This fly commonly deposits its eggs on the outside of the hind quarters and above the fetlocks when the animals are moving, or lower down if they are quiet.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
This fly commonly deposits its eggs about the coronet, whence the name of heel fly, and on the fetlocks, knees, and hocks.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
By means of this difference in direction we can easily select the two feet of one calf, place running nooses upon them just above the hoofs or fetlocks, and have an assistant drag upon the ropes while the feet of the other calf are pushed back.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler