bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma lactate response to submaximal and maximal exercise tests with training, and its relationship to performance and muscle characteristics in Standardbred trotters
Authors: RONÉUS N. , ESSÉN‐GUSTAVSSON B. , LINDHOLM A. , ERIKSSON Y.
Published: April 2010

Seven young Standardbred trotters, born, raised and trained at the same camp, performed submaximal and maximal work tests on a track. The submaximal test consisted of four 1,000 m runs at the trot, with increasing speed at each run. Each horse performed this test when 24, 26, 29 and 40 months old. The maximal test consisted of trotting 1,600 m and was performed at 24 and 29 months of age. Blood samples for plasma lactate analyses were obtained after each run, during the submaximal test and after the maximal test. Muscle biopsy samples were obtained at 24 and 29 months of age. The results showed marked individual differences in lactate response to submaximal effort. Early training only appeared to influence plasma lactate response in some horses. After 40 months of age the lactate response to the final submaximal test was significantly lower (7.2 mmol/l) than at 29 months (14.5 mmol/l).

A negative correlation was found between lactate concentration after all runs in the submaximal test, and the horses speed over 1,600 m. No correlations were found between lactate concentration after the maximal test and the horses' speed. The activity of citrate synthase, a marker for muscle oxidative capacity, increased from 24 to 29 months of age. The proportion of Type IIB fibres decreased, whereas that of Type I fibres increased. It is concluded that lactate response to a submaximal work test on a track can be an important tool for evaluating performance capacity of an individual horse.
Evaluation of partial arytenoidectomy as a treatment for equine laryngeal hemiplegia
Authors: LUMSDEN J. M. , DERKSEN F. J. , STICK J. A. , ROBINSON N. E. , NICKELS F. A.
Published: April 2010

The efficacy of partial arytenoidectomy was assessed in 6 Standardbred horses, with surgically induced laryngeal hemiplegia, at rest (Period A) and during exercise at speeds corresponding to maximum heart rate (Period C) and 75% of maximum heart rate (Period B). Peak expiratory and inspiratory airflow rate (PEF and PIF), and expiratory and inspiratory transupper airway pressure (PUEand PUI) were measured and expiratory and inspiratory impedance (ZEand ZI) were calculated. Simultaneously, tidal breathing flow‐volume loops (TBFVL) were acquired using a respiratory function computer. Indices derived from TBFVL included airflow rates at 50 and 25% of tidal volume (EF50, IF50, EF25. and IF25) and the ratios of expiratory to inspiratory flows. Measurements were made before left recurrent laryngeal neurectomy (baseline), 2 weeks after left recurrent laryngeal neurectomy (LRLN) and 16 weeks after left partial arytenoidectomy coupled with bilateral ventriculectomy (ARYT).

After LRLN, during exercise Periods B and C, Z1and the ratio of EF50/IF50significantly increased and PIF, IF50and IF25significantly decreased from baseline values. At 16 weeks after ARYT, Z1returned to baseline values during Periods B and C. Although PIF, IF50, IF25, PEF/PIF, and EF50/IF50returned to baseline values during Period B, these indices remained significantly different from baseline measurements during Period C. After ARYT, TBFVL shapes from horses during Period C approached that seen at the baseline evaluation.

Partial arytenoidectomy improved upper airway function in exercising horses with surgically induced left laryngeal hemiplegia, although qualitative and quantitative evaluation of TBFVLs suggested that some flow limitation remains at near maximal airflow rates. These results indicate that, although the procedure does not completely restore the upper airway to normal, partial arytenoidectomy is a viable treatment option for failed laryngoplasty and arytenoid chondropathy in the horse.
Immunoreactive insulin‐like growth factor I and insulin in blood plasma and milk of mares and in blood plasma of foals
Authors: HESS‐DUDAN F. , VACHER P.‐Y. , BRUCKMAIER R.M. , WEISHAUPT M.A. , BURGER D. , BLUM J.W.
Published: April 2010

