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CASE DESCRIPTION An 8-year-old Brahman-cross bull was evaluated for left hind limb lameness of 2 months' duration. The lameness was first noticed during a rodeo bucking performance, immediately after the bull appeared to land inappropriately on the affected limb. CLINICAL FINDINGS Physical examination findings revealed left hind limb lameness, ataxia, and left-sided epaxial muscle atrophy. Palpation per rectum along the lumbar portion of the vertebral column revealed evidence of exostosis of the ventral aspect. High-definition infrared thermal imaging revealed a pattern of reduced skin temperature in the area of the left lumbar and gluteal regions suggestive of a disruption in the sympathetic control of peripheral blood flow. Nuclear scintigraphy revealed a focal area of increased radioisotope uptake on the left ventrolateral aspect of the L2-3 intervertebral joint. A presumptive diagnosis of ventrolateral vertebral spondylosis resulting in spinal nerve impingement was made. TREATMENT AND OUTCOME 200 mg of methylprednisolone was epidurally injected at the site of the lesion, and treatment with polysulfated glycosaminoglycans was initiated (500 mg, IM, every 4 days for 7 treatments, then monthly thereafter). The lameness and ataxia observed in the left hind limb resolved within 1 week after treatment began. Subsequently, the bull was discharged from the hospital and was used successfully for semen collection and live-cover breeding. CLINICAL RELEVANCE Use of thermography for the bull of this report provided additional insight into neurovascular physiologic function that classical imaging modalities are unable to provide and, when combined with nuclear scintigraphy, aided in identifying the most critical lesion in a complex clinical case.

Objective: To determine whether testicular needle biopsy is detrimental to testicular function in clinically normal bulls., Design: Prospective study., Animals: 6 mixed-breed mature bulls., Procedure: A randomly selected testicle from each bull was biopsied with a 14-gauge needle biopsy instrument. Bulls were then evaluated over a 90-day period for changes in scrotal temperature and thermal patterns, ultrasonographic appearance, and quality of spermatozoa. At the end of the 90-day study, bulls were castrated, and testicles were examined grossly and histologically., Results: Changes were detected in scrotal temperatures and thermal patterns and in the breeding soundness examination results during the first 2 weeks of the study. However, there were no long-term changes in semen quality over the course of the experiment. Hyperechoic areas were detected on ultrasonographic examination and corresponded to the areas of penetration by the biopsy instrument. Microscopic lesions that were indicative of testicular dysfunction were not found., Conclusions and Clinical Relevance: Results indicate that testicular biopsy is a safe procedure in bulls. Testicular biopsy could possibly be used to further examine bulls that have less than satisfactory results for breeding soundness examinations.

Objectives: To use lipopolysaccharide (LPS) to create synovitis in the midcarpal joint of ponies, and to assess the morphologic, histochemical, and immunohistochemical effects of synovitis on articular cartilage of the third carpal bone., Animals: 2- to 3-year-old ponies, 6 control (group 1) and 6 treated (group 2)., Procedure: Synovitis was induced in 1 midcarpal joint of group-2 ponies by intra-articular injections of LPS (0.02 micrograms/kg of body weight), morphine (0.1 mg/kg), and saline solution (group 2a) and a morphine and saline solution alone in the contralateral midcarpal joint (group 2b). Articular cartilage sections and attached synovial membrane from the third carpal bones were examined by immunohistochemical distribution of interleukin 1 beta, tumor necrosis factor (TNF)-alpha, TNF receptors (P55, P75) and 3-B-3(-) epitopes, and by localization of proteoglycans (metachromatic staining). Proteoglycan extracts were assessed by metachromatic staining or western blotting and immunohistochemical staining, using anti-3-B- antibodies., Results: Enhanced immunoreactivity for the cytokines and receptors was found in inflamed synovial membrane and noncalcified cartilage (group 2a more than 2b). Metachromasia of the noncalcified cartilage was greater in group-1 than in group-2a and group-2b specimens. In group 2a, chondrocyte hypertrophy and enhanced immunoreactivity for 3-B-3(-) epitope in areas of increased cytokine immunoreactivity suggested possible phenotypic change of the chondrocytes in response to synovitis. Immunohistochemical analysis by western blotting of proteoglycan extracts indicated strong 3-B-3(-) epitope immunolocalization in group-2a, weaker staining in group-2b, and barely detectable stain in group-1 specimens, which correlated with in situ immunolocalization., Conclusions: Intra-articular administration of LPS may be used to induce a synovial environment conductive to increased immunoreactivity of interleukin 1 beta, TNF-alpha, and its receptors in equine synovial membrane and articular cartilage. These cytokines may be involved in the early phenotypic change of chondrocytes that is believed to occur in osteoarthritis and is characterized in this study by enhanced 3-B-3(-) epitope immunoreactivity and chondrocyte hypertrophy.

