Piglet scours

Pathogenic (disease-causing) strains of E. coli are the most common cause in suckling and weaned pigs.

Dietary or nutritional scours may be caused by:

• changes in the quality, texture and quantity of feed
• toxic elements in either the feed or water (e.g. arsenic in excess or high levels of specific salts in the water)
• low iron levels after birth (complications with intestinal infections).

Bacterial scours (Escherichia coli (E. coli)) may be caused by:

• salmonellosis
• swine dysentery
• campylobacter infection (adenomatosis, necrotic ileitis, proliferative haemorrhagic enteropathy).

E. coli organisms normally live in the animal's gut and pass out in the dung of grower and adult pigs

Viral scours may be caused by:

• swine fever
• transmissible gastroenteritis (not present in Australia)
• rotavirus
• reovirus.

Parasitic scours may be caused by:

• high levels of internal parasites such as gastrointestinal (digestive) worms or coccidiosis.

Baby pig scours

• Piglets can appear healthy at birth with the sow supplying enough milk.
• Litter suddenly becomes affected between 12 and 96 hours of age.
• Some piglets may die while others show diarrhoea and listlessness.
• Scours appears light in colour, very liquid and foul-smelling.
• Septicaemia, toxaemia, rapid dehydration and loss of vital electrolytes cause death unless you treat the pigs quickly.
• Antibodies in colostrum (first form of milk) may protect the piglets for up to 36 hours, best absorbed within the first hours of life. Colostrum is rich in the sow's antibodies, developed by her exposure to the piggery's resident organisms.
• Colostrum protection may be inadequate because the:
  • sow lacks milk—sow has agalactia (failure to secrete milk) or sow dies
  • piglet is too weak to suckle (runts, stores of energy exhausted, prolonged birth process)
  • sow has lack of visible teats and has started to secrete colostrum several days before, causing low antibody levels at farrowing
  • sows, particularly the younger ones, were not adequately exposed to all strains of bacteria in the piggery
  • introduced animals lack antibodies to all strains of bacteria in the piggery
  • new strains of E. coli were introduced by outside pigs.
• Unhygienic farrowing pens may have too many bacteria for the piglet’s natural defences.
• Cold or wet environments may weaken the piglet.

Pre-weaning scours (2–3 weeks old)

• Often referred to as 'milk scours'.
• Causes severe setbacks but few deaths.
• E. coli are well established in the gut, but some factors allow the pathogenic (disease-causing) strains to multiply rapidly.
• Colostrum protection is very low by week 2. However, the milk continues to protect the gut lining with low levels of antibodies.
• Piglets’ (active) immunity is still immature.

Weaners (3–4 weeks old)

• Active immunity is immature, and passive immunity, acquired from colostrum, is very low.
• Contact may occur with new strains of bacteria.
• Solid food is an abrupt change compared to sows' milk which is easily digested. Gut enzymes and bacteria are not fully developed. When pigs gorge, bacteria multiply in undigested food causing pathogenic (disease-causing) strains to thrive.
• Chronic, post-weaning coliform (fermenting milk bacteria) scours commonly occurs in piglets housed in contaminated, cold pens.
• Ongoing overwhelming doses of E. coli and other bacteria cause scours.

Pigs

By 1 week of age, piglets may eat small amounts of solid food. The gut chemicals (acids, enzymes) and bacteria present at this age are more efficient at digesting milk than grains or animal proteins.

Up to 4 or 5 weeks of age, the digestive system is unable to handle large amounts of dry food. Undigested food in the lower gut allows potentially pathogenic strains of E. coli to multiply and spread.

Overproduction of milk by the sow may overload the piglets' intestines, predisposing to E. coli scours.

Piglets at weaning may suffer stress if they are:

• placed in new surroundings
• mixed with strangers
• separated from a heat source
• exposed to a new strain of E. coli chronic scours.

Water/electrolyte loss

• Water and electrolytes (salts) maintain physiological balance within the body.
• Dehydration prevents normal body function.

