Seasonal Changes in the Morphology of Wool Follicles in Finewool and Strongwool Merino Strains Grazing at Different Stocking Rates in Southern Australia

The study investigated the impact of stocking rate and Merino strain on wool follicle morphology in southern Australia's Mediterranean environment. Finewool and Strongwool Merino sheep were observed at 9 stocking rates, with skin biopsies taken monthly from February to June. After the seasonal break in April, the proportion of 'normal' follicles decreased, and inactive follicles increased, with variability between animals. Stocking rate significantly affected follicle inactivity, but Merino strain did not. Maximum follicle inactivity occurred in May, coinciding with minimum fibre diameter and liveweight. Minimum fibre diameter and its variation accounted for most of the variance in staple strength, while inactive follicles contributed less. The study suggested that nutritional stress might cause these follicular changes, and management strategies focusing on fibre diameter and shearing timing could improve wool strength. Further research was needed to understand the impact on other wool characteristics.