Sheep Shearing is done mechanically either with clippers, a pair of scissors or by power-operated machines. Hand shearing is the most primitive and time-consuming. It causes stress to both the animal and the shearer, leaves up to 1.25 cm of wool on the body and the fleece is not cut evenly, resulting in double cuts and reduced staple length. Machine shearing is much faster, leaves less wool on sheep, and cuts fleece most evenly. It is used extensively all over the world.
Chemical shearing was developed in the United States, Development of Agriculture Station at Beltsville in the USA by feeding 24 mg of cyclophosphamide (CPA) per kg live weight. This chemical removes the wool within 3 days starting from the 12th day after drug administration. The wool comes off in patches and thus for the days the wool is shedding the sheep will have to be confined. Further, the drug adversely affects the development of the foetus, leaves a residual effect on meat, and removes wool too close to the skin exposing the animal more seriously to environmental stresses, and hence the method has not been adopted for commercial use.
Most flocks are usually shorn twice a year, i.e. March-April after the winter and September-October after the rains. In some states, sheep are shorn thrice a year, although this is not a correct way as it produces wool with a very short-staple. Shearing at an improper time of the year affects the health of the sheep adversely. Since fleece protects sheep from cold and serves as an insulator against heat, there is a considerable success on sheep after shearing, and unless they obtain nutritious grazing, the growth of wool may be seriously retarded and health receives a setback.
The spring-clip (March-April) is generally white and the autumn c% (September) is to a large extent canary- coloured in the north-western Indian plains where about two-thirds of the total wool in the country is produced. The problem with canary coloured wools is that the yellow colour cannot be removed by the conventional scouring methods. Further, these wools show light fugitivity, cannot be dyed in pastel shades and are not suitable for producing crease-resistant fabrics and, therefore, fetch about 20 per cent lower price than the corresponding white wools. The canary colouration of wools can be reduced by shearing sheep before the onset of staining, protecting them from solar radiation till the fleece is more than 2 cm long or by grazing them in the cooler hours of the day and by resorting to evening feeding of supplementary feeds or fodders. The sheep should, therefore, be shorn during June and again during October. The longer June clip can be utilized on the worsted system and shorter October clip on the woollen system.
A shearing shed and yard should have a forcing pen, a concrete or brick-paved drafting yard, a sweating pen, a catching pen where the sheep are shorn, and finally a pen for keeping shorn sheep. A wool section to carry out the sorting of fleece and rolling tables along with bins for classing the fleece in addition to sufficient space for storing wool packs is also required. The design and size of the shearing shed and the wool godown will depend on the number of sheep that would be available for shearing during a particular shearing season.