External parasite control in sheep

WITH the warm weather we currently are experiencing, external parasites in sheep will start to become a problem. The main external parasite we are familiar with this time of the year is flystrike but ticks, lice and scab can also have a significant effect on the animal health and welfare. Managing and controlling these external parasites must be carried out on sheep farms regularly.

The wool and skin of the sheep is the area where these external parasites live. Regular checking of the flock is particularly important for lowland sheep in fields. Ensuring that sheep are kept as clean as possible through dagging and shearing will reduce the risk of flystrike but will also give you a good indication if there are any other external parasites present such as lice, scab or ticks. Obviously from now, shearing adult sheep will be the main preventative from flystrike with lambs requiring some form of pour on or dipping.

You should also ensure sheep handling facilities, yards and trailers are kept as clean as possible to reduce the risk of spread of external parasites. It is reported that scab and lice can survive off the sheep for up to 17 days, and still infest other sheep. Where sheep are purchased, it is advised to treat them on arrival.

Good management practices on farms can help delay the outbreak of external parasites and even the severity of an outbreak but most farms will require some use of chemical control.

There is increasing awareness now about the correct use of animal health products so as to reduce resistance. It is important to follow the guidelines of using the right product in the right amounts at the right time and used and administered the right way. The withdrawal periods of any product used on farm is another important consideration when choosing a product so that it does not impact future slaughter dates.

There is a range of preventative treatments to combat the various external parasites available to farmers. The chemical products available are administered via plunge dipping and pour-ons. The use of pour-ons for the treatment of external parasites has become popular due to the ease of application. Again there are various types of pour-on products available so it is important to use the correct product so that product will work to the best efficacy.

Treating lambs now with long lasting pour-ons will ensure season long protection and will also make sure that withdrawal periods are completed before the first lambs are ready for sale. This makes the treatment per lamb more cost effective while also reduces the amount of product type required as it is governed by bodyweight.

For flystrike prevention ensure the correct pour-on applicator nozzle is used and spray along the back and around the tail of the sheep at the recommended rates. These products contain chemicals that prevent the blowfly eggs from hatching and maggots from developing.

The plunge dipping of sheep occurs less now than years ago due to the labour requirement. Dipping products will prevent and treat for flystrike as well as give good control for other external parasites so basically a good dipping will cover all parasites in one go. Pour on products will not cover all parasites in one go. Mobile dipping services are also available. Sheep dip products are licensed for plunge dipping with the sheep completely submerged in the dip rather than being sprayed on which some mobile systems use.

Good safety measures should be in place when administering any of these products as chemicals that can be harmful to humans. Protective clothing, gloves, face shield, masks are essential when sheep dip is being handled in concentrated form. Spent containers of pour-on should be disposed of correctly to avoid any run off into watercourses.