Concentration of (total) globulin was relatively stable in blood plasma of mares, but rapidly decreased in colostrum to very low levels within 2 days after parturition. In foals, after intake of the first colostrum, globulin increased within 1 day in blood plasma, but remained at lower concentrations than those measured in mare plasma. Concentrations of immunoreactive insulin (iI) were high during the first 2 months of lactation in blood plasma of mares and then decreased, were high in first colostrum and then decreased drastically, and remained at low concentrations up to weaning in blood of foals. In mares, concentration of immunoreactive insulin‐like growth factor I (iIGF‐I) in plasma increased during late pregnancy, peaked 2 days after parturition, and then gradually declined until weaning. iIGF‐I was highest in first colostrum and then dramatically decreased within the first 2 days of lactation. In foals, iIGF‐I gradually increased over the first 2 months of life. IGF‐I in the horse appears to be bound to proteins of similar molecular weight as in cattle. The study demonstrates different patterns of changes in plasma iIGF‐I and iI concentrations in mares and their foals, whereas iI, iIGF‐I and globulin changes in colostrum and milk occurred in parallel. Furthermore, plasma iI and iIGF‐I behaved differently, while colostrum iI and iIGF‐I behaved similarly, in mares compared with dairy cows.
Geographical variation of seropositivity toEhrlichia risticii(equine monocytic ehrlichiosis) of horses in New York state
Authors: Atwill E. R. , Mohammed H. O. , de la Rua‐Domenech R.
Published: April 2010

A total of 2,579 serum samples from horses in New York state during 1985–1986 were examined for seropositivity toEhrlichia risticiiusing the indirect fluorescent antibody technique.

Cluster analysis statistical technique was used to group counties according to their estimated EME‐disease rate (seropositive proportion of sampled horses). Counties were clustered into 4 groups of different EME‐disease rates, representing high (86% seropositive), medium (66% seropositive), medium‐low (47% seropositive) and low (6% seropositive) risk regions. The logistic regression statistical technique was used to examine whether the geographic variation ofE. risticiiseropositivity is due to other EME‐risk factors. Risk factors known to be associated with EME (age, breed, sex, month of sample submission) have not contributed to the apparent geographical variation of the disease in New York state. This lack of an association between equine host factors or temporal factors with the geographical variation of EME suggests that conditions necessary for establishment of EME endemic foci involves other factors. The county equine population density and presence of a major equine racetrack were not associated with the geographical variation of the disease in New York state. The high risk regions for EME were located predominately along river valleys, but an explanation of why EME activity varies geographically remains speculative.
Borrelia burgdorferiinfection in UK horses
Authors: CARTER S. D. , MAY C. , BARNES A. , BENNETT D.
Published: April 2010

Antibody levels (IgG and IgM) toBorrelia burgdorferiwere measured in the sera and synovial fluids of UK horses. Western blotting againstB. burgdorferiwas also used on samples from seropositive horses. A low incidence of seropositivity was shown in horses from most parts of the UK. This increased in areas that have a high incidence of human and canine borreliosis (Norfolk and south coast). Leptospira infections of horses did not cause cross reactions in theB. burgdorferiELISA. Most horses did not display clinical signs of Lyme disease. As with dogs and man, it is apparent thatB. burgdorferiinfection occurs in horses in the UK but clinical Lyme disease is uncommon.
Vascular perfusion in horses with chronic laminitis
Authors: HOOD D. M. , GROSENBAUGH D. A. , SLATER M. R.
Published: April 2010

Vascular perfusion casts were used to define and characterise the macroscopic perfusion defects present in the distal digit of 11 horses affected by chronic laminitis. Five clinically normal horses were used as controls. Based on clinical history and clinical status, horses with chronic laminitis were classified as being potentially treatable or clinically refractory. Eleven macroscopic vascular defects were noted in the casts from horses with laminitis. Four types of lesions were identified in the submural laminar circulation, 3 in the coronary bed and 4 were associated with the solar circulation. Multiple defects were present and a definite trend was noted for the perfusion defects to be worse in the casts of clinically refractory subjects than in those considered treatable. This information suggests that evaluation of circulatory status should add significantly to the ability to separate treatable from clinically refractory patients. Results also indicated that ventral displacement of the third phalanx (sinkers) and compression of the solar vasculature are more prevalent than is presently thought.
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

Changes 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

The 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

Evoked 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

The 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

A 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

The 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

To 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

Five 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

Muscle 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

Post 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

A 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

A 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

The 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

It 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

Isolated 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.
Proximodorsal first phalanx osteochondral chip fragmentation in 336 horses
Authors: KAWCAK C. E. , MCILWRAITH C. W.
Published: April 2010

