NERVE damage to the cow and/or her calf are commonly caused by the calf having been stuck at the hips for several hours and/or excessive traction during delivery of the calf.
Damage can lead to the cow being unable to rise and consequently being culled. Loss of the cow is a great financial loss and considerable welfare concern and both could be avoided. Similarly, nerve damage to the calf can lead to many problems including failure to suck sufficient colostrum early on increasing the risk of developing joint ill and meningitis as well as localised navel infections.
The nerves most commonly damaged in cattle are: Cow - Obturator nerve; Hip-lock during anterior. Presentation of the calf is the most common cause of adductor paresis (obturator nerve and sciatic nerve injuries) in the cow. Specific diagnosis proves very difficult in recumbent cattle unwilling to make any attempt to rise. Predicting the duration of recumbency also proves very difficult, but allowing up to two weeks is probably acceptable provided that cattle are on an appropriate lying surface (deep straw/pasture), move around frequently (every few hours), develop no pressure sores, and have a normal appetite. Prevention is simple - avoid calves becoming stuck at the hips and do not apply excessive traction during calf delivery.
Severe abduction “doing the splits” can also occur when the cow loses her footing on wet slippery surfaces often when attempting to regain her feet after treatment for hypocalcaemia. The clinical presentation varies depending upon underfoot conditions, from only slight incoordination of the hind quarters on sound footing cows to severe abduction on wet slippery surfaces with cattle unable to regain their footing. The most appropriate action is to hobble the cow’s pelvic limbs just above the fetlock joints (Fig 1) but check regularly for skin abrasions.
Inflatable cushions, webbing nets and swim tanks can all be used to support the cow that is unable to stand but all are very time consuming on busy farms and cows are usually culled after a week or so if still unable to stand unaided. Good buliding design avoids sharp corners and wet slippery surfaces especially for recently-calved cows.
Peroneal nerve paralysis results in flexion of the hock and the dorsal surface of the hoof may contact the ground, and is typically seen in cows after a period of recumbency following calving. This condition improves without treatment over several weeks. Good underfoot conditions are important.
Tibial nerve injury results in flexion of the hock and slight knuckling of the fetlock joint typically affecting both hind legs (Fig 2). This condition follows a difficult calving with excessive traction but generally improves without treatment over several weeks. Good underfoot conditions are important to allow the cow to walk around without risk of slipping/falling.
Calf - Brachial Plexus
Brachial plexus injury in the foreleg occurs very occasionally during excessive traction of a large calf in anterior presentation especially when a standing cow suddenly lies down with the calf halfway out.
This injury results in the inability to extend the elbow, carpus and fetlock and bear weight on the affected limb in severe cases. There is a loss of muscle over the shoulder with resultant prominent spine of the shoulder blade. There is a dropped elbow, flexion of the distal limb joints and scuffing of the hooves as the leg is moved forward. The foot is knuckled over at rest (Fig 3).
Splinting the distal limb to prevent contracted flexor tendons in neonatal calves is problematic and may lead to pressure sores under the splint unless undertaken carefully. This task should be undertaken by a veterinary surgeon.
Femoral nerve injury is common after a calf in anterior presentation becomes hip-locked when Femoral nerve injury is common after a calf in anterior presentation becomes hip-locked when excessive traction is used to aid delivery. Injury can be either uni- or bilateral and results in the inability to extend the stifle joint, bear weight and extend the affected leg. Calves with bilateral femoral paralysis are unable to stand and adopt a dog-sitting posture (Fig 4). Calves with a unilateral lesion have difficulty rising and the pelvis is markedly tilted toward the affected side. Calves with femoral nerve paralysis injuries may take 9-12 months to fully recover.
When the calf presents in anterior longitudinal presentation, two people pulling should be able to extend both foreleg fetlock joints one hand’s breadth beyond the cow’s vulva within 10 minutes. Any greater traction to achieve such progress forewarns of potential hip-lock and its consequences.
Excessive traction can also cause rib fractures in the calf and obturator nerve injury, vaginal tears and haemorrahage in the cow. NADIS is sponsored by EBLEX, Merial Animal Health, Pfizer Animal Health.