bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contact area and pressure distribution changes of the equine third carpal bone during loading
Authors: PALMER JAN L. , BERTONE ALICIA L. , LITSKY A. S. 
Published: April 2010

SummaryChanges in contact area and pressure distribution with loading were evaluated on the proximal articulating surface of the equine third carpal bone using safranin‐O dye staining and pressure sensitive film techniques. A significant increase in percentage contact area resulted as the applied load was increased from 3115 to 9000 N (54.93%± 7.99 vs 61.43%± 7.37 respectively, P = 0.016). The area in contact shifted towards the dorsal aspect of both the radial and intermediate facets of the third carpal bone. Changes were also detected in the mean pressure under the same loading conditions. There was a significant increase (P<0.05) in the mean pressure on the dorsomedial to dorsolateral aspect of the radial facet and the dorsomedial to middle‐lateral aspect of the intermediate facet with increased loading. A trend towards an increase (P <0.10) in mean pressure was detected on the middle‐medial aspect of the radial facet and the middle‐medial to palmar‐lateral aspect of the intermediate facet. There was no significant increase (P>0.05) in mean pressure with an increase in load from 3115 to 9000 N at the palmar aspect of either facet. The increase in contact area and mean pressure with loading in the most dorsal and dorsomedial aspect of the radial facet may explain the large amount of third carpal bone trauma seen in this location in racing horses.
Pharmacodynamics and pharmacokinetics of carprofen in the horse
Authors: LEES P. , McKELLAR Q. , MAY S. A. , LUDWIG B. 
Published: April 2010

SummaryThe pharmacokinetics and pharmacodynamics of the nonsteroidal anti‐inflammatory drug (NSAID) carprofen have been evaluated in 6 horses using a model of acute nonimmune inflammation. Following intravenous administration of 0.7 mg racemic carprofen/kg bwt, mean values for pharmacokinetic parameters were 18.1 h (elimination half‐life); 0.25 l/kg (volume of distribution, Vd [area]); 58.9 ml/min (clearance); and 57.9 μg/ml.h (area under plasma concentration time curve). Mean exudate: plasma concentration ratios exceeded 1.0 at all sampling times between 2 and 48 h. Swelling at the site of acute inflammation was significantly reduced but exudate leucocyte numbers were unchanged. Although carprofen produced moderate suppression of serum thromboxane B2and exudate prostaglandin E2synthesis, these effects were not related to carprofen concentrations in plasma or exudate. It was concluded that the anti‐oedematous action of carprofen was not attributable to inhibition of cyclo‐oxygenase.
Interaction of gentamycin and atracurium in anaesthetised horses
Authors: HILDEBRAND S. V. , HILL T. 
Published: April 2010

SummaryEvoked hind limb digital extensor tension (hoof twitch) was maintained at 40% of baseline for 1 h by atracurium infusion in 7 horses anaesthetised with halothane. After 1 h, atracurium was discontinued and hoof twitch allowed to recover to 75%. Atracurium was again given by infusion to maintain 40% twitch for a second hour, then 2 mg gentamycin/kg bwt were given i.v. Atracurium infusion was continued for a third hour, and then hoof twitch was again allowed to recover spontaneously to 75%. Gentamycin reduced twitch strength from 40 ± 1% (mean ± sem) to 29 ± 4% within 7.0 ± 1.5 min (P = 0.02). Twitch gradually returned to pre‐gentamycin strength over the course of the next hour. Recovery of hoof twitch from 50% to 75% took 7.7 ± 0.7 min for atracurium alone and 11.5 ± 2.7 min for atracurium plus gentamycin (P = 0.03). Recovery from 50% twitch to 75% fade recovery took 13.8 ± 0.8 min for atracurium alone and 13.7 ± 1.2 min for atracurium plus gentamycin. At 75% recovery of fade, hoof twitch was 87 ± 3% for atracurium alone and 82 ± 4% for atracurium plus gentamycin. Reversal of the block with edrophonium and subsequent recovery of the horses from anaesthesia were uneventful. It was concluded that, although gentamycin did augment the neuromuscular blockade of atracurium, the effect was minimal.
A silver‐impregnation and immunocytochemical study of innervation of the distal sesamoid bone and its suspensory ligaments in the horse
Authors: BOWKER R. M. , ROCKERSHOUSER SARA J. , LINDER K. , VEX KELLY B. , SONEA IOANA M. , CARON J. P. 
Published: April 2010

