Mice and animal health

Mice are known to carry diseases that can pose a risk to livestock, most likely transmitted through contaminated hay and other feed sources

Mice in hay – What's the risk?

When mice levels are high, producers should be mindful that stored hay, or the hay you are buying in, could have some level of contamination from mice.

It is important producers consider their options before using or purchasing potentially contaminated hay, as it can carry risks, such as:

  • Livestock avoiding hay due to smell
  • Leptospirosis in cattle
  • Botulism in livestock.

Leptospirosis

Leptospirosis, commonly known as ‘Lepto’, is a disease transmitted through mice urine via direct contact or contamination of water and food sources. Strains of the disease can cause abortions and reproductive losses in cattle but not normally in sheep.

Cattle can be vaccinated against Leptospirosis, but this requires two injections four to six weeks apart. There is no vaccine available for sheep, but Leptospirosis is not thought to cause clinical disease in sheep.

Leptospirosis is also a zoonotic disease that can cause serious illness in people. For more information on this disease, visit NSW Health.

Botulism

Botulism is a disease seen in animals that eat dead decaying carcasses, including mice carcasses, or contaminated food sources. Symptoms include paralysis and sudden death, with very few animals recovering.

There is a vaccine available for both cattle and sheep, but it also requires two injections, so if you are planning on vaccinating, thinking ahead is key.

If landholders have concerns over the potential impact of mouse numbers on their livestock health, please contact your local district veterinarian or private veterinarian.

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