More than 200 delegates from the New Zealand Grassland Association’s 85th conference visited Mt Pleasant sheep and beef farm in Maraeweka last week.
Vet and Wormwise facilitator Dave Robertson, of North Otago, gave a presentation on parasite management.
Association organising committee member and sheep and beef farmer Grant Ludemann, of Windsor, introduced Mr Robertson.
Mr Ludemann told delegates about Mr Robertson helping him address drench resistance issues on his farm.
Mr Robertson said he had worked with Mr Ludemann on his trading operation for six years, which relied on drench to grow lambs quickly.
"When drench began failing for him we had to look at how we were going to maintain his business," Mr Robertson said.
After making changes to his system, Mr Ludemann was able to finish more lambs and grow them quicker than before, Mr Robertson said.
Drench resistance was "not all doom and gloom".
Drench was a revolution for pastoral farmers when it was first released about 40 years ago. Farm systems had focused on killing the worms in the guts of sheep.
"In a green grass situation like we have now, 95% of the parasite population is in the environment."
Monitoring was an important part of managing parasites.
A faecal egg count showed if ewes or lambs needed to be drenched or if it could be delayed.
Egg counts before drenching at weaning time and 10 days after show if the drench had been effective.
If ewes were well-fed and metabolically stable they should not require drenching, Mr Robertson said.
A way to reduce the amount of parasites eaten by livestock was having cattle graze a paddock, then remove them to allow pasture to grow and then introduce ewes.
Cattle did an "amazing job hoovering up sheep parasites and sheep do the same for cattle", Mr Robertson said.
"How you integrate your cattle, ewes, lambs and calves in a grazing rotation will vastly influence the amount of parasite exposure those animals will have."
