Gwyn said technical and compliance-related investigations are still ongoing following searches of three properties by warranted officers of the ministry on March 27.
He declined to comment on reports that the searches were related to the possible illegal importation of non-certified veterinary preparations.
MPI has consistently listed seven likely routes of entry: imported live cattle, other imported animals, imported frozen semen, imported embryos, imported veterinary medicines and biological products, imported feed and imported used farm equipment.
However, just one of those -- imported veterinary medicines and biological products – was redacted from the publicly released Pathways Report.
Gwyn said he could not comment on a redacted section of the report.
“The reason it was redacted is we didn’t want it in the public domain for a number of reasons, which I am not going to comment on.
“But I would exercise caution on which pathway is of greater or lesser risk because there are also a number of activities -- technical investigations for want of a better word, such as genotyping, for example -- which are still ongoing.
“Our position at the moment is they are all of very low probability and there’s no conclusive evidence to rank any of those above any of the others. So we are still working on all the pathways as being possibilities.”
The number of confirmed infected properties has risen to 30 (including two more farms in the Ashburton district), one of which was identified through the nationwide milk surveillance and testing.
Every dairy farm has supplied one bulk milk sample and two rounds of mastitic milk samples. Gywn said the sampling is now complete and the testing is 93% complete.
The Ashburton farm is so far the only one identified through the testing but Gwyn said even that farm has proved to be linked to other infected properties by animal movement.
“That gives us a high level of confidence to say the disease is not endemic. It does have an animal movement to one of the previous infected properties so at this stage all 30 properties are connected by some form of animal movement,” he said.
