Sheep dips: safe handling and usage

Sheep dips are veterinary medicines used to protect sheep from pests. There contain three main types of drugs:

  • Organophosphate sheep dips (diazinon)
  • Pyrethroid sheep dips (cypermethrin)
  • Formamidine sheep dips (amitraz)

Sheep dips must be diluted with water in the sheep bath before use. Handling the concentrated chemicals is hazardous, so precautions are crucial when handing it, as well as during dipping and in disposing spent dipwash.

Dipping sheep

Dipping sheep involves:

  • Adding the right amount of concentrate to the bath initially (known as charging the dip)
  • Fully immersing the animals for the proper time,
  • Replenishing the concentrate as needed (known as re-charged),
  • Collecting any run-off from freshly-dipped sheep,
  • Cleaning the bath if it becomes fouled, and
  • Properly disposing of the spent dip wash.

Care is needed in handling and managing freshly dipped sheep. Dip that drains from freshly dipped sheep should not be allowed to enter streams or other watercourses as it may pollute them and cause fish deaths.  

Sheep baths vary greatly in size. Knowing the capacity of the bath is critical to be able to ‘charge’ the bath. Baths should be carefully calibrated either by using permanent side markings or using markings on a graduated stick. If graduated stick is used it must always be used at the same position in the bath. Markings should also show the level at which replenishment or ‘topping-up’ is needed.

When a sheep leaves the bath after being dipped, it will take with it a considerable volume of dip wash, a large proportion of which will drain back into the bath. The wool of the sheep selectively absorbs the chemical from the dip wash, meaning that the run-off is more dilute than the original wash. This is the reason why dips need to be replenished or re-charged regularly.

Use of sheep dips through showers or jetting equipment

Sheep dips should be used in dip baths only.  No data of their safety or efficacy have been provided to show that they can be used through sheep showers or similar equipment. Use dips according to the instructions on the product labelling/package leaflet.  If used incorrectly they could be harmful to animals, the user or to the environment and is against the law.

Protective measures

To minimise exposure to dips:

  • Plan the work carefully,
  • Use a well-designed dipping facility, and
  • Wear suitable protective clothing (typically consisting of:
    • Non-lined synthetic rubber gloves [heavy duty gauntlet style PVC or nitrile at least 0.5mm thick],
    • Wellingtons,
    • Waterproof trousers or leggings, and
    • Waterproof coat or bib-apron (made of nitrile or PVC).

When handling the concentrate use a face shield.

Protective clothing should be in good condition and should be washed after use.

Whichever chemical is used, it is essential to wear suitable protective clothing when:

  • Handing the concentrate,
  • Working with diluted dip,
  • Handling freshly dipped sheep,
  • Washing concentrate containers or delivery systems (where applicable), and
  • Disposing of the spent dipwash.

In the event of accidental spillage, wash all concentrate or splashes off the skin immediately.

Special additional precautions for organophosphates (diazinon/diamplyate):

Due to the risks of human contact with dip concentrate, concentrate may be added to water in the dip bath only by using a closed dispensing transfer system and should not be poured directly from the product container.

The Health & Safety Authority has issued advice when dipping sheep or handling animals afterwards; handlers are most at risk from absorption through the skin.

Cases of heavy contamination should be treated as an emergency.  

  • Remove contaminated clothing immediately,
  • Rinse affected areas of the skin with water,
  • Take the patient straight to hospital.

The symptoms of mild poisoning are a feeling of exhaustion and weakness that may be accompanied by cramp-like abdominal pains, diarrhoea, excessive sweating, constricted pupils and salivation for up to 24 hours after exposure. Severe poisoning can cause general muscle twitching and convulsions.

Doctors can obtain advice on clinical management of organophosphate exposure from the Poisons Information Centre, Beaumont Hospital, Dublin 9 (phone 01 809 2566). All cases of organophosphorus poisoning must be treated in hospital.

Special additional precautions for pyrethroids (cypermethrin):

Cypermethrin is not an organophosphate. Cypermethrin is a potential skin sensitiser and may cause tingling effects on exposed areas of human skin.

Special additional precautions for amitraz:

Amitraz is not an organophosphate. If poisoning is suspected, treatment should be symptomatic and supportive, paying particular attention to monitoring of cardiac and respiratory function. Do not use atropine. Do not induce vomiting.

Care in the disposal of spent sheep dip

Once sheep have been dipped, the waste dip water that remains in the bath as well as the run-off from treated animals is known as spent dip.  Advice for safe disposal of spent dip is particular to individual products – consult the label/package leaflet.