Best practice for delivering poultry vaccines

Good practice is essential to get the most out of water delivered vaccines.

Administration of vaccine via drinking water is an ideal way to carry out mass vaccination of a variety of birds, including turkey poults, broilers or layer pullets.

However, getting it right is critical to achieving the desired outcome, warns Merial Animal Health avian manager Helen Houghton.

“Vaccines delivered through drinking water are live attenuated viruses or bacteria and, as such, they can be delicate,” she says. “They must reach the bird in good condition otherwise it will not have the effect of stimulating an immune response and providing protection against future field challenge.”

For broiler chickens probably the most important vaccine applied through drinking water is a Gumboro vaccine, such as Gallivac IBD. Layer birds receive a variety of vaccines during the rearing period including those providing salmonella protection, while many turkey flocks are also vaccinated against haemorrhagic enteritis virus (HEV).

“In theory, vaccination through drinking water provides a much simpler solution than, for instance, individual injections,” says Ms Houghton. “However, there are a number of steps which have to be carried out to ensure success. Good staff training, correct procedures and attention to detail are key.”

Water quality can vary considerably from one farm to another, and may even vary from one house to another – whether it is mains water or borehole. While the chlorine added to mains water is important to protect human health, it also kills the live viruses or bacteria in vaccines. Borehole water, on the other hand, can contain high metal ion content which is also detrimental to vaccines.

In the past, skimmed milk powder has been used as a stabiliser, designed to bind the chlorine and protect the vaccine. While this worked, it had drawbacks including clogging drinker lines and providing an ideal growing medium for bacteria.

Recently, water stabiliser products, such as Vac Pac Plus, have come on to the market that are designed to neutralise the effects of chlorine and minerals without the disadvantages of skimmed milk powders. The blue dye in the product enables farm managers to track the vaccine through the drinking lines, and even identify those birds that have drunk from the water containing the vaccine.

Water sanitising products are also routinely used on some farms to remove biofilm and help prevent its build-up in the drinking lines. If this is the case, they must be discontinued for at least 24 hours before drinking water vaccination, as they will damage the vaccine.

The lines should be primed before presenting the vaccinated water to the birds. This ensures that they only have access to the vaccinated water during the designated period – normally two to four hours depending on the vaccine being administered. This is a time-consuming process, but one that is necessary.

Lines should be raised and drained to remove all the non-vaccinated water and only lowered once the blue water with the vaccine can be seen coming through. Once this has been done the lines can be lowered to allow the birds to drink the vaccinated water over the appropriate period of time.

Following vaccination, flush out the dosing system with clean water.

Key points before vaccination

• Correct vaccine storage – between +2 and +8 °C
• Visually check the vials – if the vaccine appears discoloured, or moisture is present, then don’t use and seek veterinary advice
• Avoid exposure of vaccine to direct sunlight, heat, disinfectants, chlorine, detergents, and heavy metal ions
• Only use clean equipment – eg plastic measuring jug and buckets which are kept specifically for vaccination and are labelled
• Ensure no sanitising products are present in water system

Key Points when applying the vaccine

• Administer the vaccine over correct period of time as directed by manufacturer/veterinarian
• Calculate the volume of water the birds will consume in the allotted time
• Ensure dosing equipment being used is clean as it can harbour harmful residues
• Prepare vaccine stock solution using clean equipment in a clean area
• Only mix vaccine into water containing water stabiliser product
• Raise the drinker lines in house and dim lights to minimise stress on birds
• Prepare the stock solution
• Prime drinking system with vaccinated water
• Lower all lines to correct level once all are primed and return lights to correct intensity
• Observe birds drinking to ensure that all are satisfactory
• Walk through the house after one hour to encourage more bird activity at the drinkers