Listen: Bad seeds - All affected farms identified

Herd of dairy cows Supplied to the NZ Herald by Dairy NZ

More than 500 farmers were accidentally sold the wrong seed, which has caused them to inadvertently grow crops connected to the deaths of hundreds of dairy cows in 2014.

Farmers who assumed they had bought a new seed variety, Hawkestone yellow-fleshed Cleancrop swede, were sold a white-fleshed swede, HT-S57, that was linked to dairy cows suffering from liver disease, photosensitivity and dying three winters ago.

DairyNZ's Strategy and Investment Leader Dr Bruce Thorrold spoke to The Country's Jamie Mackay today saying the mistake was "hugely disappointing."

"Clearly there's been a monumental error made in the supply chain somewhere and farmers are now having to work through the consequences of this."

Dr Thorrold told Mackay "the only positive aspect of this is that we're finding this out now and not in three months' time."

Solving the problem is going to be "relatively straight forward" as well according to Dr Thorrold as the two varieties of swede are easily recognisable, one being yellow and the other white.

Listen to Jamie Mackay's interview with Dr Bruce Thorrold below:

Also on today's show Jamie caught up with the company behind the error, speaking to the General Manager of PGG Wrightson Seeds, David Green.

Green admits his company has made a serious mistake with the seed mix up, but that the white-fleshed swede doesn't mean instant death for sheep and cows.

Green also reports that PGG Wrightson Seeds has identified all affected farms - "it's our understanding at the moment that we know and have already communicated with those 556 farmers."

Listen to Jamie Mackay's interview with David Green below:

As for compensation, Green says PGG Wrightson Seeds is currently too busy dealing with understanding what has happened and communicating with affected farmers at the moment, "we haven't even contemplated further down the track and what that looks like."