bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and validation of a periarticular injection technique of the sacroiliac joint in horses
Authors: ENGELI E. , HAUSSLER K. K. , ERB H. N.
Published: April 2007

Reasons for performing study: Sacroiliac joint osteoarthritis has been recognised as a significant cause of poor performance in competition and racehorses. Reliable diagnostic tools are currently lacking. The diagnosis has been based typically on exclusion of other possible causes of poor performance, back pain and hindlimb lameness.

Objectives: To develop a safe, reliable and minimally invasive periarticular or intra‐articular injection technique of potential use for diagnosis and therapy of sacroiliac joint disease in horses.

Methods: Twenty‐six horses were used to develop and assess a medial approach to the sacroiliac joint with a 15 gauge, 25 cm long spinal needle. InPart I, the cadaveric study, the spinal needle was introduced cranial to the contralateraltuber sacraleand advanced along the medial aspect of the ipsilateral iliac wing until the dorsal surface of the sacrum was encountered. One ml methylene blue (MB) was injected in both sacroiliac joint regions of the sacropelvic specimens. The location of MB‐stained tissues relative to the sacroiliac joints was recorded after dissection and disarticulation of the sacroiliac joint. InPart II, thein vivostudy, 18 horses were used to validate thein vivoapplication of the sacroiliac joint injection technique. Horses were restrained in stocks and sedated in preparation for needle placement. One ml MB was injected bilaterally prior to euthanasia. Stained tissues were identified and recorded at necropsy. Successful joint injections were characterised as having MB located intra‐articularly or ≤2 cm periarticularly from the sacroiliac joint margin and localised to the middle or caudal third of the sacroiliac joint.

Results: Intra‐articular MB was not observed in any specimen. However, MB‐stained tissue was identified periarticularly in all injection sites (n = 48). Based on the predetermined success criteria, 96% of the methylene blue depots were located at the middle or caudal third of the sacroiliac joint. Dye‐stained tissue was located ≤2 cm from the sacroiliac joint margins in 88% of the specimens. Median distance of the MB from the sacroiliac joint margins was 1.0 cm (range 0.2–3.8 cm). The overall success rate considering both location and distance of the MB‐stained tissue relative to sacroiliac joint margins was 83% (40 of 48 joints).

Conclusions: The injection technique provides a reliable, easy to perform and consistent access to the medial periarticular aspect of the sacroiliac joint.

Potential relevance: The described injection technique has the potential for both diagnostic and therapeutic applications in the medical management of equine sacroiliac joint disease. Further investigation is necessary to evaluate clinical efficacy and potential adverse effects.
Screening of the equine intestinal microflora for potential probiotic organisms
Authors: WEESE J. S. , ANDERSON M. E. C. , LOWE A. , PENNO R. , DA COSTA T. M. , BUTTON L. , GOTH K. C.
Published: April 2007

Reasons for performing study: Probiotics have not been demonstrated to provide any beneficial health effects in horses, possibly because of improper selection of probiotic organisms. This study was designed to identify lactic acid bacteria of equine origin with predetermined beneficial properties which might make them useful as therapeutic probiotics.

Hypothesis: A small percentage of lactic acid bacteria that are native to the intestinal tract of horses possess properties that may be useful in the treatment and/or prevention of gastrointestinal disease in horses.

Methods: Faecal samples were collected from healthy mature horses and foals. Lactic acid bacteria were isolated and tested for the ability to grow in acid and bile environments, aerotolerance andin vitroinhibition of enteropathogens. One isolate that possessed these properties was administered orally to healthy mature horses and foals and gastrointestinal survival was assessed.

Results: Of the 47 tested organisms, 18 were deemed to be adequately acid‐ and bile‐tolerant. All were aerotolerant. Four organisms markedly inhibitedSalmonellaspp. One isolate,Lactobacillus pentosusWE7, was subjectively superior and chosen for further study. It was also inhibitory againstE. coli, moderately inhibitory againstS. zooepidemicusandC. difficileand mildly inhibitory againstC. perfringens.After oral administration, this isolate was recovered from the faeces of 8/9 (89%) foals and 7/8 (87.5%) mature horses.

Conclusions:Lactobacillus pentosusWE7 possessesin vitroandin vivoproperties that may be useful for the prevention and treatment of enteric disease in horses.

Potential relevance: The beneficialin vitroandin vivoproperties thatL. pentosusWE7 possesses indicate that randomised, blinded, placebo‐controlled efficacy studies are warranted.
Detection of EHV‐1 and EHV‐4 DNA in unweaned Thoroughbred foals from vaccinated mares on a large stud farm
Authors: FOOTE C. E. , LOVE D. N. , GILKERSON J. R. , WHALLEY J. M.
Published: April 2007

Reasons for performing study: A silent cycle of equine herpesvirus 1 infection has been described following epidemiological studies in unvaccinated mares and foals. In 1997, an inactivated whole virus EHV‐1 and EHV‐4 vaccine was released commercially in Australia and used on many stud farms. However, it was not known what effect vaccination might have on the cycle of infection of EHV‐1.

Objective: To investigate whether EHV‐1 and EHV‐4 could be detected in young foals from vaccinated mares.

Methods: Nasal and blood samples were tested by PCR and ELISA after collection from 237 unvaccinated, unweaned foals and vaccinated and nonvaccinated mares during the breeding season of 2000.

Results: EHV‐1 and EHV‐4 DNA was detected in nasal swab samples from foals as young as age 11 days.

