(57) For the collecting of ferromagnetic foreign bodies or samples in the fore-stomachs of a ruminant a collecting unit is used, which is introduced through the animal's mouth, which has been forced wide open by means of a mouth dilator, and through the pharynx and the oesophagus, and which is attached to one end of a connecting element in such a way that it is possible to remove the collecting unit again by pulling the other end of the connecting element. It is suggested that a loop is introduced through one of the animal's nostrils, picked up in the pharynx, pulled out through the mouth, and connected to the other end of the connecting element.
Hereby it is possible-to introduce the collecting unit in a known manner through the mouth of the animal, but as long as the unit remains in the stomach of the animal the connecting element is led out from the stomach through the oesophagus and the pharynx and out through the nose. This implies that the animal's mouth can be shut during the collecting, which may therefore be stretched over a longer period - several days, if desired - as the animal can continue to eat and drink in the normal way.