Showing papers in "American Journal of Veterinary Research in 2000"
TL;DR: Epidural administration of opioids may provide long-lasting analgesia in horses without excitation of the CNS, and tramadol and morphine significantly increased threshold and analgesic effects.
Abstract: Objective—To evaluate and compare effects of epidurally administered morphine, alfentanil, butorphanol, tramadol, and U50488H on avoidance threshold to noxious electrical stimulation over the dermatomes of the perineal, sacral, lumbar, and thoracic regions in horses. Animals—5 healthy adult horses. Procedure—Using a Latin square complete repeatedmeasures design, horses were randomly assigned to receive 1 of 6 treatments (morphine, alfentanil, butorphanol, tramadol, U50488H, or sterile water) at intervals of at least 7 days. Agents were injected epidurally at the first intercoccygeal epidural space, and electrical stimulation was applied at repeated intervals for 24 hours to the dermatomes of the perineal, sacral, lumbar, and thoracic regions. Avoidance threshold to electrical stimulation was recorded. Results—Administration of butorphanol, U50488H, and sterile water did not induce change in avoidance threshold. Alfentanil increased avoidance threshold during the first 4 hours, but not significantly. Trama...
172 citations
TL;DR: Concentrations of acetic, propionic, and isovaleric acid were significantly higher in gastric juice, and number and severity of nonglandular squamous gastric lesions were significantly lower in horses fed alfalfa hay-grain, whereas valeric acid concentrations and butyric acid were useful in predicting severity of those lesions in Horses fed bromegrass hay.
Abstract: Objective—To measure pH, volatile fatty acid (VFA) concentrations, and lactate concentrations in stomach contents and determine number and severity of gastric lesions in horses fed bromegrass hay and alfalfa hay-grain diets. Animals—Six 7-year-old horses. Procedure—A gastric cannula was inserted in each horse. Horses were fed each diet, using a randomized crossover design. Stomach contents were collected immediately after feeding and 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, and 24 hours after feeding on day 14. The pH and VFA and lactate concentrations were measured in gastric juice. Number and severity of gastric lesions were scored during endoscopic examinations. Results—The alfalfa hay-grain diet caused significantly higher pH in gastric juice during the first 5 hours after feeding, compared with that for bromegrass hay. Concentrations of acetic, propionic, and isovaleric acid were significantly higher in gastric juice, and number and severity of nonglandular squamous gastric lesions were significantly lower in...
165 citations
TL;DR: Vaccination against M hyopneumoniae induced local, mucosal, humoral, and cellular immune responses, and reduced the severity of lung lesions in challenged pigs, suggesting that mucosal antibodies, mediation of the inflammatory response, and cell-mediated immune responses are important for control of mycoplasmal pneumonia in pigs.
Abstract: Objective—To evaluate immune responses induced by administration of Mycoplasma hyopneumoniae bacterin to pigs. Animals—60 healthy 7- to 10-day-old cross-bred boars. Procedure—Pigs were assigned to 1 of 4 pig groups (15 pigs/group): vaccinated, challenged; vaccinated, nonchallenged; nonvaccinated, challenged; nonvaccinated, nonchallenged. Vaccinated pigs received IM injections of a mycoplasma bacterin on days 0 and 14, whereas nonvaccinated pigs received saline (0.9% NaCl) solution. Pigs in the challenged groups were inoculated intratracheally with M hyopneumoniae on day 42. Pigs were euthanatized and necropsied 41, 44, 48, and 70 days after the first vaccination, and proportion of lung surface with pneumonic lesions was determined. Percentage of lymphocyte subpopulations and number of interferon-γ (IFN-γ) secreting lymphocytes in blood and tissues, cytokine and antibody concentrations in bronchoalveolar lavage (BAL) fluid, and serum antibody concentrations were determined. Results—Vaccination against and ...
160 citations
TL;DR: It is suggested that apparent differences in the trotting gait between Labrador Retrievers and Greyhounds are mainly attributable to differences in size, and that dogs of these 2 breeds move in a dynamically similar manner at the trots.
Abstract: Objective—To compare the trotting gaits of Labrador Retrievers and Greyhounds to determine whether differences in locomotion are attributable to differences in their manner of moving or to body size and shape differences between these 2 breeds. Animals—8 healthy 5-month-old Greyhounds and 5 healthy Labrador Retrievers between 6 and 18 months old. Procedure—A series of 4 force platforms was used to record independent ground reaction forces on the forelimbs and hind limbs during trotting. Values of stride parameters were compared between breeds before and after normalization for size differences. Standard values of absolute and normalized stride period and stride length were determined from linear regressions of these parameters on relative (normalized) velocity. Forces were normalized to body weight and compared at the same relative velocity. Results—Greyhounds used fewer, longer strides than the Labrador Retrievers to travel at the same absolute speed. After normalization for body size differences, most m...