Conclusions: These results confirm that EHV‐1 and EHV‐4 circulate in vaccinated populations of mares and their unweaned, unvaccinated foals.

Potential relevance: The evidence that the cycle of EHV‐1 and EHV‐4 infection is continuing and that very young foals are becoming infected should assist stud farms in their management of the threat posed by these viruses.
Arthroscopic debridement of subchondral bone cysts in the distal phalanx of 11 horses (1994–2000)
Authors: STORY M. R. , BRAMLAGE L. R.
Published: April 2007

Reasons for performing study: Historically, there has been a consensus that conservative management of subchondral cystic lesions of the distal phalanx carries a poor prognosis. Surgical management has been advocated; however, there are no reports documenting its routine use and successful surgical treatment.

Objectives: To describe arthroscopically‐guided curettage of distal phalangeal subchondral cystic lesions (SCLs) and report the qualitative and quantitative results in 11 affected horses age 16–33 months.

Methods: Medical records of horses with previously treated lameness resulting from SCLs of the third phalanx were reviewed. Arthroscopic debridement of the SCLs was described. Follow‐up information was obtained from race records and telephone contact with owners and trainers. The sign‐rank test was used to compare performance of operated racehorses to that of unoperated siblings.

Results: Ten of the 11 horses (91%) in the study returned to athletic soundness after surgical treatment and had performance records similar to their siblings.

Conclusions: Data show that arthroscopic debridement of distal phalangeal SCLs is a viable treatment for affected horses age 16–33 months and can result in a successful return to intended athletic performance. No horses younger than 16 months or older than 33 months were treated and results in horses younger or older than this group may vary in success.

Potential relevance: The description of treatment and approach used for arthroscopic curettage will increase awareness of this option and increase treatment options for this condition.
Reliability and repeatability of thermographic examination and the normal thermographic image of the thoracolumbar region in the horse
Authors: TUNLEY B. V. , HENSON F. M. D.
Published: April 2007

Reasons for performing study: Thermographic imaging is an increasingly used diagnostic tool. When performing thermography, guidelines suggest that horses should be left for 10–20 mins to ‘acclimatise’ to the thermographic imaging environment, with no experimental data to substantiate this recommendation. In addition, little objective work has been published on the repeatability and reliability of the data obtained. Thermography has been widely used to identify areas of abnormal body surface temperature in horses with back pathology; however, no normal data is available on the thermographic ‘map’ of the thoracolumbar region with which to compare horses with suspected pathology.

Objectives: To i) investigate whether equilibration of the thermographic subject was required and, if so, how long it should take, ii) investigate what factors affect time to equilibration, iii) investigate the repeatability and reliability of the technique and iv) generate a topographic thermographic ‘map’ of the thoracolumbar region.

Methods: A total of 52 horses were used. The following investigations were undertaken: thermal imaging validation, i.e. detection of movement around the baseline of an object of constant temperature; factors affecting equilibration; pattern reproducibility during equilibration and over time (n = 25); and imaging of the thoracolumbar region (n = 27).

Results: A 1°C change was detected in an object of stable temperature using this detection system, i.e the ‘noise’ in the system. The average time taken to equilibrate, i.e. reach a plateau temperature, was 39 mins (40.2 in the gluteal region, 36.2 in lateral thoracic region and 40.4 in metacarpophalangeal region). Only 19% of horses reached plateau within 10–20 mins. Of the factors analysed hair length and difference between the external environment and the internal environment where the measurements were being taken both significantly affected time to plateau (P<0.05). However, during equilibration, the thermographic patterns obtained did not change, nor when assessed over a 7 day period. A ‘normal’ map of the surface temperature of the thoracolumbar region has been produced, demonstrating that the midline is the hottest, with a fall off of 3°C either side of the midline.

Conclusions: This study demonstrates that horses may not need time to equilibrate prior to taking thermographic images and that thermographic patterns are reproducible over periods up to 7 days. A topographical thermographic ‘map’ of the thoracolumbar region has been obtained.

Potential relevance: Clinicians can obtain relevant thermographic images without the need for prior equilibration and can compare cases with thoracolumbar pathology to a normal topographic thermographic map.
Effect of systemic lidocaine on visceral and somatic nociception in conscious horses
Authors: ROBERTSON S. A. , SANCHEZ L. C. , MERRITT A. M. , DOHERTY T. J.
Published: April 2007

Reasons for performing study: Commonly used analgesics (nonsteroidal anti‐inflammatory agents, opioids and α2‐agonists) have unwanted side effects. An effective alternative with minimal adverse effects would benefit clinical equine pain management.

Objectives: To compare the effect of lidocaine or saline on duodenal and rectal distension threshold pressure and somatic thermal threshold in conscious mature horses.

Hypothesis: Systemically administered lidocaine would increase somatic and visceral nociceptive thresholds.

Methods: Lidocaine (2 mg/kg bwt bolus followed by 50 μg/kg bwt/min for 2 h) or saline was administered to 6 horses each carrying a permanently implanted gastric cannula, in a randomised, blinded cross‐over design. Thermal threshold was measured using a probe containing a heater element placed over the withers which supplied heat until the horse responded. A barostatically controlled intraduodenal balloon was distended until a discomfort response was obtained. A rectal balloon was inflated until extruded or signs of discomfort noted.

Results: Thermal threshold was increased significantly 30 and 90 mins after the start of lidocaine infusion. There was no change in duodenal distension pressure and a small but clinically insignificant change in colorectal distension pressure in the lidocaine group.

