Pig Feeding and Nutritional Requirements

Pigs, like humans, can eat everything. This means that pig feeding can be of both animal and vegetable origin. Although they accept most foods, this does not mean that the quality of their food is not important.

Pigs will not thrive on grazing and fibrous feed alone. For pigs to be healthy and produce well, they need to get enough good quality feed to eat.

Nutrition and feeding management are very important aspect of swine production. Therefore, it is extremely important that swine producers have a good understanding of the nutrient requirement of swine during each phase of their life cycle, a knowledge of the feed stuff which can be used in swine feeding and an appreciation of the final point of feeding management for economic production of swine.

Unfortunately, many swine farmers keep them in rather poor conditions and so are not able to make as much profit as they should. Swine are particularly affected by dirty, drafty housing and quickly becomes sick.

They are also affected by poor feeding. The major groups of essential nutrients for pigs are energy, protein, minerals, vitamins and water.

Nutritional Requirements of Swine

1. Water

Water is one of the most important nutrients. Swine of all ages should have free access to fresh and clean water at all times. Drinking water is the first requirement for all animals.

Clean and fresh water for drinking should be available all the time. Pigs drink about two to five times as much as they eat, depending on the amount of moisture in the feed. Even if you feed them at will, it is advisable to have extra drinking water available.

When an animal is under stress, due to heat or disease, it will stop eating but will need extra water to drink. A lactating sow with 10 piglets needs at least 25 litres of water per day.

Clean the drinking pan or trough at least once a day. Modern drinking nipples are a lot cleaner, but should be examined daily to check that they are functioning properly. Although pigs like to wallow in water, to cool down or for fun, this is not necessary and they should not be allowed to lie down in their drinking water.

Limiting water intake will result in reduced growth rate and efficiency of gain in pigs and reduce milk production in lactating sows. A severe limitation of drinking water can cause death in pigs.

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The requirement of water is influenced by many factors including environmental temperature and humidity, composition of the feed and weight of the pig.

The table below shows the water requirement of pigs for each kilo of feed/litre.

Fattening pigs… 2.5

Lactating sows… 5.0

Dry sows….. 3.0

Piglets’… Ad-libitum (freely as needed)

2. Energy

Apart from water, energy is the most important food requirement of the pig and will most rapidly influence its survival if withdrawn. It is normally measured in heat units, traditionally as calorie, but now the megajoule (MJ) is the most commonly-used unit (where 1 MJ = 0239 MCals).

Nursing pigs derived most of their energy from fat and lactose sugar in milk. Most of the energy for growing pigs is derived from metabolism of starch because of insufficient amylase starch digestive enzyme in the small intestine.

For all weight classes of pigs, the metabolizable energy (M.E.) is approximately 96% of the digestible energy requirement.

Energy requirement of pigs are influenced by their weight which influences the maintenance requirement by their genetic capacity for growth or milk synthesis and by the environmental temperature in which they are housed.

The energy requirement for maintenance is directly related to metabolic body weight and is approximately 110kcal of digestible energy (D.E.) per kilogram body weight. Some examples are maize, rice, sorghum, cassava, sweet potato and cereal grain.

You can assess whether the pigs are getting enough energy by looking at their condition. When there is extra energy available, the animal will store it as body fat. If the pig is very thin, it means that there is a shortage of energy and the pig’s productivity will be very low. However, if reproductive sows are too fat, their productivity will decrease.

3. Protein

Protein consists of some 20 basic units known as amino acids. Nine of the amino acids required by the pig cannot be synthesized by its body, and they must be supplied in the diet.

If they are present in insufficient quantities, the pig will not grow and may not even survive.

Swine require 10 essential amino acids in its diet for normal body function. A good quality protein is one that provides the amino acids in the amount and proportion necessary for the particular need of the pig (growth, reproduction and lactation).

Protein food are oil seed e.g. cotton seed, soybean groundnuts coconut bean, peas, blood meal, fishmeal, etc. amino acid requirement are influenced mostly by age and weight of the pig. In a daily basis the requirement increase as the pig increases weight.

Protein is necessary for physical development: growth, breeding and milk production. Protein is the most important nutrient in the body, because all organs, muscles and enzymes are made of proteins.

In the feed, the protein quality is as important as quantity. It is important that the pig gets the right type of amino acids because it uses these to build its own protein (muscle protein, milk protein etc.).

The best quality protein (and the highest protein concentration) is from animal products, like fishmeal, milk or meat meal. Some protein of animal origin should be included if possible, especially for the young animals, which need to grow a lot. (Compare with nutritional needs of children.).

By-products from plant oils also have a high protein content, e.g. soybean meal or groundnut cake. However, cereals do not have enough protein and need to be supplemented with protein-rich products.

4. Minerals

Compared with energy and protein, minerals are required in very small amount. Thirteen minerals are required in the diet. Major minerals include calcium, phosphorus, sodium, magnesium, choline and the trace minerals includes iron, iodine and selenium.

The two minerals required in the greatest amount by swine are calcium and phosphorus. Adequate levels of both calcium and phosphorus must be included in the diet for strong skeletal structure.

