The measurement and sources of variation of loose wool bulk in Romney, Coopworth, and Perendale breeds

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 A94072 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.

Section: Records and Measurementsmentioning

confidence: 99%

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

Wuliji

Dodds

Andrews

et al. 1995

“…Mean fibre diameter (YFD and EFD) and fibre diameter variation (YFDSD and EFDSD) were measured by Fibre Fineness Distribution Analyser (Lynch & Michie 1976) and later by Fineness Distribution Analyser. Beginning in 1982, with the development of suitable instrumentation, each sample was also measured for loose wool bulk (YWB and EWB) (Bigham et al 1984a) and for Commission Internationale de l'Eclairange (CIE) brightness (YY and EY) and CIE Z values (Bigham et al 1984b). CIE Y-Z was calculated for yearlings and ewes as a measure of yellowness (YY-Z and EY-Z) (Edmunds 1977 …”

Section: Traits Measured or Calculatedmentioning

confidence: 99%

Single trait selection for yearling fleece weight or liveweight in Romney sheep—correlated responses in liveweight, fleece traits, and ewe reproduction

Morris

Johnson

Sumner

et al. 1996

Self Cite

An experiment was carried out to study direct and indirect responses to selection in Romney sheep. There were two selection lines, one selected for greasy fleece weight (GFW) and the other for liveweight (LW), maintained alongside a control line (CO). Data from lambs born in 1967-90 were analysed to quantify the correlated responses to selection. By 1990, there had been an average of nine generations of selection with an average generation interval of 2.7 years. The correlated responses analysed included yearling and ewe greasy and clean fleece weights, washing yield, yearling and ewe fleece quality traits (staple length, mean fibre diameter, fibre diameter variation, loose wool bulk, Commission Internationale de l'Eclairange (CIE) Y value (brightness) and CIE Y-Z value (yellowness)), birth weight, weaning weight, yearling liveweight, ewe pre-mating weight, and ewe reproductive rate (fertility, litter size, weaning percentage, and lamb survival). Correlated responses were estimated as the deviation of selection lines from the CO line, and genetic correlations were obtained by restricted maximum likelihood techniques. Direct responses measured in the GFW and LW yearlings were 1.7 and 1.2% per year, respectively. Correlated annual responses were 0.7% in yearling liveweight in the GFW line and 0.2% in yearling fleece weight in the LW line. Corresponding annual changes in ewe performance were 1.5% in greasy fleece weight and 0.5% in pre-mating weight in the GFW line, and 0.0 and 1.2% respectively in the LW line. Mean fibre diameter increased in yearlings and ewes of the GFW line, but did not change in the LW line. There were small but significant increases in staple length in both lines. Loose wool bulk among GFW yearlings was reduced by 0.12% per year but did not change significantly in ewes. Yearlings and ewes of the LW line both showed an increase in bulk (0.15 and 0.43%, respectively). Relative to the CO flock, CIE Y-Z among yearlings increased significantly by 1.35% per annum and 0.25% per annum in the GFW and LW flocks respectively. Among ewes it increased in the GFW line whereas the opposite occurred in the LW line. There was no significant change in percentage ewes lambing as a result of GFW or LW selection. Litter size increased and lamb survival to weaning decreased significantly, but there was a net increase per year in lambs weaned per ewe lambing (0.27% per year for the GFW line and 0.48% per year for the LW line). A95024

“…Tensile strength was expressed on a clean weight basis, as the mean kg force per gram per m of length (N/Ktex). Clean scoured and carded samples from the October 1988 shearing and from the contralateral sample taken on Day 392 were measured for bulk and resilience using a WRONZ bulkometer following the procedure of Bigham et al (1984a). Two 3 g scoured and carded subsamples from the midside samples collected at the October 1988 shearing and the contralateral sampling on Day 392 were colour-tested using a Hunterlab D 25 D2M Colorimeter (Bigham et al 1984b).…”

Section: Measurementsmentioning

confidence: 99%

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

Morris

McCutcheon

Blair

et al. 1994