The Ministry for Primary Industries (MPI) will not charge anyone for animal welfare offences after an investigation into the condition of cattle ferried across Cook Strait last month.
The Jersey cows were being taken from a farm in the upper South Island to a meat processing plant in Wellington.
A member of the public took exception to the cows' bony appearance and laid a complaint.
MPI said animal welfare inspectors interviewed the farmer, the stock agent who arranged the transport, the truck driver and the owner of the transport company.
Workers and the vet at the processing plant were also questioned as part of the investigation.
Nelson-Marlborough district compliance manager Ian Bright said there was no evidence the 50 cows were suffering any physical harm through poor body condition.
Mr Bright said although the cows were not in prime condition, they were able to be transported and processed, and no animal welfare offence was committed.
MPI said it had received more than 200 animal welfare complaints relating to farm stock so far this year.
There have been no prosecutions yet, but it said many of the cases were still being investigated.
The ministry said 698 complaints were reported last year, 18 of which resulted in charges being laid.