An 8-year-old 800-kg (1,760-lb) Brahman-cross bull was evaluated for left hind limb lameness of 2 months' duration. The lameness was first noticed during a bucking performance when, at approximately 6.2 seconds into the ride, the bull appeared to land inappropriately on the left hind limb. Immediately, the left hind limb appeared weak and unable to support subsequent bucking attempts. The owner noticed a lower frequency and height of bucking throughout the remainder of the ride. As the rider dismounted, the bull tightly circled, stumbled, and fell on both hind limbs.
Following the ride, the bull was immediately transported to an attending veterinarian, who made a diagnosis of gonitis in the left femorotibial joint on the basis of evidence of degenerative joint disease on survey radiography and partial palliation of lameness after intra-articular administration of anesthetic. The bull received a single intra-articular injection of methylprednisolone acetatea and sodium hyaluronateb (volume of each medication and site of injection were not reported) and was confined to stall rest for a 6-week period. When the lameness failed to improve, the bull was referred to the John Thomas Vaughan Large Animal Teaching Hospital at Auburn University for evaluation.
Initial observation of the bull on arrival revealed an altered gait affecting the left hind limb. The bull was also observed to occasionally hold the left hind limb elevated momentarily in the swing phase of the stride. In these instances, the stride length appeared to be extended and the foot slapped down onto the ground. In addition, mild proprioceptive deficits were detected, which were more pronounced while the bull circled to the left.
Physical examination revealed subtle unilaterally asymmetric muscle atrophy in the left lumbar epaxial muscles. Firm pressure in this area elicited signs of pain with ventroflexion of the vertebral column. Mild joint effusion was palpable in both the right and left tarsal joints and the left femorotibial joint. Palpation per rectum revealed mild bony proliferation along the ventral aspect of the lumbar and sacral portions of the vertebral column, consistent with bridging spondylosis. Findings of the remainder of the physical examination were unremarkable.
On the basis of history and physical examination findings, the alterations in the bull's gait appeared to be consistent with lesions in the caudal thoracic or lumbar portions of the spinal cord, causing grade 1/5 ataxia affecting the left hind limb. Specific differential diagnoses for similar clinical cases in cattle and other species include vertebral spondylosis or spondylitis, vertebral body abscess, vertebral trauma or fracture, spinous process impingement, degenerative joint disease of the articular facets, compressive mass or neoplasia (principally spinal enzootic lymphosarcoma), intervertebral disk disease, fibrocartilaginous emboli, and paravertebral soft tissue injury.1–7 The effusion in the left tarsal and femorotibial joints made it difficult to fully attribute the alternation in the bull's gait to a lesion affecting the spinal cord. Differential diagnoses for joint effusion include degenerative joint disease, osteochondrosis, trauma including damage to the cranial cruciate ligament or meniscus, septic or infectious arthritis, and synovitis.8–10
Results of initial serologic testing ruled out infection with bovine leukemia virus and the potential for lumbosacral enzootic lymphosarcoma. Survey radiographs of both hind limbs, including images of the phalangeal, metatarsal, tarsal, and femorotibial joints, were provided by the referring veterinarian. Evidence of osteoarthritis was detected in multiple joints, including a mild periosteal reaction in the left lateral aspect of the distal and proximal interphalangeal joints as well as osteophyte formation on the medial and plantar aspects of both tarsal joints. The left femorotibial joint had evidence of flattening of the medial femoral condyle and areas of sclerotic bone on the medial femoral condyle and tibial plateau. These radiographic findings were consistent with lesions reported by others in similarly aged bulls.11,12 No general consensus currently exists on what constitutes normal radiographic changes in aging rodeo bulls; therefore, the clinical importance of these findings was unknown.
Standing radiography of the lumbar portion of the vertebral column revealed ventral spondylosis on multiple caudal lumbar vertebral bodies (Figure 1). Lateral spondylosis was also observed between the L2-L3 and L3-L4 vertebral bodies, as suggested by the contour and sclerosis of the vertebral end plates. The cranial and caudal aspects of the spinous processes of the visible lumbar vertebrae appeared irregular.
