For some years we have used a little instrument, which can be made by any worker in metal, consisting of a steel point riveted into a short cannula made to fit on one end of the ring while open.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
Whenever the person in charge of the cow is convinced that gas has ceased to issue from the cannula the instrument should be removed.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
The rim surrounding the mouth of the cannula should be in contact with the skin.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler