Summer rainfall/tablelands and slopes
Merino wool, Prime lamb production, Cattle
A microscope in the home office and worm tests that can be done at the same time as dinner’s being prepared have made the monitoring and management of parasites a lot simpler for New England graziers Greg and Kathie Tighe.
But despite running their own worm control program, the Tighes were grateful to have $1000 to spend on outside help as a result of winning the New South Wales section of the WormBoss ‘Take control of worms’ promotion.
They used the money to carry out another drench resistance test and assist with routine monitoring and identification of prevalent worm species in their flock of 3000 Merino ewes on Kelso, near Inverell.
It's all part of the Tighes’ commitment to controlling worms and avoiding resistance through a combination of regular testing, rotational grazing and breeding stronger sheep.
Despite their best efforts, they say they are drenching more now than they were 15 years ago, when the WormKill program using closantel successfully controlled worms for more than a decade before it broke down.
The lack of a single drench to control worms, particularly in ewes, which face the added challenge of sustaining a lamb, prompted the Tighes to implement a number of strategies to fine tune control of the parasites.
Five years ago, Kathie Tighe completed a two-day course in the use of a microscope to analyse faecal samples for worms, which has enabled her to anticipate potential outbreaks
Worm egg counts are regularly monitored before deciding when to drench, and the same science is used to determine how effective the drench is, by collecting and testing faecal samples 10 days afterwards.
Knockdown drenches are preferred over long acting products, which the Tighes have found tend to have a tail that can encourage resistance in the region's prevalent barber's pole worm.
Kathie also receives the monthly WormBoss emails, containing updates on worm activity in NSW, with local information contributed by Armidale vet, Rad Nielsen.
It was Dr Nielsen, from Veterinary Health Research in Armidale, who assisted the Tighes with their latest drench resistance test, and he admires their commitment to managing for worms—a problem he says is the biggest issue the graziers in the region
“There is a perception amongst a lot of grazier s that strategies like drench resistance tests are time-consuming and finicky,” Dr Nielsen said. “It is incredible though, what can be achieved through a combination of monitoring, using the right drench and the spelling of pasture or rotational grazing to lower the worm burden.”
A large part of Veterinary Health Research’s work is testing new products for pharmaceutical companies, and Dr Nielsen says while there are new drenches in the pipeline, it's not as if they are ‘rolling off the presses’.
“We are running into a big headwind in terms of the chemicals we rely on,” he said.
“The new ones offer a bit of a reprieve but if we maintain the same practices of drenching on gut feeling or just every four weeks under set stocking rates, we’ll come unstuck.”
Greg Tighe is taking another factor into account in the war against worms—breeding for worm resistance.
He holds a production sale on Kelso every March, selling all his wether weaners, four and a half year-old ewes and a third of his one and a half year-old ewes. For three years he's been measuring his sheep for worm resistance as part of the Nemesis program, but says that has its own challengers.
“You can single-trait select and make rapid progress, but perhaps at the cost of other traits like production or wool quality,” he said.
“Running all ewes also makes it much more of a challenge because there is very little time in a year when you can sacrifice the animals’ performance.”
The use of grazing strategies such as spelling pasture for longer has helped, but the season also plays a major part, especially in outbreaks of barber's pole.
“This year we had such a hot dry summer that we only drenched every two or three months,” said Mr Tighe.
That's also where the testing comes in. Kathie Tighe says the science enables them to ‘hold their nerve’ when normally they would have thought it necessary to drench.
She says monitoring for barber's pole worm has become more efficient with the advent of the dipstick, a simple procedure that allows her to test faecal samples from 20–25 sheep at one time.
“It's more of a guide to how the whole mob is going and it’ll tell you when immature worms are present prior to an outbreak,” said Mrs Tighe.
“It's quite a straightforward process that you can do while you're getting dinner.”
WormBoss has been developed by Australian Wool innovation Ltd, the Australian Sheep Industry CRC, with support from Animal Health Alliance (Australia) Limited.