Conclusions: At the dose used, systemically administered lidocaine produced thermal antinociception but minimal changes in visceral nociception.

Potential relevance: At these doses, lidocaine may play a role in somatic analgesia in horses.
Concentration of methylprednisolone in the centrodistal joint after administration of methylprednisolone acetate in the tarsometatarsal joint
Authors: SERENA A. , SCHUMACHER J. , SCHRAMME M. C. , DEGRAVES F. , BELL E. , RAVIS W.
Published: April 2007

Reasons for performing study: The centrodistal (CD) and tarsometatarsal (TMT) joints are often injected individually with a corticosteroid to resolve lameness caused by osteoarthritis (OA). There are no data available regarding diffusion of methylprednisolone (MP) from the TMT joint to the CD joint.

Hypothesis: A therapeutic concentration of MP diffuses into the CD joint after methylprednisolone acetate (MPA) is administered into the TMT joint.

Objective: To measure the concentration of MP in the CD joint after MPA was administered into the TMT joint.

Methods: MPA was administered into a TMT joint of 16 horses. At different times, the ipsilateral CD joint of these horses was injected with a small amount of saline and recovered saline was measured for concentration of MP using high performance liquid chromatography.

Results: Six hours after administration of MPA into the TMT joint, a therapeutic concentration of MP was found in all 10 CD joints sampled at this time.

Conclusions: Horses with pain arising from the distal 2 joints of the hock can be treated by administering MPA into the TMT joint alone.

Potential relevance: Administering MPA into the TMT joint only, to treat OA of the distal 2 hock joints, reduces the difficulties and risks associated with centesis of the CD joint.
Dose responses to inhalation of endotoxin, hay dust suspension andAspergillus fumigatusextract in horses as measured by levels and activation of matrix metalloproteinase‐9
Authors: SIMONEN‐JOKINEN T. , PIRIE R. S. , McGORUM B. , MAISI P.
Published: April 2007

Reasons for performing study: Airway matrix metalloproteinases (MMPs) increase after endotoxin (LPS) exposure, but there are no reports describing dose‐dependent increases or activation following exposure.

Objectives: To study matrix metalloproteinase‐9 (MMP‐9) and ‐2 (MMP‐2) responses in bronchoalveolar lavage fluid (BALF) from heaves‐susceptible and control horses following inhalation of hay dust suspension (HDS), LPS andAspergillus fumigatusextract (AFE).

Methods: Heaves‐susceptible (n = 7) and control (n = 6) horses received inhalation challenges with 3 different doses of HDS and LPS. Heaves‐susceptible horses (n = 6) also received 3 different doses of AFE and one dose of AFE depleted of endotoxin (AFE‐LPS). BALF collected following inhalation challenges was analysed using gelatin zymography. Gelatinolytic bands were identified as complex, pro‐MMP‐9, active MMP‐9, pro‐MMP‐2 and active MMP‐2 based on molecular weights.

Results: Each challenge substance induced a dose‐dependent elevation in gelatinolytic activity. The dose‐dependency was most evident for pro‐MMP‐9 and total MMP‐9 levels in heaves‐susceptible horses following LPS challenges.

Conclusions: There is a dose‐dependent elevation in MMP‐9 in BALF of heaves‐susceptible and control horses following inhalation challenge with organic dust and some of its components, elevation being more marked in heaves‐susceptible horses. Organic dust components vary in their pro‐inflammatory potential.

Potential relevance: This study supports the role of MMPs in the pathogenesis of heaves and highlights the potential value of protease inhibitors in attenuating the airway inflammatory response to inhaled organic dust.
Lameness associated with foot pain: results of magnetic resonance imaging in 199 horses (January 2001‐December 2003) and response to treatment
Authors: DYSON S. J. , MURRAY R. , SCHRAMME M. C.
Published: April 2007

Reasons for performing study: The diagnosis of foot‐related lameness often remains elusive and it can be difficult to offer rational treatment, or to predict outcome.

Objectives: To describe the spectrum of injuries of the foot identified using magnetic resonance imaging (MRI), to determine their relative prevalence among MRI diagnoses and to establish the long‐term results of treatment.

Methods: The MR images of horses examined from January 2001‐December 2003 were reviewed. Horses were selected for MRI if the pain causing lameness was localised to the foot using perineural analgesia but any clinical, radiological or ultrasonographic abnormalities were insufficient to explain the degree of lameness. The clinical significance of lesions identified using MRI was determined with reference to the results of local analgesia, radiography, ultrasonography and nuclear scintigraphy.

Follow‐up information was obtained in January 2004 for horses which had been examined 6‐36 months previously and the outcome classified as excellent (horse returned to full athletic function without recurrent lameness), moderate (sound, but only in light work), or poor (persistent or recurrent lameness).

Results: One hundred and ninety‐nine horses underwent MRI examinations. Deep digital flexor (DDF) tendonitis was the most common injury (59%) with primary injury in 65 horses (33%) and a further 27 horses (14%) having lesions of the DDF tendon and navicular bone. Seventeen percent of horses had injuries to multiple structures, including 24 with DDF tendonitis. Desmitis of a collateral ligament (CL) of the distal interphalangeal (DIP) joint was the second most common injury (62 horses, 31%), with primary injuries in 30 horses (15%) and a further 32 horses (16%) that had CL desmitis in conjunction with other injuries.

