Pig Feed: What It Contains and How to Choose the Right Diet

By Dr Duncan Houston

Choosing pig feed involves more than finding a bag with a pig on the front. A newly weaned piglet, a growing pig and a sow feeding a litter have different nutritional needs.

The aim is to provide a balanced diet that supports healthy growth or reproduction, suits your feeding system and gives you good value for the feed purchased.

Quick answer: Standard commercial pig feed usually combines cereal grains, protein sources, amino acids, vitamins and minerals. Choose a complete feed designed for your pigs’ weight and production stage, follow its feeding directions and provide reliable access to clean water. There is no single ration that suits every pig throughout its life.

What is standard pig feed made from?

The ingredients vary with availability, price and the animals being fed. Common components include:

Feed component	Common examples	Main purpose
Cereal grains	Wheat, barley, maize and sorghum	Supply much of the diet’s energy.
Protein sources	Soybean meal, canola meal and field peas	Supply amino acids for growth, tissue maintenance and milk production.
Added amino acids	Lysine, threonine and methionine	Help balance the amino acids supplied by other ingredients.
Fats and oils	Suitable feed-grade vegetable oils or fats	Increase energy concentration where the formulation requires it.
Mineral ingredients	Limestone, phosphate sources, salt and trace mineral premixes	Support bones, fluid balance and normal body functions.
Vitamin premixes	Formulated combinations of essential vitamins	Help ensure the complete diet meets vitamin requirements.

A good formulation balances these components together. Simply mixing grain with a protein meal does not automatically produce a complete pig diet.

Pigs need a different feeding approach from cattle.

Pigs have a single-chambered stomach and cannot use coarse forage as efficiently as cattle. They can obtain nutrients from pasture and other fibrous ingredients, but grass, hay and vegetable scraps should not be assumed to meet their requirements.

Outdoor pigs still need a properly balanced feeding programme. The contribution from grazing varies with pasture quality, season, pig size and how much they actually eat. A green paddock is not a nutritional analysis.

Check whether you are buying complete feed or a supplement.

These products have different jobs:

• Complete feed: Designed to supply the required nutrients for the stated class of pig when fed as directed, with water supplied separately.

• Concentrate or balancer: Designed to be mixed with specified ingredients, often grain, at a stated rate.

• Vitamin and mineral premix: Supplies selected nutrients in small quantities. It is not a complete feed or a replacement for a protein source.

Read the directions carefully. A concentrate that looks expensive per bag may be economical when correctly incorporated into a ration, but it must not be fed as though it were a complete diet.

Pellets and meal describe the feed’s physical form. Either can carry a balanced formulation; neither guarantees that it suits your pigs.

1. Match the feed to the pig’s stage of production.

Start with the animals you have, including their approximate weights and whether they are growing, pregnant or producing milk.

Pig group	Feeding priority	What to look for
Newly weaned piglets	Establish feed intake and support an immature digestive system	A starter or weaner diet for their age and weight, using suitable digestible ingredients.
Growing pigs	Support muscle growth and sound development	A grower ration with an appropriate balance of energy, amino acids and minerals.
Finishing pigs	Maintain efficient growth towards market specifications	A finisher diet suited to body weight, growth potential and the intended market.
Pregnant sows and gilts	Support pregnancy while managing body condition	A gestation programme with individual feed allowances where needed.
Lactating sows	Support milk production and limit excessive condition loss	A lactation diet and feeding system that support adequate nutrient intake.

Young pigs have limited feed intake and particular digestive needs. Moving them onto a cheaper grower ration too early can compromise the nutrients they receive.

Breeding females also require attention beyond the feed label. A sow nursing a large litter faces very different demands from a sow in early pregnancy. Replacement gilts and breeding boars need programmes that support development or reproduction while managing body condition.

2. Look beyond the crude protein percentage.

Crude protein is useful information, but it does not tell you whether the pig receives the right balance of usable amino acids.

Lysine is particularly important because it is commonly the first limiting amino acid in cereal-based pig diets. That means growth can be constrained by insufficient lysine even when the ration contains plenty of other protein.

Ask the supplier about the diet’s energy level and digestible lysine specification. You may see “standardised ileal digestible lysine”, or SID lysine, which accounts for amino acid digestibility.

Compare specifications on the same basis. Total lysine and digestible lysine are different measures.

As pigs grow, the nutrient concentration they require changes. Moving through suitable starter, grower and finisher feeds is called phase feeding. It helps match nutrient supply to requirements and can reduce unnecessary feed expense.

3. Confirm how much to feed and when to change diets.

Ask your supplier for the recommended weight range, feeding method and transition instructions for each product.

There is no reliable universal number of kilograms per pig per day. Intake depends on body size, diet energy, environment, health and production stage.

Growing pigs and breeding animals may require different feeding arrangements. Where feed is measured out, weigh a typical scoop rather than assuming its volume represents a fixed weight. Recheck after changing products.

For breeding stock, use body condition and reproductive stage to review allowances. Giving every sow the same amount can leave some too thin and others too fat.

