Fig. 1
Timeline showing the synchronising protocol and sequence of animal treatments and recordings. PGF2α analogue treatment (PGF2α) on day 0 and 11 and body condition scoring (BCS) on day 0; GnRH analogue treatment (GnRH) on day 13 at time 0 (T0); transrectal ovarian ultrasonography (filled triangle) to identify animals with a mature corpus luteum on day 11 (− 48 h) and from day 13 at T0 and every third hour from 9 h following T0 (+ 9 h) until the time of ovulation (+n h)