As part of the care you give to your sheep throughout the year, parasite control is significant as an ongoing task. Internal parasites such as worms are treated, according to life cycles and levels/burdens, with internal treatments, e.g. drenches. Your flock can also be susceptible to external parasites, and these require topical treatments. Sheep dipping is a commonly-used practice, but there are many safety aspects to consider.
This method can help to reduce the spread of disease through the flock – parasites such as ticks and lice are controlled, and harmful bacteria on the skin is killed. Sheep scab, caused by a mite, is a significant issue as it can spread quickly, particularly through direct contact, but also through the environment. Dipping is also used to minimise blowfly strike – this is more prevalent in the summer months, however, flocks can be at risk up until December.
Dipping is generally carried out in the autumn, and is part of the plan to get your ewes as healthy as possible for the next breeding season/tupping. They will also have the wool around their tails clipped. These procedures minimise the risk of infection and treat any issues so that the flock can gain better condition.
Here we look at the significant issues involved in sheep dipping.
What is sheep dip?
A sheep dip is an enclosed area, such as a tank or a vat, where animals can be treated with pesticide which is mixed/diluted with water. The sheep are then dried off in a holding pen, prior to getting moved to other areas of the farm.
The term sheep dip is used for both the tank and the chemicals used. The latter can be in the form of pastes, powders, or concentrated solutions. The tank often consists of a concrete or metal container, which has a sloping floor. It may also have a removable lid/cover to protect it from the rain, and also in transferring the tank contents to another location for processing. More recent improvements to the system include safety devices, such as shut-off valves. There are also mobile dipping tanks/systems which may be used by contractors.
Pour-on applications also exist, and the choice between this and immersion can depend on the set-up of your farm. It can also depend on whether you perform the dipping yourself, or if you hire someone to do it for you. Pour-on or injectable treatments may be considered preferrable, as they reduce contact with the chemicals involved in dipping. These commonly include organophosphate (OP) pesticides, such as malathion and parathion, and also synthetic pyrethroids.
An ongoing concern with sheep dips is the risk of environmental contamination, particularly drinking water sources. The design of the dipping tank/area is extremely important, and precautions must be taken to ensure that the run-off is contained effectively so that surface waters and water sources are not affected (OPs can adversely affect aquatic plants and animals). There are several restrictions placed on the location of dipping facilities, and include distance from water sources, as well as the likelihood of drainage down slopes into these sources.
OP pesticides are considered toxic to humans, and poisoning can occur over extended periods of time. They can be absorbed through the skin, as well as ingested. Neurological damage is known to result from long-term direct exposure, and in extreme cases, has affected those living near areas where sheep dipping occurs. They have also been linked to reproductive issues, birth defects, and cancer, amongst other health problems. However, these problems are more widely known about now, and there are precautions that can be taken.
Dipping may be deemed necessary/unavoidable, so there are ways to reduce exposure to sheep dipping chemicals. By allowing adequate ventilation, you can reduce inhalation of vapours. The dipping tank can have screens/boards to minimise splashing, and a lip to minimise overtopping. You can also use personal protective equipment (PPE), which can include respiratory protection.
Any clothing/reusable equipment should be washed down prior to leaving the dipping area, and the rinsings should be directed into the tank. In order to reduce direct contact, you can use a metal crook to assist with the moving of sheep through the dip. It is possible for the dip preparations not yet absorbed to be washed off your flock’s fleece, so it is important to either keep them under cover for 24 hours, or plan to dip when there is no rain forecast.
It is important to ensure that your tank is not damaged, or has any holes that can result in leaks; tanks constructed in one piece can minimise this potential problem.
Used dip solution can be removed from the tank by use of a vacuum system – make sure you only use/keep the tubing for dip movement. A common way of dealing with used solution is to use a chemical treatment to break down the pollutants involved. If you use the method of spreading it on your land, you must have a permit – there are considerable risks of groundwater contamination involved. There are companies that deal with waste/surplus sheep dip, but ensure that they have the required permits and licences.
By keeping comprehensive records of what you buy, when you use it, safety precautions taken, and how you disposed of waste, you have a backup should any inadvertent contamination occur – it may be proof that you acted responsibly. In the UK, you must have a certificate of competency before dipping, and you even need this before you can obtain the chemicals required.
When buying the chemical preparations needed for dipping, make sure you only obtain enough for the current season. Long-term storage increases the risks of leakage/environmental contamination. Ensure that all containers are firmly closed, and store them in a safe, locked area.
By being aware of all these issues when dipping your sheep, and acting positively upon them, you are able to minimise the risks to yourself and to others. You will be able to look after your flock effectively whilst gaining a reputation for being a responsible professional.