Vet on Call: Diarrhoea in calves and the effective treatment

It is well-known that diarrhoea is the leading cause of calf death on both dairy and beef farms. Diarrhoea is a complex group of illnesses caused by bacteria, viruses, parasites and nutritional problems.

The illness causes farmers lots of losses particularly in calves below 90 days old.

The loss of a calf, even at birth, impacts heavily on the farm’s profitability and the sustainability of the livestock population, considering a calf takes nine months to be conceived and born.

A loss at any time before maturity means a farmer has to wait for at least another one year before getting another calf.

The heifer calf has a greater premium than the bull one because it is the basis of sustainability and expansion of the herd.

During the one year that a farmer waits for another calf, the dead calf would have been close to attaining the first conception had it survived.

Four farmers have called me in the last two weeks lamenting about the death of their heifer calves.

Wanjiru from Nyandarua told me she had lost five calves in four days. Mutisya who resides in Machakos had lost three in two weeks while John from Thika had lost a highly prized heifer calf.

Then there was Barasa from Kakamega who said he had lost two calves in one week and he was worried he would also lose another one that was sick.

It was not surprising that all reported the calves had died of diarrhoea. Their ages ranged from 30 to 120 days. Except for John’s calf, all the others had been treated by the area service providers, but they still died.

Wanjiru narrated that her calves were treated for between two and three days before they succumbed to the diarrhoea.

They were given a white powdery drug by mouth once or twice but none showed sign of improvement. I confirmed with Wanjiru, from a used drug container, that the product was Kaolin, chemically known as hydrated aluminium silicate.

Mutisya’s calves were given some tablets by mouth. All of them showed some signs of improvement but the diarrhoea relapsed in full vigour and the calves died.

I was not able to confirm the identity of the product used. John’s calf was found sick in the evening. It was weak, looked depressed and had no appetite.

COMPRISED MULTIPLE DRUGS

The farm manager decided to call me the following day, but the calf died at night. He still asked me to carry out a post-mortem examination to find out if the other calves and cattle were at risk.

Barasa said his calves had developed diarrhoea, weakness and inability to stand before dying. He was worried his six-month-old heifer would also die of diarrhoea. The animal had been treated for diarrhoea for three days but was producing mucous instead of dung.

I discussed on the phone with his paravet service provider and advised on an alternative course of treatment. By the time of writing this article, the heifer had recovered but Barasa called me and said the treatment had been expensive.

“Well, the cheaper treatment never saved your calves,” I responded in jest. I explained the treatment went beyond his cost expectation because it comprised multiple drugs and the service provider had given some of them as injections for five consecutive days.

Many farmers all over the world go through similar situations because diarrhoea in calves has no one sure cure. The most common cause is infection by Escherichia coli (E. coli) and salmonella species of bacteria either singly or in combination.

The former is the most common of all intestinal bacteria and is also the one that causes most of the bacterial diarrhoea. I will, therefore, explain how E. coli causes infection to your calves and the best way that your service provider should deal with it.

E. coli is also called the faecal bacteria because it is found in the faeces of all living organisms, including humans. It mainly resides harmlessly in the large intestines and the rectum in naturally controlled numbers.

However, changes in the internal intestinal environment such as stress, injury, reduction of other harmless bacteria by drugs or type of food, among other factors, may cause the bacteria to multiply, spread to the small intestines and cause infection.

Overfeeding calves with milk, for instance, can cause abnormal fermentation that may damage the intestinal wall and enable infection by the otherwise harmless bacteria. This will result in illness and diarrhoea.

The most important and common way that E.coli causes infection is by mutating or changing its genetic code. The bacteria can change its genes to form a group of new strains called the enterotoxaegenic E. coli or (ETEC).

The ETEC are infective bacteria and they cause disease even when the gut environment is normal. They can be bacteria that mutate while still in the large intestines or are ingested from the calf’s environment.

INVADES SMALL INTESTINES

Once in the digestive tract, ETEC invades the small intestines and multiply. They attach themselves to the cells of the walls of the small intestines and produce lots of bacterial toxins.

The toxins make the intestinal cells secrete a lot of water into the intestinal space and also prevent the absorption of water in the large intestines thereby causing diarrhoea and dehydration.

In addition, the toxins also cause the removal of sodium and chloride ions from the body into the intestines and the minerals are voided in the diarrhoea.

The toxins further cause breakages in the intestinal wall allowing them and bacteria to move into the bloodstream from where they are distributed throughout the body.

The distribution causes poisoning of the whole body with the general signs of sickness, including fever, lack of appetite, weakness, inability to stand and diarrhoea.

In general, this disease is called collibacillosis when it only appears as diarrhoea. Once it spreads in the whole body, it is called collibacillosis septicaemia, meaning poisoning by bacteria and their toxins.

You may now appreciate why ETEC infection requires a complex treatment plan approached from the different aspects of the disease.

When diarrhoea is the only sign and the calf has good appetite, it is recommended that the animal be kept under observation without treatment and be given high quality feed and lots of water.

Some cases may resolve from the body’s immunity. If there are signs of generalised infection such as fever and loss of appetite, then the calf should be treated with antibiotics given both by mouth and injection for a period of three to five days depending on the severity of the infection. The service provider must use drugs that are known to act on ETEC strains and other bacteria like salmonella.

If a lot of fluids and minerals have been lost through diarrhoea, then fluids with glucose and minerals, especially sodium, chloride and potassium should be given either by mouth or injection.

Kaolin is a commonly used product to manage diarrhoea but unfortunately, it only works by coating the intestinal wall but does not kill bacteria.

It is, therefore, only useful in cases where the diarrhoea would resolve without treatment or where protection of the intestinal wall is the only treatment required.
The best way of preventing ETEC diarrhoea is to ensure calves consume sufficient colostrum within the first 24 hours of life to get the mother’s immunity, ensure good nutrition, management and high levels of hygiene. There are also vaccines that help in preventing the disease, but that is a subject for another day.