To investigate the availability of behavioral evaluation by dynamic body acceleration (DBA), we examined the effect of floor cleaning, commonly practiced in stalls, on the changes in behavioral condition of beef cattle using DBA measurement. Two experiments were conducted; one with Japanese Black breeding cows and another with Japanese Black fattening steers. In the experiments, data from tri-axial accelerometer on back of the animals and timelapse images were collected for 12 hours per day for three consecutive days: the day before cleaning, the day of cleaning and the day after cleaning. The activity measurements (DBA values) were calculated from the tri-axial acceleration datasets and the behavioral types (lying or non-lying) were classified from the timelapse image datasets. Changes in the DBA values and behavioral types among the observation days were analyzed. The result showed that, compared with “before cleaning”, lying time increased and non-lying time decreased significantly in “day of cleaning” and “one day after cleaning” (P<0.05). Also, DBA values decreased significantly in “day of cleaning” and “one day after cleaning” (P<0.05). Furthermore, the DBA values during non-lying time significantly increased in “day of cleaning” and “one day after cleaning” (P<0.05), which indicated that the energy consumption of the beef cattle increased after floor cleaning because the floor became softer to walk on. Hence, the use of DBA could identify subtle different responses of beef cattle to floor cleaning conditions in non-lying behavior. It was concluded that DBA is a useful indicator to evaluate the behavioral changes of beef cattle in detail.

It is well known that cattle is a large contributor to environmental impacts, especially enteric methane emissions. In this study, the impacts of enteric methane emissions from dairy and beef production (Japanese Black fattening) in Japan were analyzed based on the two metrics; (i) expressed as CO₂-equivalents (CO_2e) using 100 year Global Warming Potential (GWP₁₀₀) and (ii) CO₂ warming equivalent (CO_2we) derived from GWP* which considers additional warming as a function of the time line of short lived methane emission. The later metric can be used to guide climate action aligned with temperature-based climate stabilization goals. Data of historical enteric methane emissions from dairy and beef cattle from 1990 to 2020 were used and the future methane emissions till 2050 were predicted based on the data by assuming than milk and beef production were maintained at the level in 2020. Two alternative scenarios (1% and 2% reductions per year of enteric methane emissions) were also evaluated in addition to the base scenario (no reduction). The continues reduction of enteric methane emission for commonly used metric (CO_2e) from dairy production was resulted from decreasing animal numbers. The negative values for enteric methane emission by CO_2we were obtained all over the years (including the future predictions) despite positive CO_2e, this being because CO_2we is related with the level of 20 years ago. In contrast, enteric methane emissions from beef cattle production were relatively stable compared with dairy cattle production. It was suggested that Japanese beef production would approach climate neutrality in the future if enteric methane emission can be reduced by more than 1% per year.