Accidents during the administration of boluses were 0.093%in electronically identified small ruminants in a range of severity from mild (0.075%: bolus stopped in the oropharynx or in naso-pharynx, easy to deal with in the field ,with correct handling by a trained technician) to fatal episodes (0.011% bolus in trachea; 0.07% rupture of the oesophagus , see Fig. 5).