145 citations
TL;DR: Results suggest that TGF-beta1 enhances chondrogenic differentiation of bone marrow-derived MSC in a dose-dependent manner and leads to dose-related increases in area and intensity of type-II collagen immunoreaction.
Abstract: Objective To determine the morphologic and phenotypic effects of transforming growth factor beta1 (TGFbeta1) on cultured equine mesenchymal stem cells (MSC) and articular chondrocytes. Sample population Bone marrow aspirates and articular cartilage samples from a 2-year-old and two 8-month-old horses. Procedure After initial isolation and culture, MSC and chondrocytes were cultured in Ham's F-12 medium supplemented with TGF-beta1 at a concentration of 0, 1, 5, or 10 ng/ml. Medium was exchanged on day 2, and cells were harvested on day 4. Medium was assayed for proteoglycan (PG) content. Total RNA was isolated from cell cultures, and expression of aggrecan, decrin, collagen type-I, and collagen type-II mRNA was assessed by means of Northern blot analyses. Cell cultures were stained with H&E or toluidine blue and examined histologically. Additional cultures were examined after immunohistochemical staining for type-I and -II collagen. Results MSC cultures exposed to TGF-beta1 had an increased cellular density with cell layering and nodule formation that was most pronounced in cultures treated with 5 ng of TGF-beta1/ml. Expression of collagen type-II mRNA in MSC cultures exposed to 5 ng of TGF-beta1/ml was 1.7 times expression in control cultures, and expression of collagen type-I mRNA was 2.8 times expression in control cultures. Treatment of MSC with TGF-beta1 led to dose-related increases in area and intensity of type-II collagen immunoreaction. Conclusion Results suggest that TGF-beta1 enhances chondrogenic differentiation of bone marrow-derived MSC in a dose-dependent manner.
145 citations
TL;DR: This direct measurement method provides 3-dimensional kinematic data for flexion-extension, lateral bending, and axial rotation of the thoracolumbar portion of the vertebral column of horses walking on a treadmill.
Abstract: Objective—To determine movements of the vertebral column of horses during normal locomotion. Animals—5 young Dutch Warmblood horses that did not have signs of back problems or lameness. Procedure—Kinematics of 8 vertebrae (T6, T10, T13, T17, L1, L3, L5, and S3) and both tuber coxae were determined, using bone-fixated markers. Measurements were recorded when the horses were trotting on a treadmill at a constant speed of 4.0 m/s. Results—Flexion-extension and axial rotation were characterized by a double sinusoidal pattern of motion during 1 stride cycle, whereas lateral bending was characterized by 1 peak and 1 trough. Ranges of motion for all vertebrae were: flexion-extension, 2.8o to 4.9o; lateral bending, 1.9° to 3.6°; axial rotation, 4.6° to 5.8°, except for T10 and T13, where the amount of axial rotation decreased to 3.1° and 3.3°, respectively. Conclusion and Clinical Relevance—During locomotion, 3 types of rotations are evident in the thoracolumbar vertebrae. Regional differences are observed in the...
142 citations
TL;DR: Lack of expression of COX-2 in normal bladder epithelium and its substantial expression in transitional cell carcinoma cells suggest that this isoform may be involved in tumor cell growth.
Abstract: Objective—To evaluate expression of cyclooxygenase (COX)-1 and COX-2 in the urinary bladder epithelium of clinically normal dogs and in transitional cell carcinoma cells of dogs. Animals—21 dogs with transitional cell carcinoma of the urinary bladder and 8 dogs with clinically normal urinary bladders. Procedure—COX-1 and COX-2 were evaluated by use of isoform-specific antibodies with standard immunohistochemical methods. Results—COX-1, but not COX-2, was constitutively expressed in normal urinary bladder epithelium; however, COX-2 was expressed in neoplastic epithelium in primary tumors and in metastatic lesions of all 21 dogs and in new proliferating blood vessels in 3 dogs. Also, COX-1 was expressed in the neoplastic cells. Conclusions and Clinical Relevance—Lack of expression of COX-2 in normal bladder epithelium and its substantial expression in transitional cell carcinoma cells suggest that this isoform may be involved in tumor cell growth. Inhibition of COX-2 is a likely mechanism of the antineoplas...
141 citations
TL;DR: Computed tomography and computed tomographic osteoabsorptiometry were superior to conventional radiography for detecting small osteochondral fragments and nuclear scintigraphy was a sensitive indicator of subchondral bone change but lacked specificity for describing lesions and discerning normal bone remodeling from damage.
Abstract: Objective—To determine effects of treadmill exercise on subchondral bone of carpal and metacarpophalangeal joints of 2-year-old horses. Animals—12 healthy 2-year-old horses. Procedure—Horses were randomly assigned to the control (n = 6) or exercised (6) groups. Horses in the exercised group ran on a high-speed treadmill 5 d/wk for 6 months. Horses in the control group were hand walked for the same amount of time. Results of clinical, radiographic, nuclear scintigraphic, and computed tomographic examinations, and serum and synovial concentrations of biochemical markers of bone metabolism were compared between groups. Results—Exercised horses were significantly lamer at the end of the study than control horses. Radionuclide uptake in the metacarpal condyles, but not in the carpal joints, was greater in exercised horses, compared with control horses. Exercised horses also had a higher subchondral bone density in the metacarpal condyles than control horses, but such differences were not detected in the carpal...
