During our day to day working it is not uncommon to be presented with a cow that has non specific symptoms. This ranges from a decrease in milk yield, loss of body condition, temperature and a decreased appetite. Whilst this presentation could include many diseases including pneumonia, metritis and mastitis it is not uncommon to occasionally diagnose traumatic reticulopericarditis. More commonly known as tyre wire or hardware disease. Alun takes us through this condition, the causes, effects and treatment.
What is Hardwear Disease?
Hardwear disease is caused by the cow eating a sharp metal object. This is normally a piece of wire from tyres used on a silage clamp, and are starting to degrade. After the cow ingests the object it sits in the bottom of the cows second stomach, the reticulum. During the normal cudding process the reticulum contracts. This causes the wire to penetrate the wall of the reticulum and the diaphragm and perforate the pericardial sac. This is the sac which the heart is held in. This causes an infection around and sometimes within the heart, as well as a more generalised infection within the abdominal or thoracic cavity.
A closer examination of the cow will normally reveal an increased heart rate, with the heart sounds being muffled due to the pericardial sac being full of fluid. You could also see enlargement of the jugular vein and sometimes a pulse in these vessels as the heart contracts. One common diagnostic test for traumatic reticuloperitonitis is the withers pinch test, in a normal cow if you pinch their withers the cow should dip and perform a shrug like action. In a cow with tyre wire they will be reluctant to perform the dip, or will grunt whilst dipping; indicating pain.
Treatment normally includes a prolonged course of antibiotics, NSAIDs and the use of a magnet to try and ‘catch’ the offending piece of wire. In particularly valuable animals we can perform surgery to try and locate and remove the wire.
As with all diseases, prevention is better than cure. In the case of tyre wire, one of the easiest preventative measures is to substitute tyres on the silage clamp for sand or gravel filled bags. If tyres must be used they should be inspected frequently and any ones showing signs of degradation should be discarded. Another cheap and easy preventative action is to bolus every animal with a magnet. The magnets are inexpensive and in my opinion a sound investment. At the cost of less than £2 each they only have to save one cow every few years to pay for themselves. The use of magnets in mixer wagons is also a common method used to try and prevent cows accidentally being fed dangerous wires.
As always if you have any concerns relating to traumatic reticulopericarditis feel free to talk to your vet.
A Brief Case Study of Traumatic Reticulopericarditis:
I was presented with a reasonably high yielding cow. Her milk had crashed, she had a temperature and was unwilling to stand or move. The farmer had previously treated her with Betamox and Metacam. During the course of my examination I discovered the cow had a temperature. Pulses were visible in her jugular groove in her neck. She had a really high heart rate of 100 bpm and her heart sounded ‘wishy washy’.
We decided to continue the current treatment as well as giving her a magnetic bolus. Unfortunately the cow continued to deteriorate and she was euthanised on welfare grounds 48 hours later.
Below are a few pictures that I took during the postmortem examination, illustrating how quickly a severe infection can develop:
The cows heart was removed from the carcase. As you can see above there is a severe level of infection on the outer aspect of the heart, and an infection is starting to become established on the internal heart structures.
The offending piece of wire that killed this cow was still within the stomach. The other end was perforating the pericardial sac, causing the infection and severe discomfort around the heart.