At the Pig and Poultry Fair a producer came to the Zoetis stand to ask me “Can you develop a vaccine that you could give to the sow, that would protect her entire litter all the way until slaughter?”; I really wish the answer to this question could have been yes, but unfortunately it is unlikely.
How do sow vaccinations protect the litter?
The basic function of colostrum is to provide energy and protection against disease. The disease protection is provided by antibodies.
An antibody is a little protein which circulates in the blood. Its job is to bind to foreign invaders e.g. bacteria or virus, to neutralise them so they cannot cause disease. Most of these antibodies are specific at what they can bind to e.g. an antibody against PRRS won’t be able to bind to a flu virus.
We can influence what type of antibodies a sow passes onto her piglets by vaccinating her around the time she is making colostrum. For example we can give her a vaccine against Clostridium three weeks before farrowing, she will react to the vaccine and create high levels of Clostridium antibodies in her blood and these antibodies will then pass into the colostrum. If the colostrum is consumed within the first 6 hours of life the piglets will absorb the antibodies into their own blood stream and they should be protected from Clostridium related disease.
So why doesn’t this protect piglets for life?
Well unfortunately these maternally derived antibodies (MDA) start to degrade after a certain amount of time. The confusing thing is that each type of antibody, for each disease, degrades at a different rate. This is one of the reasons why certain piglet vaccines can be given early and some must be given when the animal is older: If the piglet is given a vaccine when it still has a high level of MDA against the same disease, then the maternal antibodies will neutralise the contents of the vaccine before the piglet can make its own immune response. So it will not create its own antibodies, meaning when the MDA degrades the piglet will have no specific protection against the disease.
The good news is that vaccine technologies are progressing all the time which are able to negate or overcome MDA, allowing the piglet to make its own immune response and providing earlier protection against disease. An example of this is Suvaxyn® PRRS MLV, the first PRRS vaccination which can be given from one day of age as it has been proven to stimulate immunity in the piglet despite the presence of PRRS MDA.
Vaccines are undoubtedly the future in disease control, so to that producer at the pig fair – we will keep developing products that make your life easier and are better at preventing disease, but I think a sow vaccine that protects her piglets for life might be a little ambitious at the moment!
Suvaxyn® PRRS MLV contains modified live porcine reproductive and respiratory syndrome (PRRS) virus, strain 96V198. For the active immunisation of clinically healthy pigs from 1 day of age in a PRRS virus contaminated environment, to reduce viraemia and nasal shedding caused by infection with European strains of PRRS virus (genotype 1). POM-V. For information about side effects, precautions, warnings and contra-indications, please refer to the product packaging and package leaflet.
For further information please contact Zoetis UK Limited, Walton Oaks, Dorking Road, Tadworth, Surrey KT20 7NS. www.zoetis.co.uk Customer Support: 0845 300 8034. Use medicines responsibly (www.noah.co.uk/responsible). Date of preparation: May 2018. AH346/18