The four major external parasites that cause problems for sheep and cattle are flies, ticks, lice and sheep scab. There are a number of problems associated with flies. BLOWFLIES These almost certainly have a large impact on animal welfare. UK infections are primarily caused by the greenbottle fly. The life cycle is very quick with females laying eggs on sheep, which hatch after about 12 hours. Mature larvae then pupate in the soil before maturing into adults. When populations of larvae become high they will attack the living tissue of the animal causing severe damage. FLIES CAUSE MAJOR PROBLEMS AND ECONOMICAL LOSSES IN BOTH SHEEP AND CATTLE One of the tell tale signs of sheep scab is sheep that rub themselves on gates or fences to try and alleviate the irritation. This can cause further distress. Parasite control: External FLY CONTROL PRODUCTS FOR CATTLE Product Dose Active ingredient Withdrawal Swish for fly and midge control Deltamethrin Edible tissue 20 days, milk 0 days Flydown Spot Solution 10ml dose/animal Deltamethrin 17 days PRODUCTS LICENSED FOR PREVENTION AND/OR TREATMENT OF BLOWFLY STRIKE IN SHEEP 2016 Product Company Chemical Name Blowfly Product Lice Product Tick Product Withdrawal CLiK Elanco AH Dicyclanil (IGR) 16 weeks P No No 40 days CLiKZiN Elanco AH Dicyclanil (IGR) 8 weeks P No No 7 days CliK Extra Elanco AH Dicycanil 19 weeks P No No 40 days Crovect Elanco AH Cypermethrin 6-8 weeks P + T Kills existing lice Up to 10 weeks 8 days Ectofly 12.5mg/ml Bimeda Cypermethrin 6-8 weeks P + T Kills existing lice No 8 days Dysect Zoetis Alpha-cypermethrin 8-10 weeks P + T Kills existing lice 8-12 weeks 49 days Fly & Lice Spot On Zoetis Deltamethrin Treats established strike only 4-6 week reduction in incidence Up to 6 weeks 35 days Vectocert 1.25% Downland Cypermethrin 6-8 weeks P + T Kills existing lice 8 weeks 8 days Vetrazin Elanco AH Cyromazine (IGR) 10 weeks P No No 28 days Zermasect Sheep Downland Alpha-cypermethrin 8-10 weeks P + T Kills existing lice 8-12 weeks 49 days P= prevents blowfly T = treats blowfly Information correct at the time of publishing – check the data sheet and product packaging before applying the product and check the application rates and/or withdrawal durations have not changed. Blowfly strike usually occurs between May to September, but changing weather patterns and high temperatures in late autumn can see this problem extended. There are a number of products available for control, namely products which when applied prevent the eggs hatching, to ingredients more familiar to an agronomist containing Cypermethrin or Deltamethrin. The prevention period can vary from 8 to 16 weeks according to the product used. HEAD FLIES Cause considerable irritation to both sheep and cattle and are responsible for the transmission of bacteria causing summer mastitis. There are various products available for treatment. LICE Infestations occur primarily in the winter months in both cattle and sheep. The problem can cause severe irritation, and cause a reduction and disruption in feeding patterns due to constant rubbing against feed barriers etc. Hair loss, particularly around the neck area, is common. SHEEP SCAB Now recognised as one of the most problematical external diseases in sheep. It is caused by the mite Psoroptes ovis, surface feeding mites that are oval shaped and about 0.75mm in length. The transfer of the mite is mainly from carrier sheep to uninfected animals, including purchased sheep being introduced to a clean flock, or by exposure to the mites from contaminated wool left on fences/ hedges, but also sheep transport and handling facilities. Most problems occur during the winter and spring months, but, there have in recent years been outbreaks in late summer and autumn. The feeding mite will cause considerable damage to the skin, leading to inflammation and intense itchiness to the animal. DECTOMAX® INJECTION Dectomax® Injection is a single injection endectocide treating worms and sheep scab with a single intramuscular injection. An ideal product as part of a quarantine dose also for worm control around lambing. Dectomax Injection is effective against Benzimidazole resistant worms. NB: 70 day meat withdrawal. ZERMEX/CYDECTIN The product of choice for prevention and treatment of Sheep Scab is Zermex/Cydectin 2% injectable for sheep. Zermex has a persistent effect preventing infection or re-infection with sheep scab for up to 28 days. When treating or preventing sheep scab (such as when quarantine treated sheep are introduced to the farm) the benefits of a product with persistent effect cannot be underestimated. Sheep scab mites can survive on the sheep for up to 17 days which means mites can easily re-infest other animals. This is unlikely to happen when using a product with a persistence claim of at least 28 days. Failure to identify signs of sheep scab early or instigate appropriate treatment, can result in severe production loss. Sheep scab in pregnant ewes can result in the birth of small lambs, and subsequent high prenatal lamb mortality rates or poor lamb growth. Wool loss, serious exudation, inflammation and self- inflicted trauma due to sheep scab in a Mule gimmer. Please contact customer services: e: livestock@agrii.co.uk t: 0845 6073322 Please contact customer services: e: livestock@agrii.co.uk t: 0845 6073322 13 LIVESTOCK HEALTH & NUTRITION 12 LIVESTOCK HEALTH & NUTRITION