Exercise induced pulmonary hemorrhage in horses: American College of Veterinary Internal Medicine consensus statement.

BACKGROUND: Published studies of exercise-induced pulmonary hemorrhage (EIPH), when assessed individually, often provide equivocal or conflicting results. Systematic reviews aggregate evidence from individual studies to provide a global assessment of the quality of evidence and to inform recommendations. OBJECTIVES: Evaluate evidence to determine: if EIPH adversely affects the health, welfare or both of horses; if EIPH affects the athletic capacity of horses; the efficacy of prophylactic interventions for EIPH; and if furosemide affects the athletic capacity of horses. ANIMALS: None. MATERIALS AND METHODS: Systematic review. A panel of 7 experts was formed to assess evidence in the peer reviewed literature addressing each of the 4 objectives. Methodology followed that of the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Publications were assessed for quality of evidence by working groups of the panel, and a summary of findings was presented in tables. Recommendations were based on quality of evidence and were determined by a vote of the panel. RESULTS: Much of the evidence was of low to very low quality. Experimental studies frequently lacked adequate statistical power. There was moderate to high quality evidence that EIPH is progressive, is associated with lung lesions, that it adversely affects racing performance, that severe EIPH (Grade 4) is associated with a shorter career duration, that furosemide is efficacious in decreasing the incidence and severity of EIPH, and that administration of furosemide is associated with superior race performance. CONCLUSIONS AND CLINICAL SIGNIFICANCE: Strong recommendation that EIPH be considered a disease and a weak recommendation for use of furosemide in management of racehorses with EIPH.

Effects of added chelated trace minerals, organic selenium, yeast culture, direct-fed microbials, and Yucca schidigera extract in horses. Part I: Blood nutrient concentration and digestibility.

The objective of this study was to test the hypothesis that feed additives such as chelated minerals, organic Se, yeast culture, direct-fed microbials, and Yucca schidigera extract would improve nutrient digestibility when included in an equine diet. Horses (Quarter Horse geldings 4.5 to 16 yr of age; mean BW 522 kg ± 46 kg) were acclimated to 100% pelleted diets formulated with (ADD) and without (CTRL) commercially available sources of the aforementioned additives followed by a 14-d collection period of feces and urine. Chelated sources of Cu, Zn, Mn and Co were utilized versus sulfated forms, at a 100% replacement rate. No significant differences among apparent the digestibility of DM, ADF, or NDF (P= 0.665, P = 0.866, P = 0.747, respectively) were detected between dietary treatments. Likewise, no differences in apparent digestibility of Cu (P = 0.724), Zn (P = 0.256), Mn (P = 0.888), Co (P = 0.71), or Se (P = 0.588) were observed. No differences were observed in serum Cu, Mn, or Co concentrations between ADD and CTRL at acclimation or collection time points (P > 0.05). While no difference in serum Zn concentrations were observed between ADD and CTRL groups at acclimation (P > 0.05), they were statistically higher at the collection time period for horses consuming CTRL (P < 0.0001). Whole blood Se concentration was greater in the CTRL group versus the ADD group both at acclimation (P = 0.041) and collection (P = 0.005) time periods. In reference to time, serum Cu concentrations increased (P = 0.012) for animals consuming CTRL, but not ADD (P > 0.05). Serum Zn concentrations of horses consuming both ADD (P = 0.021) and CTRL (P < 0.0001) increased over time from acclimation to collection time points. No time differences (P > 0.05) were observed in serum Mn concentrations. Serum Co concentrations increased over time in horses consuming both ADD (P = 0.001) and CTRL (P = 0.021). From acclimation to collection, whole blood Se concentration increased for horses consuming CTRL (P = 0.01) but not for ADD (P > 0.05). The results of this study indicate no effect on nutrient digestibility due to the inclusion of chelated minerals, organic Se, yeast culture, direct-fed microbials, and Yucca schidigera extract for horses at maintenance.

Effects of added chelated trace minerals, organic selenium, yeast culture, direct-fed microbials, and Yucca schidigera extract in horses: II. Nutrient excretion and potential environmental impact.

