To relax the uterus in cattle, usually at the time of parturition. In particular: 1In heifers to delay delivery to allow full preparation of the soft birth canal. 2As an aid to obstetrical manoeuvres in dystocia e.g. malpresentation and malposture. 3To relax the uterus for caesarean section. 4To delay and therefore programme delivery to permit observation of parturition e.g. avoidance of night time delivery. 5To facilitate the replacement of prolapsed uterus. 6In embryo transfer to ensure less traumatic manipulation of the uterus.