Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Animal Science

Major Professor

Don O. Richardson

Committee Members

M. J. Montgomery, Robert Walker


The primary objectives of this study were to resubstantiate the importance and effectiveness of dry cow therapy and to compare dry treatment and teat sealing as mechanisms for reducing the incidence of new mastitis infections and for eliminating existing infections during the dry period.

Data used in this study were obtained from quarter samples from 71 cows at The University of Tennessee, Knoxville dairy herd. This data included bacterial analysis of each sample taken at two different test periods, one prior to drying off and the second within 10 days after freshening.

The cows were assigned to four treatment groups. Group 1 received no treatment and served as the control group. Group 2 cows received the teat sealant. Group 3 cows were infused with a commercial dry cow treatment and in the fourth group, cows were dipped in the teat sealant in addition to the dry cow therapy. Since the teat sealant was not designed for the dry period, cows were resealed every two weeks. (It was also not a germicide so an iodine teat dip was used under the sealant.)

The change in infection status between the two sampling periods was the primary response measurement.

The use of dry cow treatment was found to be very effective in eliminating existing infections of Staphylococcus aureus and Streptococci and preventing the incidence of new infections. The results of this study reinforce the use of dry cow therapy as a form of mastitis control but do not provide a basis for the recommendation of the use of teat sealants. It should be realized that the sealant used in this study was not designed for use in the dry period and a more effective sealant could be developed in the future.

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