Farmers are being reminded about new docking rules this spring after new rules came into effect last year.
Tail docking is not mandatory but can be done to reduce the risk of flystrike, which can be painful and sometimes fatal for sheep.
New regulations for tail docking came into effect in May 2021, in an effort to improve sheep welfare by clarifying how tail docking should be done and who can carry it out.
Although tailing is a common farming practice, it is a significant procedure for the lamb.
New offences and penalties for breaches of the rules, including fines of $500 and possible criminal charges, were also introduced.
Beef + Lamb NZ biosecurity and animal welfare senior adviser Will Halliday said it was important all farmers were on the same page for the practice.
"The minimum length allowable will be at the distal end of the caudal fold, which is the little skin flap that attaches the base of the tail to the lamb's rear end," Halliday said.
"Now for most farmers, that wouldn't have actually changed anything, but unfortunately it's caused a bit of confusion in various parts of the country as to whether or not we should be cutting tails longer than we have done," he said.
"We seem to have got through last season okay, but we've received quite a few calls about the confusion and wondering why we have to change, particularly from Southland."
Some farmers raised concerns about the practicality of the new regulations, Halliday said.
"One of the concerns is that it could be more difficult to crutch and it's a bit of a pain for the shearer to do so, but nothing that's been proven yet," he said.
"Some people have talked about the possibility of increased flystrike and more dags on the sheep, but we're still looking at the evidence as to how severe that actually is."
The new regulations brought New Zealand into line with those of its major trading partners, which require the docked tail to entirely cover the vulva in ewe lambs and an equivalent length in males, Halliday said.