The effect of frequency and time of shearing on the reproduction and wool growth of Bungaree South Australian Merino ewes

Abstract

Two hundred and seventy-five Bungaree South Australian Merino ewes were divided into three groups after shearing in June 1963 at Trangie Agricultural Research Station. One group was shorn in December 1963 and 1964 (December group), another in June 1964 (June group), while the third group was shorn at all three of these times (Dual group). The ewes were joined with rams on February 25, 1964. Twenty-nine days later 88 per cent of the ewes shorn in December (December and Dual groups) had exhibited oestrus compared with 72 per cent in the unshorn (June) group (P<0.05). Shearing in December also increased the percentage of wet ewes. Pre-lambing shearing did not influence lamb losses. Shearing twice a year (Dual group) increased the wool production of dry ewes compared with shearing once in the same 12 month period. The increases in clean fleece weight when the additional shearing in the Dual group was in December and June were 15 and 10 per cent respectively. However, Dual shearing did not increase fleece weights over the December group when the ewes were pregnant at the time of the additional shearing in June. Dual shearing improved wool colour and reduced fleece rot, but the wool of the Dual group had fewer crimps per inch and poorer handle than the June shorn wool (P<0.05). Estimated wool returns favoured the groups shorn once per year (P<0.05).