Standing lateral radiographic view of the lumbar portion of the vertebral column of an 8-year-old 800-kg (1,760-lb) Brahman-cross bull that suddenly became lame in the left hind limb during a rodeo bucking performance. Ventral spondylosis is visible on multiple caudal lumbar vertebral bodies (black arrows). Lateral spondylosis is visible between the L2-L3 and L3-L4 vertebral bodies, as suggested by the contour and sclerosis of the vertebral endplates. The cranial and caudal aspects of the spinous processes of the visible lumbar vertebrae appear irregular (white arrow).
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Standing lateral radiographic view of the lumbar portion of the vertebral column of an 8-year-old 800-kg (1,760-lb) Brahman-cross bull that suddenly became lame in the left hind limb during a rodeo bucking performance. Ventral spondylosis is visible on multiple caudal lumbar vertebral bodies (black arrows). Lateral spondylosis is visible between the L2-L3 and L3-L4 vertebral bodies, as suggested by the contour and sclerosis of the vertebral endplates. The cranial and caudal aspects of the spinous processes of the visible lumbar vertebrae appear irregular (white arrow).
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Standing lateral radiographic view of the lumbar portion of the vertebral column of an 8-year-old 800-kg (1,760-lb) Brahman-cross bull that suddenly became lame in the left hind limb during a rodeo bucking performance. Ventral spondylosis is visible on multiple caudal lumbar vertebral bodies (black arrows). Lateral spondylosis is visible between the L2-L3 and L3-L4 vertebral bodies, as suggested by the contour and sclerosis of the vertebral endplates. The cranial and caudal aspects of the spinous processes of the visible lumbar vertebrae appear irregular (white arrow).
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Results of ultrasonographyc of the left femorotibial joint confirmed the presence of suspected degenerative joint disease. Although the cranial and caudal cruciate ligaments as well as the medial and lateral collateral ligaments appeared ultrasonographically normal, an increase was identified in the amount of synovial fluid in the medial femorotibial joint, and the articular surfaces appeared irregular.13
Given the uncertain relevance of these collective findings, infrared thermographic imagingd was performed in an attempt to identify active areas of inflammation that may have been contributing to the overall lameness. In a method similar to that described elsewhere,14 the bull was first restrained in a closed stall and allowed approximately 30 minutes to acclimate to ambient temperature. Global thermal images were initially obtained at a focal distance of 3 m from the anterior, posterior, left, and right perspectives while the bull stood unrestrained. The bull was then confined between 2 narrowed gates, and images of specific body regions were taken at a focal distance of approximately 1 m. Accompanying software was used to calibrate skin surface temperature with ambient temperatures and produce a qualitative scale of the range of temperatures for each image. Images were visually examined for changes in isothermic patterns and absolute skin temperatures, with symmetry compared between paired joints and regions when appropriate.
The surface temperatures for the left hind limb appeared approximately 3° to 4°C lower than those for the right hind limb and both forelimbs (Figure 2). Despite evidence of potential osteoarthritis in multiple joints of the hind limbs on survey radiographic and ultrasonographic images, no focal areas of increased surface temperature associated with any joint were evident on thermographic images. This suggested a lack of active inflammation in these areas. Although the 2-month delay between the onset of lameness and hospital admittance could have resulted in a tempering of inflammation and a return of physiologically normal skin temperatures in these areas, the continued lameness that was evident in the bull during that period was expected to be accompanied by ongoing inflammation and alterations in surface temperatures.
