Tahnee Manton, Northern Tablelands Local Land Services Livestock Officer
The mice that are and have been present in the Northern Tablelands over the past months mean a large proportion of stored livestock feed has not only been eaten by the mice, but has also probably received some degree of contamination. Aside from causing damage, mice carry disease that pose a risk to the health of our livestock and caution needs to be taken if the remaining feed is to be utilised.
Leptospirosis, or “Lepto” as it is more commonly known, is a major risk as it can be spread by mice urine. There are quite a significant number of different strains of Lepto, and two of these strains are known to cause abortion in cattle (L. hardjo and L. Pomona). There is a vaccine available to prevent this, but vaccinations in general are an important part of any animal health program.
If you are planning on feeding out any hay or feed that has been contaminated by mice, it is recommended that your cattle are fully vaccinated for Lepto well in advance of providing the feed (two shots 4-6 weeks apart for full immunity).
As previously mentioned, there a number of different strains of Lepto that mice carry. The other strains have the potential to infect humans who are handling the feed. If you do have to handle the feed, wear the appropriate protective clothing when touching it to help reduce the risk (long sleeves and pants, gloves, eye protection and a mask). Please see the link below to the latest fact sheet from NSW Health on Lepto: https://www.health.nsw.gov.au/Infectious/factsheets/Pages/leptospirosis.aspx
Lepto vaccines are normally available as 7-in-1 vaccines, with the Lepto additional to the normal 5-in-1 components that cover the clostridial diseases. If there is mice carcass contamination of the feed due to baiting, a botulism vaccination may also be a worthwhile consideration. Using a botulism vaccine that has a 12-month booster compared to the 3-year variety is preferred, and should be a normal component of a vaccination program if feeding silage.