SummaryThe innervation of the navicular bone (os sesamoideum distale) and its suspensory ligaments (ligamenta sesamoidea collateralia) (CSL) or proximal suspensory ligament and the ligamentum sesamoideum distale impar or the distal sesamoidean impar ligament (DS‐impar ligament) was examined using combined anatomical techniques of silver impregnation and immunocytochemistry. Silver impregnation studies revealed an abundance of nerve fibres present in both the CSL and DS‐impar ligament with the latter having relatively more nerve fibres. These silver‐impregnated nerves coursed parallel to and were associated with the vasculature rather than appearing to innervate the vessels. Immunocytochemistry identified several sensory‐related neuropeptides (calcitonin gene‐related peptide (CGRP), substance P (SP) and neurokinin A (NKA)) in the nerves of the navicular bone and suspensory ligaments. More peptidergic nerves were evident within the synovial membrane and loose connective tissue in the dorsal part than in the palmar aspect of the CSL. In the CSL along the synovial membrane bordering the distal interphalangeal joint, the CGRP, SP and NKA were present in the nerves of vessels as well as the intimal layer of the distal interphalangeal joint. In the DS‐impar ligament, there were many more nerves innervating vessels and the synovial membrane between the navicular bone and the third phalanx than were present in these structures in the CSL. Nerves with all 3 peptides entered the navicular bone via the proximal border and the distal groove to innervate the perichondrium, trabeculae and osteons. SP‐like nerves also innervated the cortical bone underlying the articular cartilage. We suggest that these sensory nerve peptides contribute to the pathology of the navicular syndrome. The distribution of the nerves in the CSL and the DS‐impar ligament could explain the clinical effects of local anaesthetics injected into the distal interphalangeal joint.
Cardiorespiratory and metabolic responses to exercise in horses with various abnormalities of the upper respiratory tract
Authors: KING C. M. , EVANS D. L. , ROSE R. J. 
Published: April 2010

SummaryA standardised incremental exercise test was performed by 9 racehorses with idiopathic laryngeal hemiplegia (ILH), 1 horse with maxillary sinus cysts, 1 horse with epiglottic entrapment, 1 horse with a lesion on the vocal folds, and 1 horse with pharyngitis. Two of the horses with ILH were retested after laryngoplasty and ventriculectomy. The findings were compared with those from 20 normal racehorses. Heart rate, plasma lactate concentration, arterial blood gases, stride frequency, oxygen uptake (V̇o2) and carbon dioxide production were assessed during treadmill exercise on a +10% slope. The group of horses with ILH had significantly (P<0.01) lower peak V̇o2values (136 ± 5 ml/kg/min) than did the normal group (154 ± 3 ml/klg/min). These values represent mean ± sem. Horses with ILH also had significantly higher (P<0.05) arterial carbon dioxide tensions (Paco2) at 10 m/s and lower speeds at a heart rate of 200 bpm (V200) than the normal group. The horse with maxillary sinus cysts had higherPaco2tension at 10 m/s than normal, and abnormal values for several cardiorespiratory and metabolic indices. Horses with vocal fold lesions, aryepiglottic entrapment and pharyngitis had arterial blood gas and cardiorespiratory indices that were similar to those of normal horses. One horse which underwent corrective surgery for ILH showed improvements in arterial blood gases and cardiorespiratory indices during exercise, while the other horse had values which were the same as, or worse than, values before surgery. We conclude that the measurement of arterial blood gases and cardiorespiratory indices during treadmill exercise is useful in determining the effect on exercise capacity of various upper airway abnormalities in racehorses.
Biokinematic analysis of the Swedish Warmblood riding horse at trot
Authors: HOLMSTRÖM M. , FREDRICSON I. , DREVEMO S. 
Published: April 2010

SummaryThe trotting gait of 4 approved Swedish Warmblood stallions with a mean gait score ≤8.67 (maximum score = 10) at official performance tests was recorded by high speed film (˜250 frames/sec). Angular patterns and hoof trajectories of the left fore and hind limbs were analysed, and presented as mean and standard deviation curves. The horses had a mean stride duration of 794.0 msec (sd 13.7) and the mean diagonal advanced placement was +29.8 msec (sd 7.6). The variation in angular patterns between the horses was greatest during the swing phase. The trajectory of the hind hoof reference point and the shoulder joint angle showed the largest maximum variation (44 and 29% of the total range, respectively). The swing phase retraction was much longer in the forelimbs than the hind limbs. The shoulder joint angle, fore and hind fetlock joint angles, hock joint angle and pelvis inclination decreased during the first part of the stance phase and are assumed to be important for weight absorption and storage of elastic strain. Kinematic gait analyses have potential in the selection of performance horses.
Endoscopie anatomy and map of the equine bronchial tree
Authors: SMITH BARBARA L. , AGUILERA‐TEJERO E. , TYLER W. S. , JONES J. H. , HORNOF W. J. , PASCOE J. R. 
Published: April 2010