Poor nutrient absorption

• Body reserves may be used for energy instead of nutrients from food.
• Energy stores, in very young pigs, are easily used up causing death or coma.
• Body condition is lost, in chronic cases, and pigs may be so distressed they stop eating.

Septicaemia/toxaemia

• Toxins may be released into the bloodstream (septicaemia and toxaemia) due to the spread of rapidly multiplying bacteria.
• Sudden death without signs of scouring may follow.

Predisposes to other diseases

• Poor body condition may result in other organisms causing disease.
• Pneumonia may occur as a secondary complication in young pigs.

Intestinal damage

• Severe bouts may take the digestive track a while to repair the damage.
• Affected pigs may become 'poor doers' and scour at intervals afterwards.

Acute and sub-acute weaner scours

• Common—particularly in pigs weaned between 14 and 28 days of age. Pathogenic strains of E. coli are present in the gut at weaning, and multiply in favourable conditions.
• May occur 4–7 days after weaning:
  • sudden death
  • staggering
  • animals on their sides with limbs paddling
  • varying degrees of scouring
  • reduced growth rate
  • rough appearance.

• Bacteria build-up in the farrowing pen can overwhelm the young pig's defence system.
• Other diseases present may predispose young pigs to scours e.g. pneumonia, iron deficiency anaemia.
• When conditions are suitable for the pathogenic strains of bacteria to predominate, outbreaks of disease occur.

Preventing sucker scours

• Reduce bacteria in farrowing pens by cleaning, disinfecting and spelling after each litter is weaned (the all-in all-out system is ideal).
• Encourage immunity by:
  • controlling agalactia (failure to secret milk) in the herd
  • ensuring that piglets receive colostrum early in life, fostering them on another sow if necessary
  • mixing gilts with older sows or feeding them sow dung before mating and during late gestation to stimulate immunity to resident bacteria
  • restricting the number of animal introductions from outside piggeries
  • vaccinating sows with E. coli vaccine before farrowing.
• Reduce stress by:
  • providing a warm, dry creep area
  • reducing the sows feed intake temporarily by 30%, if scouring occurs at 2-3 weeks; the piglets will get less milk and therefore less burden on their gut.

Preventing weaning scours

• Offer the weaner diet fresh to suckling pigs each day from an early age (5-7 days). If piglets eat solid food too young, they can be predisposed to nutritional scours. However, if you change their diet at weaning, the impact will be less severe. This will also encourage good changes in digestive gut bacteria and enzyme secretion.
• Mix piglets of similar size at weaning where possible.
• Avoid weaning into large groups (10-15 pigs is ideal in a weaner pen but may not be practical in some sheds).
• Ensure a clean, dry, warm environment; ideally into pens which remain clean and dry.
• Restrict food intake, particularly around the 3-5 day mark when weaners may gorge. Offer small amounts of food a few times daily to greatly help. If you do restrict feeding, then adequate trough space is essential (up to 25kg liveweight, 150mm per pig).
• Feed simple weaner diets rather than high-nutrient diets, and use animal rather than vegetable protein.
• Weaning at an older age is recommended (30-35 days rather than 21-25 days) if scouring is a problem
• Ensure fresh water is always available. Weaner pens should have watering devices similar to those in the farrowing pen (so that piglets know how to use them).

• Ensure that piglets get colostrum within the first few hours of life.
• Use antidiarrhoeals (e.g. bentonite or kaolin clay) to protect the gut wall.
• Replace lost electrolytes and fluids by adding electrolytes to drinking water.
• Reduce bacteria in the gut with antibacterial agents (avoid drug abuse to prevent resistance developing).
• Discourage certain strains of bacteria from multiplying in the gut.
• Reduce severity at 2–3 weeks of age by temporarily restricting the sows feed intake by 30% for a limited time.
• Restrict feed for 12 hours to help scouring weaners.
• Move pigs to a clean pen if their pen is grossly contaminated. Aim at a high standard of hygiene.
• Provide a heat source, as warmth is beneficial. Keep the environment warm and dry. Aim to prevent it rather than cure.