Subjective Evaluation of Teat Canal Anatomy

Abstract

Since radiographic techniques have shown that streak canals with larger diameters tend to milk-out faster and are more susceptible to new intramammary infections, a practical visual test was sought to provide easier determination of cows with either extremely narrow (slow milking) or extra wide (susceptible to new infections) streak canals. A subjective teat classification scheme was developed to describe five different teat-end shapes in 159 Holstein and Brown Swiss cows in the University of Nebraska dairy herd. Approximately one-fourth of the cattle had pointed or round teat ends, one-half had flat or near flat, and one-fourth were either disk or cone-shaped at the distal end. The correlation coefficient of repeated observations varied between .67 and .84, generally increasing as the time span between observations shortened. About 40% of variation in future classification scores is unaccounted for by past classification scores and may be the result of human error. I conclude, however, that this teat classification scheme has sufficient repeatability as an aid to selection, especially in springer heifers close to freshening. © 1973, American Dairy Science Association. All rights reserved.