bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of pressure distribution under an English saddle at walk, trot and canter
Authors: FRUEHWIRTH B. , PEHAM C. , SCHEIDL M. , SCHOBESBERGER H.
Published: April 2007

Reasons for performing study: Basic information about the influence of a rider on the equine back is currently lacking.

Hypothesis: That pressure distribution under a saddle is different between the walk, trot and canter.

Methods: Twelve horses without clinical signs of back pain were ridden. At least 6 motion cycles at walk, trot and canter were measured kinematically. Using a saddle pad, the pressure distribution was recorded. The maximum overall force (MOF) and centre of pressure (COP) were calculated. The range of back movement was determined from a marker placed on the withers.

Results: MOF and COP showed a consistent time pattern in each gait. MOF was 12.1 ± 1.2 and 24.3 ± 4.6 N/kg at walk and trot, respectively, in the ridden horse. In the unridden horse MOF was 172.7 ± 11.8 N (walk) and 302.4 ± 33.9 N (trot). At ridden canter, MOF was 27.2 ± 4.4 N/kg. The range of motion of the back of the ridden horse was significantly lower compared to the unridden, saddled horse.

Conclusions and potential relevance: Analyses may help quantitative and objective evaluation of the interaction between rider and horse as mediated through the saddle. The information presented is therefore of importance to riders, saddlers and equine clinicians. With the technique used in this study, style, skill and training level of different riders can be quantified, which would give the opportunity to detect potentially harmful influences and create opportunities for improvement.
Endoscopic scoring of mucus quantity and quality: observer and horse variance and relationship to inflammation, mucus viscoelasticity and volume
Authors: GERBER V. , STRAUB R. , MARTI E. , HAUPTMAN J. , HERHOLZ C. , KING M. , IMHOF A. , TAHON L. , ROBINSON N. E.
Published: April 2007

Reasons for performing study: Endoscopic scoring of airway mucus quantity and quality has not been critically assessed.

Objectives: To evaluate mucus scores for 1) observer‐ and horse‐related variance and 2) association with inflammation, mucus viscoelasticity and measured volume.

Methods: Variance of scoring within and between observers and over time within horses were determined for airway mucus accumulation, apparent viscosity, localisation and colour, and correlations of mucus accumulation scores with neutrophil ratios in secretions. The relationship of accumulation score to measured volumes of ‘artificial mucus’ was investigated. Correlations of mucus accumulation, apparent viscosity and colour scores with measured viscoelasticity were tested. Viscoelasticity was compared between tracheal secretion samples collected ventrally and dorsally.

Results: Mucus accumulation scoring showed excellent interobserver agreement and moderate horse‐related variance, was related to measured volumes of ‘artificial mucus’, and correlated well with neutrophilic airway inflammation. Scores of mucus viscosity, colour and localisation showed high observer‐related variance. Mucus accumulation, apparent viscosity and colour scores did not correlate with measured tracheal mucus viscoelasticity, but dorsally‐localised mucus showed 2‐fold higher measured viscoelasticity than ventrally‐localised samples.

Conclusions: Mucus accumulation scores are a reproducible measure of mucus volumes in the trachea.

Potential relevance: Endoscopic scoring of mucus accumulation is a reliable clinical and research tool. In contrast, apparent viscosity, localisation and colour scores should be interpreted with caution.
A dose titration of triamcinolone acetonide on insulin‐like growth factor‐1 and interleukin‐1‐conditioned equine cartilage explants
Authors: Sandler E. A. , Frisbie D. D. , MCIlwraith C. W.
Published: April 2007

Reasons for performing study: Previousin vitropilot studies have defined a potentially beneficial effect of insulin‐like growth factor‐1 (IGF‐1) and triamcinolone acetonide (TA) on interleukin‐1 (IL‐1)‐conditioned equine cartilage. Furthermore, an optimal dose for IGF‐1 treatment alone has been documented previously using the same test system as in the current project.

Objectives: To perform a dose titration of TA on IL‐1‐conditioned equine articular cartilage explants in the presence of an optimised IGF‐1 dose, in order to optimise a triamcinolone concentration for use in combination with IGF‐1 for future investigations.

Methods: Cartilage explants were harvested from the distal femur of a normal horse. The effect of a clinically relevant TA dose range was evaluated in the presence of IL‐1 and IGF‐1 through measurement of proteoglycan (PG) matrix metabolism (synthesis and degradation).

Results: TA and IGF‐1 in combination inhibited the IL‐1‐induced release of PG matrix components (glycosaminoglycan or GAG) from the articular cartilage, as well as producing a significant increase in GAG synthesis.

Conclusions: This experiment provided proof of principle that a combination treatment appears to be able to combat the IL‐1‐induced matrix depletion, while enhancing anabolic metabolism within the articular cartilage.

Potential relevance: The use of IGF‐1 in conjunction with TAin vivohas the potential to provide beneficial anabolic effects not seen with TA alone.
High detail radiography and histology of the centrodistal tarsal joint of Icelandic horses age 6 months to 6 years
Authors: Björnsdóttir S. , Ekman S. , Eksell P. , Lord P.
Published: April 2007

Reasons for performing study: Osteoarthrosis (OA) in the distal tarsal joints, bone spavin, is a well known condition which is common in Icelandic horses age 6–12 years.