Mean conduction velocity of sensory axons of the dorsal penile nerves of clinically normal bulls was determined by recording action potentials evoked by cutaneous stimulation. Locations of stimulating and recording electrodes were standardized. Overall mean +/- SD conduction velocity was 55.1 +/- 5.1 m/s. Mean +/- SD velocity recorded from the distal electrode was 53.3 +/- 4.9 m/s; velocity recorded from the middle electrode was 55.3 +/- 5.0 m/s; and velocity recorded from the proximal electrode was 56.7 +/- 5.1 m/s. Differences among means were not significant. Four bulls had mean conduction velocities of 54.0 m/s and 48.4 m/s before and 3 weeks after castration, respectively.

A native African bull was examined for ataxia of 10 days' duration. Clinical signs included bradycardia, ataxia, hypermetria, and dysphonia. Cerebrospinal creatine kinase activity was high. Thermographic evidence of bilateral accessory nerve dysfunction was observed. This finding was supported by electromyographic studies. Survey and positive contrast radiographs were nondiagnostic. Clinical signs exacerbated after radiographic examination. Treatment included dexamethasone and flunixin meglumine administered IV.

Equine amnion and live yeast cell derivative were evaluated as a biological dressing and as a topical wound medicament respectively, in the treatment of granulating wounds of the distal portion of the limbs of horses. Wounds measuring 2.5 x 2.5 cm were created on the dorsomedial aspect of the metacarpal and metatarsal region of all 4 limbs of 9 horses. Each wound was assigned randomly to 1 of 3 treatment groups: group C, treated with a nonadherent bandage as a control; group A, treated with amnion beneath a nonadherent bandage; and group L, treated with live yeast cell derivative beneath a nonadherent bandage. Rates of contraction and epithelialization were not significantly different among groups. Percentage of epithelialization for group A was significantly greater throughout the study than for the other groups. Number of days to complete healing was significantly less in group A and significantly greater in group L than in group C. Incidence and severity of exuberant granulation tissue were significantly less in group A than in the other 2 groups. Group L had more frequent and severe cases of exuberant granulation tissue than the other 2 groups.

The carotid artery of clinically normal goats was examined, using duplex ultrasonography and arteriography. The diameter of the carotid artery was measured by use of two-dimensional ultrasonography and Doppler ultrasonography, respectively, before and after xylazine administration. The diameter of the artery was also measured by use of an arteriography technique in halothane-anesthetized goats. There was no significant difference between the mean diameter of the carotid artery measured by ultrasonography in conscious nonsedated goats and that determined by arteriography in goats under halothane anesthesia. On the other hand, ultrasonography of xylazine-sedated goats revealed an increase of carotid artery diameter of 20 to 30%. There was no change in the velocity of blood flow after xylazine administration.

To establish a clinically practical procedure for recording the equine EEG, 25 healthy adult horses and 6 newborn foals were used. Recordings were taken with the animals alert and tranquilized, confined in metal stocks, or physically restrained. The dominant alert waveforms of adult horses were fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 microV-dominant 10 to 15 microV). Underlying this fast activity was slower (0.5 to 4.0 Hz) activity with medium-to-low voltages (10 to 40 microV). Twelve of the 25 adult horses had EEG frequencies in the alpha frequency range (10 to 15 Hz, 10 to 50 microV). Eight horses were given xylazine and 17 were given acetylpromazine. Those given xylazine had generalized slowing with several distinct frequency patterns (25 to 40 Hz, 5 to 30 microV; 10 to 15 Hz, 10 to 80 microV; and 0.5 to 4.0 Hz, 10 to 90 microV). Horses given acetylpromazine had fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 microV). Underlying this activity were slower waveforms (1 to 4 Hz) with medium-to-low voltages (5 to 10 microV). Occasional well-formed spindle activity was observed (10 to 14 Hz, 10 to 50 microV). Acetylpromazine had little effect on the EEG recording, whereas xylazine exerted a substantial effect. All leads were synchronous with lower voltages in the left frontal, right frontal, and transfrontal leads. The alert pattern of a newborn foal was characterized by low frequency (2 to 6 Hz) with medium-to-high voltages (20 to 90 microV).(ABSTRACT TRUNCATED AT 250 WORDS)