SummaryTo develop a bronchoscopic map of the equine respiratory tree, the major airways of the lungs of 6 healthy Thoroughbred horses were systematically explored with a flexible fibreoptic endoscope through a tracheostomy while the horses were sedated in stocks. With the carina as the reference point, measurements were made of distances to the branches of the major airways using markers on the shaft of the endoscope. All branches were explored until the narrowing of their diameters prevented further advancement of the endoscope. Positions of origins of branches from the parent bronchus were recorded in relation to a 12 h clock. Branching patterns of the right and left lungs were similar. Seventeen branches of the principal and caudal lobar bronchi of the left lung, and 18 branches of the principal and caudal lobar bronchi of the right lung were identified. Mean explorable distances from the carina to the ends of the right and left caudal lobar bronchi were 34.0 ± 3.5 (sd) and 34.5 ± 3.0 cm, respectively. Generally, smaller horses had shorter explorable bronchial lengths. Branching patterns of the parent bronchi were fairly consistent among horses, particularly the branches closest to the carina. After endoscopy and euthanasia, the lungs were removed, and dried with pressurised air flowing through them for 7–10 days. Attempts to explore the airways of the dried lungs endoscopically were relatively unsuccessful, because airways were much smaller in the dried lungs, and many of the branches were distorted when compared with their ante‐mortem appearances. However, having a dried lung specimen as a reference during the bronchoscopic procedure was useful for maintaining orientation in the lungs. Radiographs were used to estimate the location of the origin and destination of each airway branch in relation to the nearest intercostal space. This makes the airway map useful when lesions identified radiographically are to be lavaged.
Haematological, bone marrow and clinical chemical changes in neonatal foals given canine recombinant granulocyte‐colony stimulating factor
Authors: ZINKL J. G. , MADIGAN J. E. , FRIDMANN D. M. , KABBUR M. B. , REYNAL‐O'CONNOR J. , ANDRESEN J. W. 
Published: April 2010

SummaryFive Thoroughbred and Quarter Horse cross foals were given 20 μg canine recombinant granulocyte‐colony stimulating factor (rcG‐CSF) per kg bwt intramuscularly (i.m.) on the day of birth and 10 μg rcG‐CSF/kg for 13 additional days. During this time and for an additional 21 days haematology, bone marrow and clinical chemical analyses were performed. After one day of rcG‐CSF administration leucocyte and neutrophil counts increased from 9.16 × 109/1 to 23.44 × 109/1 and from 6.45 × 109/1 to 19.61 × 109/1, respectively. The counts continued to increase for the next 3–4 days and then there was a slight decrease. A second increase followed and the leucocyte and neutrophil counts increased to 52.84 × 109/1 and 45.16 × 109/1 on the day after the last rcG‐CSF administration (Day 15). The counts decreased rapidly immediately after the administration of rcG‐CSF was stopped and then at a slower rate. The cell counts were still higher than in the controls at the end of the study period (Day 35). Bone marrow cellularity increased from 10–25% before rcG‐CSF was given to 60–80% after 5 days. The increase in cellularity was due to increased myeloid activity because the myeloid to erythroid ratio increased from 2.7 to 8.8. Serum chemistry changes were minimal although foals given rcG‐CSF at various times had lower glucose concentrations and increased alkaline phosphatase and gamma glutamyl transferase activities.
Skeletal muscle characteristics in red blood cell normovolaemic and hypervolaemic Standardbred racehorses
Authors: RONÉUS MERIKE , PERSSON S. G. B. , ESSÉN‐GUSTAVSSON BIRGITTA , ÁRNASON T. 
Published: April 2010

