Many injections used in farm animals are designed to be given in the muscle, and one of the most common sites used is the gluteal muscle (the rump). A recent paper published by the University of Nottingham looked at the dangers of damage to the sciatic nerve in the hind limb associated with intra-muscular injection.
The sciatic nerve is a large nerve which runs through the gluteal muscle. In the study, participants (vets, farmers and vet students) were asked to choose a needle and place it where they would inject a live cow for an intra-muscular injection. The sites were plotted and then the carcass dissected to show the position of the nerve.
They found that 69% of injections were placed in a location that could cause damage to the sciatic nerve, and this was worse in thin cows. If the gluteal muscle is to be used for injection, the needle should be placed a hand’s width behind the hook bone and to the side. This site is further forward and further to the side that many of us are used to.
This video produced by the University of Nottingham explains more about the risk of iatrogenic damage to the sciatic nerve in dairy cattle