Fig. 3
Physical activity, milk progesterone concentrations in cows, and follicular size and time to ovulation in heifers and cows; the results are presented as mean (SD). Mean (SD) in cows (n = 9) for physical activity (%) (activity measured in the past 6 h relative to activity measured at the same time of day in the past 7 days) measured by an automatic activity monitoring system and mean (SD) in progesterone (ng/ml) in milk given by time (h) from the last PGF2α analogue treatment (time = − 48 h); mean (SD) in heifers and cows (n = 32 and 10, respectively) for the diameter (mm) of the dominant follicle measured until ovulation by ultrasonography following GnRH analogue treatment at time = 0 h; number of ovulations at the point of final ultrasonography (1.5 h after ovulation) following GnRH analogue treatment at time = 0 h; two heifers did not ovulate