There are several methods by which coccidia vaccines can be applied, but probably the most convenient, consistent, reliable and accurate way is via coarse spray in the hatchery. Spraying the vaccine directly on to the feed risks desiccating the oocysts and that is one of the few weak points of oocysts.
Other options such as via the drinking water are also suitable, but this is tedious and involves some risks, for example, in the case of long nipple drinker lines oocysts will be deposited at the bottom and can also be retained along the nipple mechanism.
In some countries the vaccine is applied by spray on the farm at the time the chicks are received. This method is also effective but it is time-consuming for the staff, there is inconsistency between farms, portable sprayers or backpacks are not as accurate as cabin sprayers and it can be counterproductive for the day old chicks if water and feed withdrawal are increased after an already long journey.
As shown in the title, oocyst distribution is the key factor for the success of spray vaccination in the hatchery. The first challenge that we face is maintaining a homogenous distribution of the oocysts in the suspension. Once the vaccine is diluted in the total amount of water that will be used for vaccination, the oocysts have to be kept evenly distributed in the vaccine solution. To achieve this nowadays, magnetic stirrers or aquarium oxygenation systems are used. As the vaccine solution is used and the volume decreases, if no adjustments are made to the speed of the magnet or the bubbling, the oocysts will be unevenly distributed in the solution and consequently the vaccine will not be applied evenly. Some boxes will receive high numbers of oocysts, while others will receive low numbers or, in extreme situations, no oocysts at all. Nowadays, technology allows us to control this critical point of the process with more precise stirring mechanisms such as the one used in HIPRASPRAY®. The vaccine container in HIPRASPRAY® has a volume level control and the stirrer mechanism adjusts itself automatically according to the level in the container.
A second challenge for a homogenous distribution of the oocysts is the time when the vaccine is actually sprayed. There are two main parameters that have to be controlled, droplet size and spray pattern.
Oocysts have to be ingested so a really coarse spray is needed, over 200 µm, preferably 250 µm, at the time of vaccination. To obtain such a large droplet size, the type of nozzle, the volume of vaccine solution and the pressure of the piston have to be considered.