A continuous series of electroencephalograms (EEG) was obtained from each of 6 mature horses which had been given xylazine and ketamine hydrochloride IV. Electrocardiograms and respiratory rates were also obtained. The EEG of the unsedated standing adult horse displayed a dominant fast activity in the range of 25-35 Hz, 5-30 microV superimposed over slower 1-4 Hz, 10-50 microV activity with occasional 10-14 Hz, 10-40 microV spindle-type activity. The xylazine-sedated horse displayed hypersynchronous EEG patterns, with the dominant activity being 1-3 Hz, 10-70 microV with overlying mixed frequencies of 5-10 Hz, 10-40 microV and 10-14 Hz, 10-40 microV spindle-type activity. Some 25-35 Hz, 5-10 microV activity was present in 5 of the 6 horses. Ketamine administration 3 minutes after xylazine injection caused an increase in high-voltage slow activity. The dominant frequency was 1-3 Hz, 20-100 microV, with superimposed mixed irregular frequencies of 6-10 Hz, 10-50 microV and 10-14 Hz, 10-40 microV spindle-type activity. All horses developed some degree of second-degree atrioventricular (AV) heart block approximately 23 s after xylazine was injected. The second-degree AV heart block disappeared approximately 1 minute and 30 s after ketamine was injected in 4 of the 6 horses. The remaining 2 had second-degree AV heart block throughout the recording period (15 to 18 minutes). Respiration rates were depressed after xylazine was given and became irregular and apneustic after ketamine injection. The cyclic rate of respiration varied from 19 to 30 breaths/minute. Xylazine depressed heart rates from 13% to 41% (mean 29.3%). Heart rates became faster or remained unchanged after ketamine was administered.

Thermographic and radiographic evaluations of the tarsus (hock) were done on 20 Standardbred racehorses before and after exercise at three consecutive 6-week intervals. All horses were from the same stable and given the same care and training under identical schedules and conditions. Normal thermographic patterns were established before and after exercise. These patterns corresponded to the underlying tarsal vasculature. Postexercise thermal patterns indicated a warming trend, and the increases were uniform. Abnormal thermal patterns were more localized and did not conform to the normal underlying vascular distribution. Five of the 20 horses trained successfully and competed professionally, with 1 of the 5 showing abnormal thermographic changes. Four horses were too slow to race, and all of these had abnormal thermographic changes of their tarsi. The medial aspect of the right tarsus was more commonly involved than the lateral in these horses. Only one horse was clinically lame and exhibited thermal increases, as well as radiographic changes in the right tarsus. The remaining horses were removed from training due to miscellaneous causes. It was believed that the four horses that failed to make minimum track times (for racing) suffered discomfort in their tarsi sufficient to impair performance. This problem was attributed to early subclinical inflammatory changes within the joints. Though difficult to recognize radiographically, these early changes were conspicuous as abnormal thermographic patterns typical of inflammation.

The vascular anatomy of the adrenal glands and a surgical technique for bilateral adrenalectomy in the equid are described. Bilateral adrenalectomy was performed in six ponies and one horse via bilateral transcostal retroperitoneal approaches through the 18th rib during a single anesthetic period. Complications included hemorrhage from the right side only and pneumothorax which usually occurred on the right side. One pony died as a result of the surgical technique. Maintenance of adrenal function was accomplished with desoxycorticosterone pivilate and prednisolone.

Six ponies and 1 horse were bilaterally adrenalectomized (BADX). The survival time of 2 of the 7 animals after BADX was 24 and 72 hours without supplemental corticosteroids. The cause of death was not related to the surgical technique. The biological half-life of cortisol (hydrocortisone) was estimated to be 2.1 +/- 0.6 hours. The disappearance of cortisol in the horse was found to be biphasic, composed of redistribution and elimination phases. Pathophysiologic changes (ie, increased serum sodium and chloride, increased PCV, and decreased serum potassium) similar to those seen in other species after BADX were found. Clearance of electrolytes was calculated, using the creatinine clearance method. These values were inversely correlated with the changes seen in serum electrolytes.

