The meninges are the membranes that cover the brain and spinal cord in all animals. Meningitis simply refers to inflammation of these layers and, in cattle, it is most commonly caused by bacteria. When discussing meningitis in cattle, it is best to consider the two most common presentations:

  • Septic meningitis in the neonatal calf, and,
  • Listeriosis, which is a common meningoencephalitis (inflammation of both the meninges and brain) in adult cattle.

    • The focus in this article is on septic meningitis in the neonatal calf, while information on listeriosis can be got here.

    Cause

    Meningitis in the neonatal calf almost always occurs after septicaemia. Bacteria and their toxins travel in the bloodstream and settle out in the blood vessels of the meninges, leading to the disease. Calf septicaemia much more commonly leads to joint ill following the spread of bacteria from the navel or intestines. However, in a small percentage of cases, meningitis ensues. In most cases, the bacteria involved are those that are also associated with calf diarrhoea, ie E coli and salmonella dublin.

    The most common predisposing factor for septicaemia and meningitis in calves is a failure of passive transfer of colostral antibodies (protective antibodies against infections). Calves are basically born immunologically naive with virtually no immune system and are very dependent on the cow’s colostrum to give them that initial immunity.

    If calves do not take in sufficient good quality colostrum within the first six hours after birth, their ability to combat infection, in the form of diarrhoea, pneumonia or septicaemia, is dramatically reduced. Therefore calves with meningitis that have had a failure of passive transfer of immunoglobulins are unlikely to respond to treatment.

    Symptoms

    The clinical symptoms of bacterial meningitis depend on the stage of infection. Initially calves tend to be depressed and have a high temperature. These signs rapidly progress to more classic signs associated with inflammation and fluid build-up (oedema) around the brain. Such symptoms include rigidity of the neck, blindness, nervousness or twitching (hyperaesthesia), ‘star gazing’ where the head is bent back with the eyes looking upwards (opisthotonus) and occasionally convulsions or a coma.

    Other signs that may be seen can be attributed to general septicaemia such as joint ill, navel ill, diarrhoea, inflammation of the pupil of the eye (uveitis) and pus in the front chamber of the eye (hypopyon). Many of these symptoms are not very commonly seen and it would be difficult for a farmer to recognise, and so the diagnosis of meningitis requires a thorough veterinary examination.

    Treatment

    When advanced clinical signs are present, treatment is often futile. The brain is very sensitive to inflammation and brain damage often occurs quite quickly. Early veterinary treatment with broad-spectrum antibiotics) will give the best chance of recovery. These must be combined with anti-inflammatories to reduce the fluid build-up around the brain. Supportive care is very important, including soft, dry bedding and the administration of oral or intravenous fluids as necessary.

    Prevention and control

    The key to preventing neonatal meningitis and neonatal septicaemia is good colostrum management and good hygiene in the calf housing. The calf will be much less likely to get sick if he/she has a strong immune system, obtained through the consumption of antibodies found in colostrum. Also, if the calf is not exposed to as much pathogenic bacteria which can be achieved by ensuring a hygienic calving area, good calf housing and adequate dipping of the navel directly after birth.

    In terms of colostrum, newborn calves should receive 10% of their bodyweight of colostrum within two hours of birth, for a Holstein Friesian calf (35 to 45kg) this is approximately three litres while for a heavier continental calf (60kg) up to six litres would be required. This will ensure the calf has a strong immune system to fight disease. Absorption of antibodies from colostrum drops off dramatically by 24 hours of age, so ideally a 12 hour old dairy calf should have received 5 to 6 litres while a large continental calf should have received 10 litres.

    One of the main portals of entry of bacteria into the calf’s bloodstream after birth is via the navel. The navel should, therefore, be dipped with a concentrated iodine solution (or a chlorhexidine based dip; or oxytetracycline spray) at least twice: once immediately after birth and again 12 hours later. However, more importantly the calf should be kept on a clean dry bed.