bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exercise‐induced pulmonary haemorrhage (EIPH) in horses results from locomotory impact induced trauma ‐ a novel, unifying concept
Authors: SCHROTER R. C. , MARLIN D. J. , DENNY E. 
Published: April 2010

SummaryExercise‐induced pulmonary haemorrhage (EIPH) in horses, although of major welfare and economic importance worldwide, is of uncertain cause. It is accepted that the dorsocaudal region of the lung is particularly prone to the condition, but present theories of causation cannot satisfactorily explain the mechanism or pattern of occurrence. We propose that EIPH results from locomotory impact induced trauma; the mechanism being similar to that producing lung tissue damage following thoracic impact injury.In impact injury, the localised impulsive load on the chest wall is transmitted by pressure waves through the lung at a slower speed than in the chest wall. The waves are subsequently reflected from the distal chest wall and other structures, producing a complex pattern of wave motion; waves travelling from regions of large cross‐section to narrower ones are amplified in magnitude, consequently these regions can experience very high local stresses. Compression/dilation and shear waves are produced within the parenchyma and the latter particularly have been implicated as the cause of parenchymal damage and rupture with oedema and haemorrhage. This form of soft tissue damage has been shown to occur at remarkably low loads with an impact velocity greater than about 11 m/s and pressure exceeding approximately 14 kPa.In the horse, the lung is subjected to comparable levels of locomotory derived impulsive force during moderate to high speed exercise and this is the basis of the mechanism causing EIPH. During locomotion, the force following ground‐strike of the front legs is transmitted, with some attenuation, through the forelimbs to the scapulae. The anatomical arrangement of the scapula, coupled with the direction of the force at the shoulder (scapulo humeral joint) produces an impulsive force on the rib cage, approximately just below mid height of the frontal aspect of the chest approximately over the fourth rib. As a result, pressure waves are transmitted through the lung parenchyma towards the dorsal and caudal regions; these waves are subsequently reflected at the distal chest wall, spine and diaphragm causing a complex pattern of wave interaction. The observed locations of EIPH are at the sites where wave intensity is expected to be greatest due to changes in cross section and reflection. Based on available information, it is estimated that impulsive forces of more than 100 kPa, lasting approximately 10 ms, would be applied to the chest wall by each scapula in a 500 kg horse when galloping; this level of force would be sufficient to cause oedema and haemorrhage as observed in impact induced injury.
Tapeworm infection is a significant risk factor for spasmodic colic and ileal impaction colic in the horse
Authors: PROUDMAN C. J. , FRENCH N. P. , TREES A. J. 
Published: April 2010

SummaryThe association between the equine intestinal tapewormAnoplocephala perfoliataand specific types of intestinal disease was investigated by matched case‐control study using coprological and serological diagnosis. We have previously shown that the host IgG(T) response to 12/13 kDa antigens ofA. perfoliatacorrelates well with infection intensity, therefore this antibody response was used to investigate the risk of colic at different levels of parasite infection intensity. One hundred and three spasmodic colic cases with an equal number of controls matched for age, breed and gender, and 20 ileal impaction cases each with 2 similarly matched controls were obtained. Cases of spasmodic colic were much more likely (odds ratio = 8.0) to be associated withA. perfoliatainfection detected coprologically than controls. Serological diagnosis revealed an increasing risk of spasmodic colic with increasing infection intensity. Calculation of an aetiological fraction suggests that 22% of spasmodic colic cases in this study were tapeworm associated. No significant association was found between colic and strongyle egg count. Conditional logistic regression analysis demonstrated that the relationship between colic and A.perfoliatainfection intensity was not confounded by strongyle egg count and there was a linear relationship between infection intensity and the log‐odds of spasmodic colic. For cases of ileal impaction, a strong association was found between colic andA. perfoliataas diagnosed by coprological means (odds ratio of 34.0). Serological diagnosis also revealed a strong association that increased with higher levels of infection intensity (odds ratio = 26.0). The aetiological fraction for the ileal impaction data suggests that 81% of the ileal impaction cases in this study were tapeworm associated. This study concludes thatA. perfoliatais a significant risk factor for spasmodic colic and ileal impaction colic in the horse; and that the risk of spasmodic colic increases with infection intensity.
Effect of copper supplementation on the copper status of pasture‐fed young Thoroughbreds
Authors: PEARCE S. G. , GRACE N. D. , FIRTH E. C. , WICHTEL J. J. , HOLLE S. A. , FENNESSY P. F. 
Published: April 2010

