Making sure all incoming sheep are quarantined for at least three
weeks and securing an accurate diagnosis of any ectoparasite problems
are absolutely crucial if the industry is to maintain any momentum
in its campaign to eradicate sheep scab.
Dipping must take place more than
14 days after drenching.
Independent sheep consultant Lesley Stubbings stresses that
flocks are at their most vulnerable to sheep scab - and many other
diseases - when they bring sheep into the flock. She is urging sheep
farmers to minimise these risks by sticking to a strict quarantine
period, as recommended by SCOPS.
“Every sheep coming onto the farm is a real threat and must
be tackled responsibly - a minimum quarantine period of three to
four weeks is essential. During this time they should be treated
with both a levamisole (yellow) and macro-cyclic lactone (clear)
wormer to remove any resistant worms and, ideally, also treated
against scab. Remember, though, that if you are planning to use
an OP dip, dipping must take place more than 14 days after drenching,” she
Lesley Stubbings also says that producers need to work closely
with their vet to secure an accurate diagnosis of ectoparasite
problems within the flock. “It is vital that we use the control
options available to us (OP dip, the injectables and pour-ons)
very carefully. It’s no good using an injectable just because
you think you have a scab problem. If the problem is not scab -
and is lice, for example - the injectable will be ineffective and
you will simply have hastened the day when intestinal worms become
resistant to these products.”
For effective scab control, independent sheep vet Chris Lewis
recommends a move back to OPs, particularly now that the introduction
of genuinely closed-transfer systems - such as the water-soluble
sachet-based approach favoured by Coopers Ectoforce - means dippers
can no longer come into direct contact with the diazinon concentrate.
Indeed, since the advent of these systems, there have been no further
human adverse reaction reports to the VMD, he points out.
“Used responsibly, plunge dipping with an OP is the gold
standard sheep ectoparasite control system, with no recorded resistance.
If you use an OP correctly you can be confident you will get rid
of scab and protect your sheep against further infestation for
up to 4 weeks. OPs are also fully effective against lice and keds
too, and have a short withdrawal period at only 35 days,” he
Chris Lewis also points out that sheep producers have a real opportunity
to crack down early on scab this year by using an OP dip for
summer blowfly control. “Apart from effective blowfly control,
OPs also kill any scab mites persisting on the body during the
warmer months,” he says.
“The mites are found in the groin, around the tail head,
in the fissure near the eye, and in the ears. Then, when the temperature
falls, the mites migrate back onto the body to produce clinical
scab. As scab is highly contagious, these sheep then become a source
of infection for the whole flock. And it is often these sheep that
are the most common cause of new scab outbreaks in apparently isolated
flocks,” he explains.
Guard Against Lice and Tick Threat at Lambing Time
Farmers to question DEFRA minister over bovine TB fears
Biosecurity on the Agenda for Agricultural Shows