Application of the 'tracking signal' method to the monitoring of udder health and oestrus in dairy cows

Two time series models, namely, the moving average model of lag 14 (MAM) an d the tracking signal method (TSM), have been used to detect oestrus and ud der health in dairy cows based on activity data and electrical conductivity , respectively. The results show that the use of on-line activity data allo wed us to obtain high values of sensitivity and specificity for oestrus det ection irrespective of the model used. Regarding udder health, sensitivity and specificity values showed that the number of clinical and subclinical. mastitis. cases detected was similar for the two models, but the specificit y value using TSM resulted in a significantly higher value than MAM. Thus, the TSM method could be considered advantageous because of reduction in the number of false positive in healthy cows. The results show that electrical conductivity data of mixed milk samples are useful to detect both clinical and subclinical mastitis with a good sensitivity, if the milk electrical c onductivity on-line is correctly measured. (C) 2001 Elsevier Science B.V. A ll rights reserved.