By Trudi Baird
Presently, footrot is thought to cost the merino industry in excess of $3m but is estimated to cost the sheep industry as a whole (in this country) between $80m and $100m.
And unless progress is made in dealing with the problem, Footrot which was originally considered predominately a merino disease, is set to increase further into meat breeds as farmers increasingly turn to exotic breeds to increase meat production.
Dr John Hickman, of Lincoln University, said historically merinos were bad for footrot but they have improved greatly. On the other hand, while romneys have historically had more resistance, footrot in our meat breeds is on the increase as new breeds like Texel, East Friesian and Finn are being introduced for fat lamb production.
Footrot in sheep has been given media attention over the past six weeks following on from what was probably the first ever in-depth NZ research into the subject.
At this stage, it is not known how much of a problem footrot is in our meat breeds and Dr Hickman said he would like to see Meat NZ come on board and be involved as the research moves to the next level.
The research team is currently working on getting good quality information to farmers to assist them in better managing the problem.
Work is also being done on genetic markers and breeding for resistance. This area was highlighted as a key point in the research:
“Sheep exhibit considerable variation in disease susceptibility, both within and between breeds, and this variation appears to be heritable. Differences in antibody responses and cellular responses to footrot have been observed among individual sheep, suggesting variation in the response of sheep to (footrot) infection is in part immunological in origin.”
As a result a genetic marker test has been developed and is already being used by farmers for selecting footrot resistant animals.
The footrot bacteria is predominately carried by sheep and goats. It does not live in the ground and is thought to only survive on the ground for about three days.
Dr Hickman said the problem lies with animals that are continual carriers. In other words, they show no symptoms of the problem but spread it. And while farmers tend to only notice the problem when an animal is limping, if a farmer looks closely at a sheep’s hoof, the problem can be recognised as little pockets of infection in the hoof.
Dr Hickman said it will not be possible to eliminate footrot but the idea behind the current work is to bring the problem down to a level where farmers can live with it.