Abstract

Two stock management practices were investigated for their effect on transfer of bacteria from the environment onto teat ends of dry dairy cows. Cows (n = 20) were required to walk or trot along races (1.2 km) deemed to be "clean" or "dirty". Cows walked along "clean" or "dirty" races were similar in dirtiness of the udder, and bacterial loading of the teats. Cows that trotted along `dirty` races showed a significant increase in degree of dirtiness of the teats and legs, and increased contamination of teats with coliform bacteria. Cows grazed for 24 hour periods using standard break-fencing systems, with (n = 20) or without (n = 20) the addition of back-fencing were assessed for the number and type of bacteria present on teat-ends. Cows that grazed paddocks with back-fencing had visually dirtier udders, but there was no difference in bacterial contamination of teats compared to those cows grazed without back-fencing. These studies suggest that the risk of bacterial contamination, and by extrapolation, risk of intra-mammary infection, may be mitigated by the speed with which cows are moved along races. However, grazing on muddy, soiled paddocks should not be discounted as a significant risk factor for mastitis.

S-A, Turner, JH Williamson, and SJ Lacy-Hulbert

Proceedings of the New Zealand Society of Animal Production, Volume 68, Brisbane, Australia, 92-95, 2008