Effects of atropine, scopolamine and xylazine on the placement of an orally administered magnet in cows.

This study was carried out to determine whether the administration of atropine, scopolamine or xylazine to cows before the administration of a magnet orally would help to position it in the reticulum. The transit time of the magnet through the oesophagus was also measured. Sixty Swiss Braunvieh cows were examined by radiography and ultrasonography to locate the reticulum. They were then divided into six groups of 10. Before the administration of the magnet, a control group received 4 ml saline solution subcutaneously, one group received 0.10 mg/kg of atropine subcutaneously, a second received 0.05 mg/kg of atropine intravenously, a third received 0.15 mg/kg of scopolamine intravenously, a fourth group received 0.02 mg/kg of xylazine intravenously, and the cows in the fifth group were positioned so that their forelimbs were 30 cm lower than their hindlimbs during the administration of the magnet. The passage of the magnet through the oesophagus was timed with a stopwatch and monitored with a compass. In the control group the magnet passed through in less than 60 seconds, but in four of the cows receiving either atropine or xylazine intravenously, or having their forelimbs positioned lower than their hindlimbs, it took longer than 60 seconds. In the cows receiving atropine subcutaneously or scopolamine intravenously, it took the same time as in the control group. All the cows were radiographed one-and-a-half hours after the administration of the magnet to determine its location. In seven of the 10 cows in the control group, the magnet was located in the reticulum, but in the other three it was in the cranial dorsal blind sac of the rumen. In the other five groups the magnet was located in the reticulum of between four and seven of the 10 cows, but in the cranial dorsal sac of the rumen, the rumen or in other sites in the other cows.