The objective of this study was to test the hypothesis that an equine diet formulated with chelated trace minerals, organic selenium, yeast culture, direct-fed microbials (DFM) and Yucca schidigera extract would decrease excretion of nutrients that have potential for environmental impact. Horses were acclimated to 100% pelleted diets formulated with (ADD) and without (CTRL) the aforementioned additives. Chelated sources of Cu, Zn, Mn, and Co were included in the ADD diet at a 100% replacement rate of sulfate forms used in the CTRL diet. Additionally, the ADD diet included organic selenium yeast, DFM, and Yucca schidigera extract. Ten horses were fed the 2 experimental diets during two 42-d periods in a crossover design. Total fecal and urine collection occurred during the last 14 d of each period. Results indicate no significant differences between Cu, Zn, Mn, and Co concentrations excreted via urine (P > 0.05) due to dietary treatment. There was no difference between fecal Cu and Mn concentrations (P > 0.05) based on diet consumed. Mean fecal Zn and Co concentrations excreted by horses consuming ADD were greater than CTRL (P < 0.003). Differences due to diet were found for selenium fecal (P < 0.0001) and urine (P < 0.0001) excretions, with decreased concentrations found for horses consuming organic selenium yeast (ADD). In contrast, fecal K (%) was greater (P = 0.0421) for horses consuming ADD, whereas concentrations of fecal solids, total N, ammonia N, P, total ammonia, and fecal output did not differ between dietary treatments (P > 0.05). In feces stockpiled to simulate a crude composting method, no differences (P > 0.05) due to diet were detected for particle size, temperature, moisture, OM, total N, P, phosphate, K, moisture, potash, or ammonia N (P > 0.05). Although no difference (P = 0.2737) in feces stockpile temperature due to diet was found, temperature differences over time were documented (P < 0.0001). In conclusion, the addition of certain chelated mineral sources, organic Se yeast, DFM, and Yucca schidigera extract did not decrease most nutrient concentrations excreted. Horses consuming organic selenium as part of the additive diet had lower fecal and urine Se concentrations, as well as greater fecal K concentrations.

Effect of sodium bisulfate on skin and hooves of horses.

OBJECTIVE: To evaluate the safety of sodium bisulfate for use in horse barn environments by determining its irritant effect on skin and hooves. ANIMALS: 6 female mixed-breed ponies. PROCEDURE: Sodium bisulfate was applied to clipped intact skin of 6 ponies to evaluate its irritant effect after single (48 hours) and repetitive (6 h/d for 10 days) applications; similar areas of skin were used as untreated control sites. In addition, sodium bisulfate was applied to the sole of both front hooves of each pony and covered with wet gauze, and the entire hoof was covered with adhesive tape for 48 hours. RESULTS: Contact with moistened sodium bisulfate for 48 hours had no effect on pony skin. Contact with sodium bisulfate for 6 hours on 10 consecutive days did not cause gross changes but did cause mild to moderate microscopic changes including epidermal necrosis, hyperkeratosis, capillary congestion, edema, and diffuse mixed inflammatory cell infiltrate. All changes were limited to the epidermis and superficial dermis. Gross changes in hoof sole, signs of lameness, and increase in digital pulse pressure or pulse intensity were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Duration of contact with sodium bisulfate in this study was in excess of that expected under typical husbandry conditions. Despite this fact, gross changes in skin and hooves were not detected. Microscopic lesions were confined to the epidermis and superficial dermis. Results suggest that contact with sodium bisulfate under these conditions is safe.

Effect of daily floor treatment with sodium bisulfate on the fly population of horse stalls.

OBJECTIVE: To determine application rate and effectiveness of sodium bisulfate to decrease the fly population in a horse barn environment. SAMPLE POPULATION: 12 privately owned farms in southeastern Pennsylvania. PROCEDURE: Application rates of sodium bisulfate were approximately 2.3 kg/stall, 1.1 kg/stall, and 0.5 kg/stall. Two or 3 stalls were treated, and 1 or 2 stalls were not treated (control stalls) at each farm. Farm personnel applied sodium bisulfate in treated stalls daily for 7 days. Fly tapes were hung from the same site in treated and control stalls. After 24 hours, the fly tape was removed, flies adhering to the sticky surface were counted and recorded, and a new fly tape was hung. This procedure was repeated daily during each of the testing periods. RESULTS: Following the application of 2.3 kg of sodium bisulfate/stall, the numbers of flies collected on the fly tape were significantly decreased in treated stalls, compared with control stalls during the same time periods on 9 of the 12 farms evaluated. Following the application of 1.1 kg of sodium bisulfate/stall, fly numbers were significantly decreased in treated stalls on 6 of the 9 farms evaluated. Following the application of 0.5 kg of sodium bisulfate/stall, fly numbers were significantly decreased in the treated stalls on 3 of the 4 farms evaluated. CONCLUSIONS AND CLINICAL RELEVANCE: Our findings suggest that sodium bisulfate would be effective for fly control in horse barns.