To evaluate the use of thermography in equine medicine, a three-phase study was conducted. In the first phase, six horses were examined thermographically, before and after exercise, to determine a normal thermal pattern. In the second phase, nine horses with acute and chronic inflammatory processes were examined thermographically. In the third phase, thermography was used to evaluate the effectiveness of anti-inflammatory drugs on chemically induced inflammatory reactions. All normal horses tested had similar infrared emission patterns. There was a high degree of symmetry between right and left and between front (dorsal) to rear (palmar, plantar) in the legs distal to the carpus and the tarsus. The warmer areas of the thermogram tended to follow major vascular structures. The coronary band was the warmest area of the leg. Heat increase due to exercise did not substantially alter the normal thermographic pattern. Use of thermography in clinical cases successfully detected a subluxation of the third lumbar vertebra, a subsolar abscess, alveolar periostitis and abscess, laminitis, serous arthritis of the femoropatellar joint, and tendonitis. Thermography was effective in quantitative and qualitative evaluation of anti-inflammatory compounds in the treatment of chemically induced inflammation.

A needle-tipped catheter or subminiature pressure transducer was implanted in the corpus spongiosum penis (CSP) of Shetland Pony stallions to determine pressure during coitus. Electrodes for monitoring the electromyographic (EMG) activity were implanted in the ischiocavernosus (IC) and bulbospongiosus (BS) muscles. The mean peak CSP pressure recorded with the catheter was 762 mm of Hg, and with the subminiature pressure transducer, it was 994 mm of Hg. The simultaneous occurrence of the CSP pressure peaks and bursts of BS muscle activity indicated that these muscles were the likely source of energy for the increased pressures, which were far greater than the systemic blood pressure. This conclusion was further supported by the finding that anesthesia of the BS muscles greatly reduced the CSP pressures of the stallion during attempted coitus.

Thermographic patterns of the bovine scrotum were established in 15 clinically normal bulls and were compared with patterns in 10 bulls with scrotal and testicular diseases. Thermography of a normal scrotum was characterized by a symmetrical and constant thermal pattern with a temperature gradient of 4 degrees to 6 degrees (C) from the base to the apex of the scrotum. There was a significant difference (P less than 0.05) in the temperature from the base to the apex of the scrotum (34.94 +/- 0.60 C to 30.11 +/- 0.91 C). Lack of thermal symmetry was seen in bulls with unilateral lesions. Inflammation of one testicle increased ipsilateral scrotal infrared emission temperature 2.5 degrees to 3 degrees (C) above that in the contralateral side. If both testes were inflamed and hyperemic, there was an overall increase in scrotal temperature of at least 3 degrees (C), and a reduction in temperature gradient of 2 to 3 degrees (C) from the base to the apex of the scrotum. Area temperatures in bulls with chronic testicular degeneration with fibrosis were reduced.

The pharmacokinetics of gentamicin were studied in six healthy mature horses of mixed breeding and of both sexes. A parenteral preparation of gentamicin sulfate (5% aqueous solution) was administered rapidly (IV) at the dosage level of 5 mg/kg of body weight. Venous blood samples were taken at 0 (base line), 0.083, 0.25, 0.5, 0.75, 1, 2, 4, 8, 12, 24, 36, 48, 72, 96, and 120 hours after gentamicin administration. Serum gentamicin was measured by a radioimmunoassay technique. The gentamicin concentration data was fitted to a one- and two-compartment open model with first-order elimination from the central compartment with the aid of nonlinear least squares program. The data were found to be best described by the two-compartment model with r2 = 0.997. Half-life, as determined from the terminal phase was 2.54 +/- 0.33 hours. Calculation of the total body clearance provided a mean of 1.16 +/- 0.11 ml/minute/kg of body weight (1.04 to 1.31 ml/minute/kg, range); the volume of distribution calculated from the area under the curve was determined separately for each animal and had a mean value of 0.254 +/- 0.036 L/kg. The initial exponential decline (alpha) in gentamicin serum concentration had an average value of 3.75 +/- 1.86 hours-1, whereas the terminal values were described by beta = 0.275 +/- 0.036 hours-1. Other pharmacokinetic values determined also are presented.

Lateral and frontal thermographic patterns of the head of normal horses before and after exercise were characterized to aid the diagnosis of diseases of the head. Surgical induction of Horner's syndrome was done in four horses by isolation and transection of the vagosympathetic trunk. One clinical case and the surgically induced cases of Horner's syndrome were evaluated clinically. Thermographic findings of the clinical case were similar to the experimental cases.

