Sheep handling: Care is the key when opting for dipping
Essential to ensure the dip or pour-on product treats the targeted parasites
Published 23/04/2014 | 02:30
Dipping sheep remains a crucial role in the control of Ecto-parasites on many Irish farms.
All sheep dips, whether they contain organophosphates or a synthetic pyrethroid, must be treated with respect and handled appropriately to ensure the user, the animal or the environment are not damaged in any way through their usage.
While it is not the function of this article to advise on the health and safety procedures required at dipping time, it is essential that each operator reads, understands and implements the health and safety recommendations for each product available on the market. Minimum requirements include a face visor, arm length gloves, wellington boots and a dipping apron.
There are a number of products available for sheep dipping, but I don't intend to go into the details of any individual product.
What is important, regardless of the product, is that you follow the manufacturer's guidelines closely to ensure the best response to the product and the maximum return on your investment.
Organophosphate (OP) dips were the traditional category of products used for dipping sheep, but their usage has declined due to their potential health impacts on farmers. Dipping can be stressful on the sheep as well and precautions to protect the animal need to be taken.
Sheep should not be dipped when full, wet, tired or thirsty, or when they have open wounds.
Sheep should be dipped after two to three hours' rest and early on a dry day. Lambs should be dipped separately from ewes to minimise the risk of lambs suffocating or drowning.
Rams and fat stock may require assistance through the dip tub.
With the use of OP dips, care should be taken to avoid using any drenches that may interact with the OP dips.
Allow an appropriate lag time between dipping and drenching if this is an issue. All this information is available on the leaflets provided by the manufacturers with the products.
The dip bath should be replenished both in terms of volume of water and dip concentration in line with the manufacturers guidelines. Knowing the volume of your dip tub is essential.
Follow the 4x100pc rule when dipping. This means 100pc of the flock in each session; immerse 100pc of the sheep's body in the dip; keep the animal in the dip for 100pc of the recommended time (60 seconds) and dip at 100pc of the recommended strength of the dip mixture until the last animal has been dipped.
Post-dipping lameness can also be a concern and may be caused by excessively dirty dipping solutions.
It is caused quite often by Erysipelothrix rhusopathiae, which is commonly found in soil and sheep faeces. Once again, this is a problem that correct management can help to avoid.
In recent years, we have witnessed the availability of many pour-on type products for the control of fly strike in sheep and the use of injectables for the control of scab.
Importantly, the active ingredient in some injectables is the same as the active ingredient found in some worm drenches and there are concerns in Britain over the potential role this might play in anthelmintic resistance development.
Pour-on type products can be a very attractive alternative to dipping, not least as they do not require specialised equipment.
Care must be taken in the use of any pour-on or dip to ensure it is capable of treating the parasite you are targeting. Some products are much narrower in range than others, with certain products only covering blow-fly strike.
Secondly, withdrawal periods need to be considered carefully, especially in lambs coming close to being finished.
Withdrawal periods range from seven to 40 days. In some cases, the withdrawal period is linked to the period of efficacy, with longer withdrawal periods linked to longer periods of efficacy. With blow fly strike remaining the main concern, there are management approaches which can also be taken to minimise the risk of a problem.
These include tail docking lambs, crutching ewes and lambs, ensuring faecal material does not build up around the tail head (dosing and dagging are important here).
However, despite the best efforts of the farmer, we still see clean sheep infected by blow-fly, so vigilance during high risk periods is also essential.