Calf Case: Femoral Nerve Injury

Monica Kovacs: ,  March 2013 | Edited by Jennifer Enzie and Cody Creelman

 

Case Presentation:

In mid-March we received a call from a producer at a commercial cross cow-calf operation asking us to check out a 3 week old calf. When we arrived, the calf was lying down and sleeping comfortably. When prompted to stand, he got up and was bright and alert, however, he only bore weight on his left hind leg.

From taking a thorough history, we learned that this calf was fairly large at birth and so his dam, being a small heifer, had trouble giving birth (dystocia).  He was a hard pull because he was “hiplocked” for a period of time. Hiplock is when the position of the calf’s hips are such that they will not fit through the heifer’s smaller pelvis—picture trying to fit a square peg into a round hole. You can “unlock” a calf in this situation in several ways; the most common approach is to attempt to rotate the calf while applying traction at a downward angle to get the hips in a position to fit through the narrow, oval shaped pelvis. In this particular situation, the calf was able to be unlocked and once out he looked normal and bright. However, in the first few days of life the crew noticed that he was spending most of his time laying down. It took about 3-4 days for him to stand and get around on his own; normally a calf should be up and exploring within the first day of life. According to the protocol of this particular cow-calf operation, this calf was vaccinated at birth with Inforce 3 and Somnu-Star Ph (both vaccines against bovine respiratory disease). At the same time he was also ear tagged and given 1 litre of colostrum.

A physical exam was then performed on this calf. The first observation made was that the calf could not bear weight on his right hind leg. When encouraged to walk on it, the leg would buckle underneath him.  The calf was assessed to have no pain in the area, as there were no pain indicators given when the hips or hind legs were palpated, extended, flexed or manipulated in any way. There also was no heat or swelling found anywhere along the legs or hips, indicating an absence of noticeable inflammation. His leg bones and hips were also assessed for any fractures and were found to be normal. When the muscles of the left and right hind legs were compared for symmetry and size, it was found that the muscles on the right thigh (quadriceps) were smaller then the left.  The hip also appeared to drop or slope down toward the right side.

 

 

Diagnosis: 

What the veterinarian found was typical of a femoral nerve injury. This can occur when the calf gets hiplocked and excessive force is used when trying to pull the calf out. During the difficult and forceful pulling, the hips of the calf can overextend, causing injury to the femoral nerve — the nerve responsible for movement in the quadriceps (thigh) muscles and extension of the stifle. When the femoral nerve is damaged on one side, the calf cannot bear weight on that leg and buckles with each step. If both sides are affected at the same time, they are sometimes called “creeper” calves because of the way they walk and sit like a dog with both hind legs sticking out.

In this case only the right side was affected.  The smaller muscles we saw on the right side were indicative of nerve damage because loss of nerve stimulation to muscles can cause rapid muscle atrophy (degeneration) within 7-10 days. One complication from femoral nerve damage is a lateral dislocation of the kneecap (also known as a luxating patella) because the muscles that normally keep it in place are weakened.

There is no treatment for this condition and time of recovery will depend on the degree of damage that has occurred. Some cases may take anywhere from 9-12 months for a full recovery as nerve healing and regeneration is a very slow process. During recovery the calf should be in a well bedded area to prevent further injuries, and may need assistance to nurse. An anti-inflammatory may be used for a few days to reduce inflammation in the area and help speed healing.

Prevention of these types of injuries starts with being aware of the amount of force used to pull a calf from a cow with dystocia. If an excessive amount of traction is used and there is little to no progress within 10 minutes, the situation should be re-evaluated or a veterinarian consulted.

 

References:

Aiello, S.E. 2012. Merck Veterinary Manual 10th Ed. Merck & CO Inc. Whitehouse Station, NJ

Fubini, S., N. Ducharme. 2004. Farm Animal Surgery. Saunders, St. Louis Missouri

NADIR Health Bulletin 2009. From the National Beef Association . Link: https://docs.google.com/viewer?a=v&q=cache:3dDD9cq7ww8J:www.nationalbeefassociation.com/extras/09-11NerveDamageatCalving.pdf+femoral+nerve+paralysis+calf&hl=en&gl=ca&pid=bl&srcid=ADGEEShI28ZV0sNwKx8wnRm2xZMXPihBkwzNFHVsHeHZylpXNlCvOfNC6Uhm8b_vBOPedEWBvv0ga8gClFSqfW25QqAco1V-6uW2Lxdl-hPlGFCuIMhLGj9NJCaX4-10M6J86p4zWUs2&sig=AHIEtbSktjgQWXSJc7Mp4aM4HZ-a6U5BCw

Smith. B.P. 1996. Large Animal Internal Medicine 2nd Ed. Mosby- Year Book.Inc. St Louis Missouri

VETM 505: Clinical Skills III. Bovine Lameness- Diagnosis, Treatment and Management Lab Manual.