Free-range table-birds being reared from slower growing breeds need a different vaccination regime from that of faster-growing broilers, when being immunised against Gumboro disease.
This previously-unknown fact has emerged from laboratory and field trials, involving several hundred thousand birds on farms throughout the UK, carried out by Lohmann Animal Health in conjunction with poultry vets.
"When using a ‘hot' vaccine conventional broilers in the UK are normally vaccinated at around 14-16 days when their maternal immunity is waning," said Adam Goddard, Lohmann's UK sales consult. "However, we've found this maternal immunity lasts longer in the slow-growing breeds which are reared both indoors and out."
Realistically, the correct day of vaccination for free-range table-birds is more likely to be achieved by using the vaccine date predictions for broiler-breeders, rather than that of the broiler, under the Deventer formula, which gives calculations for different types of bird.
He therefore advises producers to consult their vets who can take blood samples to get an accurate prediction regarding optimum timing of vaccination with their own particular flocks.
"Our trials have shown that, in general, and depending upon the breed used, the decline in maternal immunity is delayed - perhaps for 4-5 days. So, in order to get a better ‘take', we recommend vaccinating these birds later or using an IBD vaccine that ‘takes' in the presence of high maternal immunity." said Mr Goddard.
Gumboro disease - also known as Infectious Bursal Disease - can cause severe losses in chickens and outdoor-reared birds are more susceptible to the disease due to environmental influences.
Earlier this year Lohmann Animal Health launched a new ‘hot' vaccine, classified as an ‘intermediate plus' against the very virulent form of Gumboro disease. The company says that because of its ability to break through high levels of maternal antibodies, it allows vaccination to take place earlier than with other existing vaccines.
Lohmann Animal Health has launched AviPro IBD Xtreme vaccine against Infectious Bursal Disease — also known as Gumboro Disease — in broilers, commercial layers and breeders.
According to Lohmannn, it is highly effective against the vvIBDV (very virulent IBD virus), it breaks through high levels of maternal antibodies, and controls mortality with no loss of flock performance.
Since the 1980s the acute form of IBD has caused significant economic loss to the poultry industries in several countries. The vvIBDV, a more aggressive form first described in Europe in 1986, is now widespread throughout the world and can cause losses of 30-60 per cent in layers and 5-25 per cent in broilers.
Chicks are most susceptible between one and six weeks. Early in their lives they are protected by maternally-derived antibodies (MDAs), but these antibodies will neutralise live IBD vaccines when they are given too early. However, being highly invasive, the AviPro IBD Xtreme vaccine is able to overcome these MDAs so can be given earlier to provide greater protection from an early age.
Exact timing of vaccination depends primarily on the level of MDAs and the breakthrough titre of the vaccine on the one hand, and the virulence of the field virus and infection pressure on the other.
When compared with four of its main competitors in a trial with SPF birds AviPro IBD Xtreme outperformed them. It had the highest number of sero-positive birds, the highest mean ELISA-antibody titre seven days after vaccination and the best protection against clinical symptoms and mortality after a challenge with vvIBDV,” commented Brigitte Othmar, regulatory affairs manager at LAH.
“With the addition of AviPro IBD Xtreme, Lohmann Animal Health has now completed its range of live IBD vaccines and is able to provide its customers with the appropriate solution for any Gumboro problem,” she added.
AviPro IBD Xtreme can be applied via the drinking water or eye-drop and is presented in vials of 1,000 and 2,500 doses.
More information on this vaccine can be found on the Lohmann Animal Health website http://www.lah.de/.
AviPro Salmonella vac E, the live oral vaccine against Salmonella enteritidis made by Lohmann Animal Health, is now available in larger size vials of 5,000 doses, supplied in packs of ten. More information from: Anna-Christina Riebau, Lohmann Animal Health, Germany. Telephone: +49 (0) 4721 747 217