Bovine Reproduction. Группа авторов
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Distal Limb
Lameness involving the distal limb usually has a traumatic origin. Most often, acute and severe lameness can be attributed to a severe concussive force, entanglement or entrapment of the lower limb within a fence or handling device, or foreign body penetration of the skin with invasion of deeper structures. Young cattle are predisposed to joint sepsis due to hematogenous spread of bacteria from the umbilicus, digestive tract, or lungs in times of general immune compromise [11].
Joint sepsis often presents as severe lameness of several days' duration. Many cases will not respond to broad‐spectrum antibiotics administered by the owner. The animal will have an elevated heart rate and usually an elevated rectal temperature. Thorough examination should be performed under appropriate restraint, preferably on a hydraulic tilt table. Radiographs should be performed to detect any concurrent fractures. Both systemic and local antibiotics via vascular perfusion should be administered. In severe cases, joint lavage must be considered. In these cases, it may be difficult to lavage the joint space due to fibrin accumulation within the joint. Fibrin deposition seems to increase with subsequent flushes, and in those cases that are slow to respond to treatment, arthrotomy or arthroscopic surgery may be the only option to remove the fibrin deposits from the joint. Surgical drain placement is not advised due to the risk of contamination even with proper bandaging. In cases where there are financial constraints and osteomyelitis is already present, aggressive curettage of the area may be the only alternative. Active lavage can be incorporated with sterile bandaging to provide continued protection, although compression bandaging may suppress desired drainage [12]. When there is marked reduction in exudate coming from surgical wounds, polymethyl methacrylate (PMMA) beads impregnated with an appropriate antibiotic might be considered for placement in the remaining joint space. When the beads are used, the goal is joint ankylosis, which cattle seem to take well. When wounds no longer need attention, it is best to immobilize the limb in a cast, with consideration to using transfixation pins. Cattle tolerate the process well as long as a support bandage protects the contralateral limb. Due to the expense of these procedures, clients may only elect to have these procedures done for cattle with high economic or emotional value.
Figure 16.19 Sole view of interdigital fibroma. Notice the ulceration that has occurred due to contact with the ground.
Sequestra should be surgically removed. Most often, these occur on the lateral aspect of the metatarsus and are directly related to trauma from kicking a hard object like a gate or post or entrapment of the limb within a confined space (Figure 16.20). On presentation, most cattle with a sequestrum will have an associated draining tract. Surgical removal can be performed under vascular anesthesia and sedation while the animal is restrained in lateral recumbency unless there is extensive bony proliferation that should also be removed, in which case general anesthesia should be considered. A surgical drain should always be incorporated in the closure, as there is virtually no way to close the entire dead space after removal of the sequestrum. The drain should be removed four to five days after surgery and recovery may take up to two weeks.
Figure 16.20 Sequestrum formation of the lateral cortex of MTIII in a yearling.
Sepsis of the superficial and/or deep digital flexor tendon is usually due to traumatic injury (laceration of the caudal pastern or heel bulb area) or due to extension of deep infection from a chronic hoof rot lesion. Parenteral antibiotics alone will not resolve this problem; surgical drainage is performed and a drain placed from the pastern, through the tendon sheath and above the dewclaw. Extensive and chronic sepsis may require complete resection of the superficial and deep flexor tendons, after which partial closure with packing and drain placement is a must. Active or passive lavage may be provided, with several bandage changes required to resolve the issue. The drain should be removed in five to seven days. Apply a hoof block to the non‐affected claw and cast the limb to the carpus or tarsus to alleviate pain and allow better ambulation. After four weeks the cast may be removed. Some deep digital flexor tendons may spontaneously rupture after treatment, which will cause the patient to walk on the heel bulb.
Proximal Limb
Lameness involving the femorotibial joint usually involves a traumatic episode such as a bullfight, breeding injury, or restraint accident. Suspected stifle injuries should be addressed immediately, and treatment should be aimed at decreasing inflammation and reducing the development of degenerative joint disease. Diagnostics often include observation of ambulation and weight bearing, amount of joint effusion present, joint laxity and the direction of laxity, radiographs, and ultrasound (which may not be possible in larger individuals) [13]. Arthrocentesis is used to rule out sepsis, and total cell count should be less than 2500 WBC/μl and protein less than 4.5 g/dl. Ideally, positive pressure joint lavage should be performed with a sterile isotonic fluid solution containing antibiotics and anti‐inflammatories [14]. Follow‐up therapies may include repeated lavage and regenerative medicine modalities such as plasma‐rich protein or stem cell therapy. Strict stall confinement is necessary for healing. Some injuries take up to six months to heal, and severe cranial cruciate or collateral ligament tears may require strict immobilization with a Thomas splint. These cases should be treated with long‐term non‐steroidal anti‐inflammatory drugs (NSAIDs). Of course, such injuries carry a very guarded prognosis when considering pasture soundness and return to breeding. If only the medial meniscus is involved, arthroscopic surgery may be of benefit in valuable individuals [15].
Lameness associated with the shoulder or elbow joint is often caused by trauma and can have a significant impact on ambulation. Non‐weight‐bearing lameness usually equates to serious injury such as a fractured scapula or fracture of the olecranon. A lesser degree of lameness may be observed with subchondral cysts or ligamentous injuries to supportive structures. Intra‐articular anesthetics may temporarily improve lameness but rarely resolve all of the pain during examination. Treatment of these joints is usually relegated to the use of intra‐articular injections unless surgical repair is financially feasible, for example compression plating of a fractured olecranon.
The carpus is probably the least affected large joint in beef cattle. Most lameness associated with this joint occurs in bucking bulls. Degenerative joint disease is observed in older bucking stock due to chronic hyperextension of the carpus when the bull “goes vertical.” This condition responds fairly well for a time to intra‐articular injections of anti‐inflammatories and the administration of NSAIDs.
Upward Fixation of the Patella
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).