At Christchurch District Court yesterday he was sentenced to 300 hours of community service, ordered to pay reparation of $223 for veterinary costs and was banned from owning cows for five years.
The damage to the tails occurred from about the end of October until late December 2010, with the farm owner being alerted to the situation at that time by another farm worker.
Canterbury/Westland District Compliance Manager Peter Hyde said a veterinarian had discovered that 46 per cent of the 500 cows had fractured or dislocated tail bones, or soft tissue damage to the tail as a result of a twisting or lifting of the tail.
"This is the largest percentage of animals in a single herd we have seen that have been deliberately physically injured," Mr Hyde said.
"This sort of behaviour will not be tolerated, and the court has made this message very clear."
As a result, Jackson was suspended from his duties under suspicion of serious misconduct in the form of mistreating his stock and was advised of a disciplinary hearing.
He later abandoned his position at the farm with no notice.
Today, the MPI said people in charge of animals have an obligation to the welfare of those animals, but accepted the vast majority of farmers and industry take their obligations very seriously.
Animal welfare breaches can be reported on the MPI's hotline - 0800 008333 where calls can be treated in confidence if necessary. "MPI and industry will continue to work together to help ensure this type of incident does not occur in the future," a spokesman said.
Earlier this month, Waikino farmer Lourens Barend Erasmus was jailed for two years and one month for breaking the tails of 115 cows and hitting the animals with steel pipes and milking cups in the cow shed.