Prognosis was best for horses with traumatic injuries of the middle or distal phalanges, with 5 of 7 horses (71%) having an excellent outcome. Horses with primary lesions of the DDF tendon or CL of the DIP joint had excellent results in only 13 of 47 (28%) and 5 of 17 horses (29%), respectively. Horses with combined injuries of the DDF tendon and navicular bone, or primary navicular bone abnormalities, had a poor outcome, with the majority of horses suffering persistent lameness.

Conclusions: A wide variety of lesions associated with foot pain were identified using MRI, a high proportion of which were primary soft tissue injuries with a guarded prognosis for return to full athletic function.

Potential relevance: It is now possible to propose more rational treatment strategies for the variety of foot injuries identified using MRI than had previously been possible; however, further information concerning aetiopathogenesis of these injuries is needed to improve their management.
Standing oral extraction of cheek teeth in 100 horses (1998‐2003)
Authors: DIXON P. M. , DACRE I. , DACRE K. , TREMAINE W. H. , McCANN J. , BARAKZAI S.
Published: April 2007

Reasons for performing study: Extraction of cheek teeth (CT) by the conventional repulsion technique requires general anaesthesia and carries a high rate of post operative complications. Consequently, an alternative method of extraction, i.e. orally in standing horses, was evaluated.

Hypothesis: The need for and risks of general anaesthesia could be avoided and post extraction sequelae reduced by performing extractions orally in standing horses.

Methods: One hundred mainly younger horses (median age 8, range 2‐18 years) with firmly attached CT that required extraction because of apical infections, displacements, diastemata, idiopathic fractures and the presence of supernumerary CT had the affected teeth (n = 111) extracted orally under standing sedation. Follow‐up information was obtained for all cases, a median of 16 months later.

Results: Oral extraction was successful in 89 horses and unsuccessful in 11 due to damage to the CT clinical crown (n = 9) during extraction, for behavioural reasons (n = 1) and because the apex of a partly extracted CT fell back into the alveolus following sectioning (n = 1). Predispositions to extraction‐related CT fractures were present in 5 of the 9 cases, i.e. advanced dental caries (n = 2) and pre‐existing ‘idiopathic’ fractures (n = 3). The iatrogenically fractured CT were later repulsed under standing sedation (n = 3) and under general anaesthesia (n = 6).

Eighty‐one of the remaining 89 horses had successful oral CT extraction with no or minimal intra‐ or post operative complications occurring. Post operative complications in the other 8 cases included post extraction alveolar sequestration (n = 3), alveolar sequestration and localised osteomyelitis (n = 1), localised osteomyelitis (n = 1), incorporation of alveolar packing material into alveolar granulation tissue (n = 1), and nasal discharge due to continued intranasal presence of purulent food material (n = 1) and to ongoing sinusitis (n = 1). The above sequelae were treated successfully in all cases, with general anaesthesia required in just one case. Following oral extraction, significantly (P<0.001) fewer post operative problems developed in 54 horses with apically infected CT in comparison with 71 previous cases that had repulsion of apically infected CT at our clinic.

Conclusions and potential relevance: Oral extraction of cheek teeth is a successful technique in the majority of younger horses with firmly attached CT and greatly reduces the post operative sequelae, compared with CT repulsion. Additionally, the costs and risks of general anaesthesia are avoided. Further experience and refinement in the described protocol could potentially increase the success of this procedure and also reduce the incidence of post operative sequelae.
Deep digital flexor tendon force and digital mechanics in normal ponies and ponies with rotation of the distal phalanx as a sequel to laminitis
Authors: McGUIGAN M. P. , WALSH T. C. , PARDOE C. H. , DAY P. S. , WILSON A. M.
Published: April 2007

Reasons for performing study: Previous studies have implicated tension in the deep digital flexor tendon (DDFT) in the rotation of the distal phalanx (DP) after the breakdown of the dorsal laminae caused by laminitis. Howeveer, once the DP has rotated, the DDFT should become shorter, reducing the force it exerts on the DP.

Objective: To compare DDFT force and ground reaction forces (GRFs) in normal ponies and ponies with rotation of the DP as a sequel to laminitis.

Methods: Six normal ponies (Group 1) and 6 sound ponies with 6‐13° of rotation of the DP in relation to the dorsal hoof wall (Group 2) were assessed at trot using forceplate and motion analysis. The force in the DDFT was calculated by assuming that the extending moment at the distal interphalangeal (DIP) joint resulting from the GRF was equal to the flexing moment created by the force in the DDFT during the stance phase (inverse dynamics).

Results: In early stance, the peak DDFT force (mean ± s.d.) in the normal ponies was 1.92 ± 1.63 N/kg. However, in Group 2, the point of zero moment was palmar to the centre of rotation of the DIP joint for the first 40% of stance and hence DDFT force was zero. Force in the DDFT reached a peak of 10.00 ± 3.56 N/kg at 60.7 ± 5.6% of stance in Group 1 and 6.41 ± 1.37 N/kg at 79.2 ± 9.6% of stance in Group 2.

Conclusions: DDFT force in Group 2 laminitic ponies was much reduced until late stance, when it neared normal values.