136 citations
TL;DR: The early immunoglobulin repertoire of neonatal foals comprised IgGa, IgG(T), and IgA; endogenous synthesis of IgGb could not be detected until 63 days after birth; the restricted repertoire of immunoglOBulins in foals may influence humoral immune responses to vaccination.
Abstract: Objective—To determine concentrations of IgA and IgG subclasses in serum, colostrum, milk, and nasal wash samples of adult horses and foals. Animals—Seven 2-year-old Welsh ponies, 27 adult mixed-breed horses, and 5 Quarter Horse mares and their foals. Procedure—Serum was obtained from ponies and adult horses. Colostrum and milk were obtained from mares and serum and nasal wash samples from their foals immediately after parturition and on days 1, 7, 14, 28, 42, and 63. Nasal wash samples were also obtained from 23 adult horses. Concentrations of immunoglobulins were determined by use of inhibition ELISA. To determine transfer of maternal isotypes to foals, concentrations in colostrum and milk were compared with those in foal serum. Serum half-lives of isotypes in foals were also determined. Results—IgGb was the most abundant isotype in serum and colostrum from adult horses, whereas IgA was the predominant isotype in milk. The major isotype in nasal secretions of adult horses and foals ≥ 28 days old was IgA...
135 citations
TL;DR: Selective COX-2 inhibitors are a new class of drugs with anti-inflammatory effects similar to conventional NSAID but with fewer adverse effects and development of these agents for veterinary use would be facilitated by the convenience of using a canine cell line as a model system to screen COx-1 and COZ-2 inhibitor activities in vitro.
Abstract: Objective—To establish an in vitro assay and determine the differential suppressive activity of non steroidal anti-inflammatory drugs (NSAID) on cyclooxygenase (COX)-1 and COX-2 isoenzymes in dogs. Procedure—COX activity was evaluated in the presence and absence of 4 NSAID (meloxicam, tolfenamic acid, carprofen, and ketoprofen), using a canine monocyte/macrophage cell line that constitutively expresses COX-1, but can be induced to express COX-2 when incubated with lipopolysaccharide. Inhibition of prostaglandin E2 (PGE2) synthesis by each NSAID was measured by enzyme immunoassay and attributed to specific COX-1 or COX-2 activity through assessment of COX messenger RNA expression by use of northern blot analysis and reverse transcription- polymerase chain reaction (RT-PCR). The COX selectivity of each drug was evaluated from dose-response curves by calculating a ratio (COX- 1:COX-2) of inhibitory concentration values on the basis of concentrations that reduced PGE2 by 50% in each COX model. Results—Meloxic...
134 citations
TL;DR: The results indicate that lithium dilution is a suitable method for measuring cardiac output in horses as well as being accurate, it avoids the need for pulmonary artery catheterization and is quick and safe to use.
Abstract: Objective—To assess the suitability of lithium dilution as a method for measuring cardiac output in anesthetized horses, compared with thermodilution and transesophageal Doppler echocardiography. Animals—6 horses (3 Thoroughbreds, 3 crossbreeds). Procedure—Cardiac output was measured in 6 anesthetized horses as lithium dilution cardiac output (LiDCO), thermodilution cardiac output (TDCO), and transesophageal Doppler echocardiographic cardiac output (DopplerCO). For the LiDCO measurements, lithium chloride was administered IV, and cardiac output was derived from the arterial lithium dilution curve. Sodium nitroprusside, phenylephrine hydrochloride, and dobutamine hydrochloride were used to alter cardiac output. Experiments were divided into 4 periods. During each period, 3 LiDCO measurements, 3 DopplerCO measurements, and 3 sets of 3 TDCO measurements were obtained. Results—70 comparisons were made between LiDCO, DopplerCO, and triplicate TDCO measurements over a range of 10 to 43 L/min. The mean (± SD) of...
TL;DR: Exposure of horses with COPD to hay dust components resulted in an increase in IL-8 secretion at the bronchoalveolar surface, which may play a role in the pathogenesis of COPD.
Abstract: Objective—To analyze effects of hay dust exposure on interleukin-8 (IL-8) concentration, percentage of neutrophils, and neutrophil chemotactic activity in bronchoalveolar lavage fluid (BALF) of hor...
TL;DR: It is demonstrated that repetitive endurance exercise in dogs is associated with lipid peroxidation and a reduction in plasma antioxidant concentrations, indicating that the antioxidant mechanisms of minimally trained dogs may, in some instances, be inadequate to meet the antioxidant requirements of repetitive endurance Exercise.
