Tahnee Manton, Livestock Manager, Local Land Services Northern Tablelands
The mice that are and have been present in the northern highlands for the past few months mean that much of the stored feed has not only been eaten by the mice, but has also likely received some degree of contamination. In addition to causing damage, mice carry diseases that pose a risk to the health of our livestock and care must be taken if the leftover feed is to be used.
Leptospirosis, or “Lepto” as it is more commonly known, is a major risk because it can be spread through the urine of mice. There are quite a number of different strains of Lepto, and two of these strains are known to induce abortions in cattle (L. hardjo and L. Pomona). There is a vaccine to prevent this, but vaccinations in general are an important part of any animal health program.
If you plan to feed hay or feed contaminated with mice, it is recommended that your livestock be fully vaccinated against lepto well before providing feed (two injections 4-6 weeks apart for full immunity) .
As mentioned earlier, there are a number of different strains of lepto that mice carry. The other strains have the potential to infect humans who handle food. If you must handle the food, wear 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 NSW Health fact sheet on Lepto: https://www.health.nsw.gov.au/Infectious/factsheets/Pages/leptospirosis.aspx
Lepto vaccines are normally available as 7 in 1 vaccines, with lepto in addition to the normal 5 in 1 components that cover Clostridial diseases. If there is contamination of the mouse carcass of the feed due to the baiting, a botulism vaccination may also be a valid consideration. The use of a botulism vaccine that has a 12-month booster over the 3-year-old variety is preferable and should be a normal part of a vaccination program if silage is given.