The teat canal is an invagination of the outer teat surface. Its epithelial constitution is, however, highly specialized as indicated by its high turnover rate, its unique function in trapping bacteria, and in sealing the teat canal between milkings. The keratin of the teat canal is in a dynamic state of generation and degradation. Repeated removal during milking of keratin contaminated with or colonized by bacteria plays a significant role in preventing mastitis (Murphy, 1959; Capuco et al. 1992). To study the biology of the keratin lining, e.g., its turnover, and its relation to mastitis defence, reliable methods of collecting keratin in vivo for quantitative and qualitative analysis are necessary. Bright et al. (1990) compared methods for keratin collection in vivo and suggested that a tapestry needle was a suitable tool for collecting repeatable, representative samples of keratin for lipid analysis from single teat canals of living cows.