Abstract: Objective—To determine whether repetitive endurance exercise in sled dogs was associated with substantial lipid peroxidation, decreases in antioxidant capacity of the serum, and skeletal muscle damage. Animals—24 lightly trained sled dogs. Procedure—16 dogs completed a 58-km run on each of 3 consecutive days; the other 8 dogs (control) did not exercise during the study. Blood samples were collected before the first exercise run and after the first and third exercise runs. Plasma isoprostane and serum vitamin E concentrations, total antioxidant status of plasma, and serum creatine kinase activity were measured. Results—Plasma isoprostane concentrations in dogs in the exercise group were significantly increased after the first exercise run and further significantly increased after the third exercise run. Serum vitamin E concentration was significantly decreased after the first exercise run in dogs in the exercise group, and this change persisted after the third exercise run. There was a significant linear relationship between plasma isoprostane concentration and the logarithm of serum creatine kinase activity (adjusted r 2 = 0.84). Conclusions and Clinical Relevance—Results demonstrate that repetitive endurance exercise in dogs is associated with lipid peroxidation and a reduction in plasma antioxidant concentrations. We interpret these results as indicating that the antioxidant mechanisms of minimally trained dogs may, in some instances, be inadequate to meet the antioxidant requirements of repetitive endurance exercise. (Am J Vet Res 2000;61:512–517)
TL;DR: In cats, transdermal administration provides sustained plasma concentrations of fentanyl citrate throughout a 5-day period and has potential for use in cats for long-term control of pain after surgery or chronic pain associated with cancer.
Abstract: Objective—To compare pharmacokinetic and pharmacodynamic characteristics of fentanyl citrate after IV or transdermal administration in cats. Animals—6 healthy adult cats with a mean weight of 3.78 kg. Procedure—Each cat was given fentanyl IV (25 mg/cat; mean ± SD dosage, 7.19 ± 1.17 mg/kg of body weight) and via a transdermal patch (25 µg of fentanyl/h). Plasma concentrations of fentanyl were measured by use of radioimmunoassay. Pharmacokinetic analyses of plasma drug concentrations were conducted, using an automated curvestripping process followed by nonlinear, leastsquares regression. Transdermal delivery of drug was calculated by use of IV pharmacokinetic data. Results—Plasma concentrations of fentanyl given IV decreased rapidly (mean elimination half-life, 2.35 ± 0.57 hours). Mean ± SEM calculated rate of transdermal delivery of fentanyl was 8.48 ± 1.7 mg/h (< 36% of the theoretical 25 mg/h). Median steadystate concentration of fentanyl 12 to 100 hours after application of the transdermal patch was 1....
TL;DR: Reduced GR expression in blood neutrophils of periparturient dairy cows was associated with increased serum cortisol concentrations, leukocytosis, and neutrophilia, and may cause increased susceptibility to mastitis.
Abstract: Objective —To determine effects of parturition on glu cocorticoid receptor (GR) expression in neutrophils , serum cortisol concentration, and total blood leukocyte and neutrophil counts in periparturient dairy cows . Animals —23 Holstein cows . Procedure —Blood samples were collected from 8 multiparous and 5 primiparous periparturient cows a t various times from 28 days before parturition until 14 days after parturition. Glucocorticoid receptor expres sion in neutrophils, serum cortisol concentration, and total blood leukocyte and neutrophil counts were determined. Results were compared with results from control samples obtained from 5 multiparous and 5 primiparous Holstein cows in midpregnancy. Results —Neutrophils from periparturient cows had 49% reduction in GR expression at calving, compared with GR expression 2 to 4 weeks before calving, and 39% reduction, compared with neutrophils from cows in midpregnancy. Reduction in neutrophil GR expres sion began 1 week before calving and was most severe at calving and 24 hours after calving; a significant diffe r ence in GR expression was detected between primip arous and multiparous cows. Serum cortisol concentra tions and total leukocyte and neutrophil counts were significantly increased at calving and returned to base line values by 24 hours after calving. Significant nega tive correlations were detected between neutrophil GR expression and serum cortisol concentration, tota l leukocyte count, and neutrophil count . Conclusions and Clinical Relevance —Reduced GR expression in blood neutrophils of periparturient dairy cows was associated with increased serum cortiso l concentrations, leukocytosis, and neutrophilia. Thus , GR down-regulation in neutrophils may be involved in periparturient neutrophil dysregulation and may cause increased susceptibility to mastitis. (Am J Vet Res 2000;61:14–19)
TL;DR: A decrease in T-cell responses to mitogens or MpS was observed in cows clinically infected with M paratuberculosis, compared with subclinically infected cows, suggesting that activated T cells may delay the progression of paratubculosis.