Objectives: To determine the nature, location and age of appearance of early radiographic and histological changes in the centrodistal tarsal joint (CD) of young Icelandic horses.

Methods: Slab sections from the CD of young Icelandic horses were examined by high detail radiography (age 6 months to 6 years, n = 111) and histology (age 6 months to 4 years, n = 82) to detect and describe the early changes indicative of OA. Horses younger than 5 years were unridden.

Results: Chondronecrotic lesions histologically similar to those described in the early pathogenesis of OA were seen in 33% of the joints, located both medially and laterally. Radiographic sclerosis of the subchondral bone was recorded in 60% of the specimens, most often medially. Medial location was not associated with chondronecrosis, but was strongly related to age. Sclerosis was an infrequent finding on the lateral side, and was probably secondary to chondronecrosis in the corresponding part of the joint. Small defects in the subchondral bone were considered to be the most specific radiographic sign of OA as they were strongly associated with chondronecrosis.

Conclusions: The high prevalence of chondronecrosis in the young horses indicates an early onset and slow progression of the disease. The early appearance also shows that the initiation of the disease is unrelated to the use of horses for riding. As clinical manifestation of OA in the distal tarsal joints is most often described in mature or old horses, the first stages of the disease are not likely to result in clinical signs. Subchondral bone sclerosis did not appear to be a primary factor in the development of OA in the CD but was considered to reflect an uneven distribution of biomechanical forces within the joint.

Potential relevance: The development of OA in the CD of young Icelandic horses seems to be due to poor conformation or joint architecture rather than trauma or overloading. These aetiological factors are likely to be of importance for OA in the distal tarsal joints in other breeds as well. The influence of hindlimb conformation and the architecture of the distal tarsal joints on the biomechanics of joints need to be investigated, preferably by locomotion analysis in young horses.
Collagenase‐1 (MMP‐1) activity in equine synovial fluid: influence of age, joint pathology, exercise and repeated arthrocentesis
Authors: Brama P. A. J. , Van Den Boom R. , DEGroot J. , Kiers G. H. , Van Weeren P. R.
Published: April 2007

Reasons for performing study: Matrix metalloproteinases (MMPs) are considered candidate biomarkers for both physiological and pathological tissue remodelling because of their key role in articular cartilage homeostasis. As disruption of the collagenous architecture is thought to be pivotal in chronic degenerative diseases such as osteoarthritis (OA), the collagenases form an interesting subset of the MMPs. The significance of any biomarker in synovial fluid (SF) can be assessed properly only when fluctuations in patterns induced by physiological processes such as development and growth, and by external influences and interventions such as exercise and repeated arthrocentesis, are known and taken into account.

Objectives: To investigate the activity of MMP‐1 in equine SF at different stages of development and in joints affected by OA, and the influence of exercise and repeated arthrocentesis thereon.

Methods: MMP‐1 activity was determined in SF of normal joints of fetal, juvenile and mature horses, and in SF of horses suffering from OA, using an internally quenched fluorogenic peptide substrate. MMP‐1 activity was also measured in SF from horses subjected to an exercise regimen and those subjected to repeated arthrocentesis.

Results: An age‐related decline in the SF levels of active MMP‐1 was observed. MMP‐1 activity was 15‐fold higher in fetal than in juvenile animals, which showed significantly higher MMP‐1 activity levels than mature horses. In SF of OA joints, MMP‐1 activity was increased. Exercise did not affect MMP‐1 activity in SF, but repeated arthrocentesis (within 60 h) increased MMP‐1 activity significantly.

Conclusions: The high MMP‐1 activity in SF of young individuals parallels the high metabolic activity occurring during rapid growth and differentiation at early age. The elevated MMP‐1 activity in SF of OA joints probably reflects pathological matrix degradation, confirming the potential of MMP‐1 to serve as a biochemical marker for early joint disease. Moderate exercise is not likely to influence the outcome of MMP‐1 activity measurements in equine SF, but arthrocentesis should be taken into account as a possible confounding factor.

Potential relevance: Given the crucial role of the collagen matrix for tissue integrity, MMP‐1 activity may be a useful tool in diagnostic, therapeutic or prognostic studies in horses suspected of OA. However, care should be taken to exclude fluctuations in MMP‐1 activity induced by physiological processes such as development and growth, and by interventions such as repeated arthrocentesis.
Tissue‐specific dysregulation of cortisol metabolism in equine laminitis
Authors: Johnson P. J. , Ganjam V. K. , Slight S. H. , Kreeger J. M. , Messer N. T.
Published: April 2007

Reasons for performing study: The role of glucocorticoids (GCs) in the pathogenesis of laminitis is incompletely understood. Local tissue activity of GC is regulated by the steroid converting enzyme, 11β‐hydroxysteroid dehydrogenase‐1 (11β‐HSD‐1). Changes in integumentary (skin and hoof lamellar) 11β‐HSD activity occurring during laminitis could affect the extent to which GCs are involved in its development.

Hypothesis: That changes in integumentary 11β‐HSD‐1 activity associated with the laminitic condition would lead to elevated local tissue levels of GCs, which could subsequently contribute, through paracrine and autocrine mechanisms, to the further development of laminitis; and that similar changes in 11β‐HSD‐1 activity would be evident in both skin and hoof lamellar tissue.

