Water Medications and Beyond
16th July 2011
In our last article we looked at treating birds with antibiotics through the water, in particular we focused on how to calculate the dose rate and effectively deliver the necessary amount of treatment through different water systems. This time, we will look at what comes next. What protocols can be put into place to help prevent the recurrence of disease or the development of other problems as a consequence of antibiotic therapy.
The effective medication of laying birds through the drinking water depends on far more than simply getting the correct dose of treatment into water system and watching the birds drink themselves better! Apart from achieving the correct dose it is important to consider other factors, timing of treatment, interactions with other medications and ongoing support after treatment. Once the treatment has ended and the birds have returned to good health it is also important to consider the consequences of antibiotic therapy.
When electing to treat your flock with antibiotics there are a host of factors which the prescribing veterinarian and the producer must take into account. First and foremost, will the antibiotic in question treat the disease condition in your birds?
Not all antibiotics are the same; different active ingredients will have a different effect on different bacteria. This is not a question of developing resistance, but a more fundamental reflection of how individual antibiotics act upon different groups of bacteria. So, for example, a particular antibiotic may work well against E.coli but have no effect at all against Mycoplasma. With this in mind it is obviously very important to know what type of bacteria is responsible for the disease in your flock and the best way to find this out is to have your friendly vet conduct a post mortem examination and run bacterial cultures on the relevant diseased tissues. Such investigations are vital to ensure that antibiotics are used in a responsible way; to help prevent the development of resistance and to ensure that treatments remain cost effective.
Sometimes a post mortem examination will quickly offer your vet the information they need to make a diagnosis, and following bacteriological cultures and sensitivity testing a choice of an appropriate and effective antibiotic can be made. In these cases, it is hoped that the successful completion of the necessary course of treatment will rid your flock of disease. Unfortunately, some diseases of poultry will not just disappear, and whilst treatment may help to damp down clinical signs, or reduce transmission, the producer must remain very vigilant to any reoccurrences. On other occasions post mortem examination will identify an obvious sign of disease, ie enteritis or egg peritonitis, but the underlying cause of this disease is less clear. In these cases treatment may be aimed at resolving the symptoms whilst efforts are made to identify the underlying cause, whether infectious, management or environmental in origin, or as is more often the case, a combination of several factors. In either case following treatment it is prudent to submit further birds for post-mortem examination to monitor the response to treatment and to identify if and when further diagnostics or treatments are required. When an underlying cause of the disease has not been identified ongoing consultation with breed technical advisers, nutritionists and vets is essential to maintain productivity.
A proactive approach is essential following a course of antibiotics as ongoing interventions may make the difference between successful treatment, and failure. When considering gastro-intestinal diseases and enteritis, follow-up support through pro, or pre-biotics, changes in the ration or the administration of oregano extract products either through the feed or in the water can have a considerable effect on feed intake, helping to minimise bodyweight and evenness issues and helping to stabilise gut health. Multivitamin preparations can also be invaluable in promoting good bird immunity and minimising stressors which may result in recurrences of disease.
The term bacteria is rather non-specific. It refers to a domain of single celled organisms of incredible diversity. Bacteria are everywhere. Quite apart from the pesky critters which can cause disease in your birds, there are bacteria thriving in virtually every conceivable environment on earth, so called extremophiles have been discovered in sulphurous hot springs, the Great Salt Lake, and even in nuclear waste. Of the bacteria living happily on your poultry units many will be non-pathogenic, some will be true pathogens directly causing disease, some will be opportunistic pathogens taking advantage of existing diseased states or reduced immunity to contribute to disease processes, and some will be of benefit to your birds’ health as part of a healthy gut flora. The challenge for conscientious producers is to reduce the flock’s exposure to pathogenic or opportunistic bacteria, minimise stress to optimise immunity and address any diseases in the most effective and prompt way possible.
The nice warm, wet environment in your drinker lines is like a luxury spa resort for many bacteria and algae. As the bacteria grow and multiply they create a biofilm of dead cells and excreta which provides further protection for the bacteria making effective removal through chemical treatment of the water more and more difficult. High bacterial loads in the water lines can come from a contaminated water source (more commonly associated with borehole supplies which have not been chlorine treated), poor management of uncovered header tanks where high levels of bacteria or algae can grow, poor cleaning and disinfection of in-line dosing machines, illness in the birds resulting in reduced water intake and reduced water flow through the pipes, and even in water treatments with antibiotics, vitamins or minerals.