SummaryThe effect of copper supplementation of pasture fed mares and foals on the copper status of the foals, in terms of plasma, soft tissue and bone copper concentrations and caeruloplasmin activity, was investigated. Twenty‐one Thoroughbred foals from either control mares (n = 9), or copper‐supplemented mares (n = 12) were divided randomly into control (pasture only, n = 10) or supplemented (pasture and oral copper sulphate, n = 11) groups. The pasture diet was grazed by all animals, and contained 4.4–8.6 mg Cu/kg dry matter (DM). The copper supplement for the mares contained copper sulphate equivalent to 0.5 mg Cu/kg liveweight (LW)/day. This daily dose was converted to allow administration as a thrice weekly dose (i.e. multiplied by 7/3) which was given for 13–25 weeks prior to foaling. The supplemented foals, also dosed 3 times a week, received 0.2 mg Cu/kg LW/day at age 21 days, which was increased to 0.5 mg Cu/kg LW/day at 49 days and was continued at this level until euthanasia at 150 days. Foal plasma copper concentration and caeruloplasmin activity increased from birth to 21 dayspost partumand then plateaued at a concentration similar to the mare, but the rise in these indices was not affected by copper supplementation of the mare or foal. Copper supplementation of the foal increased foal liver copper concentration at 150 days (P<0.03). Copper intake of diets containing approximately 8–28 mg Cu/kg DM is well reflected by liver copper concentration, but is poorly reflected by bone, other soft tissue copper concentrations and circulating copper status indices.
Effect of copper supplementation on the evidence of developmental orthopaedic disease in pasture‐fed New Zealand Thoroughbreds
Authors: PEARCE S. G. , FIRTH E. C. , GRACE N. D. , FENNESSY P. F. 
Published: April 2010

SummaryThe effect of copper status on the evidence of bone and cartilage lesions was investigated in 21 Thoroughbred foals. The foals and their dams were grazed on pasture containing 4.4–8.6 mg Cu/kg dry matter (DM). Four treatment groups were created by randomly allocating mares and their foals to either copper supplemented (0.5 mg Cu/kg liveweight (LW)/day), or control (pasture only) groups. This experimental design allowed the effect of copper supplementation of mare and foal to be examined independently. Parameters of bone and cartilage development were assessed in the foals bothin vivo, and atpost mortemat approximately age 150 days. Mare copper supplementation significantly (P<0.01) decreased radiographic indices of physitis in the distal third metatarsal bone of the foals at 150 days, and the prevalence of articular cartilage lesions (P<0.05). Articular cartilage lesions were minor in all foals, with no evidence of clinical developmental orthopaedic disease (DOD)in vivo, with the exception of minor radiographic changes assessed atpost mortem.Copper supplementation of the foal had no effect on any of the bone and cartilage parameters. Copper supplementation of the mares did not abolish DOD in the growing foals, emphasising the probable multifactorial nature of this condition. However, mare supplementation may be a useful treatment regime on a farm where the incidence and severity of DOD are of concern.
Gross, histological and histomorphometric features of the navicular bone and related structures in the horse
Authors: WRIGHT I. M. , KIDD LISA , THORP B. H. 
Published: April 2010

