Vaccines and water tackle major poultry diseases

Water is an important medium for the delivery of live vaccines, the majority of which have been developed to tackle viruses such as infectious bronchitis and Newcastle disease.

The survival of the living element of the vaccine is paramount and maintaining a high standard of water quality is fundamental, explains Michael Clark of the Minster Veterinary Practice, based at Sutton Bonington, near Nottingham.

Heavy metals in particular can kill off the live element, along with disinfectants and chlorine, he says.

“The advice from drug companies is to avoid adding disinfectants to water two days before, and two days after administering a live vaccine. This recommendation must be taken seriously, to allow the vaccine to work properly.”

Commercial water conditioning agents are useful, however.

“Ideally, a water conditioner should be added to the water before dosing. They will go some way towards reducing the effect of anything harmful that is present in the water and hasn’t been picked up by testing. These are highly effective in chelating chlorine and rendering it inactive.”

Most broilers will be given at least one live vaccine in drinking water throughout their lifetime, while layers may receive different live vaccines several times during the rearing stage, comments Mr Clark.

Detailed preparation is vital to the success of the medication being given, as vaccines differ in the length of time they remain active in drinking water. As a general rule, they will only be effective for two to six hours after mixing.

Many producers carry out the vaccination process in the morning, but it can be done at any time of day. The main requirement is to ensure that all the birds in the house are given an equal opportunity to take in the vaccine. Producers should have monitored their flocks, and calculated how much the birds will drink over a set time period.

“Commercially available water conditioners contain a dye, so the progress of the vaccine can be tracked through the drinking system. The water should then be drained, until the dye is clearly visible at the end of the lines. Having spent money on disease prevention, it is simply not worth cutting corners when it comes to administering the drug,” comments Mr Clark.

Another important factor is checking that the birds have received the right dose and that the drug has worked. Routine testing for antibodies to the disease should take place at least once for every crop of birds.

“If there is any doubt over whether the birds have been immunised, it is worth speaking to your vet, who will arrange for a representative from the drug company to carry out an audit.”