Three ponies and 1 horse were bilaterally adrenalectomized (BADX). The initial hypoadrenal episode after BADX was reversed with 20 mg of dexamethasone (DXM) IM (n = 2) or 20 mg of triamcinolone (TMC) IM (n = 2). Nine hypoadrenal crises were reversed with 20 mg of DXM given IM (n = 4) or 20 mg of TMC given IM (n = 5). Sodium and chloride retention and potassium excretion were documented based on changes in serum electrolytes and urinary excretion. Eight intact adult horses were randomly assigned to 2 groups to study the effects of a single IM injection of DXM (0.044 mg/kg of body weight) or TMC (0.044 mg/kg). Cortisol (hydrocortisone) suppression was found to be maximal (nondetectable amounts of cortisol) by 12 hours in both groups. Cortisol was again detectable in the DXM group at 24 hours after injection and was at pretreatment values at 168 hours. Cortisol was not detectable in the TMC group for 192 hours and did not reach pretreatment values until 336 hours. The duration of the gluconeogenic effect was compared with the duration of cortisol suppression exerted by DXM and TMC in these intact animals. Assuming that the decrease in plasma glucose coincides with the decrease in glucocorticoid activity of the respective steroid, a relative hypoadrenocortical state was found in the animals treated with DXM between the 2nd and 7th day after treatment, whereas this state occurred between the 6th and 14th day after treatment with TMC.

Circulating concentrations of angiotensin I and plasma renin activity (PRA) were determined in 45 Thoroughbreds before prerace medication (at rest), 1 to 1 1/2 hours before racing but after prerace medication (prerace), within 15 minutes after racing (immediately postrace), and between 1 to 2 hours after racing. Angiotensin I was measured by radioimmunoassay, and PRA was determined by the rate of generation of angiotensin I in plasma incubated at 37 C. Irrespective of prerace medication, there was a marked increase in angiotensin I (0.478 +/- 0.034 to 0.848 +/- 0.051 ng/ml) and PRA (0.191 +/- 0.018 to 0.522 +/- 0.061 ng/hour/ml) from the at-rest samples to the immediate-postrace samples, with the exception of anhidrotic horses in which increases in angiotensin I (0.7131 +/- 0.0794 to 0.8081 +/- 0.0608 ng/ml) and PRA (0.1635 +/- 0.0379 to 0.2176 +/- 0.0437 ng/hour/ml) were not as marked as they were in other horses. Administration of 1 mg of furosemide/kg 2 hours before racing caused an increase in PRA from 0.2438 +/- 0.0324 to 0.3706 +/- 0.1110 ng/hour/ml, whereas horses under the influence of 4 mg of phenylbutazone/kg had a decrease in PRA from 0.2090 +/- 0.0440 to 0.0669 +/- 0.0206 ng/hour/ml. Marked increases in angiotensin I and in PRA did not occur when horses were administered furosemide and phenylbutazone as prerace medication.

Unilateral orchiectomy was performed on 9 mature mixed-breed bulls with satisfactory semen quality to study the effect of the procedure on quality of semen from the contralateral testicle. Semen was collected by electroejaculation before surgery and on alternate days for 2 weeks, then once weekly for 8 weeks. Each sampling day, progressive motility and morphologic features of spermatozoa were determined, and scrotal thermograms were taken. The percentage of normal spermatozoa decreased significantly (P less than 0.05) only on postoperative day 6. Progressive motility scores varied but at the end of the study there was no significant difference from preoperative values. Scrotal thermography revealed inflammation in the contralateral side of the scrotum, beginning 3 days after surgery, but the thermograms were normal in most bulls by 3 weeks after surgery, and all thermograms were normal by 4 weeks.

Total strangulation obstruction of the caudal part of the jejunum was induced in 3 groups (each of 3 ponies) for 2, 4, and 6 hours. Coagulation tests which included blood platelet counts, prothrombin time, activated partial thromboplastin time, activated coagulation time, plasma fibrinogen level, and fibrin/fibrinogen degradation products assay were performed at specified time intervals for 1 week or until death of the experimental ponies. Another 3 ponies (sham-operated) were similarly treated, except that intestinal strangulation obstruction (ISO) was not induced. Necropsy was done on ponies that were euthanatized 9 days after the sampling period and on 2 ponies that died. Six hours of ISO resulted in severe ischemic damage to the intestines, characterized by hemorrhagic infarction, with or without perforation, in ponies that died, and total loss of mucosa with moderate to severe fibrosis of the intestinal wall in the surviving pony of this group. This damage was associated with significant coagulopathies, notably prolonged prothrombin time and activated partial thromboplastin time, decreased blood platelets count, and the presence of high levels of fibrin/fibrinogen degradation products (40 micrograms/ml). These laboratory findings are indicative of disseminated intravascular coagulation. In contrast, the jejunal segments of the ponies subjected to 2 and 4 hours of ISO were viable as revealed by histopathologic examination. There were no significant changes found in their coagulation profiles.(ABSTRACT TRUNCATED AT 250 WORDS)