Methods: Activity of 11β‐HSD‐1 was determined in skin and hoof lamellar tissue specimens obtained from normal and laminitic horses using a radiometric assay. Skin samples were obtained from 10 normal horses and from 10 horses before and after induction of acute laminitis following administration of starch via nasogastric tube. Hoof lamellar samples were obtained from 10 normal horses, 10 horses following induction of acute laminitis and 4 chronically‐foundered horses. Bidirectional 11β‐HSD‐1 activity was measured in both skin and lamellar tissues.

Results: 11‐ketoreductase activity exceeded 11β‐dehydrogenase activity in both skin and lamellar tissues. Cutaneous activity was higher than lamellar 11β‐HSD‐1 activity in all groups. Both ketoreductase and dehydrogenase activity increased in skin and lamellae following experimental induction of acute laminitis, but the increase in ketoreductase activity was substantially greater than that for dehydrogenase in the lamellae. Induction of acute laminitis was attended by increases of 227 and 220% in cutaneous dehydrogenase and ketoreductase activity, respectively, and 173 and 398% in lamellar dehydrogenase and ketoreductase activity, respectively (P<0.05).

Conclusions: The 11‐ketoreductase moiety of 11β‐HSD‐1 plays a role in equine skin and hoof lamellae regarding the regulation of local glucocorticoid activity. Increased 11‐ketoreductase activity will lead to increased local tissue GC activity by virtue of conversion of cortisone to cortisol.

Potential relevance: The laminitic condition is attended by integumentary biochemical changes that enhance the local concentration of cortisol, especially in the hoof lamellar interface. Through multiple and diverse actions, increased local GC activity contributes to the pathogenesis and morbidity associated with laminitis. Pharmacological manipulation of 11β‐HSD‐1 deserves further investigation regarding the prevention and treatment of laminitis.
Nutritional and clinicopathological effects of post operative parenteral nutrition following small intestinal resection and anastomosis in the mature horse
Authors: DURHAM A. E. , PHILLIPS T. J. , WALMSLEY J. P. , NEWTON J. R.
Published: April 2007

Reasons for performing study: There is an absence of data describing the nutritional requirements and nutritional status of horses following surgery for colic; furthermore, the potential effect of parenteral nutrition (PN) on improving nutritional status in such cases is unknown.

Hypothesis: Post operative colic cases suffer from a potentially detrimental negative energy balance and the PN formulation developed in this study would lead to clinicopathologically detectable improvements in the subjects' nutritional status.

Methods: Several clinicopathological variables, some known to be associated with nutritional status, were compared in 2 groups of horses in the post operative period following colic surgery;Group N(n = 15) were treated with PN andGroup C(n = 15) were starved routinely.

Results: Group Nhad significantly lower serum concentrations of triglycerides, total bilirubin, albumin and urea and significantly higher serum concentrations of glucose and insulin compared withGroup Cin the post operative period.

Conclusions: The control group of horses demonstrated significant clinicopathological evidence of starvation and the described PN protocol resulted in a demonstrably improved nutritional status in the treated horses.

Potential relevance: Further study is required to investigate clinical benefits and possible harmful side effects of post operative parenteral nutrition before the technique can be advocated for widespread use in practice.
Effect of anaesthesia of the palmar digital nerves on proximal interphalangeal joint pain in the horse
Authors: SCHUMACHER J. , LIVESEY L. , De GRAVES F. J. , SCHUMACHER J. , SCHRAMME M. C. , HATHCOCK J. , TAINTOR J. , GOMEZ J.
Published: April 2007

Reasons for performing study: Anaesthesia of the palmar digital nerves is claimed to attenuate lameness in some horses that are lame because of pain in the proximal interphalangeal (PIP) joint.

Objective: To determine the response of horses with pain in the PIP joint to anaesthesia of the palmar digital nerves.

Methods: Horses were video recorded trotting before and after induction of pain in the PIP joint and 10 mins after anaesthesia of the palmar digital nerves. The palmar digital nerves were anaesthetised 3 times at different sites, and the video recorded gaits were scored subjectively.

Results: The median lameness score of gaits after administration of 2% mepivacaine 1 cm proximal to the cartilages of the foot was not significantly different from the median lameness score before anaesthesia of the palmar digital nerves (P0.05), although that of 1 of 6 horses improved markedly. The median lameness score was significantly (P0.05) improved after mepivacaine was administered 2 and 3 cm proximal to the cartilages of the foot.

Conclusions: The PIP joint is unlikely to be anaesthetised when the palmar digital nerves are anaesthetised at the proximal margin of the cartilages of the foot.

Potential relevance: Pain within the PIP joint cannot be excluded as a cause of lameness when lameness is attenuated by anaesthesia of the palmar digital nerves at any site proximal to the proximal margin of the cartilages of the foot.
Why are certain premises at increased risk of equine grass sickness? A matched case‐control study
Authors: Mccarthy H. E. , French N. P. , Edwards G. B. , Miller K. , Proudman C. J.
Published: April 2007

Reasons for performing study: Equine grass sickness (EGS) occurs repeatedly on certain premises over time. Few studies have sought, or identified, the determinants of this phenomenon in order to inform advice on disease prevention strategies.

Hypothesis: Premises‐level risk factors are important determinants of whether EGS occurs.

Methods: A matched case‐control study was undertaken. Sixty premises giving rise to one or more histologically confirmed case of EGS and 120 time‐matched control premises were sampled. Data were collected on pasture management, soil nutrient content, pasture nutrient content and local weather conditions for 2 weeks prior to the onset of disease. Data were analysed by conditional logistic regression.

