Nutrition of the Weaned Pig

By Livestock Knowledge Transfer, UK - This article is the second in the series from "Getting the best from your pigs" and looks at the nutritional requirements of the newly weaned piglet.

1 May 2003

5 minute read

No. 2 Nutrition of the Weaned Pig

Weaning is a period of major stress for the young pig. Its effects are multi-factorial i.e. they include several distinct, but linked aspects of behaviour, environment, disease, immunity and nutrition (Table 1).

Table 1: Important factors for the weaned pig

Behaviour	Removal from sow is stressful Mixing aggression occurs Feeding behaviour changes (feed intake falls)
Environment	Temperature Humidity Space allocation Group size Feeder type and space
Immunity	Removal of maternal immune protection via milk Variations in Passive Immunity Immune development of young pig Altered harmless ("commensal") gut flora Introduction of new dietary antigens from the weaning diet
Disease	E. coli Rotavirus Salmonella PMWS Swine Dysentery Haemophilus
Nutrition	Digestibility and palatability Ingredient selection Protein level and source Fibre nutrition Non Starch Polysaccharides Fat level and composition Water Level of feeding : ad lib v restricted Anti-nutrient factors associated with feeds

The severity of these stresses is markedly influenced by age and several of them are much worse in the younger pig. Therefore the pig weaned at less than 8 weeks of age requires special care and attention.
It is also important not to consider weaning only in terms of nutrition, although there are many aspects of nutrition to consider as shown in Table 2.

Table 2: Factors important when considering the feeding of the weaned pig

Digestibility	Digestibility of fat, protein and carbohydrate are all-important to avoid digestive upsets. DE of 13.5-14.5 MJ/kg Several gut enzymes can be induced by feeding new feed sources, but the age of the pig is crucial. It is unlikely that "mature" gut enzymes can be induced in pigs weaned as young as three weeks by creep feeding The use of highly processed feeds can improve digestibility at weaning e.g. cooked cereals, enzyme pre-treated feeds In-feed enzymes can improve digestibility immediately post-weaning, but their effect is likely to be short-term Digestive upsets immediately post-weaning increase susceptibility to disease
Protein level and source	High protein diets (> 20% Crude Protein) increase digestive upsets Low protein diets must be of a good quality (near "ideal") for good growth Certain protein sources may aggravate weaning problems (e.g. soya bean) whereas others (e.g. milk based products) minimise any problems
Functional fibres	Fibre products and complex carbohydrates can functionally alter the gut wall and gut microflora. These include oligosaccharides and wheat fibre ingredients
Non starch polysaccharides	Non starch polysaccharides represent a wide array of molecules from small fibres to large sugars They can profoundly affect digestion and absorption of nutrients and thus feed conversion efficiency in the young post-weaned piglet
Fat level and composition	Sows milk is very high in fat(>30% Dry Matter) yet equivalent commercial weaner diets which include such high levels are likely to produce digestive upsets. Fatty acid composition of the weaning diet is important for long term growth and health.
Water	The cheapest nutrient but the most important for a post-weaned piglet. Enhanced voluntary feed intake immediately post-weaning can be achieved by liquid or gruel feeding as opposed to dry feeding
Level of feeding: ad lib vs restricted	Weaned piglets often do not eat for 24- 48 hours. However they then are likely to engorge on the weaning diet if it is available. This is often associated with digestive upset. Voluntary feed intake variation between piglets within a litter is normally very high. Some pigs will not eat after weaning for up to 3 days whereas other littermates will eat almost immediately. This variation decreases as the pigs get older.
Anti-nutrient factors in feeds (ANF)	Several feeds commonly fed to pigs contain ANF. The major ones are the protease inhibitors found in several feeds e.g. Soya, Peas. They decrease protein digestibility and growth. Processing of feeds can markedly reduce ANF activity but most compounders do not measure them directly. Residual ANF activity can still be found in several "processed" feeds.