Bovine spongiform encephalopathy (BSE)

Find out about bovine spongiform encephalopathy (BSE), the work MPI does to minimise the risk to New Zealand and how you can help.

Mad cow disease

Bovine spongiform encephalopathy (BSE) is a type of transmissible spongiform encephalopathy that exclusively affects cattle.

BSE causes mania-symptoms in cows – trouble controlling legs, erratic behaviour and increased aggression. Because of this, it's become commonly known as mad cow disease.

BSE rose to international awareness after a severe outbreak began in the United Kingdom in 1986. By the end of 2001, around 180,000 cases of the disease had been declared. At the height of the epidemic, nearly 1,000 new cases were being reported every week.

BSE was first confirmed in North America in 2003. Reported cases since its discovery have been much lower than in the UK.

The first case of BSE to occur in France was declared in early 2016.

BSE in humans

In 1996, BSE was confirmed in humans as a disease called variant Creutzfeldt-Jakob Disease (vCJD). vCJD spreads when meat from diseased cattle is consumed.

There are no known cases of vCJD in New Zealand.

Preparing to respond

An outbreak of BSE could have a severe impact on New Zealand's economy. Exports of cattle meat, semen, embryos, biopharmaceuticals and livestock could all be affected.

Many countries, including New Zealand, have import bans in place for meat and meat-products that could spread BSE. Unfortunately, BSE can also be caused by spontaneous genetic change (an abnormal change in DNA that is not passed from parents to offspring). The risk to New Zealand is incredibly low but we cannot guarantee 100% safety – early detection is one of our best defences.

MPI runs an early detection programme for TSEs. Farmers and vets can receive financial compensation for participating in the programme.

You can help

BSE can incubate for up to 8 years before an infected animal shows symptoms. It spread very quickly in the United Kingdom – most likely due to cows being fed mix containing the remains of animals no one knew were infected.

To prevent this sort of accidental spread, MPI has ruminant feeding regulations in place in New Zealand.

If you have ruminant animals – including cows, goats, sheep and deer – you must not feed them any food containing meat, organs or bones from other ruminants.

Who to contact

  • To report a pest or disease, call 0800 80 99 66.
  • If you have questions about the information on this page, email
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