Effect of lambing policy and ewe breed cross on wool growth patterns and wool quality

Abstract The effects of lambing policy (June‐ or August‐lambing) and ewe breed cross on midside patch wool growth and wool quality traits were studied for 12 months. Three ewe crosses—Border Leicester × Romney (BR), Poll Dorset × BR (PBR), and Suffolk × BR (SBR)—were used. Twenty ewes of each cross within each lambing policy and balanced for litter size had midside patches clipped at approximately 6‐weekly intervals for 1 year from April. Annual ewe fleece production was measured at the October shearings preceding and following the trial. June‐lambing ewes produced 0.6 and 0.4 kg more greasy and clean wool respectively than August‐lambing ewes ( P < 0.001). This extra wool production was not paralleled by a greater total wool growth from midside patches in June‐lambing ewes throughout the 392‐day measurement period. There was, however, a difference in the pattern of wool growth between the two groups. The seasonal decline in wool production that normally occurs over the winter months in August‐lambing ewes was reduced in June‐lambing ewes. Associated with the extra winter wool production in June‐lambing ewes was a significant increase in mean fibre diameter ( P < 0.05) and staple strength ( P < 0.001) when measured at the following October shearing. Wool from the June‐lambing ewes was brighter and whiter ( P < 0.05) than that from August‐lambing ewes. There was no difference in wool bulk or resilience between the two policies. Of the ewe crosses investigated, the BR had the highest greasy wool production (4.4 ± 0.1, 3.4 ± 0.1, 3.0 ± 0.1 kg for BR, PBR, and SBR respectively, P < 0.001), mean fibre diameter ( P < 0.05), and wool tensile strength ( P < 0.001). The SBR had the lowest wool production, mean fibre diameter, and wool tensile strength but the highest wool bulk. The practical implications of the increased winter wool production in June‐lambing ewes are discussed.