Differences in total protein concentration, nucleated cell count, and red blood cell count among sequential samples of cerebrospinal fluid from horses.

OBJECTIVE: To examine total protein concentration and cell counts of sequentially collected samples of CSF to determine whether blood contamination decreases in subsequent samples and whether formulas used to correct nucleated cell count and total protein concentration are accurate. DESIGN: Case series. ANIMALS: 22 horses. PROCEDURE: For each horse, 3 or 4 sequential 2-ml samples of CSF were collected from the subarachnoid space in the lumbosacral region into separate syringes, and blood was obtained from the jugular vein. Total protein concentration, nucleated cell count, and RBC counts were determined in all samples. RESULTS: Among 3 sequential samples, total protein concentration and RBC count were significantly lower in samples 2 and 3, compared with sample 1. Nucleated cell count was significantly lower in sample 3, compared with sample 1. Among 4 sequential samples, total protein concentration and RBC count were significantly lower in samples 2, 3, and 4, compared with sample 1. Nucleated cell count was significantly lower in samples 3 and 4, compared with sample 1. For 3 correction formulas, significant differences in corrected values for nucleated cell count and total protein concentration were detected between sample 1 and sample 3 or 4. CONCLUSIONS AND CLINICAL RELEVANCE: Because iatrogenic blood contamination decreases in sequential CSF samples, a minimum of 3 samples should be collected before submitting the final sample for analysis. Formulas to correct nucleated cell count and total protein concentration are inaccurate and should not be used to correct for blood contamination in CSF samples.

Pneumothorax in horses: 40 cases (1980-1997).

OBJECTIVE: To characterize pneumothorax in horses and to describe clinical signs, diagnostic testing, and clinical outcome of horses with pneumothorax. DESIGN: Retrospective study. ANIMALS: 40 horses. PROCEDURE: Medical records of horses with pneumothorax were reviewed to obtain information on signalment, history, clinical signs, diagnostic testing, treatment, and clinical outcome. RESULTS: Horses developed pneumothorax secondary to pleuropneumonia (17 horses), open wounds of the thorax (9), closed trauma to the thorax (7), surgery on the upper portion of the respiratory tract (3), and surgery involving the thoracic cavity (1); 3 horses had pneumothorax of unknown cause. Clinical signs included tachypnea, dyspnea, cyanosis, lack of lung sounds on auscultation of the dorsal aspect of the thorax, fever, tachycardia, signs of depression or anxiousness, and cough. Radiography and ultrasonography were useful to definitively diagnose pneumothorax. Pneumothorax was bilateral in 47.5% (19/40) and unilateral in 42.5% (17/40) of horses; designation of unilateral versus bilateral was not recorded in the remaining 4 horses. Horses with pneumothorax secondary to pleuropneumonia more commonly had unilateral pneumothorax (64.7% for unilateral vs 29.4% for bilateral; not specified for 1 horse). Horses with pneumothorax secondary to pleuropneumonia were less likely to survive than horses with pneumothorax secondary to other causes (35.3 vs 69.6% survived, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Pleuropneumonia is an important cause of pneumothorax in horses. Classic clinical signs of pneumothorax may not be evident. Radiography, ultrasonography, or both may be required for diagnosis. Prognosis for survival is better for horses with pneumothorax not associated with pleuropneumonia.

Effects of pulmonary abscesses on racing performance of horses treated at referral veterinary medical teaching hospitals: 45 cases (1985-1997).