Results: Multivariable modelling identified an association between EGS and increased soil nitrogen content, pasture disturbance and previous occurrence of EGS on the premises. None of the meteorological variables recorded in this study were significantly associated with EGS occurrence. No relationship between certain management practices (e.g. harrowing, fertilisation, reseeding) and the risk of EGS was detected.

Conclusions and potential relevance: This information is useful in understanding the causal pathway of EGS and may be used in the formulation of evidence‐based disease avoidance strategies.;
The influence of repeated arthrocentesis and exercise on matrix metalloproteinase and tumour necrosis factor a activities in normal equine joints
Authors: Van Den Boom R. , Brama P. A. J. , Kiers G. H. , Degroot J. , Barneveld A. , Van Weeren P. R.
Published: April 2007

Reasons for performing study: Matrix metalloproteinases (MMPs) and tumour necrosis factor α (TNF‐α) may be useful as biomarkers of joint disease or inflammation. However, activity of both MMPs and TNF‐α in synovial fluid (SF) may be influenced by nonpathological factors such as arthrocentesis or exercise.

Objective: To investigate the influence of repeated arthrocentesis and exercise on MMP and TNF‐α activities in SF from normal equine joints.

Methods: SF was collected from the left metacarpophalangeal, radiocarpal and tarsocrural joints of 16 horses. Eight of these horses were subsequently subjected to an exercise programme on a treadmill and 8 were box‐rested as controls. Arthrocentesis was repeated 14, 14.5, 17 and 24 days after the start of the exercise programme. General MMP and TNF‐α activities were determined in SF.

Results: Repeated arthrocentesis caused a gradual increase but the exercise regimen no significant increase in MMP activity. There was a significant increase in TNF‐α activity in SF collected from horses 2 h after cessation of the exercise programme.

Conclusions and potential relevance: When using MMPs as biomarkers for joint disease, at least 14 days should elapse after previous arthrocentesis before subsequent SF collection. Moderate exercise does not increase MMP activity in SF from normal joints and it may be possible to ignore this as a source of error in evaluating MMP activity in diseased joints.;
Pharmacokinetics of recombinant hirudin in healthy horses
Authors: Feige K. , Dennler M. , Kästner S. B. R. , Wunderli‐Allenspach H. , Demuth D. , Huber A.
Published: April 2007

Reasons for performing study: Recombinant (r)‐hirudin is a specific inhibitor of thrombin that is independent of the activity of antithrombin.

Objectives: To evaluate pharmacokinetic properties and coagulatory changes of r‐hirudin in healthy horses.

Methods: Two clinically healthy horses received a single i.v. bolus of 0.4 mg/kg bwt r‐hirudin and 6 clinically healthy horses received the same dose subcutaneously (subcut.) q. 12 h for 3 days. Coagulation times and r‐hirudin plasma concentration were determined over 720 mins and 3 days after i.v. and subcut. administration, respectively.

Results: In all horses, treatment with r‐hirudin was not associated with systemic or local side effects. After i.v. injection, the 2 horses showed an elimination half‐life of 58 and 80 mins, respectively. After subcut. administration, maximum plasma concentration of r‐hirudin occurred at 128 ± 55 mins and declined with a terminal half‐life of 561 ± 364 mins. Maximum response of activated partial thromboplastin time (aPTT) occurred 1.5 h after administration of r‐hirudin. A prolongation of 1.9 ± 0.2 times the pretreatment value was noted.

Conclusions: Pharmacokinetics of r‐hirudin in healthy horses were similar to those in man and other animal species.

Potential relevance: The results of this study indicate that r‐hirudin can be used in horses, but further studies should be performed in order to prove its effectiveness in diseased horses.;
Clinical significance of ossification of the cartilages of the front feet based on nuclear bone scintigraphy, radiography and lameness examinations in 21 Finnhorses
Authors: Ruohoniemi M. , Mäkelä O. , Eskonen T.
Published: April 2007

Reasons for performing study: Research on the clinical significance of ossification of the cartilages of the foot has been limited, despite the common nature of the condition and conflicting reports in previous literature.

Hypothesis: Some radiographic features in the ossification of the cartilages, such as incomplete fusion lines between separate centres of ossification and the ossified base, are of clinical significance.

Methods: The relationships between radiopharmaceutical uptake in bone phase nuclear scintigraphy at the heels (palmar processes of the distal phalanx, including ossification of the cartilages of the foot), radiographic extent and type of ossification of the cartilages and clinical lameness were evaluated retrospectively in 21 Finnhorses (age ≥4 years) in a total of 36 front feet.

Results: No significant relationship between height of the ossifications and radiopharmaceutical uptake at the ipsilateral heels existed. Clearly separate centres of ossification were not associated with increased uptake. Moderately increased uptake was suspected to be associated with ossification of the adjacent cartilage in only one foot. Intense uptake was present unilaterally in 4 horses, at one medial and 3 lateral heels. In 2 of these horses, a unilateral palmar digital nerve block relieved the mild lameness; 2 horses had no obvious lameness but had a history of being stiff or having locomotion problems during high speed trot. At 2 of the lateral heels, an incomplete fusion line was present between a large separate centre of ossification and the base, and the third horse had a high sidebone with bony protrusions, suggestive of chronic entheseopathy in a narrow foot. At the medial heel, an oblique radiograph revealed a faint radiolucent line at the base of the ossification. In all cartilages with intense radiopharmaceutical uptake at the heel and/or lameness, the ossified part of the cartilage was wider and more irregular compared to other ossifications of the front feet of the individual.