Abstract: Objective—To compare cytokine secretion patterns of peripheral blood mononuclear cells (PBMC) from healthy cows and cows subclinically and clinically infected with Mycobacterium paratuberculosis. Animals—5 noninfected cows, 6 cows with subclinical paratuberculosis, and 4 cows with clinical paratuberculosis. Procedure—PBMC were isolated, and concentrations or activities of secreted interleukin (IL)-1, IL-2, IL- 6, tumor necrosis factor (TNF), and interferon−γ (IFN-γ) were measured after in vitro stimulation of cells with concanavalin A (ConA), lipopolysaccharide (LPS), or a whole-cell sonicate of M paratuberculosis (MpS). Proliferative responses of PBMC were also determined after stimulation with ConA, phytohemagglutinin, pokeweed mitogen (PWM), or MpS. Results—After stimulation with ConA, cells from subclinically infected cows secreted significantly more, and cells from clinically infected cows secreted significantly less, IFN-γ, compared with cells from control cows. Cells from cows with subclinical para...
TL;DR: Treatment of cultured equine chondrocytes with IL-1beta or TNF-alpha resulted in marked alterations in expression of various matrix and matrix-related genes consistent with the implicated involvement of these genes in arthritis.
Abstract: OBJECTIVE To determine the effects of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) on expression and regulation of several matrix-related genes by equine articular chondrocytes. SAMPLE POPULATION Articular cartilage harvested from grossly normal joints of 8 foals, 6 yearling horses, and 8 adult horses. PROCEDURE Chondrocytes maintained in suspension cultures were treated with various doses of human recombinant IL-1beta or TNF-alpha. Northern blots of total RNA from untreated and treated chondrocytes were probed with equine complementary DNA (cDNA) probes for cartilage matrix-related genes. Incorporation of 35S-sulfate, fluorography of 14C-proline labeled medium, zymography, and western blotting were used to confirm effects on protein synthesis. RESULTS IL-1beta and TNF-alpha increased steady-state amounts of mRNA of matrix metalloproteinases 1, 3, and 13 by up to 100-fold. Amount of mRNA of tissue inhibitor of metalloproteinase-1 also increased but to a lesser extent (1.5- to 2-fold). Amounts of mRNA of type-II collagen and link protein were consistently decreased in a dose-dependent manner. Amount of aggrecan mRNA was decreased slightly; amounts of biglycan and decorin mRNA were minimally affected. CONCLUSIONS AND CLINICAL RELEVANCE Treatment of cultured equine chondrocytes with IL-1beta or TNF-alpha resulted in marked alterations in expression of various matrix and matrix-related genes consistent with the implicated involvement of these genes in arthritis. Expression of matrix metalloproteinases was increased far more than expression of their putative endogenous inhibitor. Results support the suggestion that IL-1beta and TNF-alpha play a role in the degradation of articular cartilage in arthritis.
TL;DR: In this paper, the effects of erythromycin, lidocaine, and metoclopramide on smooth muscle of the pyloric antrum (PA), proximal portion of the duodenum (PD), and middle portion of a jejunum (MJ) of horses were evaluated.
Abstract: Objective—To evaluate effects of erythromycin, lidocaine, and metoclopramide on smooth muscle of the pyloric antrum (PA), proximal portion of the duodenum (PD), and middle portion of the jejunum (MJ) of horses. Sample Population—Strips of smooth muscle from 7 horses. Procedure—Isolated muscle strips were suspended in a bath and attached to isometric force transducers. Once stable spontaneous contractions were observed, agents were added. Isometric stress responses were compared with the amplitude of spontaneous contractions. Results—A single dose of erythromycin to the PA increased contractile amplitude (CA) for the longitudinal smooth muscle (mean ± SEM, 76 ± 16 g/cm2) but decreased CA for circular smooth muscle (–79 ± 23 g/cm2). The inhibitory effect was decreased by tetrodotoxin, NG-nitro-L-arginine methyl ester, and a vasoactive intestinal peptide antagonist. Erythromycin increased CA for the MJ, which was maximal at 10–4M (171 ± 36 g/cm2). Lidocaine increased CA for the PD, which was maximal at 10–4M...
TL;DR: The relationship between body fat and serum leptin concentration was similar to that observed in humans and rodents and indicative of a lipostatic role for leptin in cats.
Abstract: Objective—To validate a recently developed commercially available leptin radioimmunoassay (RIA) for use with feline serum and evaluate the relationship between serum leptin concentrations and body fat mass in domestic cats. Animals—19 sexually intact male specific–pathogenfree domestic cats that weighed 3.8 to 7.1 kg and were 1.1 to 3.5 years old. Procedure—Specificity for feline leptin was evaluated by use of gel filtration chromatography and reversephase high-performance liquid chromatography fractionation of serum. Body fat mass was determined by use of the deuterium oxide (D2O) dilution method. Serum water D2O enrichment was measured by use of gas-phase Fourier transform infrared spectroscopy. Results—Body fat mass and percentage body fat ranged from 0.3 to 2.3 kg and 7.5 to 34.9%, respectively. Serum leptin concentrations were lower in the unfed versus the fed state and ranged between 1.6 and 4.9 ng/ml human equivalent (HE); mean ± SD value was 2.9 ± 0.2 ng/ml HE. Leptin concentrations increased with...
