16.7 The down forelimb tied in a tilting hydraulic chute to discourage repositioning of the animal while restrained in the chute.
Placement of the animal on a tilt table is an orchestrated team effort, usually requiring at least two people. There is inherent risk in releasing the restraints at the end of the examination or procedure. Any bovid that is expected to be in lateral recumbency for longer than 15 minutes should be fasted for at least 24 hours before the procedure to reduce possible development of rumen tympany. Also, during lateral recumbency, the animal should be continually observed for any evidence of regurgitation, especially if sedation is used. If regurgitation occurs, the animal should be immediately returned to an upright position (Figure 16.8).
Figure 16.8 Evidence of rumen tympany and/or regurgitation of rumen contents should lead to immediate removal of animal from lateral recumbency.
Local/Regional Anesthesia
The use of local anesthetics is helpful in isolating pain in the lameness examination, but proper restraint in lateral recumbency is required for administration. The application of anesthetics should only be done after local examination of the affected area and any other diagnostics (including hoof testing, radiography, and ultrasound) have been performed. Lidocaine is used because of its rapid onset of action (3–5 minutes) and short duration (20–30 minutes) (Figure 16.9).
Figure 16.9 Vascular perfusion used for local anesthesia as well as treatment.
Most often the first anesthetic administered will be a vascular perfusion of all structures distal to and including the fetlock. For regional limb perfusion, place a tourniquet (using IV tubing or bicycle inner tube) proximal to the fetlock. In a limb free of edema, wrap tightly enough to identify the dorsal digital vein and administer 15–25 ml of lidocaine. Maintain the tourniquet for 10 minutes before releasing the animal to observe for lameness. If no improvement in gait occurs, the animal is restrained again. Regional whole limb perfusion or a four‐point block may be used to isolate lameness below the elbow or stifle. To perfuse the whole limb, 30 ml of lidocaine in 50 ml of saline is administered with a tourniquet above the carpus or tarsus. This can be performed standing in a squeeze chute. The practitioner may also consider the use of intra‐articular anesthesia for individual joints; 10 ml of lidocaine is sufficient for each joint except the stifle, which usually requires a larger volume.
In beef cattle with forelimb lameness, if the cause does not appear to be in the hoof, it is often in the shoulder. This is suspected to be due to inadvertent abduction during mounting or due to falls and displacement of the limb laterally. Rear limbs can be difficult to evaluate and require more patience and effort to examine. The coxofemoral joint must not be overlooked as a cause of lameness in the rear limb. These too can be injected with anesthetics to rule in or out lameness.
Back Injuries
The back is often forgotten as a cause or contributor to lameness, particularly in the bull. Close evaluation may lead to subtle findings such as a shuffling of the rear limbs or muscle atrophy of the lumbar muscles. Pelvic injuries can happen in both sexes of cattle, and sacroiliac injuries supporting ligamentous injuries and fractures to the ilium and ischium are possible [1]. Diagnostic anesthesia in the lower back is rarely effective due to the involvement of multiple structures in most back injuries. Acupuncture and chiropractic examinations may be of value in isolating the problem. Since most radiographic equipment available in practice cannot penetrate the body mass of most mature cattle, radiographs of the spine are of little value. Sometimes, all we can do is make an educated guess and come up with a conservative therapeutic plan.
Advanced Diagnostics
Many practices now have digital radiography and digitally enhanced imaging to allow the practitioner the opportunity to clearly identify problems that could only be guessed at a few years ago. It can be a bit challenging to position the animal to get a good image of some areas, but with experience and sometimes sedation of the patient, a good study can be performed.
Ultrasound is used to evaluate soft tissue injury of ligaments, menisci, and tendon sheaths. Proper technique and an experienced skill set are necessary to fully appreciate abnormalities associated with lameness. An inexperienced operator or one with less than optimal knowledge of bovine anatomy may lead to misdiagnosis of some conditions.
Arthrocentesis is another valuable diagnostic tool for evaluation of lameness directly associated with a joint. Color, viscosity, protein content, and cellularity are used to diagnose the health of the joint and can offer a reasonable prognosis. This procedure can be performed in most practices with laboratory access. Evaluation of cell types and protein level found within the synovial fluid is most important. Cellularity should be less than 1000 cells/μl, and protein should be less than 2.5 g/dl in the normal joint.
Laminitis
Seventy percent of the lameness cases observed in beef cattle practice are associated with the hoof. Fifty percent of these cases are diagnosed with chronic laminitis, the vast majority of which are the chronic subclinical form. Acute laminitis is caused by an acute metabolic or systemic illness and is characterized by reluctance to stand, arched back, and the appearance of walking as if they were on a very hot surface (Figure 16.10).
Figure 16.10 Acute laminitis in a Hereford bull on self‐feeder.
There are no outward lesions expressed or seen on the soles of the hoof, although inflammation may be observed in the coronary band and a digital pulse may be present. Subacute laminitis doesn't usually express itself until several weeks after the insult, and the symptoms observed are sole hemorrhage and discoloration of the white line and sole tissue.
Subclinical laminitis is due to periodic upsets in normal body function. A few scenarios that can predispose to chronic laminitis include:
Mismanagement of the young growing calf
Bulls on gain test
Cattle being prepped for sale
Cattle breeds involved with progressive genetic improvement
Cattle being fitted for show
Dairy cows being fed for maximum milk production
The general appearance of a hoof with subclinical laminitis is one that flares out at the wall with a flattened sole. Closer examination reveals white line separation with abscessation, vertical and horizontal wall fissures, heel erosion, and subsolar ulcers [2]. Horizontal lines (known as hardship lines) may be observed in a portion