The results of arthroscopic surgery in the treatment of osteochondral fragmentation of the proximodorsal aspect of the first phalanx and the influence of other fetlock joint lesions on prognosis were evaluated in 336 horses. Horses were classified as: 1) returning to previous use at the same or higher class of performance; 2) returning to previous use (regardless of class of performance); or 3) failing to return to previous use. Ninety‐six horses (29%) had fragmentation alone; 140 horses (42%) had fragmentation and additional fetlock lesions, and 100 horses (29%) underwent concurrent carpal arthroscopy. Of the 100 horses that underwent carpal arthroscopy, 63 had proximodorsal first phalanx fragmentation alone and 37 had other fetlock lesions associated with the fragment. There was significant association between lesion type and return to previous use for the Thoroughbred racehorse group. There was also a significant association between lesion type and return to the same or higher class of racing for the Thoroughbred racehorse group. No significant association in return to previous use existed for racehorses vs. non‐racehorses, Thoroughbred racehorses vs. Quarter Horse racehorses, single vs. multiple joint involvement, and single vs multiple fragmentation per joint. The Thoroughbred racehorses in this study were sensitive to additional fetlock or carpal lesions, as was exemplified by the significant effect lesion type had on outcome.
Vertical tears of the cranial horn of the meniscus and its cranial ligament in the equine femorotibial joint: 7 cases and their treatment by arthroscopic surgery
Authors: WALMSLEY J. P.
Published: April 2010

Five horses with a vertical tear in the cranial horn and cranial ligament of the medial meniscus and 2 horses with a similar injury in the lateral meniscus were diagnosed from a series of 126 horses which were examined arthroscopically for stifle lameness. All the lesions had similar characteristics. The tear was about 1 cm from the axial border of the meniscus and its ligament and, in all but one case in which it was incomplete, much of the torn tissue was loosely attached in the axial part of the joint from where it was removed. The remaining meniscus, abaxial to the tear, was displaced cranially and abaxially and its torn edges were debrided. Radiographically, 6 cases had proliferative new bone on the cranial aspect of the intercondylar eminence of the tibia and 3 had calcified soft tissue densities in the cranial, medial or lateral femorotibial joint. Following surgery and a 6 month period of rest and controlled exercise, 3 horses returned to full competition work, one was usable for hacking, 2 are convalescing and one is lame after one year. It is postulated that this could be a characteristic meniscal injury in horses which can benefit from arthroscopic surgery. Better techniques for accessing the body and caudal pole of the menisci are needed if a more complete diagnosis and treatment of meniscal injuries are to be achieved.
Effect of feeding state on the response of horses to repeated bouts of intense exercise
Authors: LAWRENCE L. M. , WILLIAMS JANICE , SODERHOLM L. V. , ROBERTS A. M. , HINTZ H. F.
Published: April 2010

Four mature Standardbred horses were used in a 2‐period cross‐over design experiment to evaluate the effect of feeding state (fed or fasted) on metabolic response to 2 repeated bouts of exercise. Horses were either fasted 15 to 16 h before exercise or fasted for 12 h and then fed 2 kg of whole corn 2.5 to 3 h before exercise. In the first period, 2 horses in each feeding state were exercised. In the second period, the treatments were switched. The exercise test consisted of 2 exercise bouts separated by a 90 min recovery period. Each exercise bout included a warm‐up phase and a high intensity phase (1600 m at 11 m/s on a 2% graded treadmill). Blood samples collected during the exercise test were analysed for glucose, non‐esterified fatty acids (NEFA), insulin and lactate concentrations. Fasted horses had lower insulin concentrations and higher NEFA concentrations at the onset of exercise (P<0.05). NEFA concentrations were consistently higher (P<0.05) in the fasted horses until the high intensity phase of the second exercise bout. Feeding state did not affect heart rate or plasma lactate responses to exercise. Plasma glucose concentrations tended to decline in the fed horses during the first exercise bout. Neither a positive nor a negative effect of feeding state on horses performing repeated bouts of intense exercise were found.
How the horse moves: 2. Significance of graphical representations of equine hind limb kinematics
Authors: BACK W. , SCHAMHARDT H. C. , SAVELBERG H. H. C. M. , VAN DEN BOGERT A. J. , BRUIN G. , HARTMAN W. , BARNEVELD A.
Published: April 2010