Potential relevance: Further studies of ponies with rotation of the DP as a sequel to laminitis should assist farriery aimed at reducing the force in the DDFT through the breakover phase of stance to protect damaged dorsal laminae.
Atropine reduces dobutamine‐induced side effects in ponies undergoing a pharmacological stress protocol
Authors: SANDERSEN C. F. , DETILLEUX J. , DELGUSTE C. , PIERARD L. , van LOON G. , AMORY H.
Published: April 2007

Reasons for performing study: High‐dose dobutamine stress echocardiography has been shown to be cardiotoxic and arrhythmogenic in horses. However, the test may have benefit in practice as a pharmacological challenge of exercise without the treadmill being required.

Objectives: To investigate the effect of low‐dose dobutamine on cardiac performance in ponies previously treated with atropine, in order to develop a pharmacological protocol that allows examination of the equine heart under stimulation.

Methods: In 13 healthy Shetland ponies, heart rate (HR), stroke index (SI) and cardiac index (CI) were calculated from pulsed‐wave Doppler ultrasound measurements performed at rest and during incremental steps of dobutamine infusion. Group 1 (n = 7) received dobutamine infusion at 2 μg/kg bwt/min for 5 mins followed by incremental rates of 5 μg/kg bwt/min every 5 mins, from 5 to 40 μg/kg bwt/min. Group 2 (n = 6) received dobutamine infusion in incremental rates of 1 μg/kg bwt/min, every 5 mins, from 2 μg/kg bwt/min to 5 μg/kg bwt/min, after premedication with 2 injections of 25 μg/kg bwt of atropine 5 mins apart.

Results: The increase in CI during the pharmacological challenge was higher in Group 2 and reached about 2.5 times the resting value. This increase in CI was mediated by a significant increase in HR in both groups, while SI significantly decreased in Group 1 and did not change significantly in Group 2. Ponies of Group 1, but not those of Group 2, showed excessive restlessness and cardiac arrhythmias during the pharmacological challenge and a high intragroup variability in cardiac response.

Conclusions: The results of this study suggest that a low dose of dobutamine in ponies previously given atropine could be a helpful pharmacological protocol to perform stress echocardiography in equids.

Potential relevance: Further studies should evaluate left ventricular wall motion in horses undergoing low‐dose dobutamine protocol after pretreatment with atropine.
Biochemical markers of bone metabolism and risk of dorsal metacarpal disease in 2‐year‐old Thoroughbreds
Authors: JACKSON B. F. , LONNELL C. , VERHEYEN K. L. P. , DYSON P. , PFEIFFER D. U. , PRICE J. S.
Published: April 2007

Reasons for performing study: Dorsal metacarpal disease (DMD) is a common problem in 2‐year‐old racehorses and results in loss of a significant number of days from training. Biochemical markers of bone cell activity measured early in the training season could have value for identifying 2‐year‐old Thoroughbred racehorses that develop DMD.

Objectives: To determine the association between serum concentrations of osteocalcin, the carboxyterminal propeptide of type I collagen (PICP) and the carboxyterminal cross‐linked telopeptide of type I collagen (ICTP) measured early in the training season and the risk of DMD.

Methods: Blood samples were collected from 165 two‐year‐old Thoroughbreds during late November/early December. Osteocalcin and PICP were measured as markers of bone formation, and ICTP as a marker of bone resorption. Training and veterinary records for each horse were monitored over the following training/racing season (10 months). Cases were defined as an episode where signs of DMD were sufficiently severe for a horse to miss at least 5 consecutive days of training. Classification tree and logistic regression analysis were used to identify the most important factors suitable for prediction of DMD risk.

Results: There were 24 cases of DMD during the season (14.6% cumulative incidence), with an average time to recognition of approximately 6 months (May). The earliest recognised case was in February and the latest in September. Osteocalcin and ICTP concentrations in the early stages of the training season were significantly higher in horses that subsequently developed DMD (P = 0.017 and 0.019, respectively). DMD cases were also significantly older compared to noncases (21.04 vs. 20.44 months, P = 0.023). Using a multivariable logistic regression model, it was possible to postulate a set of diagnostic rules to predict the likelihood of DMD injury during the season. This suggested that horses with ICTP concentrations above 12.365 ug/l and older than 20.5 months are 2.6 times more likely to develop DMD.

Conclusions: The measurement of the bone resorption marker ICTP could be useful for identification of 2‐year‐olds at increased risk of developing DMD.

Potential relevance: These findings, together with other strategies such as modification of training regimens, e.g. early introduction of short distances of high‐speed exercise into the training programme, could help reduce the days lost to training as a result of DMD.
Analysis of cartilage oligomeric matrix protein (COMP) degradation and synthesis in equine joint disease
Authors: ARAI K. , MISUMI K. , CARTER S. D. , SHINBARA S. , FUJIKI M. , SAKAMOTO H.
Published: April 2007

Reasons for performing study: Cartilage oligomeric matrix protein (COMP) is abundant within cartilage; its turnover and/or degradation have been investigated in various equine joint diseases and it has been suggested that COMP fragmentation might be useful for monitoring such conditions.

Objectives: To determine whether COMP metabolism is compromised in equine osteoarthritis (OA) and whether COMP degradation is a useful joint marker representing cartilage destruction.

Hypothesis: A monoclonal antibody (mAb) with a higher affinity for degraded COMP allows discrimination of diseased joints by quantifying COMP levels and fragmentation.

Methods: A mAb (clone14G4) was generated against equine cartilage COMP. The NH2‐terminal sequence of enzyme‐cut COMP fragments recognised by 14G4 was determined, as was the efficiency of binding to COMP (using a generated COMP peptide). COMP concentration and fragmentation were analysed in synovial fluid (SF) from normal horses and those with OA.

