“She had a full udder of milk and ate all her meal in the parlour last night,” one farmer told me recently on a call-out.

He was very worried about one of his best cows, as she just lay there motionless, head down and grunting, obviously a very sick animal.

Examining her, I suspected she had peritonitis, maybe caused by a nail or piece of wire.

Because her heart rate was weak and extremely rapid, she wasn’t suitable for an operation, so I gave her a reticular magnet in the hope it might attach on to whatever was causing the problem.

Unfortunately, she died very soon afterwards, so I offered to do a post mortem.

Opening into the abdomen in the knackery, I could see she had extensive peritonitis, caused by a piece of wire penetrating the stomach, and now stuck into the heart of the unfortunate animal. She must have had an extremely painful death.

The wire, about 4in long, was obviously from a tyre. Mixer wagons will chop wire and metal into small pieces, which can be swallowed easily with silage.

Some have a magnet in them to collect such objects and I think all mixers should have these magnets.

Sometimes when a cow has a wire in the stomach, the symptoms can be vague, as the animal may appear quite sick one day and then seem perfect for several days after.

But leakage from a stomach puncture will cause peritonitis and then it may be too late to do anything.

I am often amazed to see how much a cow puts up with; seeming OK shortly beforehand and then, on opening into her, finding generalised peritonitis.

So check the tyres on the silage pit and get rid of the old frayed ones before it’s too late.

Jim Kelleher MVB MRCVS, CertDHH works at Riverview Veterinary Group, Bandon, Co Cork. Riverview Veterinary Group is part of XLVets. XLVets is a group of progressive practices who are working together to achieve a better future for agriculture and veterinary in Ireland. For information, see www.xlvets.ie.