When drinking water is supplied from a borehole regular testing must be conducted to monitor the mineral levels in the water. High levels of manganese or iron may require additional filter to be fitted, or for filters to be replaced more regularly to keep the drinking water clean and the lines clear.
The antibiotics which are routinely used in laying flocks may contain other ingredients alongside the active antimicrobial. These additional ingredients may serve to make the product more palatable to the birds, more soluble in water, more bio-available, more stable or to have a longer shelf life. The addition of these chemicals is very important to make the product as user friendly and effective as possible, however any opportunistic bacteria living in your water lines may be able to use these chemicals as food. Also, any component of the antibiotic which does not dissolve perfectly will also adhere to the existing biofilm contributing to the sludge in the pipes and further narrowing the bore.
With this in mind it is important to consider whether any disease affecting your birds, and the consequential treatment has had a detrimental effect on your drinking water system by either allowing bugs to multiply up or through a contribution to the biofilm resulting in narrower pipes and a compromised flow of water.
There are several common approaches to sanitising the drinking water and consideration must be given to ensuring that the drinking water is appropriately sanitised after any course of treatment administered through the drinking water.
Acidification of the drinking water is a cost effective way of reducing the number of viable bacteria in the drinking water. Organic acid products are used which are buffered so that they maintain the drinking water within a tight pH range. These products are usually administered through an in-line doser and due to this buffering effect the pH remains similar in the concentrated stock solution and water lines where the acid has been diluted with water from the header tank. The recognised optimal pH when acidifying the water is 4. Dose rates will vary depending on other minerals in the water which will change with geographical location across the country. The best way to ensure that the necessary pH is being achieved in the drinking water is to test the drinking water with litmus paper. Acidification of the drinking water will kill many of the potentially pathogenic bacteria, for example E.coli in the water lines. It is also believed that acidified drinking water will also help to promote a healthy balance of bacteria in the intestines by preventing an overgrowth of potentially harmful bacteria. Acidification of the water has its limits however, as the acidic drinking water will not remove any of the biofilm present on the inside of the drinker pipes, nor will it kill bacteria which are hiding within the biofilm. Acidification of the water may also promote the growth of certain algae.
Hydrogen peroxide based products may also be used for routine water sanitisation. These hydrogen peroxide products are commonly used at a high concentration to clean the water lines at terminal disinfection and many of them have a recommended lower dose rate which can be used in the drinking water while the birds are housed. Unlike water acidification, hydrogen peroxide will kill bacteria and strip out biofilm on the inside of the pipes. Products of this kind need to be used with some caution. There is a narrower safety margin than with the buffered acids and inadvertent overdosing may have a toxic effect on the birds. It is also important to remember that these products will strip the biofilm from the inside of the pipes and if a significant biofilm has already developed the pipes need to be flushed into a bucket to prevent the dislodged bacteria laden gunk blocking nipple drinkers or being drunk by the birds. However when used regularly as part of a water sanitisation program, and used following courses of medication, these products will prevent the lines becoming blocked with biofilm and limit the build up of bacteria in the drinking water.
Chlorine dioxide water treatment systems offer continuous water sanitisation to the water. The cleaning systems must be physically plumbed into the poultry shed and work by combining two chemicals which react to create a potent cleaning and disinfection chemical, chlorine dioxide. As with Hydrogen peroxide these cleaners will actively strip biofilm however as they are physically plumbed into the house for continuous sanitisation they should prevent biofilm formation and maintain a good level of drinking water cleanliness. The benefits of such systems are continuous sanitisation which should prevent problems developing, and these benefits must be weighed up against the initial costs of having the equipment installed and ongoing chemical costs.
Whatever system you use for sanitising the drinking water it is important to have a protocol in place and to consider what additional sanitisation may be required following a course of treatment through the water. If in doubt, test! Drinking water can be easily and cheaply tested for bacterial contamination by submitting water samples to your vet for TVC testing.