Results: The mAb 14G4 had a higher affinity for the smaller fragments of equine COMP, compared with a mAb (clone 12C4) generated against human COMP. The 14G4 epitope was identified as between C134 and F147. The COMP values in OA (mean ± s.d. 205.8 ± 90.9 μg/ml) were significantly higher than in the normal (133.1 ± 31.5 μg/ml) SF. On the immunoblots of OA sample, the proportions of intact COMP were significantly lower, while smaller fragments ranging from 75 to 290 kDa were higher compared with the normal SF.

Conclusions and potential relevance: The mAb 14G4 reliably detects COMP degradation as well as synthesis, and fragmentation analysis combined with quantification in SF could be useful to study equine OA.
Immunoglobulin and peripheral B‐lymphocyte concentrations in Fell pony foal syndrome
Authors: THOMAS G. W. , BELL S. C. , CARTER S. D.
Published: April 2007

Reasons for performing study: Fell pony foals are affected by a congenital fatal disease that leads to profound anaemia and immunodeficiency. Previous studies comparing healthy and affected foals have shown normal T‐cell populations, but a severe B‐lymphopenia.

Objectives: To measure the levels of individual immunoglobulin subisotypes in normal and affected Fell ponies and correlate these levels with the number of peripheral B‐lymphocytes.

Methods: Serum levels of individual immunoglobulin subisotypes were measured by ELISA and correlated with the number of peripheral B‐lymphocytes (measured by flow cytometry).

Results: Affected foals had significantly reduced serum levels of IgM, IgGa, IgGb and IgG(T) that coincided with the normal reduction in maternally derived immunoglobulin in foals and, with the exception of IgGb, correlated strongly with the B‐lymphopenia.

Conclusions: These data suggest that affected foals are unable to produce their own immunoglobulins. Therefore, once maternal immunity has waned, it may be the lack of specific foal‐derived immunoglobulin that gives rise to the clinical signs of immunodeficiency.

Potential relevance: Measurement of IgM after age 4 weeks may provide a more accessible means of confirming the status of future affected Fell pony foals than the measurement of B‐lymphocytes (a technique limited to a few specialist laboratories).
The influence of head and neck position on kinematics of the back in riding horses at the walk and trot
Authors: RHODIN M. , JOHNSTON C. , HOLM K. ROETHLISBERGER , WENNERSTRAND J. , DREVEMO S.
Published: April 2007

Reasons for performing study: A common opinion among riders and in the literature is that the positioning of the head and neck influences the back of the horse, but this has not yet been measured objectively.

Objectives: To evaluate the effect of head and neck position on the kinematics of the back in riding horses.

Methods: Eight Warmblood riding horses in regular work were studied on a treadmill at walk and trot with the head and neck in 3 different predetermined positions achieved by side reins attached to the bit and to an anticast roller. The 3‐dimensional movement of the thoracolumbar spine was measured from the position of skin‐fixed markers recorded by infrared videocameras.

Results: Head and neck position influenced the movements of the back, especially at the walk. When the head was fixed in a high position at the walk, the flexion‐extension movement and lateral bending of the lumbar back, as well as the axial rotation, were significantly reduced when compared to movements with the head free or in a low position. At walk, head and neck position also significantly influenced stride length, which was shortest with the head in a high position. At trot, the stride length was independent of head position.

Conclusions: Restricting and restraining the position and movement of the head and neck alters the movement of the back and stride characteristics. With the head and neck in a high position stride length and flexion and extension of the caudal back were significantly reduced.

Potential relevance: Use of side reins in training and rehabilitation programmes should be used with an understanding of the possible effects on the horse's back.
Three‐dimensional kinematics of the equine distal forelimb: effects of a sharp turn at the walk
Authors: CHATEAU H. , DEGUEURCE C. , DENOIX J. ‐M.
Published: April 2007

Reasons for performing study: Sharp turns are suspected to increase expression of several distal forelimb lamenesses even at the walk but the biomechanical consequences of such a movement remain unknown.

Objective: To quantify the effects of a sharp turn at the walk on the 3‐dimensional movements of the distal segments of the forelimb.

Methods: Kinematics of the distal segments were measured in 4 healthy horses invasively with an ultrasonic system. Three‐dimensional rotations of the digital joints were calculated by use of a joint coordinate system. Data obtained for a turn at the walk were compared to those obtained in a straight line.

Results: During the stance phase in a turn, the inside forelimb underwent an adduction that induced lateromotion and medial rotation in the distal interphalangeal joint and medial rotation in the proximal interphalangeal joint. These movements were maximal at heel‐off and decreased during breakover as the hoof underwent a sudden lateral rotation.

Conclusions: Walking in a sharp turn affects the kinematics of the digital joints outside the sagittal plane.

Potential relevance: This knowledge offers the opportunity to derive hypotheses on biomechanical factors that could contribute to the pathogenesis of digital injuries and on consequences for rational shoeing.
Colorectal distention in the horse: visceral sensitivity, rectal compliance and effect of i.v. xylazine or intrarectal lidocaine
Authors: SANCHEZ L. C. , MERRITT A. M.
Published: April 2007

Reasons for performing study: Most current models of visceral sensitivity testing in the horse have required visceral cannulation. Colorectal distention (CRD) is a widely used, noninvasive method for testing in other species and could be adapted for use in horses.

Objectives: To develop a protocol of controlled CRD in the conscious horse and to evaluate the effect of i.v. xylazine or intrarectal lidocaine on CRD threshold and rectal compliance.

