Detection of estrus and mastitis: Field performance of a model

A performance test of a detection model for estrus and mastitis was perform ed on four farms during several years. Sensor data of milk yield, milk temp erature, electrical conductivity and animal activity were the inputs for th e model. The sensor equipment differed between farms. On two farms leg tran sponders were used for activity measurements, on the others neck transponde rs were used. On three farms conductivity was measured of quarter milk, on one farm conductivity of only mixed milk was measured. The sensitivity for estrus varies from 63% to 80%, depending on the chosen settings, with speci ficity varying from 94% to 98%. There are great differences between farms. The sensitivity for clinical mastitis varies from 55% to 80%, depending on the model setting, with specificity for mastitis from 94% to 99%. Also for mastitis sensitivity there are great differences between farms. The equipme nt can only partly explain these differences. Other explanations are indica ted. The main conclusion is that a detection model can be useful but only i f the equipment is monitored regularly.