Conclusions: Increased radiopharmaceutical uptake, associated with a different radiographic appearance from that of other ossifications of the front feet, was a conclusive sign of clinical significance. Obscure locomotion problems were more commonly associated with ossification of the cartilages than true lameness.

Potential relevance: This information is useful in lameness and prepurchase examinations and is likely also to be applicable to other coldblooded breeds used for athletic purposes.;
Equine laminitis: cryotherapy reduces the severity of the acute lesion
Authors: Van Eps A. W. , Pollitt C. C.
Published: April 2007

Reasons for performing study: The hypometabolic and vasoconstrictive effects of cryotherapy could prevent the development of laminitis.

Objectives: To use distal limb cryotherapy to prevent laminitis induced by alimentary carbohydrate overload.

Methods: Laminitis was induced in 6 Standardbred horses that had one front limb continuously cooled in an ice/water mixture. Lameness evaluation, blinded lamellar histological grading and analysis for lamellar matrix metalloproteinase‐2 (MMP‐2) mRNA expression were used to evaluate the severity of laminitis.

Results: Cryotherapy was well tolerated and effective in cooling the feet. In each horse no lameness was observed in the treated limbs. Laminitis histology scores in the treated limbs were significantly less than those of the corresponding untreated forelimbs (P<0.05). Laminitis histology scores in the treated limbs were also significantly less than those of the untreated limbs (fore‐ and hind) as a group (P<0.05). Expression of MMP‐2 mRNA in the iced feet was significantly (P<0.05) less than that detected in the untreated feet.

Conclusions: Cryotherapy, when applied to one foot, markedly reduced the severity of acute laminitis in this study. We propose that vasoconstriction (preventing delivery of haematogenous trigger factors) and hypometabolism (reduction in lamellar MMP activity) were the primary therapeutic mechanisms.

Potential relevance: Although further research is needed, we suggest cryotherapy as a potentially effective prophylactic strategy in horses at risk of developing acute laminitis.
Equine laminitis: cleavage of laminin 5 associated with basement membrane dysadhesion
Authors: French K. R. , Pollitt C. C.
Published: April 2007

Reasons for performing study: The key lesion of laminitis is separation at the hoof lamellar dermal‐epidermal interface. For this to happen the structural and adhesion proteins of the basement membrane zone must be altered. Which proteins and how damage to them leads to the lamellar separation of laminitis is unknown.

Objectives: To investigate lamellar hemidesmosome and cytoskeleton damage and basement membrane dysadhesion using light microscopy (LM) and immunofluorescence microscopy (IFM).

Methods: Cryostat sections of lamellar tissues from 2 control and 6 Standardbred horses with oligofructose induced laminitis were studied using LM and IFM. Plectin, integrin α6 and BP230 antibody was used to label hemidesmosome intracellular plaque proteins and anti‐BP180 and anti‐laminin 5 (L5) was used to label anchoring filament (AF) proteins. Cytoskeleton intermediate filaments were labelled using anti‐cytokeratin 14. The primary antibodies of selected sections were double labelled to show protein co‐localisation.

Results: Laminitis caused reduction of transmembrane integrin α6, the AF proteins BP180 and L5, and failure of co‐localisation of BP180 and L5. Proteins of the inner hemidesmosomal plaque, plectin and BP230, were unaffected.

Conclusions: Loss of co‐localisation of L5 and BP180 suggests that, during the acute phase of laminitis, L5 is cleaved and therefore, the AFs connecting the epidermis to the dermis, fail. Without a full complement of AFs separation at the lamellar dermo‐epidermal junction occurs.

Potential relevance: Suppressing or inhibiting metalloproteinase activity may prevent L5 cleavage and therefore the lamellar dermo‐epidermal separation of laminitis.
Prolonged, continuous distal limb cryotherapy in the horse
Authors: Pollitt C. C. , Van Eps A. W.
Published: April 2007

Reasons for performing study: The recommended duration of cryotherapy in horses is currently extrapolated from human medicine. Prolonged, continuous cryotherapy (days rather than minutes) may be of therapeutic value if it is safe and well tolerated.

Objectives: To evaluate the effect of prolonged, continuous application of ice and water to the equine distal limb.

Methods: A slurry of ice and water was applied to the right forelimb of 4 Standardbred horses for 48 h. Hoof temperature, ambient temperature and ice boot temperature were logged continuously and clinical observations recorded every 2 h. Lameness examinations were performed prior to application and 1 week, 6 months and 1 year after removal of the ice boot.

Results: Continuous cryotherapy was well tolerated and resulted in marked cooling of the treated foot. No significant variation in clinical parameters was noted, and no lameness or gross pathology noted in the treated limbs at any examination period.

Conclusions: The continuous application of ice and water is a safe and effective means of cooling the equine distal limb. The extremely low, constant temperatures achieved may be of benefit in the management of various distal limb conditions.

