Dipping, pouring and spraying in sheep

Purpose : To eradicate ectoparasites, cure and prevent spread of sheep scab, ward off attacks by sheep blow-flies, remove waste material and dung from the fleece prior to shearing, thus facilitating production of clean wool.

Time : In India, sheep can be dipped immediately before the post-winter shearing and/or before the post-autumn shearing. In addition, they can be dipped 1-4 weeks after shearing, when the fleece has grown long enough to retain dip solution and also allow cuts and scratches incidental to shearing time to heal.

Dipping chemicals : BHC, Lindane (0.25%), DDT (0.5%), Garathion, Malathion (2.0%), Cimathion, Pyrethrin-arsenic sulphide powder (0.2% arsenic), coal tar-creosote (0.76%), nicotine and tobacco dips (0.1% nicotine, 15 kg tobacco leaves in 500 lit water).

Dipping tanks :-

a) Hand bath : In case of small flocks, a tank of galvanized iron (1.2 x 1.0 x 0.5 m) can be used. Sheep can be lifted one by one into the bath and kept for two minutes. The sheep are removed and placed on a drain board to drain off surplus dip back into the dip tank.

b) Swim bath : In large flocks, the dipping tank can be constructed of metal or concrete. It should be 12 feet long at the top and 6 feet long at the bottom, with a incline for the other 6 feet. The tank should be 2 feet wide at the top, sloping to one foot at the bottom, and it should be 6 feet high. The sheep should be completely immersed in the liquid (including their heads and ears).

Precautions :-

1. Follow the manufacturer's instructions thoroughly for preparation of the dip as well as its disposal.
2. Always water and rest the sheep before dipping to avoid their drinking of dipping solution.
3. Choose a bright, sunny day (neither too hot nor too cold) so that the treated animals will dry quickly and the insecticide will not be diluted by rain.
4. Avoid dipping of sheep in advanced stage of pregnancy.
5. Avoid dipping of sick animals, sheep with wounds, young lambs (less than one month old) and stock being sent for slaughter.
6. Avoid dipping of rams in breeding season to guard against injury to penis or scalding of thigh.
7. Keep sheep in the holding pen for at least five to ten minutes so that they drain properly, thus avoiding wastage of dip and resultant pollution of the environment.
8. Complete each day's dipping by 4 PM so that the sheep will have some hours to dry before nightfall.
9. Do not return treated sheep to the shed from which they came until it is completely cleaned.

B. Pouring

When an individual sheep is affected with scab or badly affected with maggots and has open wounds, dipping is not advisable. In such animals, a small quantity of dip is poured into the fleece along the back, sides and belly to achieve the objectives of dipping.

C. Spraying

Spraying sheep with a fly repellant insecticide solution over the backs and sides is an effective method of controlling ectoparasites in tropical countries. In developed countries, fly-repellant solution is sprayed in the form of a fine mist through a series of nozzles into a roomy tunnel through which the sheep are forced to pass. However, spraying can be done with the help of a power sprayer or hand sprayer in case of small flocks. Spraying is not as economical or efficient as dipping and is recommended only for young lambs which cannot be dipped.