Kinematic data of the equine hind limb are presented graphically and related to functional aspects of the hind limb in locomotion. The trot of 24 two‐year‐old Dutch Warmblood horses was recorded at 4 m/s on a high‐speed treadmill using kinematic analysis equipment. Joint angle‐time, angle‐angle, stick and marker diagrams were used to present graphically the data following standardised procedures. As the kinematic data were expressed with reference to the joint angles of the horse standing squarely and were time‐standardised to the duration of the stride cycle, mean joint curves for the total group could be calculated and therefore describe the function of the different segments of the equine hind limb. The motion of the hind limb in the sagittal plane appeared to be pendular around a rotation point in the acetabulum. During the stance phase the extension of the fetlock joint and stance flexion of the stifle, tarsal and coffin joints illustrate the shock absorption of the hind limb. In the swing phase the reciprocal apparatus, which forms the coupling mechanism between stifle and tarsal joint, also influences the fetlock joint because synchronous flexion and extension between these 3 joints were demonstrated. By graphically presenting hind limb motion we were able to illustrate the relation between kinematics and function. This graphic analysis can be used in clinical studies involving quantification of equine hind limb coordination in the sagittal plane.
Autologous blood instillation alters respiratory mechanics in horses
Authors: AGUILERA‐TEJERO E. , PASCOE J. R. , TYLER W. S. , WOLINER M. J.
Published: April 2010

To investigate physiological consequences of autologous blood instillation in the lungs of healthy horses, respiratory mechanics and bronchial response to histamine were studied in 8 Thoroughbreds before and after introducing autologous blood (n=5) and sterile saline solution (n=3) into their lungs. Blood instillation resulted in a decrease in dynamic compliance (Cdyn) and increased respiratory resistance (R). Bronchial sensitivity and reactivity were unchanged after blood introduction. There were no significant changes in pulmonary mechanics or bronchial response after saline instillation.
Effects of a 3 month endurance training programme on skeletal muscle histochemistry in Andalusian, Arabian and Anglo‐Arabian horses
Authors: RIVERO J. L. L. , RUZ MARIA C. , SERRANO A. L. , DIZ A. M.
Published: April 2010

Twenty adult (5 to 14 years old) sedentary stallions of several breeds (8 Andalusians, 7 Arabians and 5 Anglo‐Arabians) were endurance‐trained for 3 months. Duplicate biopsies from 2 different depths (20 mm, superficial sampling site; 60 mm, deep sampling site) of thegluteus mediusmuscle were collected before and after training and after 3 months of detraining. Few significant changes in muscle fibretypecomposition were recorded in response to training. The percentage oftype Ifibres in the deep sampling site of the muscle in Andalusian horses and oftype IIBoxidative fibres in the superficial region in Anglo‐Arabians had increased significantly (P<0.05) after training. The meantype IandIIAcross‐sectional area was increased significantly (range P<0.05 to P<0.0l) after 3 months' training in the deep site of the muscle in Arabian and Andalusian horses, but not in Anglo‐Arabians. The changes seen in fibre sizes disappeared after the detraining period. The mean number of capillaries adjacent totype Ifibres in the superficial sampling site of the muscle had increased significantly (P<0.05) in response to training in Andalusian and Arabian horses. However, a significant decrease in the mean number of capillaries in contact with each fibre type relative to the mean area of that fibre type was observed associated with training in the deep region of the muscle fortype IandIIAfibres in Arabians (P<0.01) and fortype Ifibres in Andalusian horses (P<0.05). It is concluded that a 3 month period of endurance training has a different effect on muscle morphology in different breeds. This period of training rapidly increases the size of the fibres with the greatest oxidative capacity (type IandIIA), particularly in the deep region of thegluteus mediusmuscle, but its intensity and duration were not sufficient to bring about a noticeable change in muscle fibre type composition and capillary density.
Haematuria, pigmenturia and proteinuria in exercising horses
Authors: II H. C. SCHOTT , HODGSON D. R. , BAYLY W. M.
Published: April 2010