5. Vitamins

Vitamins can be defined as organic compounds which function in small amounts (mg or μg) and are essential to the normal functioning of the animal body. They cannot be synthesized inadequate amounts by body tissues and when lacking, provoke deficiency diseases.

Fourteen vitamins are required by swine, all in very small amounts. Fat soluble vitamins are A D E and K. while water soluble vitamins are vitamin C and B complex, Riboflavin, Pantothenic acid, Niacin, Vitamin B12, Choline, Pyridoxine, Thiamin, Folic acid and Biotin.

Cereal, grains and plant protein supplements are very poor sources of many of the vitamins. From a practical stand point, vitamin premix should be added to swine feed.

6. Feeding

Pigs in contrast to cows and other ruminants, prefer feed that does not contain too much fibre. They have difficulty in digesting crude fibre, as unlike ruminants they do not have a composite stomach, in which micro- organisms can break down the fibrous materials.

When pigs have to find their own feed, they will consume the succulent parts of the roughage, but they need also to find roots or tubers, and they root up worms and insects to get the nutrients they need to survive and to reproduce.

However, their productivity will depend strongly on what they find. In pig production, the farmer is responsible for supplying feed every day. Pigs should be fed twice a day and always at the same times.

The quality of the feed should be good enough to allow the animals to become strong and productive.

In terms of the needs of the different pigs, this means that the young piglets require the best quality feed, especially after they are weaned off the very nutritious mothers’ milk.

At this stage, a lack of protein and minerals/vitamins will really slow down the development of the piglets.

Next in line for the high-quality feed are the lactating sows. They need to produce enough milk for their piglets, and can only do so if they receive enough nutrients themselves.

The condition of the sow’s body during the lactation period is a good indicator of whether she is getting enough feed.

A sow with poor nutrition will only manage to raise a small litter of piglets, and if her condition is so bad that she has lost a lot of weight, she will not be ready for the next reproduction cycle after weaning.

For optimal nutrition, the feeds should be adjusted to the needs of the pig, which means that different kinds of feed are used for the different ages and production stages. A commercial feed factory will produce a minimum of five different feeds.

Sow feed: preferably two different ones, because the quality of the sow feed for pregnancy can be lower than the quality of the feed they should get when they are producing milk (lactating).

Boars can also be given ‘pregnant sow feed’. If only lactation feed is available, add some cheaper ingredients, like rice bran, fruits or vegetables, for the pregnant sows. This reduces costs.

Creep feed 1: this is the highest quality feed for the youngest piglets. It should be put in the creep area where the mother cannot reach it. Feeding can start from seven to ten days after birth.

Creep feed 2: for the young piglets, starting about two weeks after weaning. By now the piglets no longer need the very best, so they can eat cheaper feed. In some places piglets only get one type of creep feed until they weigh about 20kg.

Starter feed: for young pigs over 20 kg (they should be about 10 weeks old) up to a body weight of 35-40 kg.

Fattener feed: for pigs heavier than 40 kg that are intended for the slaughterhouse as soon as they reach the marketable weight (about 90-100 kg).

The slaughter weight depends a lot on the market, but the older a fattener gets, the lower the feed efficiency (feed conversion rate) becomes.

The different categories of pigs are discussed separately because, besides the choice of the right type of feed, it is also very important how much to feed during certain periods.

For the adult animals, some additional green materials are always beneficial (appetite, vitamins etc.). This does require extra labour, especially because the leftovers have to be cleaned out of the pens.

Feeding Pregnant Sows and Gilts

Until she is first served (usually the 2nd or 3rd time that signs of heat (oestrus) are seen), a gilt needs to mature so she should receive the same feed as a lactating sow.

The daily feed allowance should be between 1.5 and 2.5 kg (depending on bodyweight). Feeding an extra 0.5 kg per day during the week before mating might increase the number of embryos (this is called flushing), but this only works when the oestrus period can be predicted.

In the first month of pregnancy the sow should be fed conservatively (1.5-2.5 kg per day). If no oestrus signs have been noticed by 21 days (which means that she is pregnant) feed the sow according to her body condition: 0.5 kg extra if she is too lean, but if she is too fat, nothing extra until the last month of pregnancy.

In the last month of pregnancy, when the embryos are growing the most, the sow should receive about 2.5-3.0 kg per day. A few days before farrowing (the mating date must be recorded!) reduce the sow’s feed gradually, and on the day of farrowing give her only 1-1.5 kg.

Feeding Lactating Sows

After farrowing it is most important that there is plenty of drinking water available. A sow with 10 piglets needs about 30-35 litres of water per day.

The daily amount of feed is gradually increased from 2 kg the day after farrowing, adding 0.5 kg each day for about 10 days after farrowing. The maximum amount of feed for the lactating sow is related to the number of piglets that are suckling:

About 1.5 kg for the sow’s maintenance and about 0.5 kg extra for every piglet. With 12 piglets, this means that the mother should eat 1.5 + 6 = 7.5 kg feed per day. This is a lot of feed and many sows have problems eating enough, especially in high temperatures. Therefore, during the lactating period, the sows feed should be of high quality, so she can obtain enough energy and protein to produce milk. On the day of weaning give the sow only 0-0.5 kg feed to stop the milk flow, and the next day put her on the schedule for empty sows (flushing): 2.5-3 kg day.

