The South Island is ahead of the North Island when it comes to controlling sheep measles as New Zealand bids for “clean sheep” status.
In the latest data released from the Ovis Management programme, farmers in the south are achieving better results controlling Taenai ovis (sheep measles) with most South Island districts recording low proportions of affected carcases.
Meat processors’ data from October 1, 2021 to June 30, 2022 show the Southland region heading the compliance ladder with one of the country’s lowest occurrences of sheep measles identified in carcases, despite it sending the highest number of animals for processing.
Of 1,919,242 sheep processed in the region from 1,510 farms, just 1,884 (0.1%) of carcasses were found to be affected.
Buller and Westport had no affected carcases after processing just over 13,000 sheep in total.
The highest number of sheep processed in a North Island area for that period was from the Gisborne district with 694,266 livestock from 431 farms, of which 5,355 (0.8%) of carcases were affected.
Opotiki, at 1.7%, recorded the second highest proportion of sheep measles nationally, followed by the Kapiti Coast at 1.1%.
The Chathams recorded the highest incidence at 7.5%, with 10 infected carcases from 134 sheep off just one farm.
Whakatane, at 0.9%, and Otorohanga and Auckland, both on 0.8%, were also among areas with higher proportions of affected stock.
Some neighbouring districts recorded significantly different results, despite similar processing numbers.
Hastings-Napier had 669,499 sheep processed from 446 farms with 4,451 (0.7%) of carcases affected, while Central Hawke’s Bay processed 653,279 sheep from 462 farms with 2,813 (0.4%) affected.
Marlborough and Kaikoura recorded the highest incidence rates for the South Island.
In Marlborough 56,716 sheep were processed from 242 farms, with 1,396 (0.9%) affected, while Kaikoura recorded 1% affected.
In neighbouring Tasman, 146,437 sheep were processed from 241 farms, with only 332 carcases (0.2%) affected.
In Canterbury, Ashburton recorded an incidence of 0.4%, Selwyn 0.5%, Timaru, Mackenzie and Waitaki 0.2%, Waimate 0.3%, and, further south, Central Otago recorded 0.3%.
Ovis or sheep measles is caused by the T ovis tapeworm, and while it poses no risk to human health it can cause blemishes in sheep meat, which is undesirable for domestic consumers and certainly for the export market.
The programme works to promote the control of T ovis through communication and collaboration and raising awareness of the importance of all dog owners regularly treating their dogs for the tapeworm.
Ovis Management project manager Michelle Simpson said controlling sheep measles is important for the primary sector.
While NZ currently has relatively low levels of sheep measles, an outbreak can result in downgrading or condemnation of otherwise healthy animals.
Only 20% of Ovis-affected carcases are detected during meat inspection at processing plants, therefore the higher the prevalence rate, the higher the risk of meat from affected animals reaching the market, Simpson said.
“It costs farmers and processors a lot of money due to condemned stock and one concern with Ovis is that if a farmer is not the one sending their lambs for processing, they may not know that they are passing the problem on.”
Simpson said the data demonstrates that sheep measles can be controlled when farmers take the simple step of regularly treating their dogs for the Taenia tapeworm.
Dogs can become infected by eating untreated meat or offal that is infected with live cysts.
T ovis is then spread to sheep through tapeworm eggs in dog faeces left in grazing areas.
Eggs can also be spread from dog faeces over large areas, predominantly by flies.
“Best practice for dog health and sheep measles prevention is for all farm dogs to be treated monthly with cestocidal [tapeworm] drugs containing the ingredient praziquantel, a cheap and effective treatment, and an All Wormer every three months.”
Simpson said all dog owners, such as hunters or farm visitors who take their dogs near farmland or where sheep graze, should also dose their dogs every month because the tapeworm has a 35-day life cycle and dosing three-monthly is not enough to stop the parasite from spreading.
As part of their on-farm biosecurity plan, sheep farmers should make this a condition of entry for all visitors bringing dogs onto the property.
While NZ currently has relatively low levels of sheep measles, an outbreak can cause a lot of damage in otherwise healthy stock.
Many other countries have much less-effective sheep measles management and this creates an opportunity for NZ’s “clean sheep” to be seen as superior by the consumer, Simpson said.
For more information or to view the T ovis prevalence map showing data for all regions go to: www.sheepmeasles.co.nz.