Potential relevance: Providing clinicians and research workers with a potent therapeutic/prophylactic modality for disorders of the equine distal limb.
Biochemical indices of vascular function, glucose metabolism and oxidative stress in horses with equine Cushing's disease
Authors: Keen J. A. , Mclaren M. , Chandler K. J. , Mcgorum B. C.
Published: April 2007

Reasons for performing study: The mechanisms underlying the increased risk of laminitis in horses with equine Cushing's disease (ECD) are poorly understood.

Hypothesis: That abnormalities in glucose homeostasis, similar to those which cause microvascular dysfunction in human diabetics, contribute to development of laminitis in horses with ECD.

Methods: Thirty‐one aged horses were divided into 3 groups based on clinical signs and dexamethasone suppression testing (DST).Group 1(n = 12) had clinical ECD as evidenced by hirsutism.Group 2(n = 10) had a positive DST but no hirsutism.Group 3(n = 9) were controls without ECD, with a negative DST and no clinical evidence of ECD. Biochemical indices of glucose metabolism, vascular function and oxidative stress were determined in single morning blood samples.

Results: Group 1 had abnormalities in glucose homeostasis, including increased levels of glucose and insulin, compared toGroups 2and3. Groups 1and2had significantly lower plasma thiol (PSH) levels and nonsignificantly lower albumin‐corrected PSH levels than Group 3, consistent with oxidative stress.

Conclusions and potential relevance: The observed abnormalities in glucose metabolism and oxidative stress could potentially contribute to development of laminitis in horses with ECD, by similar mechanisms to those that cause microvascular dysfunction in human diabetics. The absence of inter‐group differences in the biochemical indices of vascular function precludes their use as preclinical diagnostic indicators of vascular dysfunction. The study also highlighted limitations in the premortem diagnosis of ECD.
Hyaluronan in horses: physiological production rate, plasma and synovial fluid concentrations in control conditions and following sodium hyaluronate administration
Authors: POPOT M.‐A. , BONNAIRE Y. , GUÉCHOT J. , TOUTAIN P.‐L.
Published: April 2007

Reasons for performing study: Hyaluronic acid (HA) is an endogenous glycosaminoglycan used in the treatment of joint diseases, but medication control is required by horseracing authorities. Therefore, a medication control policy needs to be established.

Objectives: To establish physiological plasma HA concentrations in post race horses, determine the HA endogenous production rate and document the disposition of HA after i.v. and intra‐articular hyaluronic acid administration at recommended therapeutic doses.

Methods: Hyaluronan concentrations in plasma were determined using an ELISA specific test; concentrations in synovial fluid were determined using a radiometric binding assay.

Results: The overall mean plasma HA concentration in 120 post competition horses was 89 ng/ml. In a group of 6 experimental horses, synovial fluid control concentration was 328 ± 112 μg/ml. After i.v. sodium hyaluronate administration (37.8 mgin toto), the terminal half‐life was very short (43 ± 29 mins) and after a delay of 3 h, the plasma concentration returned to control values. The endogenous HA production rate was 33—164 mgin totoper day, i.e. 1—4 times the recommended i.v. daily dose. Twenty‐four hours after intra‐articular administration, HA concentration was not significantly different from control values (328 ± 112 μg/ml).

Conclusions and potential relevance: Due to the rapid disappearance of HA from plasma after i.v. administration and from the joint after intra‐articular administration, long‐term detection needs a more appropriate approach to be developed.
Tenoscopic surgery for treatment of lacerations of the digital flexor tendon sheath
Authors: FRASER B. S. L. , BLADON B. M.
Published: April 2007

Reasons for performing study: Lacerations to the digital flexor tendon sheath (DFTS) are a common injury in the horse, but little information is available in the literature regarding prognostic indicators.

Objective: To ascertain whether laceration of the DFTS carried a better prognosis if treated by tenoscopic lavage, debridement and repair within 36 h of the original injury.

Methods: A retrospective analysis of 39 horses treated surgically for lacerations to the DFTS was performed over a 3 year period. The injury‐to‐surgery interval was recorded as <36 or >36 h. The structures damaged by the injury were also recorded, as well as age, sex, use and outcome.

Results: Sixteen horses had laceration and contamination of the DFTS alone, of which 15 (94%) returned to their original or intended use. Sixteen horses had lacerations involving the superficial digital flexor tendon, of which 12 (75%) made a full recovery. Six horses had lacerations to both superficial and deep digital flexor tendons, 5 were subjected to euthanasia intraoperatively and one is paddock sound. Treatment within 36 h of initial laceration carried a significantly better prognosis for return to intended athletic use (25 of 28 horses allowed to recover from anaesthesia) than treatment after 36 h (2 of 5 P = 0.03; Fisher's Exact Test).

Conclusions: If sepsis is treated early using tenoscopic visualisation, lavage and repositol antibiotics, the limiting factor in return to athletic function is tendon damage.

Potential relevance: This study supports anecdotal evidence that early treatment of synovial sepsis improves the prognosis for return to intended use. It also provides information on prognostic indicators including extent of damage to collateral structures.
Effects of stylopharyngeus muscle dysfunction on the nasopharynx in exercising horses
Authors: TESSIER C. , HOLCOMBE S. J. , DERKSEN F. J. , BERNEY C. , BORUTA D.
Published: April 2007

Reasons for performing study: Nasopharyngeal collapse has been observed in horses as a potential cause of exercise intolerance and upper respiratory noise. No treatment is currently available and affected horses are often retired from performance.

