The proximal radial nerve can be damaged in cattle following lateral recumbency or from trauma to the shoulder. Affected cattle characteristically have an extended shoulder, a dropped elbow and carry or drag the carpus and fetlock partially flexed. They appear not to be able to bear weight on the affected leg but can do so if the limb is placed directly under the animal. This presentation differentiates proximal radial nerve paralysis from brachial plexus damage (or a fractured humerus) where weight bearing is not possible (Parkinson et al 2010). The author cannot recall seeing this condition in beef cattle prior to this case of two affected cows in a small beef herd in the Mudgee district.
Two cows were examined in the paddock on the 20 November 2017. Both were lame on the right front leg. Both cows developed the lameness suddenly between 2 and 4 weeks previously. Case 1 happened about one month previously while case 2 was noticed two weeks previously.
Case 1. A mature Hereford Angus cross cow was observed in the paddock to favour her right front leg. This cow had recovered somewhat in the month since the lameness was first noticed and was able to walk bearing some weight on her flexed right front leg (Figure 1).
Case 2. A mature Murray Grey cow was first observed to be recumbent and reluctant to stand. When encouraged to stand she carried the right front leg with a dropped elbow, knuckling and dragging the right front foot. However, the cow was able to able to flick the affected foot forward and bear weight on the leg (Figures 2 and 3).
This case is noteworthy in that two cases of an unusual condition occurred in a small beef herd without obvious explanation. None of the cattle had been recumbent (compressing the radial nerve) and they had not been yarded or handled recently risking shoulder trauma as might occur from rapidly exiting a crush or hitting a post. Subsequently the owner noticed that one horned cow was particularly aggressive. He considered that this animal was the most likely cause of the injury to the shoulders of the two cows.