Microscopic Structure and Fibre Morphometry of Wool in Two Indigenous Sheep Breeds of Southern India: Trichy Black and Nellore

Aims: This study investigates the micrometrical and morphological characteristics of wool from two indigenous Indian sheep breeds of Southern India: Trichy Black and Nellore. Methodology: Wool from shorn wool bales were collected as samples from six adult Trichy Black and Nellore sheep. Using light microscopy, fibre parameters: mean fibre diameter (MFD), the medullary Index (MI), and the medulla/cortex ratio (M/C) were calculated. The cuticular pattern of the various types of wool were studied using the gelatin cast technique. A novel, rapid, and cost-effective cross-sectioning technique using cellophane tape is reported for the first time, providing a practical and efficient method (taking less than 10 minutes) for forensic and textile analysis. The cortex and medullary pattern were analyzed for each wool. Results: Results reveal that Trichy Black wool comprises two fibre types (thin and thick), whereas Nellore wool exhibits four distinct types, ranging from thin non-medullated to thick highly medullated fibres. Microscopic analysis proves that both breeds possess highly medullated fibres; the Medullary Index (MI) for thick fibres of Trichy Black was 0.8, while Nellore’s medullated fibres reached an MI of 0.95. Cuticular patterns varied from imbricate in coarser fibres to coronal in finer wool. Nellore wool proved to have the highest mean fibre diameter (MFD), measuring 143.52 ± 3.95 µm. Conclusion: The present study characterizes the wool of Trichy Black and Nellore sheep. It highlights the coarse, medullated nature of these wools, typical of carpet-grade fibres, and provides essential baseline parameters for breed identification. This research advances forensic trichological applications and provides scientific foundation for breeding programs aimed at enhancing wool quality.