In November, I addressed the problems of abortion in cows in the last trimester of pregnancy.

Nowadays, the main culprits are salmonella, leptospira and neospora. In most herds, vaccination is carried out for both salmonella and leptospira, with no vaccine being available for neospora.

Since then, we have seen quite a number of abortions and other syndromes being caused by listeriosis.

Listerias are bacteria that live in the soil and are also found in poorly preserved silage.

My belief is that in silage-making during the heat wave experienced last year, the ground was so dry that soil was picked up with the grass and also that, with the grass being so dry, fermentation around the edges of silage pits was poorer than usual, resulting in more poorly preserved silage than usual.

Several aborted foetuses that we sent for analysis showed up as abortions due to listeriosis.

Listeria can also cause other problems in both cattle and sheep. It can cause a meningitis-type syndrome due to entrance to the nervous system, the most common symptom being known as circling disease, whereby affected animals will walk in one direction only and be incapable of going in the opposite direction.

Another symptom is facial paralysis, whereby the animal’s face looks lopsided, with drooling of saliva on the affected side, while the eyelid and ear on one side may droop.

This can progress to not being able to chew its food and eventual starvation.

Occasionally, the disease can limit the animal’s ability to swallow. Animals that develop meningitis can eventually become totally recumbent and have no hope of recovery.

Early recognition of the disease and prompt treatment continuing over several days will, in most circumstances, result in recovery. Occasionally, recovered animals will exhibit its head slightly tilted to one side, but live a normal life.

This year, abortions from listeriosis were much more common than before, the abortions being the only manifestation in otherwise normal cows.

There is no vaccine available for this condition, so it is hugely important to minimise exposure to poorly preserved silage or very tight grazing in dry conditions where soil is likely to be picked up.