Infrared thermographic images of the tail head and sacroiliac region (A), upper left hind limb (B), hind limbs (C), and forelimbs (D) of the bull in Figure 1. The surface temperatures of the left hind limb and gluteal region appeared approximately 3° to 4°C lower than those of the right hind limb and both forelimbs. Temperatures (°C) are represented by a color scale (shown in each image). See Figure 1 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Infrared thermographic images of the tail head and sacroiliac region (A), upper left hind limb (B), hind limbs (C), and forelimbs (D) of the bull in Figure 1. The surface temperatures of the left hind limb and gluteal region appeared approximately 3° to 4°C lower than those of the right hind limb and both forelimbs. Temperatures (°C) are represented by a color scale (shown in each image). See Figure 1 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Infrared thermographic images of the tail head and sacroiliac region (A), upper left hind limb (B), hind limbs (C), and forelimbs (D) of the bull in Figure 1. The surface temperatures of the left hind limb and gluteal region appeared approximately 3° to 4°C lower than those of the right hind limb and both forelimbs. Temperatures (°C) are represented by a color scale (shown in each image). See Figure 1 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Possible differential diagnoses for skin surface hypothermia include vascular occlusion, excessive tissue edema, and spinal nerve root irritation resulting in excessive sympathetic stimulation and peripheral vasoconstriction. Acepromazine maleatee (2 mL; 0.05 mg/kg [0.023 mg/lb], IV) was administered once, and thermography was repeated 10 minutes later. At that point, the surface temperature of the left lumbar vertebral region and left hind limbs increased to approximately the same temperature as for the right hind limb (Figure 3), suggesting that the cause of the surface hypothermia was reflex sympathetic vasoconstriction most likely due to compression of ≥ 1 lumbar spinal nerve roots.15 The pattern of altered skin temperature affecting the upper and lower areas of the left hind limb was consistent with a potentially compressive lesion affecting the left lumbar nerve roots, which concurred with the radiographic evidence.
Infrared thermographic images of the tail head and sacroiliac region (A), limbs (B), left flank and upper left hind limb (C), and hind limbs (D) of the bull in Figure 1 following IV administration of acepromazine maleate (0.05 mg/kg [0.023 mg/lb]). Acepromazine administration induced an increase in the surface temperature of the left lumbar vertebral region and left hind limb to approximately the same temperature as the right hind limb, suggesting that the cause of the surface hypothermia was reflex sympathetic vasoconstriction. See Figures 1 and 2 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Infrared thermographic images of the tail head and sacroiliac region (A), limbs (B), left flank and upper left hind limb (C), and hind limbs (D) of the bull in Figure 1 following IV administration of acepromazine maleate (0.05 mg/kg [0.023 mg/lb]). Acepromazine administration induced an increase in the surface temperature of the left lumbar vertebral region and left hind limb to approximately the same temperature as the right hind limb, suggesting that the cause of the surface hypothermia was reflex sympathetic vasoconstriction. See Figures 1 and 2 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Infrared thermographic images of the tail head and sacroiliac region (A), limbs (B), left flank and upper left hind limb (C), and hind limbs (D) of the bull in Figure 1 following IV administration of acepromazine maleate (0.05 mg/kg [0.023 mg/lb]). Acepromazine administration induced an increase in the surface temperature of the left lumbar vertebral region and left hind limb to approximately the same temperature as the right hind limb, suggesting that the cause of the surface hypothermia was reflex sympathetic vasoconstriction. See Figures 1 and 2 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Nuclear scintigraphy was performed to confirm the presence of an active inflammatory process in the left lumbar or gluteal region by IV administration of 275 mCi of 99mTc-MDP.f Ninety minutes later, furosemideg was administered IV to induce diuresis and urinary bladder evacuation of the 99mTc-MDP and improve the diagnostic quality of the image. The bull was positioned in right lateral recumbency and restrained by a portable hydraulic tilt table. Overlapping views of the caudal thoracolumbar vertebrae, sacral vertebrae, pelvic region, and both hind limbs were obtained approximately 2 hours after 99mTc-MDP administration. The images revealed a distinct focal area of increased radioisotope uptake in the area of the L2–3 intervertebral space, specifically located on the left ventrolateral aspect of that joint (Figure 4). On the basis of the anatomic location of this lesion, radiographic evidence of ventrolateral spondylosis, and physiologic implications of the hypothermic skin patterning, a presumptive diagnosis of ventrolateral vertebral spondylosis resulting in spinal nerve impingement was made.
Overlapping dorsoventral (A) and lateral (B) radiographic views of the lumbosacral portion of the vertebral column of the bull in Figure 1, showing a distinct focal area of increased radioisotope uptake in the area of the L2–3 intervertebral space specifically located on the left ventrolateral aspect of that joint. See Figure 1 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Overlapping dorsoventral (A) and lateral (B) radiographic views of the lumbosacral portion of the vertebral column of the bull in Figure 1, showing a distinct focal area of increased radioisotope uptake in the area of the L2–3 intervertebral space specifically located on the left ventrolateral aspect of that joint. See Figure 1 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
Overlapping dorsoventral (A) and lateral (B) radiographic views of the lumbosacral portion of the vertebral column of the bull in Figure 1, showing a distinct focal area of increased radioisotope uptake in the area of the L2–3 intervertebral space specifically located on the left ventrolateral aspect of that joint. See Figure 1 for remainder of key.
