Should I Give My Pigs Probiotics?

By Dr Duncan Houston

Probiotics can have a useful place in pig nutrition, particularly around weaning. But whether you keep a commercial herd, a few smallholding pigs or a miniature pet pig, there should be a clear reason for adding one.

Age, diet, health and the exact product all affect the decision. A supplement studied in newly weaned piglets may offer little benefit to a healthy adult pig.

Quick Answer

Some probiotics can support intestinal health, reduce diarrhoea and improve growth in weaned piglets, but results depend on the strain and feeding conditions. Healthy pigs do not automatically need a daily supplement. If a pig has diarrhoea, poor appetite or weight loss, investigate the cause with your vet rather than relying on probiotics alone.

How do probiotics work in pigs?

Probiotics contain live microorganisms that provide a health benefit when given in an appropriate amount. In livestock feeding, they are often called direct-fed microbials.

Pigs have a single stomach. Their digestive system differs from that of cattle, sheep and goats, so advice about supporting a ruminant’s rumen should not simply be transferred to pigs.

Depending on the strain, probiotics may help beneficial intestinal microbes compete with harmful organisms, support the gut lining and influence digestion. Products studied in pigs include particular strains of Bacillus, lactic acid bacteria and some yeasts. Those names describe broad groups, not interchangeable treatments.

What does the research actually show?

A systematic review covering 29 studies of Bacillus subtilis in weanling pigs found that many studies reported improvements in growth, diarrhoea or intestinal health. However, responses varied with the strain, dose, diet and study conditions. The researchers did not calculate a single pooled treatment effect because the studies differed substantially.

For example, a trial involving 96 weaned piglets found that adding Bacillus subtilis PB6 to a high-protein diet improved diarrhoea scores and growth compared with the unsupplemented high-protein diet.

That finding supports a particular strain in a particular feeding situation. It does not establish that every probiotic will prevent scours or treat an existing intestinal infection.

Why are probiotics often discussed around weaning?

Weaning brings several changes together: piglets move away from milk, adjust to solid feed and may encounter new housing and unfamiliar pigs. Maintaining feed and water intake during this transition is essential.

A suitable probiotic may be one part of a planned feeding programme. It cannot compensate for inaccessible drinkers, spoiled feed, inadequate feeder space or abrupt dietary changes. Reviewing those basics with your vet or pig nutritionist often reveals the most useful improvements.

Do adult pigs and miniature pet pigs need them?

For a healthy adult pig eating an appropriate diet, passing normal droppings and maintaining suitable body condition, routine supplementation is not automatically justified.

Be particularly careful when applying commercial production research to pet pigs. Faster weight gain may be useful in a growing production pig, but it is not a desirable outcome for an overweight miniature pig.

Pet pigs need a balanced diet suited to their life stage, controlled portions and reliable access to fresh water. Obesity can contribute to painful joints and reduced mobility. Assess those needs before adding another feed supplement.

How concerned should you be?

What you notice	What it means for your decision	What to do
Normal appetite, activity, droppings and body condition	No obvious digestive problem requiring a supplement	Discuss probiotics during routine nutritional planning
Recurring soft droppings, slow growth or declining appetite	Diet, parasites or intestinal disease may need investigation	Contact your vet promptly, sooner if signs worsen
Diarrhoea in a newborn piglet, or several pigs becoming affected	Dehydration or an infectious outbreak may develop quickly	Contact your vet immediately for advice
Collapse, inability to stand, severe weakness, bloody diarrhoea or breathing difficulty	Potentially serious illness	Arrange urgent veterinary care

What else could be causing diarrhoea?

Scours is a symptom, and the pig’s age helps narrow the possibilities.

In nursing and recently weaned piglets, causes include toxin-producing E. coli, rotavirus and coccidiosis. Older growing pigs may develop conditions such as salmonellosis, proliferative enteropathy or swine dysentery. Diet changes and feed quality also need assessment.

Your vet will consider when the problem started, how many pigs are affected, recent arrivals, feeding changes and previous treatments. Examination and appropriate laboratory testing may be needed.

