The wool-severing properties of 2·8% aqueous solution of calcium thioglycollate were increased by 76% by dissolving the depilatory agent in a KCl-NaOH buffer of pH 12·5. The optimum Ca-thioglycollate concentration for defleecing was 3·6%. One ml of this solution defleeced an area of 12·1 cma.

A comparison of five buffers and water as solvents for 3·6% Ca-thioglycollate indicated that the area of skin defleeced was directly related to solution pH and the stubble remaining appeared to be inversely related to solution pH. A KCl-NaOH buffer of pH 12·0 provided the optimum relationship between area defleeced (10·2 cm2/ml applied) and stubble (ca. 2 mm wool) remaining.

Single site applications of 0·1–1·0 ml of defleecing agent at skin level were compared and it was shown that the application of 0·1 ml aliquots would require 320 ml solution to defleece an average-sized sheep.

Preliminary evaluation of 6% formaldehyde buffered to pH 6 and a carbowax-citric acid solution of pH 2 showed that protection of fibres against dissolution by Cathioglycollate solutions can be sustained for 21 days. Pre-treatment with these compounds could therefore produce a protected band of wool immediately above the proposed site of wool dissolution.

The practical implications of these findings are discussed with regard to a wool harvesting programme.