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R., Beckett, S., and Walker, D. (1972). Pathophysiology of impotence in the bull. J. Am. Vet. Med. Assoc. 161: 1345–1347.
38 38 Wolfe, D., Hudson, R., Walker, D. et al. (1984). Failure of penile erection due to vascular shunt from corpus cavernosum penis to the corpus spongiosum penis in a bull. J. Am. Vet. Med. Assoc. 184: 1511–1512.
39 39 Wolfe, D. and Moll, H. (1998). Examination and special diagnostic procedures of the penis and prepuce: bulls, rams, and bucks. In: Large Animal Urogenital Surgery (eds. D.F. Wolfe and H.D. Moll), 225–227. Baltimore: Williams and Wilkins.
40 40 Ashdown, R., Gilanpour, H., David, J., and Gibbs, C. (1979). Impotence in the bull: (2) occlusion of the longitudinal canals of the corpus cavernosum penis. Vet. Rec. 104: 598–603.
41 41 Beckett, S., Hudson, R., and Walker, D. (1978). Effect of local anesthesia of the penis and dorsal penile neurectomy on the mating ability of bulls. J. Am. Vet. Med. Assoc. 173: 838–839.
42 42 Mysinger, P., Wolfe, D., Redding, R. et al. (1994). Sensory nerve conduction velocity of the dorsal penile nerves of bulls. Am. J. Vet. Res. 55: 898–900.
16 Management of Lameness in Breeding Bulls
Gary Warner1 and Jacob L. Warner2
1 Elgin Veterinary Hospital, Elgin, TX, USA
2 College of Veterinary Medicine, Texas A&M University, College Station, TX, USA
Introduction
The following discussion of lameness issues in cattle is not intended to be a recipe for how to resolve a particular problem associated with lameness. It is a compilation of knowledge gained from 40 years of serving the beef cattle industry. Lameness evaluation is an analytical process, to be taken one step at a time, giving consideration to history, age, breed, sex, environment, intended use, and nutritional state. Conducting a proper examination on the bovine animal is no different from what is done in the equine species, though the examination of cattle takes more time and requires better restraint. Bovine lameness examination requires a pen or alley with a hard surface and a tilt table or tilt squeeze chute. Proper restraint reduces the chance of injury for both the patient and the examiner. In practices that do not have proper facilities or methods of restraint, often the diagnosis of lameness comes down to a good guess (Figure 16.1).
Figure 16.1 Looks can be deceiving – a calf with spastic paresis.
Most of the literature available is derived from treatment of dairy cow lameness; very little has been reported dealing with beef cattle. By the end of the chapter, the reader should have a better appreciation of lameness conditions in beef cattle and their expected response to treatment.
Bovine lameness examinations must begin with a good history that considers duration of lameness, observation of irregularities, and the production parameters involved. During visual examination, the whole body and every limb must be evaluated before focusing on the affected limb. For instance, while examining an animal for a suspected subsolar abscess in a back hoof, do not miss the laceration on the pastern of the supporting limb and subsequent swelling indicating a septic flexor tendon sheath. Watching the animal in motion may help in ruling out proximal versus distal limb problems. Observing the entire animal is important as sometimes other limbs may be affected by the primary lameness or may contribute further to it (Figure 16.2).
Figure 16.2 Cellulitis involving the right forelimb and interdigital fibroma on the left forelimb.
Getting Back to Basics in a Lameness Examination
Unfortunately, economics dictate what practitioners are able to offer the client and the patient. Additionally, some clinical options available to other species are just not practical in bovine practice. If the problem is not obvious after visual examination, the next step is to properly restrain the patient on a hydraulic tilt table or tilt chute. Casting the animal is another option, but it is difficult without an abundance of labor and may not allow for an accurate examination. It is possible to cause harm or even create a new injury by tying a leg in a squeeze chute with the good intention to examine a lesion more closely. Since approximately 70% of bovine lameness is in the hoof, hoof testing while the patient is in lateral recumbency is an important part of the examination. If hoof testing reveals a painful area, explore the area by paring the hoof and examine any cracks, crevices, or wall separations. Often aggressive trimming of the sole will provide evidence of a puncture, laceration, or developing crack that can lead to an abscess. If no pain is elicited on hoof testing and no direct visual abnormalities are noted, attention should be directed further up the limb. Each joint should be palpated and individually flexed and extended, including the shoulder or hip. Most often, lameness caused by a joint in the lower limb can be identified by flexion or extension of the joint, eliciting a painful withdrawal of the limb by the animal. The flexor and extensor tendons must be evaluated for evidence of sepsis or rupture. If the examination at this point has still not revealed the cause for the lameness, the animal may have to undergo local anesthetic nerve or tissue infiltration in order to isolate the painful area.
Facilities for Performing the Lameness Examination
Diagnosis of lameness in the field is not ideal, and the practitioner must consider possible risks to themselves, the client or caretaker, and the animal. Having a proper facility to diagnose and provide treatment to lame individuals makes the opportunity much more appealing. Let us consider what would be the ideal setting for evaluation of bovine lameness.
The most desirable area to evaluate a bovine animal in motion is on a hard‐surfaced alley, free of rocks or other irregular debris, with access on either end to stimulate the animal to travel back and forth (Figure 16.3). Additionally, an alley or chute leading to a tilt table or a tilt chute allows the practitioner to get a closer look at all limbs, hooves, and back while preparing to place the animal in lateral recumbency (Figure 16.4).
Figure 16.3 Nice alleyway for evaluation of lameness, with room to turn the individual and observe his movement.
Figure 16.4 Crowd alley leading to hydraulic table that enables practitioner to fully evaluate lameness up close.
A hydraulic tilt table is preferred as it allows full access to the upper part of the limbs and allows the animal to be positioned in either left or right recumbency (Figures