New rules are being drawn up to reduce the risk of metal fragments penetrating the stomachs of dairy cows and other livestock from contaminated palm kernel expeller (PKE) feed.
The Ministry for Primary Industries (MPI) is introducing the rules likely in April with the feed to be screened through a four millimetre mesh and tighter criteria set for record keeping and traceability for all imported animal feeds.
The ministry says the rules will reduce the risk of harm to livestock, particularly in the dairy sector.
Sharp metal fragments sourced from the feed can puncture stomach walls and is commonly referred to as ''hardware disease'' in farming.
This is most known to occur in animals fed with contaminated PKE imported into New Zealand. The supplementary feed is used to boost the grass diet for livestock to increase production and delivers extra intake during a drought.
Ministry for Primary Industries deputy director general, Ben Dalton, said livestock damage through hardware disease was a known issue in farming and there was agreement after talks in the industry on the need for compulsory minimum screening requirements.
"It is currently a requirement for all importers to ensure that feed is fit for intended purposes. This means all animal feed should not contain physical contamination at levels that could lead to harm or distress when consumed. The new rules clarify this requirement."
Dalton said a key element of the new rules was that the screening be done in New Zealand.
He said it was difficult to know the extent of the problem or its cost to the rural sector, but it was common, according to farming organisations.
The varied methods of processing, storing and transporting PKE had made it difficult to manage the quality of feed being delivered to farmers.
If MPI becomes aware of contamination in other imported commodities, more controls will be considered as part of a wider review of animal feeds.
Dalton said existing biosecurity requirements effectively managed biological contamination, but could not cover physical contaminants and their impact on animal welfare.
The new rules will be issued by a notice under the Agricultural Compounds and Veterinary Medicine Act 1997.
All PKE imports will have to be screened in New Zealand for physical contaminants with a 4mm minimum screening mesh to remove contaminants from April 12.
Most imported PKE already screened in New Zealand meets the 4mm specification. Imports screened offshore at the moment will need to meet the new rules.
A draft outlining the new rules is on the MPI's website. The ministry is accepting comment until March 6 before the rules come into effect.