SummaryForelimb navicular bones and associated soft tissues were collected from 3 groups of horses and subjected to pathological examinations. The groups consisted of 38 horses with clinical navicular disease (ND) and 2 control groups, with no history of forelimb lameness, consisting of 25 age‐matched mature horses (A‐MC) and 9 immature horses (IC). Histological and histomorphometric studies were performed on tissue samples from 10 ND, 10 A‐MC and 5 IC horses.Gross changes seen only in ND horses included: full thickness defects in the palmar surface fibrocartilage, palmar cortex erosion, medullary lysis, flexor digitorum profundus tendon (FDPT) surface fibrillation, FDPT core lesions and adhesions between the FDPT and navicular bone. Palmar surface partial thickness fibrocartilage loss and distal border fragmentation were seen with a significantly greater incidence in ND than in A‐MC and not observed in IC. Remodelling of the proximal border, FDPT surface colouration, palmar surface fibrocartilage colouration and proximal border entheseous bone were identified in ND and A‐MC but not in IC. Mid‐ridge synovial fossae and horizontal depressions in the palmar surface were identified in all groups.Histologically palmar fibrocartilage thinning and loss were associated with reduced palmar fibrocartilage cell density and chondrocyte cluster formation. Palmar fibrocartilage fibrillation, palmar cortical bone defects, fibromyxoid stromal change in the medulla, medullary pseudocyst formation and entheseous new bone formation were all seen in ND. The adjacent FDPT showed fibrillation, tag formation and degeneration of the dorsal surface. Necrotic foci were also present within the body of the tendon. Although not always present, medullary bone pseudocysts, separate mineralised foci and most changes on the dorsal surface of the FDPT were specific to ND.Bone histomorphometric parameters were compared among groups. Cross‐sectional area reduced from the sagittal ridge to the medial and lateral margins of each navicular bone. IC navicular bones had a smaller subchondral area, subchondral bone volume and a greater osteoid volume than in the AC, indicating that these differences were age‐related. In ND the medullary area was decreased but the trabecular bone volume increased. The palmar subchondral area was increased but contained bone with an increased porosity and osteoid volume. Changes occurred from the medial to the lateral margins of the bone in horses with ND indicating remodelling of the bony elements throughout the bone in ND.The histological and histomorphometric changes in the navicular bone and palmar fibrocartilage were considered similar of those found in articular hyaline cartilage and subchondral bone in osteoarthritis.
Ex vivoSimulation ofin vivostrain distributions in the equine metacarpus
Authors: LES C. M. , STOVER S. M. , TAYLOR K. T. , KEYAK J. H. , WILLITS N. H. 
Published: April 2010

SummaryThe objective of this study was to examine several simpleex vivoloading conditions for the equine metacarpus, and to evaluate their ability to reproduce the mid‐diaphyseal bone surface strain distributions previously reportedin vivoat the walk and trot. Distributed axial compressive loads, and 9 different axial compressive point loads at −7.5 kN and −15 kN were applied to metacarpal‐distal carpal bone preparations from 6 Thoroughbred horses, aged 1–5 years. The resulting dorsal, medial, palmar, and lateral mid‐diaphyseal bone surface axial and shear strains were compared with previously reportedin vivosurface strain distributions using a root mean square error (RMSE) protocol. The effects of loading condition and load magnitude on RMSE were assessed with a mixed‐model analysis of variance. There were significant differences between loading conditions, and, in most cases, between load magnitudes, in the fit of theex vivoto thein vivostrain distributions.In vivomid‐diaphyseal bone surface strain distributions at the walk can be well approximatedex vivoby a distributed axial compressive load, or by a point load positioned 0.5 cm mediad to the sagittal midline, at −7.5 kN loads.In vivomid‐diaphyseal bone surface strain distributions at the trot can be well approximated by the −15 kN loads applied to the same locations. These simplified loading conditions can be used in designing biologically relevant loading protocols forex vivomechanical testing studies, as well as in developing boundary conditions for finite element analysis.As such, these loading conditions may be considered as tools to be used as a means of replicatingin vivoloading conditions during the intial design and testing stages in the development of fracture fixation devices, as well as in the theoretical mechanical analysis of the metacarpal structure.
An objective method for evaluating the flexibility of the back of standing horses
Authors: LICKA THERESIA , PEHAM C. 
Published: April 2010