Dropping colour alone cannot reliably identify the cause. Yellow diarrhoea, for example, does not tell you which medicine a piglet needs.

When is this an emergency?

Do not wait for a probiotic to work if a piglet stops nursing, becomes weak or develops watery diarrhoea. Some infections cause rapid fluid loss and can be fatal without prompt treatment.

Seek urgent veterinary care for collapse, bloody diarrhoea, persistent vomiting, a painful or swollen abdomen, breathing difficulty, or a pig that cannot drink. Several pigs becoming ill together or unexpected deaths also warrant an immediate call.

Treatment may require fluid and electrolyte replacement and, where indicated, medication directed at the cause. A probiotic cannot replace those measures.

What should you do next?

1. Check the pig and its environment. Note appetite, drinking, droppings, activity and whether other pigs are affected. Check that drinkers actually deliver water and that feed is fresh.

2. Contact your vet when illness is present. Give the pig’s age, the number affected and the timeline. Ask whether to collect fresh faecal samples.

3. Support hydration and nutrition safely. Young piglets need appropriate warmth and a veterinary feeding and fluid plan. Do not routinely fast scouring piglets or force liquids into a weak pig that cannot swallow normally.

4. Reduce spread. Keep affected groups apart from healthy groups as advised. Clean equipment and footwear between groups and wash your hands after handling pigs or manure.

5. Choose a supplement only with a defined purpose. Agree what improvement you are looking for and when to review the result.

How do you choose a suitable probiotic?

Ask your vet or nutritionist to assess:

• Evidence in pigs of a similar age: a weaned-piglet study may not answer a question about an adult sow.

• The exact strain: “contains beneficial bacteria” gives little information about likely effectiveness.

• Live organism count and expiry: organisms must remain viable through storage and use.

• Handling instructions: heat, moisture and feed processing can affect survival.

• Dose and delivery: use the product’s directions and check that pigs actually consume the intended amount.

There is no universal scoop size or treatment duration for all pig probiotics. More strains or a larger bacterial count do not, by themselves, demonstrate better results.

How can you tell whether it is helping?

For an individual pig, record appetite, stool consistency, activity, weight and body condition.

For a herd, your vet or nutritionist may also compare diarrhoea frequency, growth, feed use and treatment requirements over an agreed period. Record other changes, such as a new ration or improved housing, because those can influence the result.

A pig that continues losing weight or develops worsening diarrhoea needs reassessment, regardless of whether the supplement has been started.

Common mistakes to avoid

• Treating every case of diarrhoea as a simple shortage of “good bacteria”.

• Delaying veterinary care while trying different supplements.

• Assuming a human, dog or cattle product has evidence for pigs.

• Expecting probiotics to correct poor hygiene or an unsuitable ration.

• Continuing indefinitely without checking whether there is a useful benefit.

Support digestive health every day

Use an age-appropriate feeding programme, introduce planned dietary changes gradually and keep feeders and drinkers clean and accessible. Remove spoiled feed and maintain suitable housing temperatures.

For pet pigs, provide regular movement, safe rooting opportunities and enrichment within a predictable routine. A supplement should sit within a wider care plan that includes sensible weight management and veterinary advice on vaccination and parasite control.

Can I give my pig probiotics after antibiotics?

Sometimes, if your vet recommends a suitable product. They are not automatically necessary after every course. Ask about timing and compatibility with the prescribed treatment, and do not stop medication early to substitute a probiotic.

Can I use yoghurt or a human probiotic?

Neither is an evidence-based substitute for a product evaluated for the intended purpose in pigs. Strains, quantities and other ingredients differ. Ask your vet before using them as a treatment.

Can probiotics replace antibiotics or parasite treatment?

No. Some feeding studies show benefits for intestinal health, but that does not establish a probiotic as treatment for a diagnosed bacterial infection or parasite problem. Treatment should follow the diagnosis.

ASK A VET™ encourages informed decisions about supplements. Bring your pig’s age, diet, recent health changes and the product label to your veterinary discussion so you can decide whether a probiotic has a useful role.