Friday, 18 September 2020 09:47

Long-acting drench treatments called into question – again

Written by  Staff Reporters
New research has cast even more doubt on the economic value of drenching ewes with long-acting products. New research has cast even more doubt on the economic value of drenching ewes with long-acting products.

Even more doubt has been cast on the economic value of drenching ewes with long-acting products, following a recent jointly-funded Beef + Lamb New Zealand study.

The study led by AgResearch’s Dave Leathwick and co-funded by B+LNZ and AgResearch, showed that initial benefits of drenching with these products, especially to low body condition score ewes, were short-lived. It also showed the effectiveness declined in the interval after the treatments had expired. Untreated ewes tended to catch-up to their treated equivalents.

“This has also been seen in other New Zealand studies and highlights the danger of only assessing benefits at the end of the drug’s pay-out period,” Leathwick says.

He explains that many sheep farmers treat their ewes pre-lambing with long-acting drench products (capsules or injections). 

“This is in the expectation that both their ewes and lambs will benefit, however, this study shows that any benefits seen at weaning are likely to over-estimate the true value.”

This latest published research builds on previous studies from NZ and overseas, which have shown that animals treated with long-acting drenches have reduced immunity to worms because they are not being exposed to worm antigens every day.

“The sheep’s immune system needs to ‘see’ worms every day in order to function at its best,” Leathwick says.

This means that when the drug delivery ends, the ewes tend be to be less resilient to worms than those that weren’t treated.

“The true benefit is likely to be less than expected,” he adds.

These results follow on from previous studies, which highlighted that for many farmers, pre-lamb drenching may result in a net financial loss rather than gain.

This occurs because the biggest driver of financial return is lamb survival and not extra weight added to ewes or lambs at weaning.

Lamb survival is highly variable between farms and seasons, as well as treated and untreated ewes.  “This means farmers would benefit more from focusing their efforts on lamb survival to weaning than worrying about parasites,” Leathwick concludes.

Further trial work and modelling carried out in NZ showed that treating ewes pre-lambing with long-acting products increases the risk of developing drench resistance on the farm.

“For most sheep farms today, it is almost too late because resistance is now extremely common.

“For them it is now a case of farming with resistant worms. One certainty is that drench resistance will not go away if you keep drenching all the time.”

More like this

An ode to the ‘beloved’ sheep yards

When 14-year-old Lincoln High School student Rosa Macaulay was asked to write story about her favourite room, instead of choosing her bedroom like most 14-year-old girls, she chose her grandfather’s sheep yards. 

Back the sector that backs NZ

OPINION: The biggest issue currently facing our industry is environmental policy, writes Beef+Lamb NZ chief executive Sam McIvor.

Meat quota rates remain vital

A jump in the value and volume of New Zealand’s sheepmeat exports to Europe and the UK shows why preserving WTO tariff-rate quotas is so important, claims the Meat Industry Association (MIA).

Featured

Back the sector that backs NZ

OPINION: The biggest issue currently facing our industry is environmental policy, writes Beef+Lamb NZ chief executive Sam McIvor.

 

National

Lamb price down, but not weak

While lamb prices are starting the new season at around 16% below last year’s levels, they are not outright weak,…

Quota split a major worry

New Zealand meat exporters want the EU and UK to get serious on reaching a deal on post-Brexit quotas.

NZ meat exports at risk

Nearly half of our country’s meat exports are at risk unless there is urgent action by government to allow migrant…

Machinery & Products

Claas cargo wagon

CLAAS has extended the versatility, productivity and user comfort of its CARGOS dual purpose transport wagons with the addition of…

These tractors are pumping

CLAAS has announced it will introduce a new automatic tyre inflation system across its AXION and ARION series of tractors.

Great hay cut at speed

Contractors and farmers on the lookout to mow and condition at higher speeds, while producing better quality hay and forage,…

Fendt enters NZ harvest market

Farm machinery brand Fendt has expanded into the harvester market in Australia and New Zealand, with is Ideal combine harvester.

» The RNG Weather Report

» Latest Print Issues Online

The Hound

He's back!

OPINION: This old mutt understands that former Fonterra chief executive Theo Spierings has landed himself a new gig back in his…

Utu?

OPINION: Your canine crusader understands that the farmer’s favourite politician – Environment Minister David Parker – not content with implementing…

» Connect with Rural News

» eNewsletter

Subscribe to our weekly newsletter