Technical note: validation of rumination collars for beef cattle.

Two studies were conducted to evaluate a wireless rumination monitoring system (Hi-Tag; SCR Engineers Ltd., Netanya, Israel) for recording rumination in beef cattle. The system operates based on acoustics of rumination and has been used previously for monitoring rumination in both young and adult dairy cattle. Study 1 consisted of beef cattle in tie-stall housing with 72 observations for 4 cattle fed a high forage backgrounding diet and 47 observations for 3 cattle fed a high grain finishing diet. Study 2 consisted of 44 observations for 6 beef cattle fed a high forage diet in a loose-housing feedlot pen. Each observation consisted of the rumination time during a 2-h period as estimated by visual observations made by trained observers (inter-observer correlation r = 0.97) and the Hi-Tag system. The mean difference between visual and Hi-Tag rumination times was 9.8 ± 18.7 min/2 h. The rumination times from the Hi-Tag system were only moderately correlated with visual observations (r = 0.41, P < 0.001). The difference between visual and Hi-Tag rumination times was not correlated with head posture during the 2 h period (r = -0.02, P = 0.89). Physical and dietary differences between dairy and beef cattle may have resulted in the inaccuracy of the Hi-Tag system when used in beef cattle fed typical backgrounding and finishing diets. More work is required to improve the accuracy of this automated system for rumination monitoring before it can be used reliably with beef cattle.