• Anthrax (rare).
• Classical swine fever (in those countries where it is still endemic). See chapter 12
• Coliform infections and post-weaning diarrhoea *.
• Colitis (specific disease). *
• Oedema disease (diarrhoea uncommon).
• Parasites.
• Porcine epidemic diarrhoea PED. *
• Porcine enteropathy including PHE, PIA, NE & RI. *
• Rotavirus.
• Salmonellosis. *
• Spirochaetal diarrhoea.
• Swine dysentery. *
• TGE (rare in Europe now but still common in some other countries).

Pre and Post-weaning

Changes in the intestine of the pig at weaning

Fig.14-12 shows the cross section of the small intestine of the weaned piglet to consist of many thousands of finger like projections called villi, which increase the absorptive capacity of the small intestine. During suckling they are continuously bathed by sows milk which contains the immunoglobulin IgA. This becomes absorbed into the mucous covering the villi surfaces and prevents E. coli and other organisms attaching to the fingers. If they are unable to attach they are unable to cause disease. The secretary IgA also helps to destroy bacteria. After weaning time however no more IgA is available, the levels rapidly decline and bacteria damage the villi causing them to shrink. This atrophy reduces the absorptive capacity of the gut and the ability of the pig to use its food. The enzymes produced by the cells of the villi are likewise reduced. The changes result in malabsorption of food and poor digestion with or without the development of scour. The villi normally regenerate within 5 to 7 days after weaning from cells at their base called enterocytes, which multiply and migrate upwards causing the villi to return to their normal length. The rate of multiplication and regeneration is in part an environmental temperature and energy dependent phenomena. If the pig is weaned in an environment below its lower critical temperature (LCT), the rate of regeneration of the villi is reduced and in some cases ceases. (This results in the hairy pig that doesn't grow). Feed intake is a crucial part of the equation.

Other factors also increase the demand for energy and it is critical the balance is made in the first 24 hours of weaning. Draughts must be avoided.

Before weaning the piglet receives milk as a liquid feed at regular intervals. As a result the bacterial flora of the gut, although relatively simple compared with that of a mature pig, is stabilised.

At weaning cessation of milk removes secretory IgA and there is a period of starvation, followed by irregular attempts to eat solid feed. This results in a dynamic disruption of the bacterial flora of the gut which may last for 7 to 10 days before stabilising. This bacterial disruption may also contribute to poor digestion and possibly scour, particularly when high levels of pathogenic strains of E. coli are involved.

Before weaning the piglets led an ordered life, being "called" with their litter mates to suckle and obtain small amounts of milk at regular intervals, sleeping between meals in a warm creep. All this suddenly changes at weaning, the pigs finding themselves in strange surroundings with strange piglets, and only solid feed. Psychological trauma is inevitable and is likely to affect some pigs more than others, resulting in impaired digestibility and lowered resistance to disease. The more this psychological stress can be minimised the better

If poor growth is evident in the first seven days post-weaning the following options or variables need to be considered:

• Check that the weights of all pigs at weaning are to the target level.
• Check the ages of the pigs at weaning.
• Heavier but younger pigs will have a more immature digestive system.
• Group the pigs by weight or keep them in their litter groups.
• Use a highly digestible and palatable diet and mix and soak this for the first day or two with water.
• Use different diets according to body weight and age.
• Use open dishes for feeding for the first three days at least, instead of troughs.
• Feed small quantities of creep four to five times daily and remove uneaten stale feed.
• Provide easy access to fresh clean water.
• Use in-feed medication for the first ten days post-weaning.
• Check that the environmental temperature is constant and satisfies the pigs requirements particularly in the first four days post-weaning.
• Maintain a dry house without draughts.
• Reduce any form of stress.
• If pigs are housed on slatted floors provide solid comfort boards for them to lie on for the first few days.
• Remove the smallest piglets from each pen after 7 to 10 days and place them together in one pen in the same room. Their diet can then be adjusted accordingly.

Key factors that dictate the degree of villus atrophy

• Age of the pig at weaning.
• Weight of the pig at weaning.
• The environmental temperature and its fluctuations.
• Feed intake and availability of feed.
• Digestibility of the feed.
• Quality of the proteins.
• Levels of milk proteins.
• Levels of bacterial and viral challenge.

Nutrition

Only minimal amounts of solid food are eaten during the suckling period and very little before 10 days of age.

Key points to maximising feed intake

• Pigs at weaning time will eat a warm gruel better than a solid food.
• Gruel feeding reduces the degree of villus atrophy and dehydration.
• Pigs need to be encouraged to feed in the first 2 to 3 days post-weaning because the maternal discipline of suckling every 40 minutes is lost.
• Provide creep feed for the first 72 hours in open dishes 5 to 6 times a day. This will encourage the pigs to eat and avoid over eating. Piglets naturally "root" pellets from the floors rather than a trough. Recently washed metal troughs have unattractive smells.
• By experiment place the feeders in the most attractive part of the pen.
• A small pellet or crumb will increase intake. Pellet size should be 2mm or less.
• Examine the piglets mouths at weaning time to ensure there has been no damage to the gums during teeth removal. Pigs with sore infected gums will not eat.
• Use a highly palatable diet.

Creep feeding / options

The term "creep feed" here means the pre-starter diet offered to piglets before and just after weaning until they can be changed to a cheaper starter diet.

When sows were loose-housed in farrowing pens the pre-starter had to be placed in a "creep" where the sows could not get to it. Now that sows are farrowed in crates or tethers the creep is placed outside the warm creep area in a cooler part of the pen to keep it fresh but the term "creep feed" is still used.

There are a number of options:

• No creep given pre-weaning.
• Different creeps given pre and post-weaning.
• Mixed creeps given post-weaning.
• A high dense diet used pre-weaning and a low one post-weaning.
• A low dense diet used pre-weaning and a high one post-weaning
• Restricted feed for varying periods of time.
• Choice feeding.

By trial and error determine the best methods that produce a healthy rapid growing weaner.

On most farms the best method is to offer very small quantities of fresh creep feed several times a day for the last 7 to 10 days before weaning and to continue this for one to three days after weaning while gradually changing to starter rations.

Nutritional components of a good creep diet

Whilst it is not the purpose of this book to discuss nutrition in detail nevertheless Fig.14-14 shows the effects on growth rate of a simple diet compared to a complex one. A complex diet could consist of the following:

Cooked cereals 38 %, maze oil 11%, milk products 45%, Glucose and sugars 5% plus minerals and vitamins, MJ DE/kg 16.4, Protein 21 to 23%, lysine 1.3 to 1.4%, oil 20%.

Courtesy of Frank Aherne