What is diarrhoea?
Diarrhoea, or scours, occurs when intestinal fluids are not absorbed appropriately in the intestines. Usually these fluids are mostly reabsorbed and only a small amount is passed in the faeces. Anything that affects the intestines' ability to absorb fluid may result in diarrhoea.
Causes and risk factors
Where diarrhoea is the most obvious sign, the primary causes can be thought of broadly in two different groups, nutritional and infectious.
Nutritional causes include:
- acidosis (e.g. grain overload)
- lush green feed
- cobalt or selenium deficiency
- copper deficiency or toxicity
Infectious causes include:
- viruses (e.g. bovine viral diarrhoea virus)
- bacteria (e.g. Salmonella or Yersinia - see the Bacterial diarrhoea heading below)
It is important to remember that some infectious causes of diarrhoea, such as Salmonella and Yersinia, can potentially affect humans. Always practise high levels of hygiene when dealing with sick cattle.
There are many other diseases where diarrhoea presents as a secondary issue. Some of these include:
- liver disease
- peritonitis (e.g. hardware disease)
- heart failure
- chemical or plant poisonings (e.g. lead or nitrate)
Be aware of the potential for emergency diseases and how to report them
Diarrhoea can also be a sign of certain emergency animal diseases not present in Western Australia. If any of these diseases became established in WA, market access for animals and animal products could be severely impacted. Early diagnosis of an emergency animal disease is vital to allow rapid eradication of the disease and re-establishment of market access.
If you see any unusual signs of disease, abnormal behaviour or unexpected deaths in stock, including diarrhoea, call:
- your private vet
- a Department of Primary Industries and Regional Development (DPIRD) veterinary officer or
- the Emergency Animal Disease hotline on 1800 675 888.
How to diagnose the cause of diarrhoea
Early diagnosis of disease and treatment are essential to minimise production and stock losses. A vet can help diagnose the cause of diarrhoea by collecting faeces, blood or post-mortem samples for laboratory analysis.
DPIRD provides subsidised veterinary investigations for any livestock disease with high stock losses or similar disease signs to an exotic or reportable disease. For more information about disease investigation subsidies, see the webpage: Significant Disease Investigation Program.
For more information about DPIRD's livestock health surveillance program, watch this short video: Animal health surveillance in Western Australia.
Treatment decisions for cattle suffering from diarrhoea should be made in consultation with your vet. Dehydration and electrolyte losses can occur rapidly when diarrhoea is present. Depending on the cause of diarrhoea, treatment options may include responsible use of antibiotics or anthelminthics, anti-inflammatories, rehydration fluids, vaccination, mineral supplementation and ration management.
Note that antibiotics are only useful if the cause is a bacterial infection. Unnecessary use of antibiotics can contribute to development of antimicrobial resistance. See the antimicrobial resistance webpage for more information.
Identifying the cause of diarrhoea in the herd will allow you to make a sound plan about how to prevent or minimise the effect. This can include reviewing rations, grazing plans, worm management and biosecurity practices.