Influence of high temperature and humidity on rumen bacterial diversity in Holstein heifers

The effect of heat and humidity stresses on the rumen bacterial molecular diversity of heifers was studied. No statistically significant changes in the rumen microbiota composition were found in the first experiment (average body mass 250 kg) while in the second and third experiments (additional variables included the relative humidity and body weight), the microbiota composition was significantly different at elevated environmental temperatures and humidity. These shifts were accompanied by the decrease in concentration of short-chain fatty acids in the rumen.