Do you know which of these sheep has sheep scab?
Not sure? Only guessing?
Of course you are. It is impossible for you to be certain that either sheep has sheep scab without a diagnosis. Yet every year thousands of sheep are treated on the basis that people think they know. If you get it wrong it will waste your time and money, risk the health of the sheep and result in unnecessary use of products, increasing the risk of resistance in the future.
What is sheep scab?
Sheep scab is a major source of economic loss in affected flocks and is a serious threat to sheep welfare. Infestations can be very debilitating with significant loss of condition, secondary infections, hypothermia and eventually deaths.
Sheep scab is actually an acute or chronic form of allergic dermatitis caused by the faeces of the Sheep scab mite is Psoroptes ovis. The mite is just about visible to the naked eye and can only remain viable off the host (sheep) for 15-17 days. There are no other hosts for these mites, although they can remain viable on cat
Sheep scab can be contracted via any contact with live mites. This is usually through forced sheep-to-sheep contact at market, in livestock lorries, shared rubbing posts etc. However, shearing combs and cutters, contaminated clothing, tags of wool or scab attached to brambles bushes etc. can also spread scab.
Sheep scab is mainly a winter disease, with most cases occurring between September and April, although a significant number of cases do occur in the summer months, particularly on animals still full fleeced (lambs, hoggs etc) and on "ridges" of longer fleece on poorly shorn sheep.
The life-cycle takes 14 days
Early disease is involves low mite numbers and very small lesions which are virtually undetectable. Sheep with early infestations may show no signs or simply be restless, rubbing against fence posts, have soiled and stained areas of wool toss their heads or have deranged or tags of fleece. Sheep with sub-clinical scab can look perfectly normal and can unknowingly be introduced to a flock.
Later stages of infestation see high mite numbers the lesions spread. Scab mites cannot feed on the hardened scab so they are forced to go to the edge of the lesion, making it spread out. Rubbing and head tossing becomes more and more excessive, areas of wool loss may appear often with open, bleeding wounds. Sheep rapidly lose condition and serious cases will start fitting.
Get a diagnosis
If you suspect your sheep have sheep scab, don’t guess. Contact your Vet. and arrange for samples to be taken and wait for the results before taking action. Use the table below to discuss treatment options with your Vet or Advisor.
Treatment - Dip or Inject?
Not Shower or Jet
Dose for Heaviest in Group
Osmonds Gold Fleece
Cydectin 2% LA
|1 treatment gives up to 4 weeks protection||Protocol & Protection||1 SUBCUTANEOUS injection given at the base of the ear. Protection against Scab for 60 days.||2 injections SUBCUTANEOUS to treat scab 10 days apart. Must keep treated sheep isolated for 12 days after treatment. Up to 28 days protection||1 injection INTRA MUSCULAR Must keep treated sheep isolated on clean area* for 14 days after treatment||2 injections SUBCUTANEOUS 7 days apart. Must keep treated sheep isolated on clean area* for 7 days after treatment|
|70||Withdrawal Period (Days)||104||70
after 2nd injection
after 2nd injection
|Broad Spectrum||Features||Scab Only
(and susceptible worms)
1. Establish where the scab came from
If purchased or incoming sheep review quarantine protocols.
Neighbours (see below)
2. Contact neighbours with sheep in adjacent fields to warm them and/or suggest they treat at the same time as you for maximum effect and protection.
3. Check common fence-lines for gaps/shared rubbing areas. Consider double fencing any in contact with high risk neighbours.
Always read the manufacturer's instructions before use
History of Sheep Scab
Sheep scab is not a new problem in the UK, being reported as a significant cause of loss to Henry VIII in the 1530’s when the monastic flocks, the wool from which underpinned his wealth, were hit by sheep scab. It first became obligatory to report sheep scab in 1870 and between this time and 1895 the number of cases reported per year fluctuated between 1207 and 3536. In 1893 the first effective dips were introduced (arsenic and sulphur), but incidence continued to rise as sheep infested with scab were imported from Canada, the Americas and Ireland. By 1898 the Government decided to introduce the first Sheep Scab Order but real progress was only made in the 1930’s mostly as a result of a change in the national flock structure and fewer movements. However, it was the introduction of the organo-chlorines after the Second World War that saw significant progress and scab was eliminated, with the last recorded case in Hereford in 1952.
For more than 20 years we were free of sheep scab but it was re-introduced with imported sheep into Lancashire in 1973. Until 1976, individual cases were treated, but by then it has spread and a national double dipping programme was introduced in 1983. The organo-chlorines were removed in 1984 leaving only the OPs until the SPs were introduced in 1992/3. In 1988, we got very close to eradication with just 16 cases reported. However, the compulsory dipping was reduced to a single treatment in 1989 and in 1992, sheep scab control deregulated entirely. Only the introduction of the Sheep Scab order in 1997 has attempted to help with the compulsory treatment of sheep on common grazings.
As a result, the incidence of scab has risen dramatically over the last 15 years. By 1995, it was estimated there were 3,000 cases; in 1998-9 it was calculated that 5,000 flocks were affected and anecdotal evidence supports a continued increase in cases year on year in GB. Not surprisingly, in surveys of sheep farmers, sheep scab is consistently at or near the top of their list of health concerns.