Whether you can vaccinate or not you should protect your investment by applying appropriate biosecurity measures. This is not just to keep out the infectious diseases covered in this chapter, although of course if you are in a high risk area this is crucial, but to keep out some of the more serious diseases covered in other chapters too.

Some viruses, such as transmissible gastro-enteritis (TGE) virus and foot-and-mouth disease (FMD) virus spread very readily and if they are spreading in your neighbourhood they are difficult to keep out of the herd no matter what precautions you take. This is partly because they are highly infectious so that it only takes the entry of a few viable virus particles to set off a major outbreak. It is also because they are carried on the wind, or on birds or flies which are difficult or impossible to guard against. Fortunately not all infectious agents are like that. Some viruses and bacteria spread less readily. Examples in this chapter are swine vesicular disease (SVD) and classical swine fever (hog cholera). You can keep them out fairly reliably if you take appropriate biosecurity precautions.

Vehicles

You should take precautions against contamination from vehicles. The lorry picking up pigs for slaughter is a particular danger. Always insist that it has been well washed out before visiting the herd and that it also always visits your herd first. You should also take precautions against contamination from such lorries by building a safe pig-loading bay and by not allowing the driver into your pig buildings.

Pig meat products

You should not feed pig meat products unless they have been thoroughly cooked. You may not be permitted to feed them in your country and it is safer not to feed meat products at all. Do not allow anyone to take sandwiches or food into the pig buildings. Provide a designated eating place for them away from the pigs. Also, if you know of any 'back-yard' type pigs or pet pigs in your neighbourhood stress to the owners the importance of not feeding human waste food or scraps from the table. Maintenance people and builders may keep pigs at home.

Incoming pigs

Any replacement pigs coming on to the premises should come from known safe sources and should be quarantined, or at least physically separated from your own pigs, for at least a month, preferably six weeks. You can use the second half of this time to apply acclimatisation procedures to adapt them to the microbial flora of your herd, and to your feed and management procedures. The pigs can also be vaccinated if necessary.

Physical barriers

If some or all of your pig buildings are open sided or easy to access, they should be ring-fenced or walled off to protect your herd from stray animals, (particularly wild pigs), or human intruders entering your pig buildings. If your buildings are fully walled with limited access (e.g. like many in Denmark, Canada and in the mid-western states of the USA), and if the doors are strong and lockable, then a fence may not be necessary.

The necessity for strong physical barriers depends on the country in which you farm.

The most dangerous animals are wild pigs, particularly where they may be infected with classical swine fever (hog cholera) virus as in Germany, Poland and possibly Italy.

Stray dogs can spread transmissible gastro-enteritis (TGE) and probably other diseases. Whether you should keep a guard dog in the compound depends on the level of crime (pig rustling and equipment thefts). Some pig farms in countries such as Portugal have them patrolling between two parallel perimeter fences. Cats can be an asset if they are contained within the pig buildings all the time as they are in Denmark. They help to keep down the mice and rats. But if dogs and cats are kept in the pig compound or buildings, do not feed them pig meat products.

Foxes can be a problem, particularly in outdoor breeding herds but it is not known what pig diseases they may spread.

Badgers in the UK can spread bovine TB and hares in Denmark, Poland and possibly neighbouring countries under some circumstances spread Brucella suis and have infected outdoor breeding herds.

Birds, mainly starlings, spread diseases in their droppings including avian TB, erysipelas and most seriously, TGE.

Thieves are a menace, not just because they steal your pigs or equipment but also because they are probably dirty and unhygienic and may well infect your herd.

Visitors

Reduce visitors to a minimum and make any that have to enter your pig building change into clothes and boots that are kept on the farm. One way of ensuring that they change all their clothes before entry is to insist on them taking a shower. If they wash their hair while showering it adds to the farm biosecurity. Compulsory showering helps to deter visitors and raises biosecurity attitudes. You might also insist that visitors stay away from other pigs for a period of time before visiting. A minimum period would be one night. Some pig farmers with large herds insist on two nights down-time. If you do not insist on down-time, check whether your visitors have come from contaminated places like pig farms, slaughter houses, animal renderers, or post-mortem rooms. If they have, do not let them in. Make them sign a visitors' book stating that they have not been in such places.

You and the other pig attendants should follow the same rules and keep away from contact with other pigs and contaminated places too.

Control of rodents and flies

Rats can carry a variety of diseases from one pig farm to another. Mice do not travel much between pig farms but they do perpetuate infections such as salmonella and swine dysentery. Flies can carry infections such as streptococci that cause pig meningitis and can travel up to about 3km (2 miles) between pig herds.

Water, feed and bedding sources

Check on the source and cleanliness of the water you provide to your pigs. Water can bring a number of infections such as leptospira and salmonella. If in doubt, chlorinate it. Check also the water storage tanks and pipes.

Scrutinise feed sources and constituents. Avoid meat and bone meal. In the USA where there is a very rapid turn round of grains through the compounders it is thought that feed may spread TGE. If you are worried about this store it for a few days before feeding it.

Bedding, if used, should come from a pig-free source and not become contaminated by birds, rats or mice during storage.

Keep out notices

Provide large notices and a siren/klaxon type door bell so visitors can contact farm workers without need for entering the farm. Alternatively provide a mobile phone number as many mangers now carry these.