Avoid stretching complete feed with extra grain or other ingredients unless the whole ration has been recalculated. Adding energy without the matching amino acids and minerals changes the nutritional balance.

If mixing your own feed, use a formulation from a pig nutritionist, accurate scales and equipment that mixes small ingredients evenly. Include the cost of testing, labour, storage and equipment when comparing home mixing with purchased feed.

4. Check water and feeder access before blaming the feed.

A suitable ration cannot perform well if pigs struggle to reach it or their drinkers are not working.

Check daily that:

• Every drinker operates and provides an appropriate flow.

• Drinker height suits the pigs using it.

• Smaller or quieter pigs can access feed and water.

• Feeders are clean and adjusted to limit wastage without restricting access.

• Water supplies remain reliable during hot weather and equipment failures.

Test an unfamiliar water source for suitability, particularly bore water that may contain high mineral levels. Water demand and equipment requirements differ between weaners, growing pigs and breeding animals.

5. Compare the cost of growth, as well as the price per tonne.

Cheap feed is not necessarily economical if pigs need more of it to achieve the same weight gain.

Feed conversion ratio, or FCR, expresses how many kilograms of feed are used per kilogram of liveweight gain. For comparable feeds measured on the same basis:

Feed cost per kilogram of gain = feed price per kilogram × FCR

Consider this illustrative example:

	Feed A	Feed B
Feed price	$500 per tonne	$440 per tonne
Feed used per kilogram of gain	2.6 kg	3.2 kg
Feed cost per kilogram of gain	$1.30	$1.41

Feed B costs less per tonne but more per kilogram of gain under these assumed results.

These figures are examples, not current prices or performance targets. Actual results depend on the pigs, management and feeding conditions.

For useful comparisons, record feed used, weights and days between weighings. Include wasted feed in your cost calculation. Also consider delivery, storage losses, time to market and whether pigs meet the buyer’s weight and fat specifications.

Wet by-products need additional care when comparing prices. Much of their delivered weight may be water, and their nutrient content can vary. Have their dry matter and feeding value assessed before treating them as a bargain.

6. Protect feed quality after purchase.

Store feed dry, protect it from rodents and rotate stock so older feed is used first. Buy quantities you can use within the supplier’s recommended storage period.

Do not feed material that is mouldy, spoiled or contaminated. Mould toxins can reduce performance and cause serious illness, while mixing errors can expose pigs to excessive salt or minerals.

If several pigs lose appetite after a new batch arrives, retain the label, batch details and a representative sample for investigation. Your veterinarian or nutritionist can advise on appropriate feed testing.

Kitchen scraps need particular care in Australia.

Feeding pigs prohibited food waste, commonly called swill, is banned in Australia. This includes meat-containing scraps and food that has contacted meat, such as vegetables left on the same plate.

Do not assume cooking, freezing or removing visible pieces of meat makes those scraps acceptable. Restrictions also apply to imported dairy products.

Permitted fruit, vegetables or grain are not automatically a balanced diet. If you cannot establish that a leftover food is permitted and uncontaminated, do not feed it. Check your state or territory agriculture authority’s guidance before using food by-products.

Poor growth is a reason to investigate the whole system.

Review feed intake, feed quality, water access and weight records together. A balanced ration cannot correct an untreated illness or a pig that is being pushed away from the feeder.

Seek prompt veterinary advice for persistent diarrhoea, marked appetite loss or pigs falling behind their group. Collapse, seizures, severe weakness or sudden deaths require urgent veterinary attention.

Water deprivation is particularly dangerous in pigs. If a prolonged interruption is suspected, especially with abnormal behaviour or neurological signs, obtain urgent veterinary instructions for rehydration. Rapid, uncontrolled rehydration can worsen the consequences of salt poisoning.

Common buying mistakes are often simple ones.

Choosing by price alone, using one ration for every age group, confusing a supplement with complete feed and adding unmeasured extras can all undermine a feeding programme.

Keep the supplier’s feeding directions, note when diets change and assess the pigs’ response. A few consistent records are more useful than guessing whether they look bigger this week.

Frequently asked questions

Can pigs live on pasture alone?

Pasture can contribute nutrients and provide opportunities to forage, but it should not be assumed to supply a complete diet. Growing pigs and lactating sows are particularly demanding. Plan supplementary feeding around their requirements.

Are pellets better than meal?

Pellets can reduce sorting and wastage, but meal can also work well with suitable feeders and management. Compare nutrient specifications, feed quality, wastage and cost rather than choosing on appearance alone.

Does a higher protein percentage mean faster growth?

Not necessarily. The balance and digestibility of amino acids, energy intake and the pig’s growth potential all matter. More crude protein will not reliably correct a shortage of a particular essential amino acid.

When should I change from grower to finisher feed?

Use the weight range and feeding programme specified for the products you buy. Different formulations have different transition points. Review actual pig weights and performance rather than relying on age alone.

If you are unsure which feed suits your pigs, ASK A VET™ can help you understand the label, identify possible health concerns and prepare useful questions for your feed supplier or pig nutritionist. Bring the feed details, approximate weights and recent growth records so the advice can be tailored to your herd.