Date of this Version
Journal of Dairy Science Vol. 56 Issue 3 pp 411–413 Published March, 1973
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 fiat or near flat, and one-fourth were either disk or coneshaped 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 40g of variation in future classification scores is unaccounted for by past classii~cation 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.