OBJECTIVE: To determine whether results of physical or radiographic examination or biochemical analyses in adult racehorses with primary lung abscesses were associated with ability to race following treatment. DESIGN: Multiple-center retrospective study. ANIMALS: 25 Standardbreds and 20 Thoroughbreds. PROCEDURE: Medical records of horses with a primary lung abscess that were admitted to any of 4 veterinary teaching hospitals were reviewed. Results of physical examination, laboratory testing, and thoracic radiography were reviewed. Racing performance after treatment was compared with performance before illness and with performance of the general population of racehorses of similar age, sex, and breed. RESULTS: 23 of 25 Standardbreds and 13 of 20 Thoroughbreds raced after diagnosis and treatment of a lung abscess. Most horses had a solitary abscess in the dorsal to caudodorsal lung fields. Results of initial physical examination, biochemical analyses, and culture and identification of the microbial isolate were not associated with whether a horse returned to racing. For horses that had raced prior to the illness, race performance after treatment of the lung abscess was not significantly different from performance before the illness. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of racing performance in those horses that resumed racing after treatment, long-term residual lung damage did not develop in horses with primary lung abscesses that were treated appropriately. It is not known whether horses that recovered would be more likely to bleed from the site of a prior infection when resuming strenuous exercise and whether lung abscesses contributed to a failure to resume racing.

Effects of blood contamination of cerebrospinal fluid on western blot analysis for detection of antibodies against Sarcocystis neurona and on albumin quotient and immunoglobulin G index in horses.

OBJECTIVE: To determine effects of blood contamination on western blot (WB) analysis of CSF samples for detection of anti-Sarcocystis neurona antibodies, and on CSF albumin and IgG concentrations, albumin quotient (AQ), and IgG index in horses. DESIGN: Prospective in vitro study. SAMPLES: Blood with various degrees of immunoreactivity against S neurona was collected from 12 healthy horses. Cerebrospinal fluid without immunoreactivity against S neurona was harvested from 4 recently euthanatized horses. PROCEDURE: Blood was serially diluted with pooled nonimmunoreactive CSF so that final dilutions corresponded to 10(-3) to 100 microliters of blood/ml CSF, and WB analysis was performed on contaminated CSF samples. Number of RBC, albumin and IgG concentrations, AQ, and IgG index were also determined. RESULTS: Antibodies against S neurona were detected in CSF contaminated with 10(-3) microliters of strongly immunoreactive blood/ml. In CSF samples contaminated with 10 microliters of blood/ml, AQ remained within reference range. Volume of blood required to increase IgG index varied among blood samples and was primarily influenced by serum IgG concentrations. Number of RBC in contaminated samples was correlated with volume of blood added, but not with degree of immunoreactivity detected in contaminated CSF samples. CONCLUSIONS AND CLINICAL RELEVANCE: During collection of CSF from horses, contamination with blood may introduce serum antibodies against S neurona at concentrations sufficient for detection by WB analysis, thus yielding false-positive results. When blood is moderately or strongly immunoreactive, the amount of contaminating albumin may be small enough as to not increase AQ above reference range. In these cases, AQ and IgG index should be interpreted with caution.

Pulmonary aspergillosis in horses: 29 cases (1974-1997).

OBJECTIVE: To analyze medical records and identify factors that veterinarians can use to prevent pulmonary aspergillosis in horses or that would enable them to diagnose it as early as possible. DESIGN: Retrospective study. ANIMALS: 29 horses. PROCEDURE: Medical records were reviewed for horses with pulmonary aspergillosis diagnosed on the basis of characteristic postmortem findings. Information on history, clinical signs, disease progression, and postmortem findings was obtained. RESULTS: 25 of 29 (86.2%) horses had primary (n = 20) or secondary (5) disease compatible with loss of integrity of the gastrointestinal (GI) tract. The remaining 4 horses had a non-GI tract disorder; only 1 of these 4 had clinical signs associated with the respiratory tract (i.e., pleuropneumonia). Although 22 (75.9%) horses had various signs of respiratory tract disorders, an antemortem diagnosis of Aspergillus pneumonia was made in only 1 horse and was suspected in only 1 other. Fungal organisms were seen histologically in tissues other than the lung in 12 (41.4%) horses. CLINICAL IMPLICATIONS: Horses with enteritis, colitis, typhlitis, or other diseases of the GI tract that result in mucosal compromise, and horses with clinical signs of respiratory tract disease, particularly if the horse's condition is unresponsive to treatment with antimicrobial agents; should be considered at high risk of having pulmonary aspergillosis. Immunosuppression from debilitating disease may also predispose horses to aspergillosis. Because invasive pulmonary aspergillosis can be difficult to diagnose, clinicians should be aware of clinical and epidemiologic settings in which this disease would develop.

