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Future proof farming + improve profitability

Drench resistance – a growing problem

Finding new and better ways for farmers to manage parasites is a growing need. Globally, parasites are becoming increasingly resistant to drench actives and no new drench actives are on the horizon. Furthermore, major supermarket chains are concerned about the security of their supply chains and consumers are demanding fewer chemicals in their meat.

Breeding for parasite resistance is a logical response to this growing issue, as parasite resistance is a heritable trait that can be introduced into a flock relatively quickly.

“Genetics play a key role in reducing reliance on drench and sustainable management of the current products.”

Kate Broadbent, Nikau

Look after your lambs

Animals bred for parasite resistance prevent the establishment and growth of parasites in their gut. Less parasites in the gut means fewer eggs are shed on pasture, protecting your younger more vulnerable stock.

Less time and cost drenching

There is also growing awareness among farmers – terminal and maternal ones alike – that they can reduce drench costs and time and effort spent drenching their animals by improving the levels of parasite resistance in their flock.

Extending the life of effective drenches

Increasing natural levels of parasite resistance also helps farmers extend the useful life of drench actives that are currently effective at killing parasites in animals on their property.

Breeding for parasite resistance traits is a sustainable way to future proof New Zealand farms from drench resistance, improve farm profitability and improve the quality of your breeding stock and flock.

“We decreased the need for drenching so much that no flock ewes were drenched in 2017 and our rams for sale in 2018 received only 1 drench in their life.”

Peter Moore, Moutere Downs

The benefits of breeding for resistance

Farmer + Breeder benefits

  • Less reliance on drench to control parasites.
  • Less money spent on drench.
  • Less time spent in the yards drenching.
  • Sheep bred for parasite resistance are also bred for production traits meaning you can have the best of both worlds – high resistance and high productivity.
  • Naturally resistant animals shed fewer eggs, reducing pasture contamination and keeping pastures clean for young vulnerable stock.

“There are so many good reasons to breed for parasite resistance, the main reason more farmers don’t do it is because they simply don’t know much about it.”

Techion, WormFEC service provider

More Breeder benefits…

  • Tap into the power of genetics.
  • Promote yourself in a competitive market.
  • Sets you at the forefront of global best breeding practice.

Sheep industry benefits

  • Minimises the spread of drench resistance and promotes long term sustainability.
  • Maintains the NZ sheep industry’s reputation for best practice farming.
  • Helps promote NZ sheep meat as clean and green and ensure that this claim is authentic not just a marketing ruse.
  • Also helps ensure the long term integrity of the supply chain – supermarkets and food processors are increasingly concerned about the impact of drench resistance on their access to supply.
  • Fewer chemicals in sheep meat is good for long term consumer demand.

“Our sheep must perform under a maximum one life time drench, which we have maintained since we went organic 21 years ago.”

Allan Richardson, Avalon

WormFEC explained

What is WormFEC?

The WormFEC protocol was developed by AgResearch in 1994. WormFEC uses faecal egg count (FEC) challenges to identify sheep that are naturally resistant to parasites and have a low FEC, as well as sheep that are susceptible to parasites and have a high FEC. FEC is used to calculate breeding values (EBV’s) for resistance to internal parasites in sheep. It provides sheep farmers with a chemical-free alternative control mechanism to the use of anthelmintics after the emergence of anthelmintic resistance to the first classes of chemicals used.

WormFEC encompasses some 40 years of research and development by AgResearch and its forebears and the New Zealand industry. Over the last 40 years AgResearch have made big gains breeding Romney and Perendale lines where sheep bred for low FEC have 84% fewer parasites on average compared to high FEC sheep. In 2019 WormFEC as a service will have reached 25 years of continuous industry usage, with several breeders having recorded the trait for over 30 years.

“WormFEC encompasses some 40 years of research and development by AgResearch and its forebears and the New Zealand industry.”

John McEwan, Principal Scientist, AgResearch

When should I do it?

The best time to do WormFEC varies depending on the age and breed of the sheep.

For mixed breed sheep, their natural immunity to parasites starts to kick in from 4-5 months old. This is a good time to start mob FEC testing (Jan-Feb).

