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Faunsdale, AL | A bunch of those germs........... all similar, but some important differences. Tetanus, Botulism, Blackleg, Malignant edema, Overeating disease and lots of local names. They are all caused by different species oftoxin producing, anaerobic, spore forming bacteria. This means that the bacteria only can grow in a place where there is no oxygen and when they have a chance if conditions are not good to grow (too much oxygen etc), they will make a spore and go inactive. These spores will last in the soil and dust etc for many many years, in ideal conditions, probably centuries.
Then when a calf comes along and eats them up on some grazing or dust and soil contaminated feed or hay, they get into the gut and some apparently get into the bloodstream somehow.. Most of the time, they do not cause any problem. If the digestion is not perfect, sometimes the conditions in the intestine will support growth of these spores and the growing bacteria make a toxin. In the blood stream, if a muscle is bruised or fatigued badly, the conditions may support the growth of the bacteria and toxin production. This results in the large muscles of the rear legs being the most common sites for black leg. Bacteria circulate in the bloodstream of cattle fairly often, more often when they are on high grain diets and may be experiencing rumen acidosis and getting damage to the rumen lining.
In almost every case the toxin is the problem.......These things are potent. That is why the vaccines are designed to get the calf immune to the toxin if possible or the bacteria themselves if not possible to make a "toxoid".
As others have pointed out, these are among the oldest vaccines we use today and probably the cheapest to make, so vaccinating for clostridial diseases is one of those decisions where you need a good reason NOT to vaccinate.
I also vaccinate early in life, usually about 1 month old in dairy calves. Do not see deaths before that time, but do see an occasional 1/4 - 1/2% death loss if the first vaccination is delayed until 2 months. We revaccinate at 2-2.5 months at weaning and again at 4-8 months at the time of brucellosis vaccination. Usually the calf that dies will be the largest, growthiest calf in the pen. Really hits hard to loose that kind of calf. Even more when you loose multiple calves. Luckily have never had an outbreak like that. | |
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Blackleg----Anybody experience it?
