Focus On Sheep Scab

Sheep scab is caused by Psoroptes ovis, a non-burrowing, surface-feeding mite, costing the UK sheep industry annually around £8.3 million, including £0.8 million in reduced animal performance [1].

The severity of the disease is influenced by the stage of infection, the strain of P. ovis involved, the time of year, fleece length, sheep age, sheep breed and the individual host’s immune response.

Sheep scab is characterised by intense itchiness caused by the mite faeces Clinical signs are generally more severe in lambs and yearling sheep than in ewes. Sheep scab can be introduced to a flock by carrier sheep, including purchased animals, sheep returning from grazing and strays, or by exposure to mites in the environment, including contaminated fields, handling facilities, shared equipment, sheep transport and clothing.

Most sheep scab outbreaks occur during winter and spring months, in young and growing lambs, P. ovis infestation can result in rapid weight loss, debilitation and death. Low birthweights and high mortality rates in lambs born to ewes with severe sheep scab during pregnancy probably resulting from an excessive loss of body condition in the ewes.

Key Facts:

  • Scab mites can survive for 17 days off the host in wool, tags, on equipment or even under finger nails – this is why you need to move sheep to clean pasture with some treatments (pasture that has not had sheep on it for at least 3 weeks)
  • Scab mites do not feed every day so injectables may take time to kill the mites
  • Until the mite faeces is washed off the sheep, they may remain itchy
  • ML (Group 3 – clear) injectables are also wormers so ensure their use is necessary at this time of year and avoid repeat doses

What do I need to know?

  • Am I using the product for treatment or prevention?
  • Can the sheep be moved to clean pasture?
  • Can the flock be treated in one day or does the farm system require a more persistent product?
  • Have the animals had a foot-rot vaccine?

What are my injectable options?

Wynnstay Animal Health Specialists are available to discuss treatment options available to you. For details of your local advisor or SQP, please contact your local Wynnstay store.

Cydectin 20mg/ml LA Sheep Injection

  • Allows a 6 week treatment window for scab
  • No need to move to clean pasture
  • A single subcutaneous injection treats and affords 60 days residual protection

Cydectin 1% Sheep Injection

  • For the prevention and treatment of psoroptic mange for scab
  • Injection will protect against scab mite infestation for at least 28 days
  • No need to move to clean pasture


1. Nieuwhof, G.J. and Bishop, S. C. 2005. Animal Science, 81: 23-29 CYDECTIN® 20 MG/ML LA SOLUTION FOR INJECTION FOR SHEEP and CYDECTIN® 1% INJECTABLE SOLUTION FOR SHEEP contain moxidectin. POM-VPS For further information please see the product’s SPC or contact Zoetis UK Limited, Walton Oaks, Dorking Road, Tadworth, Surrey KT20 7NS. www.zoetis.co.uk. Customer Support: 0845 300 8034. Use medicines responsibly (www.noah.co.uk/responsible). Date of preparation: August 2016 AH393/16

Like this article? Why not share with your friends?

Leave Comment

Your email address will not be published. Required fields are marked *

%d bloggers like this:

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close