Citation: Journal of the American Veterinary Medical Association 250, 5; 10.2460/javma.250.5.554
The owner was advised of the diagnosis and given the options of surgical decompression of the lesion or conservative treatment that included stall rest, site-directed corticosteroid treatment, and IM administration of PSGAG. The owner was also warned that, regardless of the treatment approach chosen, the bull was unlikely to continue to perform at the same level and that doing so may further jeopardize its health. The owner chose to pursue conservative treatment and permanently retire the bull from bucking. The owner also requested a treatment option that would permit collection of semen because of the economic value of the bull and market demand for semen.
A 14-gauge, 20-cm long-term polyurethane catheterh was introduced into the epidural space through an introducer placed in the lumbosacral vertebral space. The catheter was advanced to the approximate level of the L2–3 intervertebral space (15 cm), and 200 mg of methylprednisolonea was administered. Subsequently, 500 mg of PSGAGi was administered IM as 1 of 7 PSGAG treatments every 4 days, followed by 500 mg of PSGAG administered IM once per month.
Improvement in ataxia was observed within 1 week after treatment began. A semen sample was collected via electroejaculation 2 weeks after epidural administration to determine whether the prolonged lameness or corticosteroid treatment had an adverse effect on spermatogenesis. The percentage of gross and progressively motile sperm was 50%, and the percentage of sperm with unremarkable morphology was > 80%. On the basis of these findings, it appeared that the lameness was having no ill effects on spermatogenesis. The bull was discharged from the hospital into the care of a semen collection facility to undergo additional stall rest prior to gradual introduction to routine semen collection.
Discussion
Trauma is the most common cause of lameness in rodeo bulls. The mean ground reaction force of an 885-kg (1,947-lb) bull can be estimated as 3.6 times its body weight (3,186 kg [7,009 lb]) for each forelimb and 12.2 times its body weight (10,797 kg [23,753 lb]) for each hind limb.i Mean ground contact time is reportedly 0.4 seconds for each forelimb and 0.3 seconds for each hind limb.j In addition to these factors, each bull has a unique style of bucking that may individually predispose it to specific injuries.
The Professional Bull Riders organization reports that bulls used in rodeo performances have a mean of 1 minor injury (muscle strain or laceration)/786 ride attempts, whereas a major (career-ending) injury occurs once every 9,833 ride attempts.16 Most career-ending injuries result in retirement to stud for premier performance bulls. Since the inception of Professional Bull Riders in 1992, 4 bulls have reportedly sustained life-threatening injuries severe enough to warrant euthanasia.
Spondylosis is described as an ankylosing or degenerative disease of the intervertebral joint that produces large spondylophytes or vertebral enthesophytes that span the intervertebral disk between vertebral bodies. Exostosis develops principally along the ventrolateral aspect of the vertebrae within the ventral longitudinal ligament. The etiology of spondylosis is unclear but has been linked to altered biomechanics and load bearing of the vertebral column.3,17 Mechanical stress leads to tearing of the periarticular ligaments and release of inflammatory mediators. These mediators incite metaplastic changes in the ligaments and joint capsule, eventually leading to periosteal proliferation. Painful lumbar lesions have been previously shown to affect libido in 2 breeding bulls.2 Both bulls had evidence of bridging spondylosis of the lumbar vertebrae and spinous process impingement that was surmised to have developed from repetitive dorsiflexion and ventroflexion of the vertebral column while breeding.
