Tag: "variation"

  • Seasonal Variation in Fibre Diameter and Length in Wool of Grazing Merino Sheep with Low or High Staple Strength

    The associations between fibre growth characteristics and wool staple strength were investigated in groups (n = 10) of Merino wethers with either low or high staple strength. Sheep grazed together on pastures based on subterranean clover and annual rye grass for about 13 months. The sheep were weighed and injected intradermally with [35 S]-cysteine at about 14-day intervals. Mid-side patches were harvested and dye bands placed in the wool at about 28-day intervals. Patch clean wool growth, pasture digestible dry matter/ha and pasture crude protein/ha had similar seasonal amplitudes of production (287, 286 and 267% of respective minimum). These were significantly higher than the seasonal amplitude in liveweight (24.5%). The seasonal amplitude in fibre diameter was significantly greater than that for rate of fibre elongation (71.4 and 41.4% respectively). This seasonality in fibre length and diameter resulted in statistically significant seasonal fluctuations in the ratio of fibre length growth to fibre diameter. Fortnightly variability in fibre diameter was not significantly related to variability in fibre length growth rate between sheep for individual time periods. However, for the pooled data over the experimental period a statistically significant relationship (R2 = 0.13, P < 0.01) was improved with the addition of parameters for sampling time and staple strength group. Staple strengths for the low and high staple strength groups were 25.6 and 32.8 N/ktex respectively (P = 0.057). There were no significant differences between the staple strength groups in seasonal change in liveweight, wool production or fibre parameters measured in this study but the low staple strength group had longer fibres. Staple strength was most highly correlated with mid-side fibre diameter coefficient of variation (R2 = 0.50) followed by seasonal amplitude in liveweight. more »
  • Variation in Fibre Diameter Profile Characteristics Between Wool Staples in Merino Sheep

    Two experiments were conducted to examine the variation in fibre diameter profile (FDP) characteristics between staples. The mean values of all the FDP characteristics were not significantly (P > 0.05) different between staples prepared using the same and different staple preparation techniques. The residual correlation coefficient’s between staples prepared using the same staple preparation technique for all FDP characteristics ranged from r = 0.60 to 0.96. The correlation coefficients between staples prepared using different staple preparation techniques ranged from r = 0.37 to 0.97. These results indicate that it may not be sufficient to segment a single staple for estimation of certain FDP characteristics to examine differences between individual animals. One staple is sufficient to estimate the average FDP of a group of animals. FDPs generated using different staple preparation techniques can be accurately compared for most FDP characteristics. more »
  • Variation in and Sampling of Alpaca Fleeces

    Evaluating the attributes of alpaca fleeces subjectively by eye is difficult and unreliable as alpaca fleeces show large variations in attributes. In addition, our eyes (and brain) are limited in their ability to discern fibre diameter, the average of other attributes and the extent of naturally occurring contaminants. Alpaca fleeces are also affected by environmental conditions, in particular humidity, but also by storage conditions. These same limitations apply equally to wool, mohair and cashmere. more »

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