Clinical Findings in Experimental Lesions of the Bovine Spinal Cord and Dorsal Rootlets*

Abstract

Using 20 calves of 3% months age or less, clinical signs were closely evaluated for 5, 10 or 15 days following experimental lesions of the spinal cord or dorsal rootlets. The experimental preparations included transections and hemisections at the TIO neuromere level, rhizotomy of the dorsal rootlets of the left lumbosacral plexus, and application of pressure at the L, neuromere level. The calves were necropsied at 5, 10 or 15 days post-lesion.The results of motor findings indicate that the order of return of reflexes following spinal shock in the calf is anal and tail, pelvic limb flexor and patellar reflex. It appears very likely that the gastrocnemius reflex returns at about the same time as the patellar reflex. The L, spinal nerve does not appear to be an important component of the patellar reflex in the calf. Calves are able to maintain motor control of the pelvic limbs with lesions of the spinal cord that would cause hemiparesis in dogs or humans.The sensory findings indicate that the L3 nerve is a component of the lateral cutaneous femoral nerve and extends to the cranial lateral surface of the crus. Sensory innervation by the saphenous nerve can be present even when femoral nerve innervation is insufficient to produce the patellar reflex. Transection of the portion of the spinal cord corresponding to the lateral spinothalarnic tract does not produce a contralateral area of analgesia or hypalgesia as it does in humans.It must be concluded that extrapolating information about the nervous system of humans or dogs to that of the ox may lead to erroneous results when evaluating the ox for neurologic deficits. The ox has a spinal cord which can adapt to tremendous insults and still maintain some if not all of its motor and sensory functions. Just how it does this should be of interest to those investigating the human spinal cord.