SummaryThe spinal movements in maximum arching, dipping and left and right lateral flexion were measured in 10 horses without signs of back pain. A system for motion analysis (Expert Vision System) was used to identify the position of the markers placed on the head, the spinous processes of T5, T10, T16, L3, and on 2 of the sacral spines. By definition, the maximum of the spinal movement was set when the T16 marker reached its maximum deviation from the start position. The difference between start position and maximum position was presented as per cent of the horse's height at the withers. At T16 the mean results for flexion (arching) of the back were 5.9% (s.d. 0.9), for extension (dipping) −2.4% (s.d. 0.7), for flexion to the left 4.2% (s.d. 1.1), and for flexion to the right 5.3% (s.d. 1.3).
Equine TIMP‐1 and TIMP‐2: Identification, activity and cellular sources
Authors: CLEGG P. D. , COUGHLAN A. R. , CARTER S. D. 
Published: April 2010

SummaryMatrix metalloproteinases (MMPs) are the main enzymes involved in connective tissue turnover. Regulation of MMPs is achieved by controlling production, activation of the proenzymes together with the presence of inhibitors, such as, tissue inhibitors of metalloproteinases (TIMPS). The presence of TIMPs in equine synovial fluid was assessed by the ability of the fluid to inhibit equine MMP‐9 activity using a gelatin degradation ELISA. The cellular source of the TIMPs was determined using culture supernatants of resident articular cells (chondrocytes and synovial fibroblasts) and invading inflammatory cells (polymorph neutrophils [PMN] and peripheral blood monocytes [PBM]). The TIMPs were characterised further using reverse zymography, affinity chromatography and N‐terminal amino acid sequencing.Synovial fluid was recovered from horses with articular sepsis and aseptic joint disease (AJD) and compared with that from normal horses (n = 4). TIMP activity was minimal in articular sepsis but significantly increased, albeit a small increase, in AJD when compared to normal (P<0.05). Cell culture supernatants from synovial fibroblasts, chondrocytes and PBMs contained TIMP activity, although supernatants from PMN cell culture did not. Reverse zymography of synovial fluid recovered from normal and AJD horses showed two protein bands, 22 and 28 kDa in size, exhibiting inhibitory activity against MMP‐9. Reverse zymography of culture supernatants of synovial fibroblasts and chondrocytes gave similar results whereas the culture supernatants from PMNs and PBMs showed the presence of only the 28 kDa protein. The N‐terminal amino acid sequence was obtained for the 22 kDa protein and revealed a 66% homology with human TIMP‐2.The identification of TIMPs in equine synovial fluids and cell culture supernatants suggest that they may have a fundamental role in the homeostasis of the normal joint and in the excess proteolysis which occurs in articular disease in the horse.
Total and respirable airborne dust endotoxin concentrations in three equine management systems
Authors: McGORUM B. C. , ELLISON J. , CULLEN R. T. 
Published: April 2010

SummaryThe concentrations of total and respirable airborne endotoxin in the breathing zone of a pony in 3 different management systems, on 8 occasions, are reported. Airborne endotoxin concentrations in all 3 systems were lower than those reported for many other agricultural environments. However, total airborne endotoxin concentrations in many of the conventional stables exceeded those which can induce pulmonary inflammation and bronchial hyper‐responsiveness in normal human subjects, and exceeded those which can induce bronchoconstriction in humans with pre‐existing pulmonary inflammation. Therefore, airborne endotoxin may contribute to the development of airway inflammation and dysfunction in conventionally stabled horses. Potentially detrimental effects of airborne endotoxins on the welfare and exercise performance of stabled horses can be reduced by maintaining horses in ‘low dust’ stables or at pasture, since these environments had significantly lower airborne dust and endotoxin concentrations.
Flat, hurdle and steeple racing: risk factors for musculoskeletal injury
Authors: BAILEY C. J. , REID S. W. J. , HODGSON D. R. , BOURKE J. M. , ROSE R. J. 
Published: April 2010

