there are no accreditation problems with using water chlorination, so water chlorination systems can be used on organic poultry farms. For those not wishing to use chlorine-based sanitisers, there are alternatives that can be considered and technical advice should be sought.

4.5.2 Use of equipment, sanitisers and systems that fail to ensure effective sanitation of water

New products for water sanitation should be carefully assessed. Products should claim effective water sanitation, rather than just improved bird performance, and should provide some data related to the inactivation of microbial contaminants.

Inadequate contact time may be observed when a one-tank system is used. When water demand is high in a one-tank system, water sanitised with chlorine is replenished with a significant amount of raw water, with the mix of treated and untreated water then leaving the storage tank before adequate contact time with the sanitiser. The direct injection of chlorine into the main water input line also results in inadequate contact time. In these situations chlorine dioxide may be a suitable alternative sanitiser.

A similar situation may arise when rain water or other catchment waters (including recycled water) gain entry to the storage tank without prior sanitation. While rain water carries a lower risk, roof surfaces frequented by wild birds, and in some cases ducks, can result in faecal contamination of this water. Similarly, open water tanks can be contaminated by free flying and roosting birds and possibly even by contaminated dust-laden aerosols.

Non-operational dosing systems can be caused by:

• air locks⁶ in dispensing lines (particularly during hot weather if dosing systems do not have an automatic bleeding system)
  
  
• broken and/or defective pump mechanisms
  
  
• corroded pump internals (medication pumps are often unsuitable for use with chlorine)
  
  
• fractured doser housings after frosts and other damage.
  
  
• Where there has been heavy rainfall with run-off into dams, the increased organic load demand
  can significantly impact on the level of effective sanitiser in the system. This is not an issue where
  there is automatic monitoring, as the dosing will increase automatically or an alarm will sound.

Water from creeks, dams and channels can be of poor standard, particularly during drought. It is often poorly aerated, its oxygen demand is high and, despite the addition of copious amounts of chlorine, its ability to inactivate pathogens is limited. This is where measuring ORP is a useful adjunct. Pretreatment of this water is often required.

Some producers use manual dosing with either liquid or solid chlorine but this approach is haphazard and unreliable, with resultant wide fluctuations in chlorine levels. While considered economical, this is a false economy as is does not consider the time taken and repeated labor required.

Underlying many of these dosing and system failures is the inability of the poultry farmer to identify or correct the mechanical failure. Compounding the problem, local plumbers often cannot be obtained at short notice and may lack both the understanding of precision pumps and/or the science of water sanitation.

4.5.3 Insufficient monitoring

Producers who are part of audited quality assurance programs are usually mandated to complete monitoring sheets to record water testing information. All producers should place priority on testing water frequently (i.e. daily to bi-weekly) and recording this information.

Some of the sanitisers, particularly the novel ones, have no readily available test for real-time farm testing, which is clearly a disadvantage. As previously indicated, testing for the primary chemical alone, particularly chlorine, may not give a true indication of sanitising efficacy, particularly where input water is poor. Farmers in this situation need to also test for pH and ORP.

Actual microbiological monitoring of drinking water within the poultry industry is not a common routine. When undertaken, the presence and quantification of total bacteria, coliforms and E. coli act as a marker of effective water sanitation. Sample collection, handling and delivery of the water sample to the testing laboratories can be problematic for producers, as there is a need to use sterile collection bottles and to get these to the testing laboratory within 24 hours and under chilled conditions.

4.5.4 Intermittent use of sanitation

Some farm managers turn the water sanitation system off during the administration of live vaccines, with the intention of not harming the vaccine. However, this approach opens up the possibility of contaminated water reaching birds. The correct procedure is to sanitise the water as usual and then run it into the medication tank, allow it stand overnight (or at least several hours) with skim milk powder and then add the vaccine in the normal manner. The use of medication pumps for vaccination complicates this matter of chlorinated water and vaccination because of the nature of the direct injection system. The authors of this document prefer medication tanks to dosators for vaccination and medication.

The practice of discontinuing sanitising water during facility upgrades and re-plumbing of the site opens up a risk window. On occasions farm managers find that they have depleted their stocks of sanitiser and are unable to replace this stock immediately. Again there is a period of risk until this sanitiser is replaced. To avoid the problem of depleted stocks monitor the stocks of sanitiser and usage rate and always have replacement sanitiser available.

It is necessary to sanitise water for birds of all ages, including young hatchlings.

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