Increased demand for novel drench products, which help manage parasites like worms on farm, has resulted in a supply shortage - right at the tail end of calving and lambing.
Industry association Animal and Plant Health has warned product supplies are likely to be constrained until at least March 2024, due to rising demand regionally and internationally for the products, which help manage increasing levels of resistance to traditional drenches.
This would create challenges for farmers experiencing resistance issues during the busiest time of year for many, because worms were detrimental to animal health and could cause production losses, the industry group said.
Instead, farmers could manage pastures, monitor for parasites and try out drenches still available.
Furthermore, they could try to slow development of drench resistance by ensuring there was a population of susceptible worms not exposed to drench treatment, known as refugia.
Worms in refugia eaten by sheep or goats after a drench should dilute the remaining resistant worms.
Farmer education charity Wormwise said New Zealand must keep developing tools to improve animal and crop health to support the country's farmers and growers.
It said innovation in pest and disease management benefited agriculture and the environment by ensuring optimal productivity.