TL;DR: Relationships between different gaits and speeds in the training regimen influence the incidence of bucked shins, and trainers should consider allocating more training effort to regular short-distance breezing and less to long-distance galloping.
Abstract: Objective To determine the degree to which components of the training program of 2-year-old Thoroughbred racehorses influence their susceptibility to fatigue injury of the third metacarpal bone (bucked shins). Animals 226 two-year-old Thoroughbred racehorses. Procedure Daily training information and health reports on 2-year-old Thoroughbreds were compiled from records provided from 5 commercial stables. For each horse, data (exercise variables) were collected that comprised distance jogged (approx speed of 5 m/s), galloped (approx 11 m/s), and breezed (approx 15 to 16 m/s) until a single instance of bucked shins was reported. Data were coded for analysis using cross-tabulation, graphic, and survival techniques. Results Of 226 horses, 56 had bucked shins, 9 completed the observation period without bucked shins, and 161 were lost to follow-up. Distinct training strategies were used at stables resulting in significantly different survival profiles among stables. Mean (+/- SD) allocation of exercise to breezing was 0.15 +/- 0.13 miles/wk (maximum, 0.64 miles/wk), to galloping was 4.47 +/- 1.52 miles/wk (maximum, 9.56 miles/wk), and to jogging was 2.34 +/- 1.70 miles/wk (maximum, 8.53 miles/wk). Survival (ie, lack of bucked shins during 1 year of monitoring) was found to be significantly reduced by exercise allocation to breezing, significantly increased by exercise allocation to galloping, and uninfluenced by exercise allocation to jogging. The log of the hazard ratio was reduced by 4.2 +/- 1.5/mile breezed and increased by 0.3 +/- 0.1/mile galloped. Conclusions and clinical relevance Relationships between different gaits and speeds in the training regimen influence the incidence of bucked shins. To reduce the incidence of bucked shins, trainers should consider allocating more training effort to regular short-distance breezing and less to long-distance galloping.
TL;DR: Eating and drinking behaviors were associated with signs of bovine respiratory disease complex (BRDC), but there was not an obvious predictive association between signs of BRDC in calves and eating and Drinking behaviors.
Abstract: Objective—To investigate eating and drinking behaviors and their association with bovine respiratory disease complex (BRDC) and to evaluate methods of diagnosing BRDC. Animals—170 newly arrived calves at a feedlot. Procedure—Eating and drinking behaviors of calves were recorded at a feedlot. Calves with clinical signs of BRDC were removed from their pen and classified retrospectively as sick or not sick on the basis of results of physical and hematologic examinations. Pulmonary lesions of all calves were assessed at slaughter. Results—Calves that were sick had significantly greater frequency and duration of drinking 4 to 5 days after arrival than calves that were not sick. Sick calves had significantly lower frequency and duration of eating and drinking 11 to 27 days after arrival but had significantly greater frequency of eating 28 to 57 days after arrival than calves that were not sick. Calves at slaughter that had a higher percentage of lung tissue with pneumonic lesions had significantly lower frequen...
TL;DR: Measurement of D-dimer concentrations by latex-agglutination appears to be a sensitive and specific ancillary test for DIC in dogs, therefore FDP and D- dimer assays should be performed concurrently as supportive tests for the diagnosis of D IC in dogs.
Abstract: Objective—To determine sensitivity and specificity of assays of D-dimer concentrations in dogs with disseminated intravascular coagulation (DIC) and healthy dogs and to compare these results with those of serum and plasma fibrin-fibrinogen degradation product (FDP) assays. Animals—20 dogs with DIC and 30 healthy dogs. Procedure—Semi-quantitative and quantitative D-dimer concentrations were determined by use of latex-agglutination and immunoturbidometry, respectively. Fibrin-fibrinogen degradation products were measured by use of latex-agglutination. A reference range for the immunoturbidometric D-dimer concentration assay was established; sensitivity and specificity of the assay were determined at 2 cutoff concentrations (0.30 µg/ml and 0.39 µg/ml). Results—Reference range for the immunoturbidometric D-dimer concentration assay was 0.08 to 0.39 µg/ml; median concentrations were significantly higher in dogs with DIC than in healthy dogs. Latexagglutination D-dimer and serum and plasma FDP assays had simila...
TL;DR: Devising effective on-farm strategies to control E coli O157:H7 in cow-calf herds will require an understanding of the epidemiologic characteristics of this pathogen, and implementing control strategies at all levels of the cattle industry will decrease the risk of this organism entering the human food chain.
