STOCK VETS VOICE
Words by: Lisa Whitfield
Meal not metal
H
pregnancy, calving and riding cows during oestrus, can increase the risk of metal piercing through the reticulum wall.
ardware disease must be one of the most practically named animal diseases. RUMEN MAGNET A CURE, AND I remember hearing about PREVENTATIVE it when I was in vet school and thinking The treatment for hardware disease is to myself – how interesting to a long course of antibiotics, antihave a disease which is basically inflammatories, and giving her entirely man-made – it can’t be a rumen magnet. blamed on bacteria, viruses, the Unfortunately for many weather or the mud, it is solely cows, they are found when a human-made disease. the disease is at a stage where Most farmers will have had the damage is already done, a cow diagnosed with hardware the infection is overwhelming disease at some stage in their career. and the cow is not likely to survive Lisa Whitfield While it is not something that I and thrive. see every day, most people have a story Did you know that a rumen magnet is to tell of the cow they had which died not only part of the treatment for hardware of it. disease, but can also be a very effective The worst case I have been involved with preventative? Giving a rumen magnet to was when a piece of fencing wire each cow in your herd reduces the risk of was accidentally chopped into silage, them getting sick in the first place. and the farm lost eight cows over just a few weeks. In one of those cows which I did a postmortem, a 1 inch length of fencing wire had lodged in the space between her liver and rumen, and many litres of infected fluid had formed into an abscess. Hardware disease occurs when a cow accidentally eats a sharp, often metal, object such as a nail, fencing staples, or offcuts of fencing wire. The reticulum is the sorting compartment of the cows stomachs, where large food particles are separated and sorted from fine particles. Dense objects such as metal can become The humble rumen magnet is a very lodged in the reticulum, and may puncture low-cost item. Would you spend $3.35 on the stomach wall. a cow, once in her lifetime, to reduce the Once this has occurred, the object can risk of her getting hardware disease? This track through into other parts of the body. is less than 0.001% of the average cow’s Bacteria from the gut will also track with production per season – less than 0.5kg the object, and major infection will form milk solids. leading to sickness and often the death of Administering a magnet to a cow the cow. only has to be done once as the magnet Predilection sites for infection are the lodges in the rumen or reticulum and stays abdominal cavity, liver and through the there as it is too big to pass further through diaphragm into the lungs and the heart the cow. Rumen magnets are given using – all of the structures which are in close an oral bolus applicator. proximity to the reticulum. The magnet attracts stray metal that she It is thought that anything which may accidentally ingest. With the level of increases abdominal pressure, such as concentrates going through mixer wagons,
‘The worst case I have been involved with was when a piece of fencing wire was accidentally chopped into silage, and the farm lost eight cows over just a few weeks.’
The type of metal objects commonly found onfarm which can be picked up by cows can be collected by a rumen magnet.
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Dairy Exporter | www.nzfarmlife.co.nz | June 2021
