Farmers are being urged to ensure they keep up to date with measures to control C. ovis - or sheep measles - after the Ovis Management programme reported a spike in infection rates.
Data from meat processors for October, the first month of the new season, identified that 1.38 per cent of lamb processed throughout the country was recorded as being infected. That compares to 1.13 per cent for October 2023.
Ovis or sheep measles is caused by the Taenia ovis tapeworm. Although it poses no risk to human health, it can cause blemishes in sheep meat, which is undesirable for consumers and particularly for the export market.
The Ovis Management programme works to promote the control of C. ovis through communication and collaboration and raising awareness of the importance of farmers regularly treating their dogs for the tapeworm.
Programme manager Michelle Simpson says that to minimise sheep measles in New Zealand, it’s critical to ensure all dogs on farms where sheep graze are dosed regularly with the required tapeworm treatments, and also any dogs visiting the farm.
“We do not believe we can eradicate C. ovis but the aim is to control it at around 0.5 per cent.
“There are likely to be a number of reasons for the increase. The warmer climate and some moist conditions may mean that eggs are surviving longer. Farmers have a lot on their minds and a lot of expenses so worming programmes may have slipped a bit but it is important to keep on top of it because an outbreak costs farms a lot of money in condemned stock.
“The prevalence changes as the season goes on. If we start the season with a high prevalence, then we are likely to end it with a high prevalence too.”
Michelle says farmers breeding lambs for trading needed to make sure they are taking all necessary steps to avoid sheep measles in their flocks.
“A lot of people dealing with this have inherited the problem. Traders need to ensure they have the same treatment programme in place, to protect the investment of their buyers. This isn’t pointing the finger at anyone. It’s about making sure everyone is on the same page.”
Will Halliday, senior advisor biosecurity and animal welfare at B+LNZ, says it’s vital farmers keep on top of sheep measles.
“Sheep measles is a silent thief, and you don’t know how bad it is until you see how much your carcases have been trimmed on your meat inspection report. Fortunately we have strong surveillance and effective and economical control methods, and plenty of resources available for farmers.”
Dogs can become infected by eating untreated meat or offal infected with live cysts. C. 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.
The best practice for dog health and sheep measles 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.
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 short life cycle and dosing three-monthly is not enough to stop the parasite from spreading. Any visiting dogs should have been dosed at least 48 hours before coming on farm.
For more information or to view the C. ovis prevalence map showing data for all regions, visit www.sheepmeasles.co.nz.