Abstract

Streptococcus uberis is an important mastitis-causing pathogen in cows managed under pastoral conditions. The influence of environmental conditions on S. uberis ecology in dairy farms is unknown. To evaluate associations between climatic parameters and population levels of the bacterium on the farm, farm races were monitored for S. uberis levels on a fortnightly basis from November 2003 to November 2004 at the Dexcel Lye research farm. Higher S. uberis contamination was observed in races where cow traffic was frequent and lower in areas where usage was minimal. Highest S. uberis contamination occurred in the month of August (630 cfu/g) and lowest in January (2 cfu/g). Significant associations were observed between S. uberis levels and relative humidity (r = 0.6), soil temperature at a depth of 10 cm (r = -0.8), solar radiation (r = -0.7) and maximum air temperature (r = -0.7). Around 70% of S. uberis clinical mastitis cases occurred in the non-lactating and calving periods, when S. uberis levels in races were above 100 cfu/g and solar radiation levels were low. It is suggested that weather conditions have a significant impact on the survival of S. uberis in the dairy farm environment.

MG, Lopez-Benavides, JH Williamson, and RT Cursons

Proceedings of the New Zealand Society of Animal Production, Volume 65, Christchurch, 153-156, 2005