Spring is approaching.
Unfortunately, spring-like conditions can sometimes result in livestock health issues.
With abundant spring growth, losses due to enterotoxaemia may be more likely.
Enterotoxaemia is caused by a toxin produced by Clostridium bacteria.
These bacteria are found in the bowel of normal, healthy cattle and sheep.
Enterotoxaemia can occur when a large amount of readily fermentable feed is present in the bowel, leading to these bacteria multiplying rapidly and producing a lethal amount of toxin.
Due to the rapid progression of the disease, an animal affected by enterotoxaemia will typically be found dead in the paddock.
On post-mortem, rapid decomposition of the carcase is seen.
Young stock up to two years of age, and that are in good condition, are most commonly affected; however, deaths may also occur in older livestock.
Little can be done to treat an animal already affected by enterotoxaemia, and so the emphasis must be on preventing this condition.
The key to prevention is to ensure all your livestock are adequately protected through vaccination.
As with any vaccination program, adult cows and ewes should be vaccinated about one month prior to giving birth, to give their calves and lambs maternal or passive immunity through colostrum.
Passive immunity lasts about six weeks, after which calves and lambs need to be vaccinated twice, with an interval of about four to six weeks (refer to manufacturer’s directions).
Most vaccines provide about 12 months of protection and should therefore be given annually.
A feature of the enterotoxaemia vaccine is that the duration of immunity it provides may be quite short.
It may only give three or four months of protection.
Therefore, it is important for each livestock owner to consider the most effective times to vaccinate their herds or flocks.
This may include a booster dose given before high-risk periods, such as the beginning of spring.
For more advice, contact your local veterinarian or Agriculture Victoria veterinary officer or animal health officer.
— Agriculture Victoria district veterinary officer Dr Jeff Cave