Pigs are fed balanced diets which are formulated to meet their requirements at different ages or stages of production.

There are 5 basic nutrients:  Energy, protein, minerals, vitamins and water. When formulating rations the balance of energy to protein is of cardinal importance and ensuring the correct levels of minerals and vitamins.

Another important consideration is digestibility which is the degree to which a feed can be broken down and absorbed by animals.

A raw material (synonyms are: feedstuff or feed ingredient) is a basic material of plant or animal origin. Examples: Fishmeal, Maize meal, soya oilcake meal, sunflower oilcake meal, full fat soya, Bran, CaCO3 , MCP, synthetic lysine, vitamin and mineral premixes.

Generally nearly all raw materials contain protein, energy, vitamins, minerals and water. Depending on origin one or other nutrient dominates. E.g. fishmeal 60-65% protein, maize meal 70-80% starch - but the other nutrients will be present even at very low levels. Raw materials are thus classified into e.g. protein feedstuffs or energy feedstuffs.

No feed of animal origin is fed to pigs. All protein is derived from either plant or fish, although fish meal is currently not being used very much.
A feed (synonyms are: ration or diet) is a mixture of raw materials; which an animal is fed to enhance maintenance, growth, reproduction, lactation etc.

These rations are mainly in the form of meal or pellets and are either fed ad-lib as in growers or carefully rationed as in sows to keep them in ideal condition.

Feeding pigs

In general breeding animals are fed a fixed amount of feed per day to match their needs, maintain condition and ensure optimal production.
Weaners and growing pigs usually have unrestricted access to feed, known as ad lib feeding.

Typically growing pigs will eat 3,5% - 4% of their body mass per day and drink double that amount of water.

At 10 kg pigs will eat

350 g /day

At 30 kg pigs will eat

± 1.2 kg /day

At 50 kg pigs will eat

± 2.0 kg /day

At 70 kg pigs will eat

± 2.5 kg /day

At 100 kg pigs will eat

± 3.0 kg /day

Dry sows eat between 1,8 kg and 2,5 kg per day, whilst lactating sows will eat anything between 6 kg and 8 kg. Rule of thumb is to feed lactating sows 2 kg plus 500 g per piglet being suckled as a maximum.

Rations during the growing phase are altered every 2-4 weeks to ensure the correct balance of nutrient to meet the requirements of the growing pig. It is important that the rations are formulated to meet the requirements of the particular breed / line of pigs and the sex.

Boars grow fastest and are normally leanest of the 3 sexes; gilts grow slowest and are generally fatter than boars but leaner than barrows (castrated males); the barrow will grow faster than a gilt but is most often the fattest of the 3 sexes unless rations are properly formulated.

Example of rations used.



Lysiene %

Energy mJ/kg

4 - 5 weeks




6 - 7 weeks




8 - 11 weeks




12 - 17 weeks




18 - 22 weeks




Source: CS Vet www.csvet.co.za