The effects of exercise on urinary excretion of red blood cells, pigments (haemoglobin and myoglobin) and protein were studied in 8 mares performing treadmill exercise at speeds eliciting 40, 60 and 95% of the maximal oxygen consumption (V˙O2max). Gross haematuria and pigmenturia were observed in all horses during exercise at the 2 higher intensities, while these findings were detected in only one of 8 mares during exercise at 40% of the V˙O2max. For the remaining 7 mares exercised at 40% of the V˙O2max, increased urinary excretion of red blood cells (RBCs) and pigments was evident after centrifugation of urine samples and reagent strip analysis of the supernatant fractions. An increase in urine flow (UF) during exercise at 40% of the V˙O2maxmay have contributed to the infrequent observation of gross haematuria and pigmenturia during exercise at this intensity. A transient increase in UF following exercise at 60 and 95% of the V˙O2maxresulted in rapid resolution of gross haematuria and pigmenturia, but increased urinary excretion of RBCs and pigments remained evident by reagent strip analysis for up to 60 min following exercise. Mean ± s.e. urinary protein excretion increased from a resting value of 2.2 ± 0.2 mg/min to 5.6 ± 0.9, 14.5 ± 4.7 and 78.4 ± 18.6 mg/min after exercise at 40, 60 and 95% of the V˙O2max, respectively. These results demonstrate that exercise induced haematuria and pigmenturia and post exercise proteinuria are common in horses. Their occurrence is transient and does not appear to be associated with any lasting changes in renal function.
Management factors associated with stereotypic and redirected behaviour in the Thoroughbred horse
Authors: MCGREEVY P. D. , CRIPPS P. J. , FRENCH N. P. , GREEN L. E. , NICOL CHRISTINE J.
Published: April 2010

A greater knowledge of the effect of management factors is required to investigate the ontogeny of abnormal behaviour in the stabled horse. A postal survey of racehorse (flat) trainers yielded information about 22 yard and management factors. The relationship of the factors to the prevalence of abnormal behaviour was analysed by logistic regression. Management factors related to the time spent in the stable showed the strongest associations with stereotypic behaviour. The risk of horses performing abnormal behaviour increased: 1) as the amount of forage fell below 6.8 kg/day, 2) when bedding types other than straw were used, 3) when the total number of horses on the yard was fewer than 75, 4) in association with box designs that minimised contact between neighbouring horses, 5) when hay, rather than other types of forage, was used.
Surgical treatment of fractures of the tibial tuberosity in 6 adult horses
Authors: WRIGHT I. M. , MONTESSO F. , KIDD LISA. J.
Published: April 2010

This paper describes the clinical and radiological features, surgical techniques used and results obtained in 6 horses with fractures of the tibial tuberosity. The horses were presented between 24 h and 8 weeks following injury. In all 6 cases, the fragments were displaced proximocranially and in 2 of these, there was comminution. Four were treated by open reduction and internal fixation using an AO/ASIF narrow dynamic compression plate and in 2 cases the fragments were removed. All horses returned to full athletic function and remained sound in follow‐up times of 17–36 months. Implant removal was necessary in 1 case.
Epidemiological risk factors associated with a diagnosis of clinical cyathostomiasis in the horse
Authors: REID S. W. J. , MAIR T. S. , HILLYER M. H. , LOVE S.
Published: April 2010

Multiple logistic regression was used to assess epidemiological risk factors associated with the diagnosis of cyathostomiasis in 87 cases of chronic diarrhoea in the horse. Age, season and the period since last receiving anthelmintics were identified as important risk factors using chi‐square and two‐sample t test analyses, whereas access to grazing, shared grazing with other horses and recurrence of signs were only weakly associated with a diagnosis of cyathostomiasis. Multivariate analysis of the parameters using logistic regression was performed. The final model included age, season and time since last deworming. At a predicted probability of cyathostomiasis of 0.5, the model had a specificity of 86.0%, sensitivity of 66.7%, overall correct classification of 79.3%, a positive predictive value of 71.4% and a negative predictive value of 83.1%. The results of this study indicated that the specified variables and factors may be useful in the differentiation of clinical cyathostomiasis from other causes of chronic diarrhoea, based on case history alone.
The effect of training on equine metacarpal bone breaking strength
Authors: SHERMAN K. M. , MILLER G. J. , WRONSKl T. J. , COLAHAN P. T. , BROWN M. , WILSON W.
Published: April 2010

Right third metacarpal bones (n=24) from Thoroughbreds, 24 to 48 months old and in race training, were tested to failure in 3 point bending. The neutral load axis was estimated and the distance from the axis to the outer dorsal cortical surface measured. Mid‐diaphyseal dorsopalmar and lateromedial outer cortical and medullary diameters were measured. Breaking strength, cortical area and area moment of inertia were also calculated. Significant correlations were demonstrated between months in training and dorsopalmar bone diameter, cortical area and area moment of inertia. Significant linear models were illustrated between the same 3 variables and number of months in training. It was concluded that increased duration of training significantly enlarges dorsopalmar bone diameter, cortical area and area moment of inertia. Training did not affect metacarpal bone breaking strength as determined by 3 point bending.