September24 , 2023

The Basics of Free Range Pig Nutrition



The Basics of Free Range Pig Nutrition

Pigs are omnivores so in nature they would consume a diet of grasses, small animals, insects, earth worms, roots and dirt just to name a few. I think we need to keep this in mind when feeding our pigs. Supplying all the nutrition a pig needs for growth, reproduction, lactation and maintenance can be quite complex.

Balance is the key to pig diets. If there is just one limiting factor in the diet you are feeding your animals it will have an effect on their performance. That could mean slower growth rates, fat pork, smaller litters, less productive sows and boars or even health problems.


Read also: vaccination schedule for pigs

What does a pig need to eat?


No one feed ingredient can supply all the nutritional requirements of your free range pigs.

Learn More

Protein, energy and lysine are the most important elements of pig nutrition. Protein and energy need to be in the correct balance and you will quite often see this expressed as grams of available lysine per megajoule of energy.

Too much energy in the diet will be converted into fat but too little will slow the growth of your pigs. Pigs require protein to develop muscle. Too little will be detrimental to productive growth and too much will just be a waste of money.

Energy in the pig diet can come from cereal grains and pulse, (wheat, barley, sorghum, peas, lupins, soybeans etc) fruits and starchy vegetables, bakery waste, milk waste, fats and oils.

Pigs require energy for bodily function as well as growth. They will need more during cold weather to keep themselves warm and outdoor pigs require more energy than housed animals because they are free to exercise. It is estimated that free range pigs will eat 15% more feed than housed, penned animals.

Protein sources are meat and blood meal, fish meal, soybean meal, canola meal, lupins, peas, milk (powder and waste), and peanut meal.

Cereal grains are relatively low in protein therefore we need to combine protein to balance the diet to meet the pigs requirements. Different ages and classes of pigs will have different needs. Very young animals need high energy, high protein diets. This will taper off as the pig reaches the finisher stage or for mature animals. The nutritional needs of the lactating sow will rise sharply while she is feeding her young.

Some sources of protein also provide good levels of energy, soybeans for example, and vice a versa. Some energy sources have no protein available at all e.g. Fats and oils.

Pigs have a very high requirement for Lysine. Lysine is an essential amino acid. It is one of many needed by pigs that must be supplied in the diet but the one that has the most detrimental affect if it is lacking. A defiency of lysine will limit the amount of protein a pig makes, slow growth and effect the productivity of sows.

Animal proteins are higher in lysine than plant proteins while plants are generally higher in energy. Canola and soybean do have both high energy and protein but their may be limited in a pigs diet because of cost or anti nutritional properties. So, the ideal basic mix for a pig diet will contain energy from cereals etc, plant protein and animal protein.

Read also: Coping with pig feed cost in Nigeria

Synthetic lysine, or any of the amino acids, can be added to the feed mix to fine tune the pig’s requirements.

Mixing your own pig feed

A very simple mix for grower pigs would be wheat, meat meal and a vitamin and mineral premix.

To make 100kg;

84 kg wheat

16kg meat meal (approx 50% crude protein)

Premix as per manufacturers instructions

This would give us a feed mix with adequate lysine of 0.71 and 14.5 mjDE per kilo.

Meatmeal is sometimes known to be low in Tryptophan so the meal would need to be tested and most usually are and will give details on the label or you can ask the manufacturer.

Wheat has a much higher energy content than other grains and this mix would not work if we substituted it for barley, sorghum etc. We would have to add another energy source and in this case soybean would be a good choice as it is high in energy, lysine and protein and would reduce the amount of meat meal required.

We could change the mix to;

78 kg barley

19kg full fat soybean meal

3kg meat meal


These are very basic mixes and only one amino acid has been balanced, lysine. The quaity and nutritional value of grains can vary tremendously. Energy and protein are sufficient for free range grower pigs.

Do make sure your ingredients are as fresh as possible as this can impact on the nutritional value of the feed.

To delve deeper into the intricacies of pig nutrition, we need to look at amino acids. To balance them all in your ration you would need the assistance of an animal nutritionist or a feed software package. As already discussed, Lysine is the most limiting amino acid for pigs. Without adequate amounts, muscle protein will not form correctly. The amount of muscle your pig could develop will be limited by the amount of lysine in its diet.

There are ten amino acids that are essential to pigs;






Methionine plus cystine

Phenylalanine plus tyrosine




Read also: Large White Pigs: facts and characteristics

Good quality proteins have most of these amino acids available in them. Grain and legume protein sources will not have enough lysine when used for formulating diets for young pigs and will need to be supplemented with synthetic lysine or balanced with meat, blood or fish meal. It is a good idea to aim for a diet that is a mix of plant protein and animal protein to balance amino acid requirements.

Contributed by: Lee McCosker Dip

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