Deer farmers are being advised to use three drench families
in combination to keep parasites under control.
It followed four years of research showing that internal
parasite resistance was becoming widespread across the
The use of a single drench family - mectins - applied as
pour-ons, along with poor application technique, were the
cause of resistance, Deer Industry New Zealand (DINZ)
producer manager Tony Pearse said.
''Replacing a mectin pour-on with an injectable can
dramatically improve growth rates, but the best bet, based on
recent on-farm trials, is to use a triple mix: a mectin
injection, plus a white/clear combination oral drench,'' he
He knew of farmers who had increased weaner growth rates from
250g a day to 400g a day by switching to a mectin injectable.
Better weaner health and a reduction in losses from yersinia
and Johne's disease had been reported, too.
Before using the preferred triple mix, Mr Pearse said farmers
should consult their veterinarian. Southland research
veterinarian Dave Lawrence, who has conducted the parasite
control trials, said deer on all farms tested so far had
internal parasites resistant to mectin drenches.
Dr Lawrence advised farmers to adopt integrated parasite
management that reduced the need for drenching and the risk
of resistance developing. That includes quarantine drenching
of incoming animals, minimising adult drenching and grazing
with other species.
The trials have been funded by DEEResearch - the agency that
channels farmer levies into research - with additional
funding from New Zealand Deer Farmer Association branches and
the Elk and Wapiti Society.