Objective: To determine the effect of bilateral glossopharyngeal nerve block and stylopharyngeus muscle dysfunction on nasopharyngeal function and airway pressures in exercising horses.

Methods: Endoscopic examinations were performed on horses at rest and while running on a treadmill at speeds corresponding to HRmax50, HRmax75and HRmax, with upper airway pressures measured with and without bilateral glossopharyngeal nerve block.

Results: Bilateral glossopharyngeal nerve block caused stylopharyngeus muscle dysfunction and dorsal nasopharyngeal collapse in all horses. Peak inspiratory upper airway pressure was significantly (P = 0.0069) more negative at all speeds and respiratory frequency was lower (P = 0.017) in horses with bilateral glossopharyngeal nerve block and stylopharyngeus muscle dysfunction compared to control values.

Conclusions: Bilateral glossopharyngeal nerve anaesthesia produced stylopharyngeus muscle dysfunction, dorsal pharyngeal collapse and airway obstruction in all horses.

Potential relevance: The stylopharyngeus muscle is probably an important nasopharyngeal dilating muscle in horses and dysfunction of this muscle may be implicated in clinical cases of dorsal nasopharyngeal collapse. Before this information can be clinically useful, further research on the possible aetiology of stylopharyngeus dysfunction and dysfunction of other muscles that dilate the dorsal and lateral walls of the nasopharynx in horses is needed.
Prevalence of superficial digital flexor tendonitis and suspensory desmitis in Japanese Thoroughbred flat racehorses in 1999
Authors: KASASHIMA Y. , TAKAHASHI T. , SMITH R. K. W. , GOODSHIP A. E. , KUWANO A. , UENO T. , HIRANO S.
Published: April 2007

Reasons for performing study: Overstrain injuries to the superficial digital flexor tendon (SDFT) and suspensory ligament (SL) are among the most common musculoskeletal injuries which contribute to the considerable wastage of racing Thoroughbreds. Many epidemiological studies have demonstrated the prevalence of and risk factors for tendon injury when racing but have not included those injuries sustained during training. However, since tendon injury during training is seen commonly in clinical practice, it is appropriate to determine the overall prevalence of tendon injury sustained during both training and racing.

Objective: To determine the prevalence of overstrain injury to the SDFT and SL during training and racing among Thoroughbred flat racehorses in Japan in 1999.

Methods: A retrospective study was performed using a sample population of 10,262 Thoroughbred racehorses. The medical information database of Thoroughbred racehorses registered by the Japan Racing Association (JRA) in 1999 was analysed for SDFT and SL overstrain injury diagnosed by a veterinarian employed by JRA during training and racing. Jump racehorses were excluded from this study.

Results: The prevalence of forelimb SDFT tendonitis and SL desmitis was 11.1% (1130 cases) and 3.61% (370 cases) of the population, respectively. In the hindlimb, there were 0.06% (6 cases) and 0.14% (14 cases), respectively. Risks of SDF tendonitis in the forelimb in 3‐year‐olds or older horses were significantly higher than in 2‐year‐olds. In contrast, the risk of SL desmitis in the forelimb at age 3 and 4 years was 2.23 and 2.11 times higher, respectively, than in 2‐year‐olds, but this increased to 5.07 times in those age ≥5 years. Entire males were at greater risk in comparison to females and geldings.

Conclusions: The results suggest that the prevalence of SDF tendonitis and SL desmitis in the forelimb was associated with the horse's age and sex. The prevalence of SL desmitis increased further with age compared with SDF tendonitis, possibly reflecting a more rapid accumulation of degeneration in this structure.

Potential relevance: The age‐related risk demonstrated in this study provides further support that overstrain injuries are associated with accumulated degeneration. These data provide a valuable resource for further research into the aetiology of tendon injury in the racehorse.
Effect of age at presentation on outcome following arthroscopic debridement of subchondral cystic lesions of the medial femoral condyle: 85 horses (1993‐2003)
Authors: SMITH M. A. , WALMSLEY J. P. , PHILLIPS T. J. , PINCHBECK G. L. , BOOTH T. M. , GREET T. R. C. , RICHARDSON D. W. , ROSS M. W. , SCHRAMME M. C. , SINGER E. R. , SMITH R. K. , CLEGG P. D.
Published: April 2007

Reasons for performing study: Subchondral cystic lesions of the medial femoral condyle (SCMFC) are well documented in horses 3 years; arthroscopic debridement or enucleation of the cyst is currently the surgical treatment of choice. However, studies of occurence and outcome following surgery in older horses are lacking.

Objective: To identify factors important in outcome for horses with SCMFC treated by arthroscopic debridement.

Hypothesis: Age of horse at presentation has a significant influence on return to work following arthroscopic treatment for SCMFC. Clinical and diagnostic findings are also significant with respect to prognosis.

Methods: A retrospective review of medical records from 6 equine referral centres identified 85 horses that underwent arthroscopic debridement of SCMFC. Clinical examination, radiographic and arthroscopic findings were analysed together with follow‐up data. Univariable analysis and multivariable logistic regression models were used to determine factors affecting return to soundness. Event‐time analysis was performed to evaluate return to work.

Results: Older horses (>3 years) were less likely to return to soundness (P = 0.02) or to work (P = 0.04) than younger horses (> 3 years). Of 39 horses age 0‐3 years, 25 (64%, 95% CI 49‐79%) returned to soundness. Of 46 horses age >3 years, 16 (35%, 95% CI 21‐49%) returned to soundness. In addition, cartilage damage at sites other than the SCMFC negatively affected prognosis (P = 0.05). The hospital where treatment was performed had no influence on return to soundness.

