Target species
Chickens (from 7 days old)
Indications for use
For active immunisation of susceptible chickens against Infectious Bursal Disease (IBD/Gumboro).
The vaccine reduces clinical signs of IBD and severe bursal lesions.
Onset of immunity: 14 days
Duration of immunity demonstrated by challenge 28 days, antibodies may last up to 15 weeks.
Contra-indications
Do not vaccinate unhealthy birds
Special warnings for each target species
None
Special precautions for use
i) Special precautions for use in animals
The vaccine may spread to unvaccinated chickens, since it is excreted via the faeces for at least 9 days. Avoid spreading to laying hens.
To reduce infection pressure before the onset of immunity, litter should be removed and chicken housing cleaned between rearing cycles.
Ensure that the drinking water is cold, clean, and free from detergents and disinfectants to ensure the viability of the vaccine.
ii) Special precautions to be taken by the person administering the veterinary medicinal product to animals
Live attenuated viral vaccine, do not spray or spill.Wash and disinfect hands and equipment after vaccinating.
Adverse reactions
On day 7 post vaccination moderate generalised lymphocyte depletion is seen in the majority of birds. Lymphocyte repopulation occurs after day 7 post vaccination and by day 28 post vaccination only mild necrosis remains in some birds.
Use during pregnancy, lactation or lay
Not to be used for birds in lay.
Interactions
No information is available on the safety and efficacy from the concurrent use of this vaccine with any other. It is therefore recommended that no other vaccines should be administered within 14 days before of after vaccination with the product.
Amounts to be administered and administration route
One dose (min. 10³ EID50) should be administered per animal by drinking water from the age of 7 days onwards.
The determination of the vaccination date is dependant on a number of factors including status of maternal antibodies, type of bird, infection pressure, housing and management conditions. Maternally derived antibodies (MDA) potentially interfere with the take of live IBD vaccines. The optimum age for vaccination therefore depends on both, the level of MDA against IBD in the flock and the capability of the vaccine to take in face of these MDA (“break-through-titre”). A high homogenicity of the flock MDA levels is important to define the timing of vaccination and guarantees the better take of the vaccine. To predict the age, when MDA have sufficiently decreased to allow effective vaccination it is advised, to test serum samples of at least 24 chicks by serology and apply the “Deventer Formula” for intermediate vaccines. For chicks from fully vaccinated or field virus infected breeders this may be at 14 days or more. Serologically negative birds may be vaccinated from day 7.
A further vaccination 7 days after the first may be necessary particularly in flocks where antibody levels vary widely between birds (i.e. CV greater than 30%), or stock originates from different sources.
Broilers:
with no maternal antibodies – from 7 days of age
with maternal antibodies – from 14 days of age
Layers/Breeders:
with no maternal antibodies – from 7 days of age
with maternal antibodies – from 3 - 4 weeks of age
Dosage and administration:
Drinking water application:
-Determine the number of vaccine doses and amount of water (see below) required. Do not split large vials to vaccinate more than 1 house or drinking system, as this may lead to mixing errors.
-Make sure that all conduit pipes, tubing, troughs, drinkers etc are thoroughly clean and free of any trace of disinfectants, detergents etc.
-Ensure that the drinking water is cold, clean, and free from detergents and disinfectants to ensure the viability of the vaccine. Use only fresh water preferably non-chlorinated and free from metal-ions. Low-fat skimmed milk powder (i.e. < 1 % fat) may be added to the water (2 – 4 grams per litre) or skimmed milk (20 – 40 ml per litre of water) to improve the water quality and to increase the stability of the virus. This however, has to be done 10 minutes prior to reconstitution of the vaccine.
-Open the vaccine ampoule under water and reconstitute contents thoroughly. Care should be taken to empty the ampoule and its top completely by rinsing them in water.
-Allow water to be consumed so that levels in drinkers are minimal before vaccine is applied. All tubing should be emptied of plain water, so that the drinkers contain only vaccine water. If water is still present, drain lines before applying vaccine.
-Apply vaccine over (up to) 2 hours, ensuring that all birds drink during this time. Birds drinking behaviour varies, it may be necessary to withhold water on some sites prior to vaccination in order to ensure that all birds drink during the vaccination period.
-The aim is to give every bird one dose of vaccine.
-Ideally vaccine should be administered in the volume of water consumed by the birds in up to 2 hours. As a general rule, apply reconstituted vaccine to cold and fresh water at the rate of 1,000 doses of vaccine to 1 litre of water per day of age for 1,000 chickens, e.g. 10 litres would be needed for 1,000, 10 day old chickens. Under hot climates or with heavy breeds this amount may have to be increased up to a maximum of 40 litres per 1000 birds. If in doubt, measure water intake the day before administering vaccine.
-Administer the reconstituted vaccine to birds immediately. Make sure that birds do not have access to unmedicated water during vaccination.
-The reconstituted vaccine should be protected from direct sunlight and temperatures above 25°C!
-The contents of opened bottles should be used all at once.
-Only the volume of vaccine should be prepared which can be applied within 2 hours.
Overdose
Overdosage is riskless, an insufficient vaccination, however, might lead to an inadequate immunisation.
On day 7 post vaccination moderate to severe generalised lymphocyte depletion is seen in the majority of birds. Lymphocyte repopulation occurs after day 7 post vaccination and by day 28 post vaccination only mild necrosis remains in some birds.
Withdrawal periods
Zero days.