SummaryMuscle biopsy specimens from the middle gluteal muscle were studied in 16 red blood cell hypervolaemic(Group HV)and 19 normovolaemic(Group NV)Standardbred racehorses. All horses were stallions, 4–8 years old and having similar mean racing performance values, as described by an individual selection index value. All horses raced regularly but those inGroup HVdid not perform as expected and were therefore referred to the clinics for exercise tolerance testing. Muscle biopsy specimens were analysed for fibre type distribution (Type I, IIAandIIB), fibre area and relative fibre area. In addition, oxidative capacity of the fibres was evaluated by staining for nicotinamide adenine dinucleotide (NADH) tetrazolium reductase, and the activities of citrate synthase, 3‐OH‐acyl CoA dehydrogenase and lactate dehydrogenase were analysed in whole‐muscle samples. With the exception of a higher percentage ofType IIBfibres inGroup HVhaving a high oxidative capacity as evaluated by the NADH stain, no significant difference were found in fibre composition, fibre area or enzyme activity between theGroups HVandNV.
An examination of the occurrence of surgical wound infection following equine orthopaedic surgery (1981–1990)
Authors: MACDONALD D. G. , MORLEY P. S. , BAILEY J. V. , BARBER S. M. , FRETZ P. B. 
Published: April 2010

SummaryPost operative surgical wound infection rates were determined for 452 cases of equine orthopaedic surgery performed at the Western College of Veterinary Medicine, Saskatoon, Saskatchewan, between January 1, 1981 and December 31, 1990. Only surgical procedures classified as clean or clean‐contaminated by the National Research Council were included in this study. The overall post operative infection rate was 10.0% (45 of 452). Clean surgeries (n=433) had an 8.1% infection rate while clean‐contaminated surgeries (n=19) had a 52.6% infection rate. Information collected from the medical records was used in univariate and multivariate logistic regression models to evaluate significant determinates of post operative infection. Significant determinates of post operative infection were: surgical classification, orthopaedic involvement, duration of surgery, administration of preoperative antibiotics and gender. Clean‐contaminated surgeries had an increased risk of infection compared to clean surgeries (odds ratio (OR)=24.3), procedures involving long bones had an increased risk of infection compared to procedures involving articular surfaces (OR =5.1), surgeries lasting 90 minutes or longer had an increased risk of infection compared to those less than 90 minutes (OR =3.6), administration of preoperative antibiotics was associated with an increased risk of infection (OR =4.6) and female patients were 2.6 times more likely to develop post operative infection than male patients.
Review of 40 cases of lung abscesses in foals and adult horses
Authors: LAVOIE J.‐P. , FISET LORAINE , LAVERTY SHEILA 
Published: April 2010

SummaryA retrospective study of 40 horses with primary lung abscesses without pleuropneumonia showed that lung abscesses occurred predominantly in young horses, usually in foals aged ≤6 months. Hyperfibrinogenaemia was present in all but 2 horses, and other common clinical and haematological findings were hyperthermia, tachycardia, polypnoea, and neutrophilic leucocytosis. The most common bacterial species isolated from transtracheal aspirates wereStreptococcus zooepidemicus(20/34) andRhodococcus equi(13/34). Most horses (23/27) discharged from the hospital were long term survivors. Of the 19 horses for which a follow up was available, 12 raced or performed the task for which they were intended. None of the indicators evaluated in this study could reliably predict the bacterial species involved or the outcome.
Evaluation of the thoraco‐laryngeal reflex (‘slap test’) as an aid to the diagnosis of cervical spinal cord and brainstem disease in horses
Authors: NEWTON‐CLARKE M. J. , DIVERS T. J. , DELAHUNTA A. , MOHAMMED H. O. 
Published: April 2010

SummaryA study was conducted over a 12 month period to assess the specificity and sensitivity of the ‘slap test’, using endoscopic evaluation, in the detection of cervical spinal cord and caudal brainstem lesions in horses. Fifteen ataxic horses were subjected to the ‘slap test’ and subsequently examined post mortem. Twelve out of the 15 had histopathological lesions consistent with their clinical signs. Thirteen horses with no history of neurological dysfunction and no histopathological evidence of cervical spinal cord or brainstem disease were used as controls. The laryngeal adductory responses exhibited by all horses were filmed and later scored independently by 3 assessors. The proportion of animals diagnosed with cervical spinal cord and/or brainstem disease, defined by histopathological criteria, was found to be statistically similar to the proportion with abnormal ‘slap test’ responses, using the McNemar chi‐Square test. Despite statistical significance between proportions, sensitivity of the ‘slap test’ was low, 50% for the left side on both days and 58% for the right side. Specificity was higher, 69% (Day 1) and 75% (Day 2) for the left side and 75% (Day 1) and 69% (Day 2) for the right side. In contrast to this, conventional neurological examination was found to be 100% sensitive and 81% specific in the detection of lesions of histopathological significance in the cervical spinal cord/caudal brainstem. Agreement between scores for the ‘slap test’ from the same assessor on different days was good, with values for kappa of 0.59 to 0.85. In contrast, agreement between assessors on the ‘slap test’ score was poor, with kappa 0.35. With a theoretical prevalence of 50% for mild posterior ataxia, the predictive value of a positive test indicated that the ‘slap test’ could at best increase the index of suspicion of cervical spinal cord or caudal brainstem disease from 50% to 70%. The predictive value of a negative test under the same conditions was lower, increasing the chance of normality from 50% to 64%.
Equine hoof function investigated by pressure transducers inside the hoof and accelerometers mounted on the first phalanx
Authors: DYHRE‐POULSEN P. , SMEDEGAARD H. H. , ROED J. , KORSGAARD E. 
Published: April 2010