Abstract: Objective—To describe the frequency and distribution of Escherichia coli O157:H7 in the feces and environment of cow-calf herds housed on pasture. Sample Population—Fecal and water samples for 10 cow-calf farms in Kansas. Procedure—Fecal and water samples were obtained monthly throughout a 1-year period (3,152 fecal samples from 2,058 cattle; 199 water samples). Escherichia coli O157:H7 in fecal and water samples was determined, using microbial culture. Results—Escherichia coli O157:H7 was detected in 40 of 3,152 (1.3%) fecal samples, and 40 of 2,058 (1.9%) cattle had ≥ 1 sample with E coli. Fecal shedding by specific cattle was transient; none of the cattle had E coli in more than 1 sample. Significant differences were not detected in overall prevalence among farms. However, significant differences were detected in prevalence among sample collection dates. Escherichia coli O157:H7 was detected in 3 of 199 (1.5%) water samples. Conclusions and Clinical Relevance—Implementing control strategies for E coli ...
TL;DR: Administration of XYL reduced the anesthetic requirement for isoflurane in horses and increased blood glucose concentration in anesthetized horses in a dose-related manner, both dose- and time-dependent.
Abstract: Objective—To quantitate dose- and time-related anesthetic-sparing effects of xylazine hydrochloride (XYL) during isoflurane-induced anesthesia in horses and to characterize selected physiologic responses of anesthetized horses to administration of XYL. Animals—6 healthy adult horses. Procedure—Horses were anesthetized 2 times to determine the minimum alveolar concentration (MAC) of isoflurane in O2 and to characterize the anestheticsparing effect (MAC reduction) after IV administration of XYL (0.5 and 1 mg/kg of body weight, random order). Selected measures of cardiopulmonary function, blood glucose concentrations, and urinary output also were measured during the anesthetic studies. Results—Isoflurane MAC (mean ± SEM) was reduced by 24.8 ± 0.5 and 34.2 ± 1.9% at 42 ± 7 and 67 ± 10 minutes, respectively, after administration of XYL at 0.5 and 1 mg/kg. Amount of MAC reduction by XYL was dose- and time-dependent. Overall, cardiovascular and respiratory values varied little among treatments. Administration of XYL increased blood glucose concentration; the magnitude of change was dose- and time-dependent. Urine volume increased but not significantly. Conclusions and Clinical Relevance—Administration of XYL reduced the anesthetic requirement for isoflurane in horses. The magnitude of the decrease is dose- and time-dependent. Administration of XYL increases blood glucose concentration in anesthetized horses in a dose-related manner. (Am J Vet Res 2000;61:1225–1231)
TL;DR: Differences for STT and STTa were detected among breeds, but significant differences were not associated with sex or age within each breed or in overall values for all dogs.
Abstract: Objective—To evaluate, for clinically normal dogs, results of Schirmer tear tests in eyes without topical anesthetic (STT) and to detect differences associated with breed, sex, age, day, and time of day in eyes in which STT was performed after use of topical anesthetic (STTa). Animals—41 Beagles, 43 Labrador Retrievers, 25 Golden Retrievers, 26 English Springer Spaniels, and 22 Shetland Sheepdogs. Procedure—Beagles had STT and STTa values measured twice daily for 5 days. Client-owned dogs of 4 other breeds had STT and STTa values measured once. Results—Mean ± SD values of Beagles for STT and STTa were 20.2 ± 2.5 and 3.8 ± 2.7 mm/min. Mean values for STT and STTa were as follows: Labrador Retriever, 22.9 ± 4.1 and 9.6 ± 3.8 mm/min; English Springer Spaniel; 20.7 ± 3.2 and 5.4 ± 3.4 mm/min; Golden Retriever, 21.8 ± 3.7 and 8.8 ± 3.1 mm/min; and Shetland Sheepdog, 15.8 ± 1.8 and 3.6 ± 2.8 mm/min. Overall mean values for STT and STTa were 20.2 ± 3.0 and 6.2 ± 3.1 mm/min. Differences for STT and STTa were dete...
TL;DR: Content of substance P in synovial fluid cannot be predicted by the radiographic appearance of the joint or its anatomic location, lending credence to the importance of neurogenic inflammation in horses.
Abstract: Objective—To correlate substance P content of synovial fluid with prostaglandin E2 content, radiographic evidence of joint abnormality, and anatomic location of the joint for normal and osteoarthri...
TL;DR: Three distinct contact areas were evident in the elbow joint of dogs, suggesting there may be physiologic incongruity of the humeroulnar joint.
