WITH many years of experience with sheep tags, Richard Webber of Exmoor-based Shearwell Data urges producers to follow manufacturers instructions for inserting eartags.
"We find most of those who complain about losing eartags are not putting them in right in the first place," he says.
"Norwegian research has shown the top part of the ear is 25% stronger than the bottom part. Therefore, we recommend aluminium tags go in the top half, while two-piece tags go between the two cartilages in the ear and about one-third of the ear length away from the head."
When sheep are not being tagged until summer/early autumn plastic tags are preferable because in warm weather they cause less irritation and stress to the lambs than steel or aluminium tags, says Mr Webber.
But if lambs are tagged within a few days of birth metal tags are equally suitable.
A recent abattoir survey of sheeps ears concluded that metal tags caused problems, but did not include any observations on aluminium tags.
He had not found these problems with aluminium tags. Applied correctly and within a few days of birth few were lost, he claims.
From his large scale field trials on electronic ID systems, Mr Webber has found the most reliable system is a bolus. None have been lost and they are proving easier to read automatically when the animals are on the move. Implanted microchips have shown a 4% loss rate, which is similar to eartags.
But boluses are more expensive than implants – costing £3 each – which means they are hard to justify commercially unless they can be recycled. Mr Webbers company and an abattoir have shown that microchip implants can be recovered and recycled many times, with consequent reductions in cost each time. *