Firstly, with spring growth, losses due to enterotoxaemia, also known as pulpy kidney, become a distinct possibility.
Secondly, a feature of the enterotoxaemia vaccine is the duration of immunity that it provides may be quite short. It may only give three or four months of protection.
Therefore, a booster dose should be given before a high-risk period, that is, before the beginning of spring.
Young stock in good condition up to two years of age are most affected by enterotoxaemia, however deaths in older stock may occur.
Enterotoxaemia is caused by a toxin produced by Clostridium bacteria, which is found in the bowel of normal, healthy cattle and sheep.
Enterotoxaemia occurs when a large amount of readily fermentable feed is present in the bowel leading to rapid multiplication of the bacteria and a lethal level of toxin production.
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.
Little can be done to treat an animal affected by enterotoxaemia, therefore the emphasis should be on prevention.
The key to prevention is to ensure all 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 to gain an active immunity. This is achieved by giving two injections at least four weeks apart.
Hopefully all producers will benefit from the upcoming spring conditions without being troubled by the problems that they may bring.
For further advice, contact your local veterinarian or Agriculture Victoria veterinary or animal health officer, or in NSW your Local Land Services.
Dr Jeff Cave is Agriculture Victoria’s senior veterinary officer.
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