Feeding Piglets Around Weaning

The piglets should receive the first colostrum from their mother as soon as possible after birth, because it gives them warmth, energy and anti- bodies against diseases. For the piglets it is best not to wean them before 6 weeks of age.

However, to get the sow into the next reproductive cycle as soon as possible, weaning at 4 weeks is better commercially. Sow’s milk has one disadvantage: it contains little iron.

Commercial pig producers give piglets an iron injection during the first week, but it is also possible to put a shovel of compost in the pen every day, in which the piglets can play and search.

This supplies them with the necessary extra iron. Piglets that lack iron have pale, whitish, unhealthy looking skin.

From the third week on, the piglets will benefit from supplementary feed, because this is when the sow’s milk production starts to decline.

The creep feed must contain animal protein and an easily digestible source of energy like maize, preferably even cooked (porridge) for better digestion.

This high-quality feed spoils easily, so the feeder must be cleaned every day and the feed refreshed. It should be kept out of reach of the sow; she will be fine with less expensive feed.

If the piglets have diarrhoea (scouring), the creep feed should be removed for a few days. Before the piglets are weaned from the mother, they need to become accustomed to other feed than milk.

Otherwise the change will be too big for them and problems might occur. Diarrhoea, caused by colibacteria in the intestines, is a frequently occurring problem in the week after weaning.

Affected piglets must be treated with antibiotics, as they can die from an infection. In the period after weaning, give the piglets the same feed for at least 10 days.

If there are no problems, you can start to gradually change over to a cheaper piglet feed. Changing to the next feed should take about five days.

1. Feeding Piglets from Two Weeks after Weaning

At about six to eight weeks of age the piglets are still very sensitive and require feed that includes animal protein and digestible starch from maize or cassava. As they no longer get sow’s milk, an additional supply of vitamins and minerals is very good for them (compare them with weaned children).

Very often farmers continue to give the same creep feed until the piglets reach 15-20 kg of body weight. The quality of the available creep feed should be taken into account when deciding when to wean the piglets.

If there is no high quality (expensive) creep feed available, the weaning time should be postponed until the piglets are six to eight weeks old. However, we recommend that the piglets be given supplementary feed after about two weeks of age.

2. Feeding Young Pigs (Body weight 20-45Kg)

By about 10 weeks the young pigs should weigh about 15-20 kg. On an intensive pig farm, they may weigh as much as 25 kg. At this age they are suitable for selling as fatteners or for rearing as replacement for breeding stock.

The best ones should be selected for breeding, but the feeding method is the same for both until they reach 50-60 kg body weight. Because this is the starting period for the fatteners, the feed is called starter feed.

The pigs’ growth will depend on the quality of the feed (energy and protein level), because their feed intake is still limited.

They can eat about 1.0 kg (for a 20 kg pig)-1.8 kg (a 40 kg pig) per day in this period. They should be fed as much as they can eat, but it is important that no rotting leftovers contaminate the feed.

It is also possible to feed them a smaller amount twice a day. This makes it easier to check the appetite and health of the pigs. It is important that the pigs finish their feed in about 15-20 minutes. It is good practice generally to keep feed wastage to a minimum.

A small amount of animal protein in the feed will still be very beneficial to the animals at this stage of their lives, so they can continue to grow more efficiently.

3. Feeding Pigs Heavier Than 40 Kilograms

Older pigs are most suited to lower quality feedstuffs and can tolerate the greatest variety in feed. Again, their growth results are directly related to the quality of feed they consume, but at this stage animal protein is not essential in their diet.

The pigs’ eating capacity is still increasing with age, but is generally between 2 and 3.5 kg per day. This means that if the market demands lean pork, it might be necessary to restrict the feed intake in the final period, to prevent the fatteners from accumulating too much fat in the carcass.

Normally, no feed restriction is necessary until the body weight has reached 70 kg. As long as fatter slaughter pigs do not command lower prices, feed restriction is not recommended because extra feed intake always results in extra body weight.

In summary, nutrition and feeding management are very important aspect of swine production. Knowledge of the nutrient requirement of swine during each phase of their life cycle is extremely important and swine are affected by poor feeding.

The major groups of essential nutrients for pigs are energy, protein, minerals, vitamins and water.

Swine do not have a rumen. The fibrous component of the diet is not utilize as efficiently as in ruminant animals.

Pigs are also dependent upon certain essential amino acids present in dietary protein from which they build their own body protein unlike the ruminant animal, swine cannot synthesis the essential amino acids from poor quality protein or from non-protein nitrogen sources.

Digestion has been defined simply as the preparation of food for absorption. It may include mechanical forces such as chewing or mastication, muscular contraction of the GIT.

The three swine feed usually available commercially are: Creep feed – 16% protein, Sow and Weaner meal 14% and Swine finishing meal 12% for fattening of swine for pork and bacon.

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