A preliminary study of the effect of inhaled nitric oxide on lung mechanics in the standing horse with histamine-induced bronchoconstriction.

The effect of inhaled nitric oxide on pulmonary mechanics was studied in normal standing horses with histamine-induced bronchoconstriction. The respiratory health status of 6 normal horses was established on the basis of history, clinical and bronchoalveolar lavage examination. Intrathoracic pressures were estimated using distal oesophageal pressures. Respiratory gas flows were measured using a heated pneumotachograph. Pulmonary mechanics variables were determined from these measurements on a breath by breath basis. Bronchoconstriction was induced by nebulizing a 0.75% w/v solution of histamine over 5 min. Pulmonary function was assessed during 4 periods: 1) while breathing room air prior to histamine challenge; 2) 5 min post histamine challenge; 3) 10 min post histamine challenge and while breathing 5 ppm nitric oxide; and 4) 14 min post histamine challenge while breathing room air. Statistical analysis included Friedman's nonparametric repeated measures analysis of variance followed by Dunn's multiple comparisons tests, where appropriate. Criteria for demonstration of nitric oxide effect on pulmonary mechanics variables were taken as a return of the variable value following nitric oxide administration towards control value and subsequent restoration of the value toward post histamine levels with discontinuation of nitric oxide. Five variables (dynamic compliance, airway resistance, maximum developed pressure, work of breathing, and peak expiratory flow) had significant changes in response to histamine. Three variables (dynamic compliance, airway resistance, and maximum developed pressure) met the above criteria, but only dynamic compliance and airway resistance showed statistical significance (P < 0.05). These results suggest that nitric oxide partly dilates small airways constricted by histamine.

Herpesvirus myeloencephalopathy in horses: 11 cases (1982-1996).

OBJECTIVE: To determine results of CSF analysis in horses with equid herpesvirus myeloencephalopathy (EHM) and to determine whether results of CSF analysis were associated with outcome. DESIGN: Retrospective study. ANIMALS: 11 horses. PROCEDURE: Medical records of all horses admitted to the veterinary teaching hospital between February 1982 and March 1996 in which EHM was diagnosed were reviewed. RESULTS: 7 horses were < or = 4 years old; 8 were admitted during January, February, or March. Six horses were febrile prior to admission, but none was febrile on the day of admission. Five horses had been stabled with other horses that had clinical signs of neurologic disease. All horses had had an acute onset of hind limb ataxia and paresis. Cranial nerve deficits were detected in 3 horses. Cerebrospinal fluid samples were collected on the day of admission from 10 horses. Protein concentration was high in 8 horses; nucleated cell count was normal in 8. Protein concentration and nucleated cell and RBC counts were not significantly different between horses that survived and horses that were euthanatized. Six horses were euthanatized, and 5 survived. All of the horses that survived remained standing or were able to stand with minimal assistance. CLINICAL IMPLICATIONS: High CSF protein concentration and normal or only slightly high CSF nucleated cell count are common in horses with EHM; however, results of CSF analysis were not associated with outcome. Horses with EHM that become recumbent have a poor prognosis for survival.

Associations between physical examination, laboratory, and radiographic findings and outcome and subsequent racing performance of foals with Rhodococcus equi infection: 115 cases (1984-1992).

