Wasting illness, cold & damp = pneumonia…
Wasting illness, cold & damp = pneumonia…
By Richard Allison
THE continuing spread of pig wasting diseases and cold damp weather will lead to more cases of pneumonia on many pig units this autumn.
Post-weaning multi-systemic wasting syndrome – PMWS – is increasing the prevalence of many different respiratory diseases, according to Oxfordshire-based pig vet Richard Potter. "PMWS appears to be driving up the number of cases of all common respiratory diseases."
About 30-50% of pigs diagnosed with the wasting disease have pneumonia, adds Stan Done of the Vet Lab Agency, Weybridge. "This is a major concern as there are no effective measures for controlling the wasting disease."
Norfolk-based pig producer Philip Richardsons stock were largely free of viral pneumonia and other lung complaints prior to contracting PMWS. However, since the wasting disease appeared on the unit in February, cases have escalated.
Initially, various combinations of antibiotics were used to control pneumonia and all young stock were vaccinated, which doubled vet costs.
The results of 64 post mortems at Mr Richardsons unit show the extent of respiratory infections following PMWS. More than 70% of pigs had fluid in the chest, were coughing and had difficulty breathing, he explains.
It is difficult to determine exactly how respiratory diseases and PMWS are connected, says VLA Bury St Edmunds Graham Jackson. "Many units which successfully avoided respiratory problems now find they cannot."
Mr Potter believes producers with PMWS need to be more aware of respiratory diseases and how to manage them, as pigs have little resistance to them. "Both stocking and ventilation rates are the key factors, get these wrong and losses will be higher."
Check ventilation fans are working adequately to maintain the balance between temperature and ventilation rate, he advises. Over the summer, windows will have been left open and autumn is the first time fans will have been fully tested.
Respiratory diseases are more common in autumn and spring, due to the wider ranges in temperature. It can be 18C during the day yet fall to 4C at night, explains Mr Potter.
"Another important measure is to ensure pigs purchased for finishing are from a herd with a compatible health status. Discuss with the producer supplying pigs and his vet to assess their background health status."
Vaccines for enzootic pneumonia are the norm with up to 80% of pigs vaccinated, says Mr Potter. "The payback is about 4:1 or greater, resulting in huge savings for producers."
The level of pneumonia on pig units has dramatically fallen over recent years, says Cheshire-based pig vet Des Leonard. "It is now at a point where outdoor herds are being targeted in vaccination programmes before growers are brought indoors. Previously, many producers have been put off catching piglets outdoors at weeks one and three."
However, overcrowding of units earlier this year, due to foot-and-mouth movement restrictions, led to many extra cases of enzootic pneumonia. Levels are only just returning back to normal with many outdoor herds having to be vaccinated.
"Another development is the increasing prevalence of Glassers disease, particularly in minimal disease units. The reason for increasing cases is unknown, as glassers disease has always been around."
Fortunately, there is a combined vaccine for enzootic pneumonia and Glassers disease, which appears to give effective protection, says Mr Leonard.
Vaccination for Glassers disease also reduced pig mortality from PMWS on one unit, says Mr Harvey. "The reduction in mortality was startling, but further investigations are required to confirm this as was observed on one farm."
There have been suggestions that vaccinating pigs can trigger PMWS. But Mr Potter believes it is better to control pneumonia by vaccinating and accept this risk instead of having no protection against pneumonia. *
PIG RESPIRATORY DISEASES
• Related to wasting diseases.
Check for adequate ventilation.
Vaccination effective.
About 30-50%of pigs diagnosed with wasting diseases will also suffer pneumonia, says VLAWeybridges Stan Done.
RESPIRATORY DISEASES
• Related to wasting diseases.
• Check for adequate ventilation.
• Vaccination effective.