Abstract: Objective—To evaluate areas of articular contact of the proximal portions of the radius and ulna in normal elbow joints of dogs and the effects of axial load on size and location of these areas. Sample Population—Forelimbs obtained from cadavers of 5 adult mixed-breed dogs. Procedure—After forelimbs were removed, liquidphase polymethyl methacrylate was applied to articular surfaces of the elbow joint, and limbs were axially loaded. Articular regions void of casting material were stained with water-soluble paint. Relative articular contact areas were determined by computer-assisted image analyses of stained specimens. Repeatability of the technique was evaluated by analyses of casts from bilateral forelimbs of 1 cadaver. Incremental axial loads were applied to left forelimbs from 4 cadavers to determine effects of load on articular contact. Results—Specific areas of articular contact were identified on the radius, the craniolateral aspect of the anconeus, and the medial coronoid process. The medial coronoid and radial contact areas were continuous across the radioulnar articulation. There was no articular contact of the medial aspect of the anconeus with the central trochlear notch. Coefficients of variation of contact areas between repeated tests and between contralateral limbs was < 20%. Significant overall effects of axial load on contact area or location were not identified. Conclusions—Three distinct contact areas were evident in the elbow joint of dogs. Two ulnar contact areas were detected, suggesting there may be physiologic incongruity of the humeroulnar joint. There was no evidence of surface incongruity between the medial edge of the radial head and the lateral edge of the medial coronoid process. (Am J Vet Res 2000;61: 1315–1321)
TL;DR: Equine seminal plasma contains a high activity of catalase that is derived primarily from prostatic secretions, which may reduce the ability to scavenge H2O2 and thereby increase the susceptibility of spermatozoa to oxidative stress.
Abstract: Objective—To characterize the activity of catalase in equine semen. Animals—15 stallions of known and unknown reproductive history. Procedure—Seminal plasma was collected from raw equine semen by centrifugation, and samples of seminal plasma were frozen prior to assay for catalase activity. Tissue samples (n = 3 stallions) from the bulbourethral gland, prostate gland, vesicular gland, and testis were homogenized, and cauda epididymal fluid was collected for determination of catalase activity. Catalase activity was determined as an enzyme kinetic assay by the disappearance of H2O2 as measured by ultraviolet spectrophotometry. Results—Catalase activity in equine seminal plasma was 989.3 ± 167.8 U/ml (mean ± SEM), and the specific activity of catalase in equine seminal plasma was 98.7 ± 29.2 U/mg of protein. Specific activity of catalase in tissue homogenates was significantly higher in the prostate gland (954 ± 270 U/mg of protein) than in the ampulla (59 ± 5 U/mg of protein), bulbourethral gland (54 ± 11 U...
TL;DR: Results suggest that in horses with black walnut-induced laminitis, there is an early decrease in LMBF followed by reperfusion prior to onset of clinical signs.
Abstract: Objective—To measure changes in laminar microvascular blood flow (LMBF) over time in healthy horses and horses in the prodromal stage of black walnutinduced laminitis and to determine the effects of glyceryl trinitrate application on LMBF in horses with acute laminitis. Animals—10 healthy adult horses. Procedure—Laser Doppler flowmetry was used to measure LMBF. Baseline measurements were obtained, horses were given deionized water via a nasogastric tube, and measurements were obtained hourly for 12 hours. Twenty-four hours later, baseline measurements were again obtained, and horses were given black walnut extract. Measurements were obtained hourly for 12 hours or until development of Obel grade-3 laminitis. At this time, 5 horses were treated with phenylbutazone, and the other 5 were treated with phenylbutazone and glyceryl trinitrate, and measurements were obtained hourly for an additional 12 hours. Results—LMBF was significantly decreased 1 and 2 hours after administration of the black walnut extract b...
TL;DR: Cattle shedding BCV from the nasal cavity and developing an antibody response against BCV were 1.6 times more likely to require treatment for respiratory tract disease than cattle that did not shed the virus or develop an immune response againstBCV.
Abstract: Objective—To determine the association between respiratory tract infection with bovine coronavirus (BCV), treatment for respiratory tract disease, pulmonary lesions at slaughter, and average daily gain in cattle in feedlots. Animals—837 calves in feedlots in Ohio and Texas. Procedure—Nasal swab specimens were obtained from cattle at arrival in a feedlot (day 0) and at various times during the initial 28 days after arrival. Specimens were tested for BCV, using an antigencapture ELISA. Serum samples were obtained at arrival and again 28 days after arrival and tested for antibodies to BCV, using an antibody-detection ELISA. Information was collected regarding treatment for cattle with respiratory tract disease and average daily gain during the feeding period. Pulmonary lesions were evaluated at slaughter. Results—Cattle shedding BCV from the nasal cavity and developing an antibody response against BCV were 1.6 times more likely to require treatment for respiratory tract disease than cattle that did not shed the virus or develop an immune response against BCV. Additionally, cattle that shed BCV from the nasal cavity were 2.2 times more likely to have pulmonary lesions at slaughter than cattle that did not shed the virus. The BCV shedding or seroconversion status did not affect average daily gain. Conclusions and Clinical Relevance—Bovine coronavirus infects feedlot cattle and is associated with an increased risk for cattle developing respiratory tract disease and pulmonary lesions. Development of appropriate control measures could help reduce the incidence of respiratory tract disease. (Am J Vet Res 2000;61:1062–1066)