In femoral nerve injury, paralysis of the quadriceps muscles, which extend the stifle joint, and partial paralysis of the psoas major muscle, which flexes the hip joint, occur.
Clinical Findings and Diagnosis of Femoral Nerve Injury in Cattle
In large, newborn calves (eg, Charolais or Simmental), use of mechanical force during an assisted birth can stretch and damage the femoral nerve. The resultant reduction in quadriceps tone reduces tension on the patella, with the result that a lateral patellar luxation may develop. The patella reflex is absent because the reflex requires an intact femoral nerve. Atrophy of the quadriceps soon becomes obvious and, although the luxated patella can be manually reduced with ease, the animal has extreme difficulty walking. The condition may affect one or both limbs. Prognosis is related to the severity of clinical signs and is better in unilateral cases.
Treatment of Femoral Nerve Injury in Cattle
Despite a fair or good prognosis, a calf with femoral nerve paralysis may be unable to suckle unaided. The patient should be maintained in a well-bedded area, and colostrum should be given as soon as possible after birth. A radiographic study should be done to exclude the possibility of fractures, particularly slipped capital physis or proximal femoral fractures, which clinically can appear similar before neurogenic atrophy is present. Administration of anti-inflammatory drugs may be useful.