Conclusions: Older horses carry a worse prognosis for both return to soundness and return to work.

Potential relevance: It is important for clients to be made aware of the difference in outcome between age groups.
Modified frontonasal sinus flap surgery in standing horses: surgical findings and outcomes of 60 cases
Authors: QUINN G. C. , KIDD J. A. , LANE J. G.
Published: April 2007

Reasons for performing study: Previous studies of sinus surgery on standing horses have been based on techniques which utilise powered hand bone saws and preserve the bone flap, which was thought to be essential for a good cosmetic result. This report describes a simplified technique applied to the standing horse where the sinus flap construction used a large skull trephine and where the bone flap is necessarily discarded.

Objectives: To assess whether the modified standing frontonasal flap (SFF) surgery offers an effective method to investigate and/or treat sinunasal disorders in the horse.

Methods: The case records of 60 horses subjected to modified SFF surgery were reviewed to analyse the efficacy of the technique when applied to a range of sinunasal disorders in terms of diagnosis, surgical findings, complications and long‐term outcomes, including cosmetic effect.

Results: Resolution of clinical signs was achieved in 54 out of 60 horses, and for the remainder the SFF technique proved useful on a diagnostic basis. The cosmetic result was, in the opinion of the owners, excellent or satisfactory in 48 of 56 (86%) horses.

Conclusions: The modified SFF technique was found to be practicable and provided satisfactory exposure of the sinus contents for diagnosis and removal of diseased tissue in a range of disorders. An acceptable cosmetic result can be obtained in the majority of horses despite rejection of the disc of overlying bone. Apart from avoiding the risks associated with general anaesthesia, the advantages of the modified SFF sugery are: a reduction of haemorrhage in the standing horse; reduced mucosal engorgement; straightforward anatomical orientation; a comfortable working height; and reduced surgery time. A sound knowledge of the functional anatomy of the area is a prerequisite before embarking on any form of sinunasal surgery. Complications are infrequent and usually transient.

Potential relevance: The modified SFF technique is a valuable alternative to other invasive methods of sinunasal surgery.
In vitro comparison of three materials as apical sealants of equine premolar and molar teeth
Authors: STEENKAMP G. , OLIVIER‐CARSTENS A. , van HEERDEN W. F. P. , CROSSLEY D. A. , BOY S. C.
Published: April 2007

Reasons for performing study: Surgical endodontic therapy is a conservative dental technique used in horses with some degree of clinical success. Failure of this procedure can partially be explained by inadequate sealing of the root apices with resultant microleakage in the periapical area.

Objectives: To assess and compare in vitro sealing ability of 3 different dental restorative materials used as apical sealants during equine surgical endodontics.

Methods: Thirty extracted equine cheek teeth were divided randomly into 3 groups and subjected to apicoectomy and apical sealing using 3 materials: reinforced zinc oxide‐eugenol cement; intermediate restorative material (IRM); a resin‐modified glass ionomer; and amalgam. After apical sealing, the teeth were submerged in a solution of Procion Brilliant Cresyl Blue stain for a period of 7 days. The teeth were then washed, embedded in resin, sectioned and assessed microscopically for dye leakage around the apical restorations.

Results: Although the materials proved effective as apical sealants, some dye leakage was encountered in all 3 groups with no statistical difference (P = 0.114).

Conclusions and potential relevance: IRM, a resin‐modified glass ionomer and amalgam all showed comparative features as apical sealants when used in vitro in equine teeth. IRM is currently regarded as the superior material in clinical situations due to its ease of handling and lesser sensitivity to environmental moisture during placement compared to the other 2 materials.
Freezability of equine semen after glass beads column separation
Authors: KLINC P. , KOSEC M. , MAJDIC G.
Published: April 2007

Reasons for performing study: The success rate of artificial insemination following the freezing of stallion semen is limited; therefore, improving the stallion semen quality after the freezing and thawing process is a necessary objective.

Objectives: To investigate the influence of glass bead column separation on the freezability of stallion semen.

Hypothesis: Glass beads in a column separator remove damaged and dead spermatozoa in the ejaculate during centrifugation.

Methods: In total, 50 ejaculates from 6 Lipizzaner stallions were studied. Each ejaculate was divided into 2 parts, one half processed following standard procedure and the second half used for the column separation procedure. After freezing, semen quality was evaluated using standard tests for motility, morphology and viability of semen.

Results: Motility and progressive motility of the column‐separated (CS) semen were significantly higher (P<0.001) before freezing and immediately, 24 and 48 h after thawing. A significant increase (P<0.001) in the percentage of hypoosmotic positive spermatozoa was observed in CS samples. The percentage of total morphological changes in the separated samples before and after freezing was significantly lower (P<0.001) compared with samples prepared using the standard procedure. A substantial decrease (P<0.001) was found in the percentage of spermatozoa with damaged acrosomes. However, the percentage of spermatozoa with coiled tails was increased in the separated samples (P<0.001).

Conclusions: Column separation before freezing has a positive effect on the quality of thawed equine semen.

Potential relevance: The quality of CS frozen/thawed samples indicates their potential use for increasing insemination success in mares.