It is important to be aware that problems with injecting birds can occur if the teams performing the task are under any kind of time pressure. This has the effect of increasing the potential for missing birds, which in itself can cause subsequent problems. For example, if we take Egg Drop Syndrome, against which a layer flock is vaccinated only once in its entire lifetime (for example with Nobilis RT+IBmulti+ND+EDS - Intervet), a ‘miss rate’ of just five percent can have a significant and potentially devastating effect on flock performance following an EDS field challenge. Similarly, pullets that receive Salenvac T or Eryvac during the rearing period if, as a result of administrator error, do not receive a proper 'primer' and ‘booster’ dose the ensuing immunity will not be sufficient to cope with a field challenge during lay. The pressure for speedy vaccination should always be weighed against the potential loss resulting from careless work.

Penning-up and presenting birds

Injecting birds can be a stressful exercise. Penning-up, catching and handling must be done very carefully to avoid smothering injuries and to minimise lameness problems in the early laying period. Stressful penning-up jeopardises the birds’ welfare and can lead to smothering. To ensure proper flock welfare, farm managers should be present at vaccination or at least when penning-up, and at the start of vaccination. They should then return periodically. Administration of inactivated vaccines needs good teamwork, with catchers helping the vaccinators by presenting the birds gently, safely and in a good position for vaccination.

There are several methods for presenting birds for vaccination. Any method is acceptable as long as the birds’ welfare is not at risk and a full protective dose of vaccine is injected into the correct area of the bird. Holding too many birds in one hand is stressful for the birds (and for the catcher) and increases the risk of missing some of them or incorrectly vaccinating.

Injection sites and methods

The most frequently used sites for injection are the breast or leg muscles (intramuscular or i.m.injection). The breast muscle is a preferable site to the leg muscle for several reasons. Leg muscles are small, particularly when the first SalenvacT dose is given, when compared to breast muscles. Leg muscles also contain important blood vessels, nerves and tendons above the hock area, which can be easily damaged by a needle, resulting in transient or permanent lameness. If the needle is inserted into this part of the leg it can easily hit the bone, leading to local inflammation and lameness. It is thought that tenosynovitis/lameness problems of the early laying period are at least partly due to rough handling and poor leg injection technique. The size and the thickness of breast muscles offer a relatively safe area for i.m. vaccination. When injecting into breast muscle, the needle should be placed so as to deposit the vaccine in the thickest part of the muscle. If the needle is inserted too close to the end of the keel or too far to the side it may penetrate the abdominal wall and the vaccine will be deposited in the abdominal cavity. This can result in mortality, in the case of a liver puncture, or peritonitis. Conversely, if the needle is inserted into the breast muscles too near the collar bone or the crop then relatively big blood vessels can be damaged resulting in haemorrhages.

Do it gently!

Injecting inactivated vaccines into poultry or other birds does not require strength. A common problem is to use excessive force when inserting the needle into the leg or breast of a bird. This can be dangerous in the case of leg vaccination as the needle can easily hit the bone causing pain for the bird and damage the bone and the periosteum (tissue surrounding and nurturing the bones).

In this context, it is perhaps not surprising that many layers vaccinated into the leg sit and show general malaise after vaccination. Excessive pressure on the ribcage by pushing the gun too hard into the breast muscles should also be avoided as the needle can reach the heart or the liver causing fatal injuries.

Inactivated vaccines definitely have a significant role to play in the health management and salmonella control of today’s poultry flocks. They are extremely useful tools for use in the fight against infectious diseases. However, it is important to realise that their effect does not spread from bird to bird and a missed bird is missed forever! Proper administration is therefore the key for success.

Commercial pullets

1000 birds –> 1 litre x age in days (from 1-42 days of age)

Broiler breeders

1st vaccination 2 litres/1000 birds (1 day of age)

2nd vaccination 50 litres/1000 birds (8th week)

Seasonal effect must be taken into account for calculation of water consumption. It is critical to measure and use the right amount of water for day-of-age vaccination. If too much vaccine water is consumed (< 2 hours), probably not all birds will have taken their dose. If not enough vaccine water is consumed (> 3 hours), birds may not have taken their full dose while the vaccine remaining in the lines or drinkers has a reduction in its potency.

For first vaccination at one day-of-age, use water meter recordings for water intake on the first day for previous flocks in the same facilities and same season to accurately determine the correct quantity of water needed. For second and third vaccination, use water meter recordings for the previous day to accurately determine the correct quantity of water in each case.