Crookwell producers Brian and Noelee Taylor have spent the last decade attempting to improve their flock's worm resistance, through genetics, drench capsules and mineral supplements. They have now reached the stage where they haven't had to drench their ewes since April 2019.
The Taylors have had Corriedales for close to 40 years and added first cross ewes to their operation following the Millennium Drought. The couple now run around 900 ewes in total.
"We split the flock into two and use a Corriedale ram to breed the replacements for the Corriedale ewes and a White Suffolk ram to breed replacements for the first cross half," Mr Taylor said.
"Then the first cross half is joined to a White Suffolk so we finish up our lambs as second cross White Suffolks.
"It's a closed flock, with only Corriedale and the occasional White Suffolk ram bought in."
Selecting for worm resistance EBVs
Mr Taylor said in the past they had been typical Southern Tablelands sheep producers, drenching systematically twice a summer.
But, in around 2010 they began to look at how they could reduce their use of drench, due to resistance concerns and to save time and money.
Their first strategy was selecting rams based on their worm resistance estimated breeding value.
"We have been purchasing rams from Roseville Corriedales, who have selected for worm resistance for 12 years," Mr Taylor said.
"We only look for rams with a negative value for worm egg counts."
In a parallel approach, they also began using capsules, a significant initial financial investment at around $4 per head, but cheaper in the long run as they were able to reduce their drenching.
"The capsule was described to us as the ewe becoming the vacuum cleaner, because as she eats the pastures she's eating up the worm eggs and because the capsule releases over 100 days they're constantly killing any intake of worm eggs the ewe takes up," Mr Taylor explained.
"We would test again after 100 days and if we needed to we would drench again."
However, in 2016, on veterinary advice, the Taylors stopped using the capsules, instead turning to a triple drench, which included abamectin.
"If the capsule fails you're on the edge of the cliff with few places to go due to resistance," Mr Taylor said.
Mineral supplement makes an impact
At the start of 2019, they trialed vitamin/mineral supplement Fabstock to improve their production.
But, after a few months of trialing it, they found they were getting impressively low faecal egg counts.
"In June 2019 we went completely to Fabstock with all our sheep, then we faecal egg counted in June this year, pre-lambing, and 50 per cent of our ewes still had zero eggs, even after a dry summer and wet autumn," Mr Taylor said.
Mrs Taylor said they thought Fabstock's sulphur content was what impacted the worms.
"Sulphur was known as an old timers remedy for worms," she said.
Mr Taylor said they had no idea this was where their journey to improve their flocks' worm resistance would lead but they were not going to rest on their laurels.
"This system that's evolved is at the moment working a treat, but we will monitor it and if it starts to falter we will look at where we tweak it," Mr Taylor said.
"We will aim to do faecal egg counts two to three times a year and one of the critical things we have found is when you do drench you should also test again in 14 days.
"At this test they have to come through as all noughts, otherwise the drench is starting to fail."
Reducing their drenching also had the added benefit of reducing the chemicals used in their system.
"The industry is under so much scrutiny from consumers, who want clean and green, if we put a drench down the ewe's throat we're putting chemicals in the system," Mr Taylor said.
"The ewes take those chemicals to the pastures, which could impact microbes in the soil. I will still use chemicals for weeds and fertiliser, but if we can take out some of the chemicals to promote the health of our soil and our product to consumers, well why not?"