OBJECTIVE: To determine whether physical examination, laboratory, or radiographic abnormalities in foals with Rhodococcus equi infection were associated with survival, ability to race at least once after recovery, or, for foals that survived and went on to race, subsequent racing performance. DESIGN: Retrospective study. ANIMALS: 49 Thoroughbreds and 66 Standardbreds admitted to 1 of 6 veterinary teaching hospitals between 1984 and 1992 in which R equi infection was positively diagnosed. PROCEDURE: Results of physical examination, laboratory testing, and thoracic radiography were reviewed. Indices of racing performance were obtained for foals that recovered and eventually raced and compared with values for the US racing population. RESULTS: 83 (72%) foals survived. Foals that did not survive were more likely to have extreme tachycardia (heart rate > 100 beats/min), be in respiratory distress, and have severe radiographic abnormalities on thoracic radiographs at the time of initial examination than were foals that survived. Clinicopathologic abnormalities were not associated with whether foals did or did not survive. Forty-five of the 83 surviving foals (54%) eventually raced at least once, but none of the factors examined was associated with whether foals went on to race. Racing performance of foals that raced as adults was not significantly different from that of the US racing population. CLINICAL IMPLICATIONS: R equi infection in foals is associated with a decreased chance of racing as an adult; however, foals that eventually go on to race perform comparably to the US racing population.

Complications associated with use of a one-hole subpalpebral lavage system in horses: 150 cases (1977-1996).

OBJECTIVE: To determine type and frequency of complications associated with use of a one-hole subpalpebral lavage (SPL) system in horses. DESIGN: Retrospective study. ANIMALS: 150 horses with 156 SPL systems. PROCEDURE: Signalment, primary complaint, method used for placement, time SPL system was in place, and complications were retrieved from medical records. RESULTS: Complications were not associated with placement, maintenance, or removal of 66 of 156 (42%) SPL systems. A minor complication was reported in association with 53 (34%) SPL systems, and a serious complication was reported in association with 37 (24%). The 3 most common minor complications were mild swelling of the eyelid (31 horses), tearing of SPL system tubing (20), and loss of the injection cap (30). Serious complications included problems with the SPL system requiring its premature removal and possible replacement (26 horses), removal of the SPL system by the horse (6), infection of the eyelid (4), loss of the footplate in the eyelid (5), and cornea ulceration (1). CLINICAL IMPLICATIONS: Proper attention to the size of the footplate and placement of the SPL system in the eyelid should decrease the risk of serious complications. Minor eyelid swelling should be expected in the first 48 hours after SPL system placement.

Effect of sodium bisulfate on ammonia concentration, fly population, and manure pH in a horse barn.

OBJECTIVE: To evaluate the effectiveness of altering the pH of manure with sodium bisulfate, thereby decreasing ammonia concentration and fly population in a horse barn environment. ANIMALS: 4 mixed-breed pony stallions. PROCEDURE: The 4-week study was scheduled with 2 weeks of treatment (with 2 application rates) and 2 weeks with no treatment (control weeks). During treatment weeks, sodium bisulfate was applied daily to the top of the bedding and straw, then spread on top. Ponies were kept in the stalls 24 hours a day during the 7-day test period and stall cleaning was not done. On day 7 of each week, ammonia concentration, manure pH, number of flies on a fly tape, and fly-evasive behavior patterns were determined. RESULTS: Sodium bisulfate applied to the horse stall environment daily of either 2.3 or 4.5 kg/9.3 m2 (5 or 10lb/ 100 ft2) decreased ammonia concentration, manure pH, and number of flies in the stall environment, compared with a control period with no sodium bisulfate. Fly-evasive behavior patterns of ponies occupying the stalls, including tail swishes, head tosses, and kicks/strikes, were decreased during the period of sodium bisulfate application. CONCLUSION: Sodium bisulfate may be an effective method of decreasing ammonia concentration and may serve as a method of fly control in horse barns.

Topical treatment of Pseudomonas sp-infected corneal ulcers in horses: 70 cases (1977-1994).

OBJECTIVE: To determine which antimicrobial agents were most effective against Pseudomonas sp-infected ulcerative keratitis, and identify any trends in the various clinical conditions associated with these bacteria that might assist in effective treatment of the disease. DESIGN: Retrospective case series. ANIMALS: 66 horses with 70 Pseudomonas sp-infected corneal ulcers. PROCEDURE: We reviewed medical records of horses admitted to the George D. Widener Hospital for Large Animals, University of Pennsylvania between July 1977 and December 1994. Records of horses that had Pseudomonas sp isolated from a corneal ulcer scraping or deep swab were included in the study. RESULTS: Aggressive topical medical treatment was successful in 57 ulcers and most likely would have been effective in 5 additional ulcers. Antimicrobial susceptibility testing indicated susceptibilities of 87, 85, and 93% to tobramycin, gentamicin, and amikacin, respectively. Although concurrent fungal infections were identified in only 2 of 35 ulcers examined, almost three fourths of the ulcers were treated with antifungal medications prophylactically. Clinical outcomes of the 70 affected eyes included: excellent vision with minimal leukoma, 73%; enucleation, 19%; blind phthisical eye, 4%; peripheral vision only, 3%; and euthanasia of newborn, 1%. CLINICAL IMPLICATIONS: Aggressive topical medication with microbial agents effective against Pseudomonas sp can result in excellent vision with minimal leukoma in most horses with corneal ulcers.