Bucking bulls have extreme dorsiflexion and ventroflexion while bucking, in addition to complex lateral and rotary movements. These biomechanics combined with the previously mentioned ground reaction forces could explain the development of the extensive degenerative changes observed in the bull of the present report. The misstep of the left hind limb during the bucking performance may have led to sudden trauma and compression of the left L2 dorsal spinal nerve root by the exostosis, which would account for the more acute onset of lameness in this case. A higher prevalence of thoracolumbar vertebral lesions has been reported for competitive jumping or dressage horses versus other horses, and this increase is believed to be due to analogously demanding spinal maneuvers.18 Radiographic evidence of similar thoracolumbar vertebral lesions was identified in the bull of the present report, but no comparative reports exist for rodeo bulls to indicate the clinical importance of this finding. Vertebral osteophytosis was prevalent in a study2 of 2- to 8-year-old dairy bulls at postmortem examination, but such lesions were often clinically inapparent even when grossly severe. In contrast, ankylosing spondylosis with complete intervertebral bridging may be a predisposing factor for progressive hind limb ataxia.19
Infrared thermographic imaging has been used as a noninvasive diagnostic tool to measure emitted thermal radiation of any object and display that information as a scaled representation of its surface temperatures. This technique has been successfully used to detect lameness, respiratory disease, mastitis, autonomic pain, stress, and scrotal thermal regulation in cattle.20–24 Surface temperatures are variable and dependent on regional blood flow and metabolism. Therefore, hyperthermic changes may reflect inflammation or an increase in metabolism in underlying tissues, whereas regionalized hypothermic changes have been associated with vasoconstriction due to increased persistent sympathetic stimulation.25
Sympathetic dysfunction disorders (also known as reflex sympathetic dystrophy) that result from spinal nerve root impingement are causes of appendicular pain in humans.26 The pain is mainly transmitted up the slow type C and A delta fibers, and effects include hyperesthesia, burning, aching, throbbing, mechanoallodynia (intolerance of pressure), and altered skin temperature of the affected limb. A similar syndrome has been described for horses.27 In the bull of the present report, we observed a pattern of regional hypothermia in the left lumbosacral area and left hind limb similar to that observed in humans and horses with reflex sympathetic dystrophy. Acepromazine maleate, a phenothiazine neuroleptic agent with α1-adrenoceptor blocking effects, was administered to determine whether the pattern of hypothermia observed in the bull was consistent with a persistent increase in sympathetic stimulation and excessive vasomotor tone. By blocking the α1-adrenoceptor, acepromazine blocked the vasoconstrictive effect of the sympathetic nervous system, resulting in vasodilation and increased blood flow and an increase in surface temperature of the left lumbosacral area, gluteal area, and left hind limb equal to that of the opposite limb.
Nuclear scintigraphy with 99mTc-MDP provided a means of imaging the lumbosacral portion of the vertebral column in adequate detail to isolate the location of the lesion to the left lateral L2–3 intervertebral space. Standing lumbar radiography was useful to initially identify lesions affecting several lumbar vertebrae; however, radiographic changes do not always correlate with active lesions. Because uptake of 99mTc-MDP increases in areas of bone with increased cellular metabolism, scintigraphy is more sensitive for characterization of areas of active inflammation and pathological change. Computed tomography or MRI would have been preferred modalities to definitively identify the primary lesion and impingement of the L2 spinal nerve root, but the size and temperament of the bull precluded their usefulness. Radiocontrast myelography would also have provided useful information concerning the degree of compression on the lumbosacral portion of the spinal cord, but the need for general anesthesia to perform each of these techniques was regarded as an unwarranted risk.
Milder spondylosis in horses and dogs reportedly responds to NSAID treatment, rest, and management changes.28 Horses with more severe spondylosis typically respond poorly to such treatment, and extended turnout is advocated in hopes that restricted activity will permit the formation of an osseous union.29 Administration of local analgesics and corticosteroid drugs can also provide relief and control of localized inflammatory processes. In a report3 of a bull with spinous process impingement, a Sarraceniaceae product and lidocaine were locally infused, and the bull was able to return to semen collection and natural service. Acupuncture for treatment of painful lumbar lesions has been described for horses30 and, at least anecdotally, may provide benefit to some bucking bulls with signs of back pain.k
Because of the compression on the spinal nerve root, perhaps the most appropriate treatment for the bull of the present report would have been surgical decompression or left-sided foraminotomy of the L2–3 intervertebral space and removal of offending osteophytes. This procedure has been successfully performed in humans and dogs with nerve root compression.31,32 Complications associated with this surgery include postoperative instability; infection; breach of the dura, inducing leakage of CSF; and inadvertent damage of the spinal nerve. The owner of the bull declined surgical decompression because of awareness that the prognosis for return to athletic performance was poor. For the owner, making use of the bull's popularity and economic value through the sale of semen was a more important consideration.
