The court heard how Erickson, who was emotional in the dock, dragged, hit, kicked and threw 115 bobby calves over two days at Down Cow.
Judge Burnett said the calves were vulnerable because they were newborns.
They were meant to be stunned and then killed but one was hung on a meat hook still alive.
Others were thrown or kicked with such force it would have caused pain and suffering, she said.
Erickson's lawyer said his client was not given sufficient instruction and felt he could not disobey his employers because he was struggling to support his wife and 4-year-old daughter.
Judge Burnett accepted Erickson was not adequately trained or supervised.
MPI compliance operations manager Gary Orr said the offending involved a significant number of calves who were treated with extreme cruelty.
"It would be nice to be in a society where young and vulnerable animals like this were not treated in this fashion."
Outside the court animal activist Lynley Tulloch, who operates a bobby calf rescue programme, said the sentence was weak.
"This was a landmark case and it demonstrates New Zealand's lack of commitment to animal welfare."
Save Animals From Exploitation executive director Hans Kriek said the sentence was finally justice for the abused calves.
However, he said SAFE remained concerned not enough was being done to protect the welfare of millions of calves born into the dairy industry each year.
Around two million calves were surplus to requirements each year.
The abuse was brought to light after Farmwatch secretly filmed Erickson in a hidden camera sting.
The Ministry for Primary Industries launched a probe last September following release of the footage.