Effect of prior lavage on bronchoalveolar lavage fluid cell population of lavaged and unlavaged lung segments in horses.

Bronchoalveolar lavage (BAL) was performed on 16 horses to determine whether it caused local or diffuse inflammation in the lungs. In 7 horses, BAL was performed in both lungs twice, 48 hours apart. Although total cell counts of the BAL samples did not change significantly, there were increased numbers and percentage of neutrophils in the second lavage fluid samples. In 5 horses, BAL was performed in 1 lung and repeated 48 hours later in the same lung and in the corresponding airway in the contralateral lung. The absolute cell count and percentage of neutrophils were significantly (P = < 0.05) increased in the second sample from the lung that was lavaged twice. In 4 horses, BAL was performed in 1 lung and 48 hours later, repeated in an adjacent airway to the first BAL site, and in the corresponding airway in the contralateral lung. Significant differences were not detected in the total or differential cell counts of the BAL fluid recovered at any time, except for an increase in neutrophil percentage in the second sample in the contralateral lung. The increased neutrophil percentage values were within the range of normal for healthy horses. Results of the study suggested that, in horses, BAL induces a localized pulmonary neutrophil influx that persists at least 48 hours and is characterized by a relative and absolute increase in the number of neutrophils in the lavage fluids. and has been shown to be a safe technique with cytologic results that correlate well with histopathologic lesions in horses. Subsequently the technique has been used to collect large numbers of pulmonary cells for study.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of a bovine hemoglobin preparation in the treatment of cyclic ovarian hemorrhage in a miniature horse.

Anemia that was secondary to ovarian hemorrhage in a 4-year-old miniature horse mare was treated prior to laparotomy with polymerized ultrapurified bovine hemoglobin (PUBH). Two previous whole-blood transfusions had resulted in acute transfusion reaction, and a suitable blood donor could not be found among 9 horses, necessitating use of the blood substitute. Subsequent blood typing revealed the mare to be Aa-negative, with allo-antibodies against Aa in serum. Serious adverse reactions were not observed after infusion of PUBH, and the mare recovered. Although the safety and efficacy of using PUBH in horses has not been established, PUBH may prove to be an excellent alternative to whole-blood transfusions, when indicated.

Unusual internal carotid artery branching that prevented arterial occlusion with a balloon-tipped catheter in a horse.

A mare with hemorrhage caused by guttural pouch mycosis was treated by insertion of a balloon-tipped catheter into the left internal carotid artery. During recovery from general anesthesia, the mare had profuse epistaxis, and was anesthetized again to determine the site of hemorrhage. The affected guttural pouch was opened to confirm that hemorrhage was from the left internal carotid artery. The mare was euthanatized, and, at necropsy, the balloon catheter was found in an aberrant branch that arose from the internal carotid artery and joined the basilar artery. The mycotic plaque was on the left internal carotid artery, distal to the origin of the aberrant branch, so that the balloon did not obstruct retrograde flow through the infected segment. Additional dissection of the internal carotid artery before insertion of a balloon catheter is recommended to identify any aberrant branches. Ligation of aberrant branches at their bifurcation with the internal carotid artery is recommended to prevent both inadvertent catheterization and retrograde flow from the cerebral arterial circle.

Hemorrhage into the guttural pouch (auditory tube diverticulum) associated with rupture of the longus capitis muscle in three horses.

Three horses were determined to have hemorrhage into a guttural pouch unassociated with mycosis, empyema, neoplasia, or foreign body. The source of the hemorrhage appeared to be the rupture of the longus capitis muscle and its associated vascular supply.