Methods: Eight horses were used for baseline studies (3 trials each) and 6 horses to evaluate treatments (4 trials, 2 per treatment). A 45 cm diameter polyvinyl balloon attached to plastic tubing was used for rectal distention following a stepwise barostat‐controlled inflation pattern.

Results: The procedure was well tolerated by all horses. Mean baseline threshold pressure was 14.17 mmHg. Xylazine i.v. resulted in significantly (P<0.05) higher mean threshold pressures compared to baseline or rectal lidocaine. Rectal compliance increased following lidocaine treatment relative to baseline or xylazine.

Conclusions: CRD offers a noninvasive method for visceral sensitivity testing in the horse. Xylazine raises CRD threshold, while lidocaine increases rectal compliance.

Potential relevance: The increased rectal compliance following intrarectal lidocaine administration may explain the benefit of its use to facilitate rectal examination.
Horses on pasture may be affected by equine motor neuron disease
Authors: MCGORUM B. C. , MAYHEW I. G. , AMORY H. , DEPREZ P. , GILLIES L. , GREEN K. , MAIR T. S. , NOLLET H. , WIJNBERG I. D. , HAHN C. N.
Published: April 2007

Reasons for performing study: Equine motor neuron disease (EMND) was diagnosed in 3 horses maintained on lush, grass‐based pasture. This contrasted with North American studies which identified limited or no access to green herbage as an important risk factor for EMND.

Hypothesis: Grazing horses that have an apparently adequate intake of pasture herbage to meet normal equine vitamin E requirements can develop EMND.

Methods: Owners of 32 European horses diagnosed with EMND completed a questionnaire regarding intrinsic, managemental, nutritional and environmental factors that could potentially be risk factors for EMND, and also regarding clinical signs, treatments and case outcome. Plasma/serum vitamin E data for these horses were supplied by the veterinarians. No control population was studied.

Results: Thirteen of 32 horses (termed the ‘grazing’ group) had part‐ or full‐time access to grass‐based pasture at the onset of EMND (median duration at pasture 12 h/day, range 3–24 h). Five of these horses were at pasture for at least 23.5 h/day at the onset of EMND, 2 of which were at pasture for at least 23.5 h/day throughout the year. Despite grazing, all these horses had a low vitamin E status. The remaining 19 horses resembled those cases reported from North America, in that they had no or limited access to pasture.

Conclusions and potential relevance: A diagnosis of EMND should not be discounted on the basis that a horse has access, even full‐time, to lush grass‐based pasture. Inadequate vitamin E intake was probably not the sole cause of either the EMND or the low vitamin E status in the grazing horses; the latter was probably the result of abnormal bioavailability or excessive utilisation of vitamin E.
The complex blood supply to the equine testis as a cause of failure in laparoscopic castration
Authors: VOERMANS M. , RIJKENHUIZEN A. B. M. , VAN DER VELDEN M. A.
Published: April 2007

Reasons for performing study: Intra‐abdominal ligation/transection of the spermatic cord may result in necrosis of the testis; castration of abdominal cryptorchids via laparoscopy has therefore become common. Notwithstanding some adaptations of the technique, a small percentage of operations fail, prompting research into the anatomical background and clinical relevance of the procedure.

Hypothesis: That an alternate blood supply may prevent complete necrosis of the testis after spermatic cord transection.

Objective: To establish the prevalence of the problem in normal and cryptorchid stallions.

Methods: In a preliminary study, the spermatic cords of 8 normal stallions were ligated and transected at different sites and in various manners. Five weeks later the testes were removed and the vitality of both the testes and epididymes was evaluated. In a prospective clinical trial, intra‐abdominal spermatic cord transection was performed in 241 cryptorchid and normal stallions. In cases of surgical failure, the testes were removed and histology performed.

Results: Examination of the specimen removed from the 8 animals of the preliminary study revealed that all epididymes were completely or largely spared. All except one testis were completely necrotic. In the patients that underwent surgery all abdominally retained testes (n = 123) were necrotic, while 5 out of 88 inguinally retained and 8 out of 236 normally descended testes had partially survived. The pattern of survival differed between inguinally retained and normally descended testes. The epididymes of these 13 horses were (largely) vital. The (partial) survival of the epididymes and inguinally retained testes was ascribed to an alternate blood supply via anastomosing vessels derived from the cremasteric artery. A tributary from the external pudendal artery was considered responsible for the partial survival of normally descended testes.

Conclusions and potential relevance: After intra‐abdominal transection of the entire spermatic cord, 5.6% of inguinally retained and 3.4% of normally descended testes failed to become completely necrotic, as a result of an alternate blood supply via the cremasteric and/or external pudendal artery. Therefore, laparoscopic castration without orchidectomy cannot be recommended as a trustworthy method for castration of inguinal cryptorchids and normal stallions.
Histopathology in horses with chronic palmar foot pain and age‐matched controls. Part 1: Navicular bone and related structures
Authors: BLUNDEN A. , DYSON S. , MURRAY R. , SCHRAMME M.
Published: April 2007

Reasons for performing study: Causes of palmar foot pain and the aetiopathogenesis of navicular disease remain poorly understood, despite the high incidence of foot‐related lameness.

Hypotheses: Abnormalities of the collateral sesamoidean ligaments (CSLs), distal sesamoidean impar ligament (DSIL), deep digital flexor tendon (DDFT), navicular bone, navicular bursa, distal interphalangeal (DIP) joint or collateral ligaments (CLs) of the DIP joint may contribute to palmar foot pain.

