Background and history

Salt poisoning or water deprivation is the most common poisoning to be seen in swine. It arises where there is a shortage or complete lack of water and the normal salt in the diet then becomes toxic. The normal levels of salt in the ration vary between 0.4 and 0.6% and even at these levels water deprivation can result in toxicity after 48 hours. The higher the level of salt in the diet the shorter is the period of water deprivation before signs are seen. However in the presence of ad lib water the pig can tolerate up to 2% or more of salt in the diet. The first signs are inappetence and whenever this occurs in a pen of apparently healthy pigs or an individual always check the water supply first.

Clinical signs

• The very early stages of disease are preceded by inappetence and dehydration. Whenever a sow or group of pigs are not eating always check the water supply first. Signs develop within 24 to 48 hours.
• The first signs are often pigs trying to drink from nipple drinkers unsuccessfully.
• Nervous signs then develop with fits and animals wandering around apparently blind.
• Pigs show signs of meningitis.
• Often a pig walks up to a wall, stands and presses its head against it.
• Incoordination.
• One sign strongly suggestive of salt poisoning is nose twitching just before a convulsion starts.
• Mortality is usually high.
• Unusual in young piglets.

Diagnosis

This is based upon the clinical signs and lack of water. Examination of the brain histologically at post-mortem confirms the disease.

Aujeszky's disease, swine fever, streptococcal meningitis and glässers disease all produce nervous signs. The condition might also be confused with middle ear infection but this only affects one individual rather than a group of pigs.

Causes

• Water shortage/deprivation.
• Excess salt in the diet.

Prevention

It must be a daily routine to check that all sources of water are adequate free flowing and available.

Treatment

The response to treatment is poor particularly if pigs have developed fits.

Rehydration of the pig is important and this can be achieved by dripping water through a flutter valve into the rectum or allowing water to drip onto the tongue from a hose pipe.

An alternate technique is to inject sterile water at body temperature into the abdominal cavity. This technique requires veterinary advice and direction.