At 7-9 months old, animals have usually had enough exposure to parasite infection for their immune system to be developed. This is a good time to do the individual FEC sampling once the mob FEC is high enough.

What do I get if I do WormFEC?

SIL combines resistance to internal parasite traits (WormFEC) and production traits into a single index – New Zealand Maternal Worth plus FEC (NZMW+F). This provides a value that is comparable across all rams, regardless of breed.

The average NZMW is 1600, but the higher the value, the better the ram’s progeny are predicted to perform for the recorded traits. Many WormFEC breeders have NZMW+F values exceeding 3000.

“Genetic improvement through selection offers one of the best long-term solutions to the increasing problem of drench resistance.”

SIL Technical Note, 2006

Parasite resistance and management

Do all sheep have a natural resistance to parasites?

Yes, all sheep have a degree of resistance to parasites, but not all animals are equal – some show more resistance to parasites, others are more susceptible.
Newborn lambs don’t have any immunity and their natural immunity kicks in at about 7 months old. You can build a more resistant flock by identifying and breeding from the most parasite resistant animals.

What is resistance to parasites?

In practice, resistance to internal parasites is measured using faecal egg counts (FEC). Lower FEC are associated with animals mounting an immune response to the parasite population in their gut and this response can reduce both the number of parasites and the amount of eggs they produce. FEC is the phenotypic (physical) on-farm measurement used by SIL breeders to predict genetic merit for resistance to parasites.

How do parasites affect my animals?

Parasites can reduce the nutritional uptake of lambs through appetite suppression and changes in grazing behaviour, as well as through damage to the gut lining decreasing the area for nutrient absorption.

To mount an immune response to parasites requires lots of energy and protein. The cost in lost production can be through depressed growth rates, weight loss, condition loss, depressed wool growth, and/or depressed milk production.

In severe cases, heavy parasite burdens can lead to animal deaths.

Beyond your drench gun, how else can I manage parasites?

An integrated approach is the best way to manage parasites.

You can reduce parasite contamination on your pasture by using different stock classes to clean up contamination. You can tap into the power of genetics by breeding for parasite resistance or through incorporating animals with parasite resistance genetics into your flock. Other useful tools include FEC testing to identify and treat animals contaminating pastures and feeding animals with high quality, clean feed such as crop and regrowth hay silage.

Can you breed for both parasite resistance and production?

You can do both! You don’t have to compromise your production traits to select for parasite resistance.

You can effectively breed for highly resistant and productive animals by selecting rams using an index which includes production trait and parasite resistance EBV’s e.g. Maternal Worth plus FEC (NZMW+F).

“We have made significant gains in reducing our reliance on drenches as well as lifting the performance of our sheep.”

Andrew Tripp, Nithdale

Questions to ask your ram breeder

Next time you go to buy a ram, ask the breeder ‘Are you breeding for parasite resistance genetics in your flock?

If they are, you could ask:

  • How long have you been testing for WormFEC?
  • Can I see your WormFEC certificate?
  • Can I see your rams’ records?
  • What progress have you made with parasite resistance?
    • Do your rams require less drenching?
    • Do your rams require less management and time in the yards?
    • Do you sell rams that have never been drenched?

Drench Resistance in New Zealand

The impact and cost of drench resistance in New Zealand

The cost of drench resistance to NZ farmers is an increasing risk. A study undertaken by Sainsbury’s in the FECPAKG2 Research Project revealed some unsettling statistics.

Visit the Sainsbury’s FECPAKG2 Project for more information.

1 Sainsbury’s FECPAKG2 Project 2014-2017. 2 Miller et al,. 2012. The production cost of anthelmintic resistance in lambs. Veterinary Parasitology 186, 376-381. 3 Techion DrenchSmart Database 2005-2018.

“The increasing threat of drench resistance, viability of the lamb sector and harsh climatic conditions in which they farm across the United Kingdom and New Zealand, poses a significant threat to our farmers, which is why together with Techion Group Ltd and Sainsbury’s Lamb Development group, we collaborated on this Project in 2014.”

 Gavin Hodgson, Head of Livestock Sainsbury’s PLC

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