Vet on call: Dealing with tetanus, skin wounds in cattle

By DR JOSEPH MUGACHIA

I get many calls, emails and WhatsApp messages from people enquiring on a wide variety of issues regarding animals, human-animal disease interactions, livestock farming and trading.

Some readers, who are mainly farmers, call to appreciate the benefits of this column. Others contact me to get a second opinion on cases affecting their animals.

It is always a pleasure to engage farmers and readers and help them solve their problems where I can. 

In some cases, I end up with actual site visits and at times I connect the callers with service providers in their areas or suppliers for those who inquire about livestock farm inputs.

I recall a farmer from Embu a few weeks ago whose cows had persistent skin wounds. I diagnosed pressure wounds and connected him with a cow mattresses supplier.

Both the farmer and the cows are now happier. The wounds are gone and to his pleasant surprise, milk production is up and veterinary bills are down.

Scientifically, pain is a milk production and release suppresser. Well-fed, comfortable animals produce more, and happily so.

You see, cows feel nice and relieved every time they discharge their hot udder load of milk. That is why they will always rush into the milking parlour at the conditioned milking time.

If milking is late, they congregate at the milking parlour and start mooing – facing the direction the milker usually comes from.

Limo from Kericho called me this week and said his young bull had a strange disease. The animal was walking as if it had rigour mortis while still alive.

NO IMPROVEMENT

The term refers to the stiffening of the body that occurs a few hours after death.

After prodding, he said the bull had been sick for three days and had been castrated three weeks earlier.

The castration wound appeared to be healing well but he noticed later the bull would stand still and some muscles would twitch.

That progressed to a tightly shut mouth and the animal could not bend to eat. Later, the legs also became stiff and the animal would fall and only stand if assisted.

At the time of reporting, the bull could not walk but would stand with the legs straight and stiff.

Limo’s animal health service provider had diagnosed tetanus and treated the animal with antibiotic and tetanus vaccine, also called tetanus toxoid (TT). He told him chances of the animal recovering were very slim.

Limo sought to know if the diagnosis and prognosis were correct and why there was no improvement. Prognosis is the likely medical cause or result of a disease condition.

It is stated as good, guarded or poor. When guarded, it means either recovery or death. Poor means the patient is unlikely to recover.

I agreed with the service provider. The bull had tetanus and was unlikely to recover.

Cases of tetanus in all animals and humans are usually reported when severe signs of stiff paralysis have already set in. At this point, prognosis is guarded to poor.

Tetanus is a disease of the nervous system caused by the toxin of the bacterium Clostridium tetani in the Clostridia family of bacteria.

Other members of the family also cause various severe diseases in humans and animals.

The tetanus bacteria are found abundantly in the soil and the gut of different animals, including humans. In the gut, they do not cause disease but contaminate the environment through faeces.

SHOW NO SIGNS OF RECOVERY

Members of the equine family comprising donkeys and horses are known to contain lots of the bacteria in their dung.

Donkeys and horses are known to be highly sensitive to tetanus. They are, therefore, routinely vaccinated against the disease. Ruminants are less easily infected and the disease is not very common in cattle, sheep and goats.

However, if the environment on a farm is highly contaminated with the bacteria, outbreaks of tetanus occur frequently. Animals on such farms should be vaccinated routinely with the tetanus toxoid.

The tetanus bacteria kill by producing the toxin under conditions of low oxygen like rotting wounds or healing and healed wounds with poor blood supply. In fact, in most cases, no obvious wound is observed.

The bacteria multiply in the infected tissues and produce toxins. Nerve endings absorb the toxins and they eventually reach the brain. 

The toxin blocks nerve function and causes sustained stimulation that keeps the skeletal muscles continuously contracted. These are the main body muscles that facilitate movement and breathing.

In the early stages of the disease, skeletal muscles have spasms observed as twitching in affected body parts. The twitches progress to tremors before the muscles contract relentlessly and cause stiffness of the appendages, including the legs, tail and ears.

The neck also becomes stiff and the jaws lock tightly. The disease is commonly called lockjaw due to the inability of the mouth to open. Sick animals eventually fall on their sides and react violently to loud sounds.

Prognosis of tetanus is good if proper treatment is done in the early stages of twitches and tremors, but once stiffness sets in, it is poor. Limo’s calf had already attained the stiffness stage by the time treatment started.

Treatment with tetanus toxoid aims at neutralising the toxin circulating in the blood and preventing further blocking of nerves.

However, the toxin blocking the nerves is not affected by the toxoid. It is eventually removed by the body to relieve the stiffening.

Antibiotics are given to kill the bacteria and stop further production of toxins. The animal should also be sedated to help it relax. It should be kept in a cool quiet place with deep soft bedding.

Visible wounds should be cleaned thoroughly with hydrogen peroxide and iodine to remove dead tissue and improve aeration.

Animals that show no signs of recovery within five to seven days should be destroyed as they are unlikely to recover.

The tetanus toxoid, the vaccine, protects the animal for about three years after full vaccination.