Impact of heat stress on dairy cow rumination, milking frequency, milk yield and quality in a pasture-based automatic milking system

Context Heat stress is an increasing concern for the Australian dairy industry.Aims This study aimed to evaluate effect of temperature–humidity index (THI) on rumination time (RT), milk yield and quality, milking frequency in a pasture-based voluntary-movement automatic system (AMS).Methods Data were collected from University Melbourne Dookie College AMS farm 3years (June 2016 March 2019). Daily RT was through transponder collar (Qwes-HR, Lely). Climatic data (maximum ambient temperature relative humidity) obtained Meteorological station calculate daily maximum THI (THImax).Key results increased with rising THImax 65, then declined after 65. Milking highest at 90, followed by steady decline afterwards. Rumination mid-range high low values.Conclusions The findings this clearly indicated that under AMS, resulted drop yield, RT.Implications With provision automation collection further mathematical modelling describing patterns thresholds conjunction different heat levels can be useful assessing animal welfare mitigate seek alternative management strategies.