Seasonal Variations in Skin and Wool Follicle Morphology of Grazing Merino Sheep with Low or High Staple Strength

ABSTRACT: Differences in skin and wool follicle morphology between 6 low and 6 high staple strength (SS) Merino sheep were examined over a 12-month period at pasture. Low SS sheep had a higher skin weight and lower percentage of normal wool follicles than high SS sheep. Low SS sheep also had a significantly higher seasonal change in the percentage of normal wool follicles than high SS sheep. There was a significant relationship between SS and minimum percentage of normal follicles, coefficient of variation in follicle bulb diameter, and the seasonal change of the incidence in normal follicles. There were significant seasonal changes in wool follicle bulb diameter, dermal papilla diameter and length but these were not related to SS grouping. The differences in skin weights and percentage of normal follicles between SS groups warrants further study as these changes may influence the selection process of sheep for improved SS