The Southland working group formed to investigate the mystery illness striking dairy cows grazed on swedes will be issuing updated advice to farmers this week.
The group, including vets and farmers as well as dairy and sheep and beef industry representatives, was set up following the death and illness of hundreds of cows that have eaten swedes, mostly a herbicide tolerant variety.
After its first meeting last week, it circulated advice on managing cows that have been affected.
This week it will focus on advising farmers on planning for next year’s swede crops.
That is an problem, because farmers will have to start planting soon, well before experts can confirm the root cause of the problem.
Southland vet Mark Bryan, whose practice has been dealing with most of the swede related cases, said at this stage, they were still looking at naturally occurring compounds called glucosinolates in the leaves of the swedes as the most likely source of the problem.
“So the hypothesis is the glucosinolates in the leaves that are building up – there’s a lot of leaf this year in general because we haven’t had the cold days,”, he said.
“HT (herbicide tolerant) swedes in particular produce a lot of leaf, so these things combined to form a sort of perfect storm as it were, of risk. And to add another level to that, we know that late season’s swedes are higher risk again, so if you add that into the mix – a lot of leaf, mild winter, late season swedes, you can see that’s why it seems to have got worse in the past couple of weeks or month.”
Source: Radio New Zealand News