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How remote parasite monitoring cuts labour and resistance

Michael Priestley 17 January 2019
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Sheep at Bowhill Farm

Fast and accurate faecal egg counts (FECs) are slowing the rate of anthelmintic resistance and saving on labour for a large Scottish Borders sheep operation. Farmers Weekly visited Bowhill Farming on the Buccleugh Estate.

Four out of the past five summers have seen the shepherds at Bowhill Farming cut anthelmintic doses at weaning time by 80-90% on historic levels thanks to laboratory-assisted parasite monitoring.

Farm manager Sion Williams and the team first embraced an online FEC service in 2014 and have saved on roughly 5,500 doses of anthelmintic wormer at weaning time in the past four years.

This means dosing only about 500 of the 6,500-7,000 lambs being produced annually; a far cry from dosing all lambs every three to four weeks, which is what the estate was doing historically.

Not only does this mean the estate farm, which became a LEAF demonstration farm in September, is saving time and money on drenches and labour, but the flock is still able to use the old, inexpensive wormers to manage parasite burdens.

See also: How to test for wormer resistance in sheep

Farm facts: Bowhill Farming

  • 5,463ha (13,500ac) of which 4,137ha is heather and rough grazing
  • 6,800 sheep and 500 suckler cows
  • 1,400 lowland sheep (Aberfield and Aberdale-cross)
  • 5,200 upland sheep (South Country Cheviots and Lanark-type Scottish Blackface)
  • 116 deer, 81ha of feed barley and oats for home use
  • 48ha of kale and brassicas
  • 32,000 layers and a 200Kw AD plant

What is it?

Worm burdens are monitored through Techion’s FECPAK G2 system. Dung is sampled and processed on farm before two high-resolution images are taken and sent to laboratories to be assessed by a trained technician.

How does it work?

How Bowhill Farming uses FECPAK g2

1) Sample dung
  • Mob sample taken of 20-30 random scoops (60-100g) of dung with spoon provided
  • This can be done in a plastic bag or with a disposable plastic glove which is turned inside out as it is taken off

2) Weighing and mixing sample
  • Each sample is then weighed and mixed with tap water in a sealable plastic bag at a ratio of 1g:3ml of water (1:1 in cattle dung)
  • Dung is then mixed into a slurry

3) Suspension of eggs
  • A small amount of slurry is added to a sedimenting container and tap water is added to the “water line”. This is left for 30 minutes for the eggs to sink to the bottom.
  • The sample is then emptied out to the “flush line”, retaining the eggs behind a small plastic block inside the sedimenter
  • Saline solution is then added to the “saline line”, allowing the eggs to float

4) Filtering and sampling
  • A sample is drawn out of the cylinder with a pipette
  • Two wells in the cassette are filled with the sample
  • The cassette is placed into an image-capture device and photographed, with the images stored on a computer/laptop
  • While this is happening, the flock manager enters information about the animals and pasture

5) Results
  • On a working day results are back with 20-30 minutes (guaranteed results in one hour within office hours), and within four hours on a weekend or the next day at the latest
  • The eggs are classified as three distinct parasite families; Strongyles, Strongyloides and Nematodirus
  • A total EPG (eggs per gram) count is given for the sample, this includes Strongyle and Nematodirus eggs. Counts are given individually for all three parasites.
  • The report will also note if coccidiosis cysts and tapeworms are present but no counts are given for these

6) Deciding to treat
  • Techion – the maker of FECPAK – advises to consider treating at an egg count of 200-500epg and above
  • The Bowhill team typically treat at 300-400epg, depending on condition, stockman’s eye, dirty tails etc

7) Drench check
  • Post-drench FECs are always recommended; how many days after treatment depends on product group
  • At seven or 14 days after the drench, a post-drench FEC is done
  • Group one (white) and three (clear) drenches are tested 14 days after dosing, while group two (yellow) are tested seven days after dosing
  • If eggs are still there, the drench might not be working and investigation is required

How is the flock managed?

The parasite year starts by closely monitoring weather forecasts in April, with a nematodirus dose given to the 2,300-2,400 lowland lambs as conditions dictate.

The lowland flock, which lambs inside from 15 March, is at greater risk of picking up roundworms as they hatch in the spring sun, whereas the hill sheep, which lamb either on 1 April or 16 April, typically avoid that hatch and are grazed more extensively, minimising the chance of picking up eggs.

The nematodirus dose is typically given in May, whenever the hatch takes place, after which the faecal egg counting begins, taking place every two weeks from June until the last of the lambs are sold the following March.

The other potential dosing point is a pre-tupping drench for breeding ewes. This used to be given every year, but is now given based on FEC results.

Benefits

Satisfactory worm control, as ratified through post-drench FECs, is being achieved through white group one (Benzimidazole), yellow group two (Levamisole) and clear group three (Macrocyclic lactone) drenches, which are used in rotation to maximise efficiency.

This means the newest orange and purple anthelmintics (groups four and five) can be used for quarantining rams – the only bought-in sheep on the farm.

Farmer Sion Williams

Sion Williams

“Slowing down the rate of resistance is probably the biggest win for me,” explains Mr Williams. “By counting eggs we can restrict the use of cheaper white, clear and yellow wormers to times when they are needed and keep them working on the farm for longer.”

But Mr Williams stresses that there are no common rules with drenching and that each year brings different challenges.

Last summer, for example, 4,000 lambs needed a wormer dose. This followed a late parasite challenge after rain followed the drought.

Cost savings

Using a clear Ivermectin drench

5,500 doses of group three drench at roughly 14.67p/dose = £806.85

(based on 10ml (2.5ml/10kg of bodyweight and 5l costing £73.35) £73.35/5000ml = 0.01467 x 10ml = 14.67p x 5,500 lambs = £806.85

Labour savings of 27.5 hours @ £15/hour = £412.50

(based on dosing 300 lambs in 90 minutes and estate labour costed to include accommodation etc)

Using the orange Monepantel drench

5,500 doses of group four drench at roughly 60p/dose = £3,300)

(based on 4ml for a 36-40kg lamb and 2.5l costing £375) £375/2,500ml = 15p x 4 = 60p x 5,500 lambs = £3,300

Suiting the system

Although collecting, processing and emailing more than 80 dung samples/year takes time, Mr Williams stresses that his flocks are run more efficiently and sustainably because of FECs.

With an average flock size of 1,800 ewes per shepherd and two shepherds working together at certain times of year across 3,800-3,900 sheep, stock handling is minimised if possible.

Efficient weight gain is vital to stop a backlog of lambs as hill lambs are weaned in August and September and come down to the lowland pastures for finishing.

Each August, lambs are sorted to three weights and three types of grazing – 35kg+ (red clover mixes), 32-35kg (silage aftermaths) and under 32kg (older leys).

Mobs are sampled prior to weaning and moving to new grazing to allow for at least a four-day egg kill period to remove eggs from lambs and so avoid any contamination of clean grazing.

Prime lambs are drawn at 37kg liveweight and more, to average 18kg carcasses on Sainsbury’s 15-22kg specification.

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