Table 4.

Tail movement sensor for calving prediction, with performance and references.

Event	Sensor Type	Device	Application	N	TI	Device Performance	Factory	References
Tail movement and raising	Accelerometer/inclinometer	Moocall	Tail base	12	24 h to 3 h	Se = 100%; Sp = 95% Se = 94%; Sp = 77%	Moocall Ltd., Dublin, Ireland https://www.moocall.com/	Giaretta et al. [51]
				118 *	24 h	Se = 75%; Sp = 63%; PPV = 56%; NPV = 79%		Voß et al. [52] 1
					12 h	Se = 69%; Sp = 74%; PPV = 44%; NPV = 89%
					4 h	Se = 66%; Sp = 89%; PPV = 34%; NPV = 97%
					2 h	Se = 43%; Sp = 93%; PPV = 21%; NPV = 97%
					1 h	Se = 19%; Sp = 96%; PPV = 9%; NPV = 98%
				54	4 h 1	PPV = 12.6%		Horvàth et al. [31]

N: number of animals. TI: time interval between calving alarm and parturition. Se: sensitivity; Sp: specificity; PPV: positive predictive value; NPV: negative predicting value. * = a total of 180 animals were involved in the study but only for 118 the sensor was already in use at the moment of calving. ¹ Data herein reported are referred only to the “HTA1h” alert, that is detection of high tail activity in the previous hour.