Scientists are making progress in developing vaccines that will protect sheep from internal parasites and reduce the use of wormers on farms.
“It is challenging, but progress is looking very encouraging,” said Dr Philip Skuce from Moredun Research Institute.
Speaking to reporters last week, Skuce said that a prototype vaccine has been developed which gives a protective immune response against the common roundworm, Teladorsagia.
“It has produced acceptable levels of protection, as measured by reduced egg counts and worm burdens in controlled experiments in lambs and ewes,” he maintained.
The vaccine has been replacing drenches and has been slowing down resistance for some five years now
“Further refinement is required to increase vaccine response, remove variation from animal to animal, and make the vaccine more broad spectrum,” Skuce added.
A vaccine has already been developed which protects sheep against the barbers pole worm.
This parasite is not common in the UK but has been a huge problem for farmers in the southern hemisphere, particularly Australia and South Africa.
“The vaccine has been replacing drenches and has been slowing down resistance for some five years now. It is working very well out there,” Skuce said.
We know TST reduces wormer use, labour and costs
During the briefing, reporters were told that research is ongoing in other areas that also aims to reduce the use of wormers on sheep farms.
Researchers are developing computer software that will help more farmers adopt a targeted selected treatment (TST) approach to wormer usage.
This is where a dose is only given to an individual lamb if it is not hitting liveweight gain targets.
“We know TST reduces wormer use, labour and costs. It can slow the development of resistance and helps maintain the efficacy of our drugs as we only have a limited number of them,” said Dr Fiona Kenyon from Moredun.
Species identification is one of these things that we need to do more of
Other ongoing research is focussed on developing new tests, as well as improving existing methods, for detecting internal parasites in sheep.
This includes designing tests that are easier to use on-farm and can accurately identify the exact species of worms present in infected animals.
“Species identification is one of these things that we need to do more of. A lot of tests work very well but there is no on-farm usage yet. I suspect that will change in time,” added Dr Dave Bartley from Moredun.