A method for health monitoring comprises electronically receiving location information for a dairy livestock that is generated by a plurality of identification devices positioned in a pen that operate in conjunction with a tag worn by the dairy livestock. The method stores the location information associated with the dairy livestock, the location information comprising a location of the dairy livestock within the pen at each of a plurality of times during a first time period. The method determines, based on at least a portion of the stored location information, a turn index parameter indicating a number of times the particular dairy livestock reverses direction during the first time period. The method determines whether the particular dairy livestock is likely to be in estrus based at least in part upon whether the determined turn index parameter is in excess of a baseline turn index parameter by more than a predefined amount.