Читать книгу Bovine Reproduction - Группа авторов - Страница 262

Upward fixation of the patella is a fairly easily diagnosed problem in the bovid. Cattle will have a hyperextended hindlimb (extension of tarsus with flexion of fetlock and all distal structure) that appears “locked” and causes the animal to drag the toe while walking. Those that have had the problem for a while will have worn down the toe on the affected limb. Occasionally an animal will exhibit the problem in both limbs, although one limb is often more severe. The condition most often affects females in the last trimester of pregnancy but is also observed in bucking bulls [16] (Figure 16.21).

Figure 16.21 Mature bred female experiencing upward fixation of the patella. Notice hyperextension and flexion of the fetlock with dragging of the toe.

This condition occurs when the patella is dislocated mediodorsally on the distal femoral trochlea and is treated with a medial patellar desmotomy. It is easier to identify the medial patellar tendon in the standing position. If there is a danger to the surgeon due to temperament, short‐acting anesthetics should be used. An appropriate anesthetic would be K‐stun (butorphanol, xylazine, ketamine) (Figure 16.22).

Figure 16.22 Excellent drug combo to facilitate brief examination of procedures in cattle.

The animal is restrained in dorsal recumbency, with the rear limb fully extended and pressure applied to the hoof with forceful downward motion. This will allow for identification of the ligament. For standing procedures, mild sedation with xylazine and a tail hold should be sufficient for restraint. Infuse a local anesthetic, starting approximately 2 cm medial to the tibial tuberosity and include the area of the medial patellar ligament that will be transected. A rib‐back scalpel blade or teat bistory is used to transect the ligament. The ligament should be transected in both legs since it is likely that the other limb will be affected. Relief is immediate and little aftercare is required; cattle can be returned to their normal environment.