SummaryA retrospective case‐control study was conducted to identify and quantify risk factors for serious musculoskeletal injury sustained at 4 Australian metropolitan racetracks. During the period of study (August 1988‐July 1995) there were 196 cases from flat racing, 52 cases from hurdle racing and 53 cases from steeplechases. The incidences of fatal musculoskeletal injuries per start for flat, hurdle and steeple races were 0.06, 0.63 and 1.43% respectively. Logistic regression identified harder track surfaces, horses being older than age 3 years, one racecourse (Flemington) and jumping races as significant risk factors which increased the risk of musculoskeletal breakdown. The incidence of fatal musculoskeletal injuries for flat races at the 4 study tracks was similar to that reported in the UK but less than the USA. Death rates for hurdle and steeple races in the study population were higher than in the UK. Strategies to reduce the incidence of serious musculoskeletal injuries may include avoidance of excessively hard track surfaces through closer regulation of track moisture content; implementation of more rigorous prerace lameness examinations of horses, particularly older horses; and altering the design and number of jumps in hurdle and steeple races. The quantification of risk, as we have reported here, is the first step towards addressing the causes of musculoskeletal breakdown and should help in applying a reasoned approach to intervention measures that may be effective in reducing racing injuries.
The effect of foot imbalance on point of force application in the horse
Authors: WILSON A. M. , SEELIG T. J. , SHIELD R. A. , SILVERMAN B. W. 
Published: April 2010

SummaryFoot imbalance is believed to be a common cause of musculoskeletal injury in the horse; its biomechanical effects are, however, poorly understood. Wedges (angle 3.7 and 5°) were attached to modified shoes to elevate one aspect of both front feet of Thoroughbred‐type horses. The point of force application during weightbearing was determined at trot using a forceplate system. A total of 8 horses were studied with a minimum of 4 providing data for each wedge condition. The results demonstrated that application of a standard steel horse shoe to a balanced foot has minimal effect on the point of force trace through stance. Alteration of mediolateral hoof balance resulted in a displacement of point of force application by about 10 mm in the direction of the wedge throughout stance. Elevation of the heels delayed unloading of the heels and elevation of the toe advanced unloading. Reassessment 24 h after shoeing showed minimal change in the point of force trace. This work demonstrates that a horse is unable to compensate for an acute foot imbalance by redistributing the load under the foot. The higher loads in the elevated region are likely to have a detrimental effect on the hoof structure and horn growth in that part of the hoof.
The role of prostanoids and nitric oxide in endotoxin‐induced hyporesponsiveness of equine digital blood vessels
Authors: BAILEY S. R. , ELLIOTT J. 
Published: April 2010

SummaryEndotoxin has been implicated in the pathophysiology of acute laminitis. The aim of this study was to examine the direct effects of endotoxin on isolated equine digital blood vessels. Equine digital veins (EDV), incubated in Krebs‐Henseleit solution containing lipopolysaccharide (LPS) (1 μg/ml) became hyporesponsive to 5‐HT after 16 h. Cycloheximide and ibuprofen blocked this effect of LPS and increased the maximum response obtained to 5‐HT when compared to control vessels. L‐nitroarginine methyl ester (L‐NAME) reversed the hyporesponsiveness caused by LPS. Vessels maintained in culture medium containing LPS also became hyporesponsive to 5‐HT, an effect which was completely prevented by ibuprofen but only partially reversed by L‐NAME.Measurements were made of 6‐keto PGF1αand nitrite production by segments of equine digital artery and vein in culture medium alone or co‐cultured with peripheral blood leucocytes. LPS did not stimulate nitrite production from vessel segments but increased nitrite release from leucocytes, an effect which was inhibited by cycloheximide and L‐NAME. Lipopolysaccharide increased 6‐keto PGF1αproduction by blood vessels, an effect which was inhibited by cycloheximide and ibuprofen but not L‐NAME. No synergistic effect on release of nitrite or 6‐keto PGF1αwas noted in co‐cultures of blood vessels and leucocytes.These data suggest that induction of cyclo‐oxygenase by LPS was a major cause of hyporesponsiveness of digital blood vessels to 5‐HT. Release of nitric oxide was not detectable in LPS‐stimulated blood vessels maintained in culture even in the presence of activated leucocytes yet L‐NAME did protect against LPS‐induced hyporesponsiveness indicating nitric oxide synthase induction may play some role in the effect of LPS. These findings are important in furthering our understanding of the pathophysiological mechanisms underlying the vascular changes which occur in acute laminitis.