Clostridial Disease

 Right from the start animals, and I suppose people, live in balance with millions of bacteria in the gut, skin surface and in the air way. Many of these bacteria are also found in soil and it is usually only when they get out of balance that things start to go wrong. Clostridial organisms are dangerous. They will be tolerated in modest numbers but once they start to dominate toxins are produced and disease follows. Clostridial toxins are some of the most dangerous substances that we have to deal with. The bacteria can only survive where there is no oxygen, but that doesn’t stop them causing disease when they rapidly increase their numbers. These are the significant diseases that they cause.

 Blackleg.

 This affects cattle and sheep. Young animals are most at risk. Spores from bacteria lodge in muscle tissue where they can survive for months. Deaths occur if there is muscle damage after exertion or bruising from animals with horns. As the bacteria multiply small gas bubbles build up in the tissues. These are painful and the toxins make the animal depressed. It is often the better individuals in a group that die from blackleg as these are the ones that take in the most feed and the most bacteria. It is rare to see an animal with blackleg that is still alive. Only once did I try to treat an animal with blackleg. I seem to remember it was late one evening, raining and dark when I injected a bullock with a large dose of crystalline penicillin under a hedge in a field that was close to a stream. I was not surprised to hear that the bullock was dead the next morning.

 Pulpy Kidney

 This is a disease of young lambs. Usually several are affected at the same time. Toxins from bacteria in the gut cause the kidneys to decompose. Levels of urea in the urine are elevated as the kidneys stop working. Ewes will sometimes develop this disease if they have missed their vaccinations depending on how many bacteria they have in their gut the toxins can take up to twenty four hours to kill.

Black Disease  

Fluke are becoming a significant problem on some farms. Young sheep often suffer as they can get liver damage when young fluke migrate through the organ. If there are spores of Clostridium novyi present in the gut some will get to the liver and release a toxin once the fluke start migrating. Black Disease will not occur if you can control the juvenile fluke before they get to the liver.

 Tetanus

 Thankfully this is not a common infection for cattle and sheep although horses are particularly susceptible to it. The bacteria grow deep within a penetrating wound where there is little or no oxygen. Castration rings and tail docking can lead to this infection. The toxin will cause nerve ending to fire uncontrollably as muscles go into spasm. It is very difficult for animals with tetanus to eat or drink as they are not able to open their mouths. Young cattle will often get bloated with tetanus. Lambs tend to go rigid and will get stuck on their side. They will stand if you lift them onto their feet but they will not be able to move. There is a tetanus anti toxin, which does help to ease the worst of the symptoms, but it is not possible for cattle or sheep to recover from tetanus once the symptoms develop so euthanasia is the only option.

 Botulism

 In some ways botulism acts in an opposite way to tetanus. Bacteria in the soil produce a toxin that contaminates the feed that cattle eat. This will lead to a flaccid paralysis, muscles become weak and the animal has a lingering death. The most common cause is when grazing animals have access to carcasses of other animals. It will occur after severe flooding or when manure from poultry farms is spread onto grass land or is left in heaps that cattle have access to. Because the cattle do not have to ingest the bacteria just the toxin there is no vaccine to protect against this disease.

 Not seen Bulling

 High yielding dairy cows are notoriously difficult to get back into calf and I sometimes wonder how they would cope now if left to their own devices. It appears that part of the explanation is that lactating cows have a 40% increase in the amount of blood that flows through their liver. This is where the fertility hormones are metabolised so they have less time to be effective. This effect is further exaggerated after feeding with liver blood flow rates increased by a further 30% giving little time for your better yielding cows to produce a follicle and show outwards signs of bulling. Fertility rates are low for cows that have not shown signs of natural oestrus within eighty days of calving. 

 Evidence Based Medicine

 For the past ten years or more the Buzz Word in the veterinary profession is Evidence Based Medicine. Which means you should only treat a dog or worm your flock if there is sufficient evidence that what you are doing is having the desired effect. Rigorous testing has to be done on all veterinary medicines to prove that they work. New vaccines normally take ten years or more to come to the market because manufacturers have to have the evidence that they are effective before they can be used.

   Cost Benefits

 Also when government funding is under such severe restraints it is difficult or impossible to get projects started unless you can prove that they will be beneficial and save many more times the money that is to be spent. Recently a study of 23 badgers vaccinated intra muscularly with a large dose of the human BCG vaccine showed that it had no effect of stopping the badgers getting tuberculosis. I have not been able to find any studies, if there have been any studies, which positively show that vaccinating badgers has any effect. It seems wrong to me that public funds are used to promote badger vaccination schemes when there is a desperate need to compensate farmers properly for the cattle that they loose to the disease.

 Weil’s Disease.

 We all know about leptospirosis cattle get it, dogs go yellow and die from it if they haven’t been vaccinated and rats carry it. There are several forms of leptospirosis that we can get. The type that cows carry is serious enough the symptoms are to develop a fever, have severe headaches, develop neck pain and have a stomach upset. On most farms leptospirosis is not as troublesome as it used to be as the disease is controlled by vaccination.

When people get leptospirosis from rats it can be a lot more serious. The headaches get worse and toxins produced start to affect the kidneys. If symptoms last for more than five days get help as it will only resolve with antibiotics and drugs to support renal function. Rats are never welcome on farms. Take particular care if you have cuts or broken skin on your hands and arms as this is a common way that the infection will get established.

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