What is salt poisoning?
Salt poisoning is toxicity due to an increase in salt (sodium chloride) concentrations in the blood.
Causes of salt poisoning
Salt poisoning occurs most commonly when livestock have been restricted from a fresh water supply for more than 24 hours. This water restriction causes a relative increase in salt concentration in the blood due to dehydration and is more likely to occur if livestock are being fed a high salt diet or one in which salt is added but inadequately mixed.
Salt poisoning can also occur if livestock consume excessively saline water. This can result from livestock:
- being watered only on water supplies which exceed safe salinity levels
- consuming water that has accumulated in salt lick or block containers
- drinking from salty puddles that form after summer rain when salts have been brought to the surface through evaporation
- being watered on troughs which have been inadequately cleaned allowing salts to build up.
This occurs less commonly as livestock become accustomed to gradual variations in water salinity and will often refuse to drink excessively saline water. It is more likely to occur when livestock are suddenly introduced to the water supply, especially if they are thirsty from travel or during high daytime temperatures. Livestock tolerances to saline water are described in the following webpage: Water quality for livestock.
Which animals are most at risk?
All livestock can be affected by salt poisoning if fresh water is withheld for longer than 24 hours. Pregnant or lactating stock, young animals or animals subjected to heavy heat stress or water loss are most at risk of salt poisoning as a result of excessively saline water.
Signs of salt poisoning
Signs of salt poisoning are often evident in a large percentage of livestock at one time and include:
- excessive thirst, abdominal pain and diarrhoea in mild or early cases
- nervous signs such as tremors, blindness, holding the head abnormally, circling and convulsions
- rapid loss of condition and weakness
- coma and death.
Treatment
Livestock affected by salt poisoning should be slowly introduced to small amounts of fresh water frequently until rehydration has occurred. If salt poisoning is a result of consuming excessively saline water, livestock should be immediately removed from this water supply. Often salt poisoning is only noticed after livestock have already had access to fresh water so preventing further access is of no benefit. Seek veterinary advice on how to further manage affected livestock.
Prevention
To prevent salt poisoning:
- Check water supplies regularly, especially if livestock are watered on troughs or bores which may malfunction.
- Only allow thirsty livestock access to small amounts of water at frequent intervals until they rehydrate.
- Avoid sudden introduction of livestock to saline water supplies. Carting fresh water for a few days to mix with saline water can help livestock adapt.
- If adding salt to rations, ensure the correct rate is added and it is adequately mixed.
- Do not allow water to accumulate in salt lick or block containers.
- Regularly clean troughs.
Diseases that look like salt poisoning:
- staggers caused by annual ryegrass toxicity, perennial rye, paspalum or phalaris
- lead poisoning
- thiamine deficiency induced polioencephalomalacia (PEM)
- exotic diseases such as bovine spongiform encephalopathy (BSE) and Aujeszky’s disease.
How a veterinarian can help
A veterinarian will be able to investigate whether salt poisoning or another disease is occurring. Your veterinarian will also be able to provide advice on the most appropriate treatment for stock in your particular situation.
Producers play a vital role in early detection of exotic diseases in Australia. If you see unusual disease signs, abnormal behaviour or unexpected deaths in your stock, ring your private veterinarian, the local Department of Agriculture and Food (DAFWA) Field Veterinary Officer or the Emergency Animal Disease hotline on 1800 675 888.
It is important to recognise and report signs of these diseases to a veterinarian quickly so that disease spread and potential impacts on trade, your industry and your community can be minimised.