Local infusion of methylprednisolone within the epidural space at the site of the lesion appeared to alleviate the pain in the bull of the present report, although this infusion was not associated with an improvement in the infrared thermal patterns of the affected limb. Epidural infiltration of methylprednisolone acetate has been shown to improve signs of pain in and mobility of dogs following acute lumbar disk herniation, comparable to improvements achieved with surgical decompression.33 A systematic review34 of randomized clinical trials regarding injection treatments for subacute and chronic back pain in humans revealed that, although controversial, epidural administration of corticosteroid drugs improved the overall pain response. However, systemic corticosteroid treatment of adult bulls is not without consequences. Two-year-old bulls that received dexamethasone (20 mg, IM) daily for 7 days reportedly developed a significant increase in the percentage of primary and secondary sperm abnormalities, compared with percentages in untreated control bulls, although this effect resolved shortly following cessation of treatment.35 Limited reports exist concerning systemic uptake of epidurally administered corticosteroid drugs, and none indicate that absorption has an effect on spermatogenesis. In light of these concerns, a breeding soundness evaluation of the bull in the present report was conducted 14 days after epidural administration of methylprednisolone, revealing no important sperm abnormalities and potential satisfactory breeding capacity as outlined by the Society for Theriogenology.36,37
Polysulfated glycosaminoglycans have a label indication in the United States for the treatment of non-infectious degenerative or traumatic joint disorders in dogs and horses.16 The proposed mechanism of action is through restoration of synovial fluid and inhibition of local prostaglandin production. The extralabel use of methylprednisolone, PSGAGs, and 99mTc-MDP in the bull of the present report was permissible under AMDUCA guidelines, as no comparable drug was labeled for use in cattle. Because of the lack of data regarding drug withdrawal times, the owner was informed that meat from this animal could not be used for human consumption.
Determining the source of lameness in bucking bulls can be difficult. A complete physical examination and thorough assessment of their history, including evaluation of recorded rides, is invaluable. Given the often fractious nature of bucking stock, infrared thermographic imaging is a useful tool for hands-off evaluation and screening for complex cases. Thermography provides immediate assessment of potential hotspots of inflammation and allows focusing of further diagnostic tests. Use of thermography for the bull of the present report provided additional insight into the disruption of neurovascular function in the affected region. Nuclear scintigraphy permitted identification of the sites of active vertebral lesions for more effective treatment. The combined use of the 2 imaging modalities provided a direct assessment of the physiologic implications of the lesions identified on survey radiography. Each was essential in defining the neurovascular injury in this bull.
ABBREVIATIONS
| 99mTc-MDP | Technetium Tc 99m–labeled methylene diphosphonate |
| PSGAG | Polysulfated glycosaminoglycan |
Footnotes
Depo-Medrol (20 mg/mL), Pharmacia & Upjohn Co, New York, NY.
Hylartin V (10 mg/mL), Pharmacia & Upjohn Co, New York, NY.
Philips HD11 XE, Philips Healthcare, Andover, Mass.
FLIR T430sc, FLIR Systems Inc, Oak Ridge, Tenn.
Acepromazine maleate injection (10 mg/mL), Boehringer Ingelheim Vetmedica Inc, St Joseph, Mo.
MDP-25, Jubilant DraxImage Inc, Kirkland, QC, Canada.
Salix furosemide 5% injection, Intervet Inc, Millsboro, Del.
Mila 14 gauge, 20-cm long-term catheter, Mila International Inc, Erlanger, Ky.
Adequan IM 10% solution, Luitpold Pharmaceuticals Inc, Shirley, NY.
Savage L, Butterwick D, Loitz-Ramage B. Estimation of ground reaction forces in bucking rodeo bulls (abstr), in Proceedings. Markin-Flanagan/USRP Summer Studentship Res 2006;1.
Dr. Lisa Willis, MidTexas Veterinary Associates, Gustine, Tex: Personal communication, 2006.
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