SummaryThe dampening of hoof impact was investigated by measuring the accelerations transmitted through structures of the hoof in horses trotting freely on an asphalt tarmac. The hoof dampened the vibrations transmitted to the first phalanx. Shoeing decreased the viscous dampening and increased the median power frequency and the maximal amplitude of the vibrations transmitted to the first phalanx.The pressure inside the digital cushion of the foreleg was recorded. The pressure dropped during the stance phase, indicating expansion of the hoof. The expansion of the hoof was not produced by frog or sole weight bearing because this would have increased the intra‐digital cushion pressure. The pressure theory of hoof function must presumably therefore be rejected. Shoeing the horses augmented the intra‐digital cushion pressure drop and probably impaired the movements of the hoof wall.
Body position and direction preferences in horses during road transport
Authors: SMITH BARBARA L. , JONES J. H. , CARLSON G. P. , PASCOE J. R. 
Published: April 2010

SummaryIt has been hypothesised that horses have a preference for facing backward in a trailer during road transport in order to minimise shifts of body weight due to accelerations and decelerations. To determine if horses have preferences for facing forward vs. backward in a horse trailer, the authors analysed the percentages of time horses spent in different body positions and directions while standing in a moving or parked horse trailer. Body positions and directions of 8 Thoroughbred geldings were videotaped while horses were transported singly and untethered in a 4‐horse stock trailer over a 32 km route of country roads; or while the same horses were untethered in the same trailer stationary in a parking lot. Analysis of the logit‐transformed percentages of time horses spent in different directions indicated that they spent significantly more time facing backward when the trailer was in motion, but not when it was parked. Several horses displayed strong individual preferences for the directions they faced during road transport.
The role of nitric oxide in the responses of equine digital veins to vasodilator and vasoconstrictor agents
Authors: ELLIOTT J. , BRYANT CLARE E. , SOYDAN J. 
Published: April 2010

SummaryIsolated equine digital veins were examinedin vitroto study the importance of the endothelium in the responses to both vasodilator and vasoconstrictor agents and to characterise the endothelial‐derived mediators involved. Carbachol (Cch; 1 μM) and bradykinin (Bk; 1 nM) caused relaxation of U44069‐induced tone by 79.5 ± 0.35 % and 73.7 ± 4.0 % respectively. Mechanical removal of the endothelium completely prevented relaxant responses to Cch and to Bk showing they were mediated by the endothelium. Treatment of veins with NG‐nitro‐L‐arginine methyl ester (L‐NAME; 30 and 300 μM) inhibited vasorelaxant responses to both Cch and Bk whereas the cyclooxygenase inhibitor, ibuprofen (10 μM) had no inhibitory effect. The inhibitory action of L‐NAME on the relaxations produced by Cch was partly reversed by L‐arginine (3 and 10 mM). Cch‐relaxations were potentiated in the presence of super oxide dismutase (15 units/ml) and inhibited by methylene blue (10 μM). The vasorelaxant effects of ATP (0.01 μM to 0.1 μM) were not dependent on the presence of the endothelium and the selective P2yreceptor agonist, 2‐methylthio‐ATP proved to be ineffective as a vasodilator. Removal of the endothelium did not enhance the vasoconstrictor effects of the α1adrenoceptor agonist phenylephrine (0.01 μM to 0.1 μM) and treatment with L‐NAME (300 μM) did not change the vasoconstrictor responses to 5‐HT (1 nM to 10 μM) or the α2adrenoceptor agonist BHT‐920 (1 nM to 1 μM). These data suggest the L‐arginine nitric oxide pathway is of primary importance in mediating endothelium dependent relaxations to Cch and BK in equine digital veins but that basal release of nitric oxide is insufficient, under the conditions used in the present study, to modulate responses to vasoconstrictor agents. No functional evidence has been found for P2y‐receptors, α2‐adrenoceptors or 5‐HT receptors on endothelial cells of equine digital veins linked to nitric oxide production.