Breeding for a sheep with bulky wool by crossbreeding Texel sires with fleece-weight-selected Romney ewes

This investigation examined an alternative option to selection within breed for improving wool bulk by crossbreeding traditional long-wooled sheep with introduced Texels. A flock of bulky high-fleece-weight sheep was established by crossbreeding high-fleece-weight-selected (HF) Romney ewes with bulky-wooled Texel rams. A local Romney control flock (LC) was formed at the same time. These two flocks were grazed together at the Gore Research Station. The HF flock established earlier and its random control (RC) flock were both located at another site (Woodlands Research Station), and were also included in the comparison through common RC-LC sire linkages. The Texel x Romney (TR) flock had significantly (P < 0.01) higher liveweights and fleece weights than its LC. The TR flock was 7 and 5% heavier than the HF flock for birth and weaning weight, and significantly (P < 0.01) heavier for spring liveweight and 16-month liveweight at 11 and 9% respectively. Wool return per head predicted for the TR flock was 10% higher than for HF Romney at 12-month-old shearing. Fleece characteristics, namely bulk (+27%) and brightness (+3%) were significantly (P < 0.01) improved for TR compared with HF Romney, whereas yield and yellowness were similar in both flocks. The effects of sex, birth/rearing ranks, and age of dams were more pronounced for liveweight than for fleece weight. Phenotypic correlations were significantly positive for spring liveweight with 16-month (2 tooth) liveweight (P < 0.001), for hogget greasy fleece with 16-month greasy fleece weight (P < 0.001), for all liveweights with all fleece weights (P < 0.05), and for yield with brightness (P < 0.01). The study highlighted that crossbreeding HF Romney (and/or screened) ewes with bulky Texel sires can improve wool bulk without substantially losing fleece weight.