EVALUATION OF BORDER LEICESTER X ROMNEY (BR), POLL DORSET X BR, AND SUFFOLK X BR EWES FOR OUT-OF-SEASON LAMBING

Three different year groups of Border Leicester x Romney (BR), Poll Do rset x BR (PBR), and Suffolk x BR (SBR) ewes were evaluated for yearli ng liveweight and greasy fleece weight, and for their 2- and 3-year-ol d lambing performance under both June- and August-lambing policies. Ma ting of the June-lambing ewes was induced using progesterone treatment and high ram:ewe ratios. Suffolk x BR hoggets were significantly (P < 0.01) heavier than PBR and BR ewe hoggets in May, October, and Januar y (at about 16 months of age). Border Leicester x Romney hoggets produ ced significantly (P < 0.01) more greasy wool at the yearling shearing than PBR or SBR hoggets. Lambing policy did not influence the proport ion of ewes lambing but there were more (P < 0.05) multiple births in August-lambing ewes. Birth weights and weaning weights of June-born la mbs were lower (P < 0.001) than those of their August-born counterpart s. Weight of lamb weaned per ewe joined was 22.1 kg for June-lambing e wes and 24.3 kg for August-lambing ewes. June-lambing ewes produced mo re wool than August-lambing ewes but the magnitude of this difference varied between years (0.1-1.1 kg) reflecting a significant (P < 0.001) policy x year interaction for fleece weight. Differences between the three ewe crosses in the proportion of ewes lambing and the incidence of multiple births were small and non-significant. Poll Dorset x BR ew es reared the heaviest lambs, whereas lambs from BR ewes were the ligh test. Border Leicester x Romney ewes produced more wool (by 0.7-1.2 kg across years and ages) than PBR ewes (P < 0.001) whereas PBR ewes out performed the SBR ewes (0.3-0.5 kg, P < 0.01) for wool production. The results of these studies are discussed in the context of the developm ent of out-of-season lambing systems and highlight the need for higher prices for out-of-season lambs to compensate for the lowered lamb pro duction.