Methods: Feet were selected from horses with a history of unilateral or bilateral forelimb lameness of at least 2 months' duration that was improved by perineural analgesia of the palmar digital nerves, immediately proximal to the cartilages of the foot (Group 1, n = 32); or from age‐matched control horses (Group 2, n = 19) that were humanely destroyed for other reasons and had no history of forelimb foot pain. Eight units of tissue were collected for histology: the palmar half of the articular surface of the distal phalanx, including the insertions of the DDFT and DSIL; navicular bone and insertion of the CSLs; DDFT from the level of the proximal interphalangeal (PIP) joint to 5 mm proximal to its insertion; synovial membrane from the palmar pouch of the DIP joint and the navicular bursa; CLs of the DIP joint and DSIL. The severity of histological lesions for each site were graded. Results were compared betweenGroups 1and2.

Results: There was no relationship between age and grade of histological abnormality. There were significant histological differences between groups for lesions of the flexor aspect, proximal and distal borders, and medulla of the navicular bone; the DSIL and its insertion and the navicular bursa; but not for lesions of the CSLs, the dorsal aspect of the navicular bone, distal phalanx and articular cartilage, synovium or CLs of the DIP joint.

Conclusions: Pathological abnormalities in lame horses often involved not only the navicular bone, but also the DSIL and navicular bursa. Abnormalities of the navicular bone medulla were generally only seen dorsal to lesions of the FFC.

Potential relevance: Adaptive and reactive change may be occurring in the navicular apparatus in all horses to variable degrees and determination of the pathogenesis of lesions that lead to pain and biomechanical dysfunction should assist specific preventative or treatment protocols.
Mechanical nociceptive thresholds in the axial skeleton of horses
Authors: HAUSSLER K. K. , ERB H. N.
Published: April 2007

Reasons for performing study: An objective measure of neck, back and croup pain is needed in horses with musculoskeletal injuries, vague upper limb lameness or poor performance.

Objectives: To establish mechanical nociceptive thresholds (MNTs) within the axial skeleton and evaluate the effects of subject status and ridden exercise.

Methods: Thirty‐six mature horses (10 nonridden; 26 actively ridden) were used to assess MNTs evoked by a pressure algometer (PA) with a 1 cm2rubber plunger tip at 62 midline and bilaterally symmetrical anatomical landmarks along the axial skeleton. Pressure was applied at a uniform rate of application until a local avoidance reaction was noted. The repeatability of 3 consecutive measurements was evaluated. Left‐to‐right comparisons and the effects of subject status and ridden exercise on MNTs were assessed.

Results: MNTs were repeatable and increased in a cranial‐to‐caudal gradient within the axial skeleton. Typically, there were no significant left‐to‐right differences. Within‐horse variability was less than between‐horse variability. Higher MNTs were measured in young, heavy, non‐Thoroughbred, castrated males, and in horses that were ridden and actively exercised.

Conclusions and potential relevance: PA provides an objective, noninvasive, and repeatable tool to measure mechanical nociception in horses. MNTs vary in horses with differing subject status and ridden exercise level.
Evaluation of an in vitro sulphidoleukotriene release test for diagnosis of insect bite hypersensitivity in horses
Authors: BASELGIA S. , DOHERR M. G. , MELLOR P. , TORSTEINSDOTTIR S. , JERMANN T. , ZURBRIGGEN A. , JUNGI T. , MARTI E.
Published: April 2007

Reasons for performing study: Insect bite hypersensitivity (IBH) is an IgE‐mediated allergic dermatitis caused by bites of Culicoides and Simulium species, and improved means of diagnosis are required.

Objectives: The cellular antigen simulation test (CAST®) with C. nubeculosus and S. vittatum extracts was assessed in a population of IBH‐affected and healthy horses. Variations in test results over a one year period and possible cross‐reactivity between different insect extracts was studied.

Methods: A total of 314 mature horses were studied using the CAST. Influence of severity of clinical signs, gender and age were evaluated, and 32 horses were tested repeatedly over one year. The kappa reliability test was used to assess agreement of the test results with different insect extracts.

Results: Horses with IBH had significantly higher sLT release than controls with C. nubeculosus and S. vittatum. The highest diagnostic sensitivity and specificity levels were attained when using adult C. nubeculosus extracts with the CAST (78% and 97%, respectively), suggesting that most horses with IBH are sensitised against Culicoides allergens. A proportion of IBH‐affected horses was found to be sensitised to allergens of Simulium spp. in addition to those of C. nubeculosus. The CAST with C. nubeculosus had positive and negative predictive values ≥80% for a true prevalence of IBH of 12–52%. In the follow‐up study, the proportion of IBH‐affected horses with a positive test result ranged from 90% in November to 68% in March. Severity of clinical signs or age did not influence test results significantly. However, IBH‐affected males achieved significantly more positive test results than IBH‐affected females.

Conclusions: The CAST with adult C. nubeculosus has high specificity and good sensitivity for diagnosis of IBH. Horses with IBH are mainly sensitised to Culicoides allergens, and some horses are additionally also sensitised to allergens in Simulium spp.

Potential relevance: The CAST is likely to be a useful test for diagnosis of IBH, even allowing the identification of IBH‐affected but asymptomatic horses. This test may also help in further characterisation of allergens involved in this condition.