Background and history

"Colitis" means inflammation of the large bowel. It is common in some countries in growing pigs and is characterised by diarrhoea. It is uncommon in home milled cereal based diets.

Affected pigs are usually 6 to 14 weeks of age and in any one group, up to 50 percent may be affected. It is not seen in adult or sucking pigs. Colitis may be seen in individual sows. A number of organisms have been implicated but spirochetes and in particular Brachyspira pilosicoli, an organism distinct from the one that causes swine dysentery, is thought to be important.

Colitis may also be associated with E.coli, coccidiosis, clostridium perfringens type A, Brachyspira hyodysenteriae, Brachyspira pilosicoli and salmonella infections.

Dietary factors also precipitate disease and pelleted feed is much more likely to be associated with the disease than meal. If the incriminating pellets are ground back to meal colitis still results, demonstrating an effect of the pelleting process. Certain components in the feed are also implicated including poor quality oils and carbohydrates: specific ones have not been identified but may include anti-trypsin factors and oligosaccarides.

Clinical signs

Usually appear in rapidly growing pigs from 6 to 14 weeks old fed ad lib on high density diets.

The early signs:

• Sloppy "cow pat" type faeces, with no blood and little if any mucus.
• Pigs appearing otherwise normal but lose bloom and growth.

As the disease and its severity progress:

• Watery diarrhoea.
• Dehydration.
• Loss of condition.
• Poor growth.

During the affected period:

• Daily gain and food conversion can be severely affected, with feed conversion worsening by up to 0.2.
• Mortality is low but morbidity can be high, ranging from 5 to 50 percent.

Diagnosis

This is based on clinical signs and the elimination of other causes of diarrhoea, in particular swine dysentery. Faecal examinations in the laboratory are necessary to assist with diagnosis together with post-mortem examinations and laboratory tests on a typical untreated pig. It is possible that porcine enteropathy may be involved.

If the herd has a severe problem examination of the terminal parts of the small intestine in pigs at slaughter would be advised together with polymerase chain reaction (PCR) tests on faeces.

Causes

• Dietary factors.
  • Disease is experienced using all types of diets but particularly those that have been pelleted rather than fed as a meal.
• Certain components in the feed may also be implicated, such as high levels of wheat.
• It is more common with diets high in energy and protein (14.5MJ DE/kg 21 percent protein).
• It is common when fat sprayed diets are fed.
• The same diet can be used on two separate farms and disease only appear on one, suggesting inherent causes.
• Continual production predisposes.
  

Prevention

• Try avoiding fat sprayed diets.
• Adopt all-in all-out management of pens.
• Use preventive medication in feed to control Brachyspira pilosicoli.
• Consider feeding home-milled cereal based diets. The following anti-colitis diet fed as a meal has been effective:
  • Wheat – 50%
  • Barley – 11%
  • Full fat soya – 15%
  • Fish meal – 7.5%
  • Hypro soya – 6.5%
  • Sharps (wheat by-product) – 5%
  • Skim milk – 2.5%
  • Vitamin lysine mineral supplement – 2.5%
  • Analysis – Protein 24%, digestible energy (DE) 14.6%, Lysine 1.35%.

Treatment

• Antibiotic therapy is not always successful because it depends on the presence of primary or secondary bacteria, but the following medicines have given responses on problem farms, using in-feed medication:
  • Dimetridazole – 200g/tonne
  • Lincomycin – 110g/tonne
  • Monensin – 100g/ tonne
  • Oxytetracycline – 400g/tonne
  • Salinomycin – 60g/tonne
  • Tiamulin – 100g/tonne
  • Tylosin – 100g/tonne
  • Valnemulin – 25–75g/tonne