bluuebunny/crossref_metadata_2025 huggingface dataset:
A long‐term study of 277 cases of equine sinonasal disease. Part 1: Details of horses, historical, clinical and ancillary diagnostic findings
Authors: TREMAINE W. H. , DIXON P. M.
Published: April 2007

The clinical and ancillary diagnostic findings in equine sinnasal disease were studied. The diagnoses in 277 referred (1984–1996) cases of equine sinonasal disease included the following (% all cases): 67 cases (24.2%) primary sinusitis, 61 (22.0%) dental sinusitis, 37 (13.4%) sinus cysts, 22 (7.9%) sinonasal neoplasia, 21 (7.6%) progressive ethmoid haematoma, 17 (6.1%) sinonasal trauma, 13 (4.7%) sinonasal mycosis, 11 (4.0%) rostral maxillary cheek tooth infection, 7 (2.5%) sinonasal polyps, 7 (2.5%) cases of nasal epidermal inclusion cysts and 14 (5.1%) miscellaneous sinonasal disorders. Many disorders showed similar clinical signs including nasal discharge (present in 88% of all cases) and facial swelling (46%). Most disorders were chronic, with a median duration of signs of 12 weeks (range 3 days‐6 years) priorto referral. Sinus cysts and sinonasal neoplasia were significantly (P<0.05) more frequently associated with gross distortion of the nasal passages and facial bones than the other sinonasal disorders. Endoscopic changes were detectedper nasumin 91% of cases, but contributed to the exact diagnosis in only 20%. Radiography revealed abnormalities in 81% of cases but was diagnostically useful in only 36%. Sinoscopy was diagnostically useful in 70% of the 61 cases where used.
Temporary transvenous atrial pacing in horses: threshold determination
Authors: van LOON G. , LAEVENS H. , DEPREZ P.
Published: April 2007

The purpose of this study was to perform temporary atrial pacing and to determine the atrial strength‐duration (S‐D) curve which displays the minimal pulse intensity necessary to achieve atrial capture. In 7 horses, atrial pacing was applied using a temporary pacing catheter and a pacemaker as electrical pulse generator. Using the stimulus reduction method, 3 approaches for atrial threshold determination were used. With the fixed pulse width method, at several pulse widths, the corresponding minimal amplitudes to achieve capture were determined, describing an S‐D curve. With the fixed amplitude method, the corresponding threshold pulse widths were determined at several fixed amplitudes. The third method proved to be the best and was a combination of both aforementioned methods to determine 2 points of the S‐D curve. From these 2 points the whole S‐D curve was calculated using a mathematical equation. Temporary pacing can be used to terminate atrial flutter, to induce atrial arrhythmias or to obtain more information about the electrophysiological properties of the heart, such as the atrial refractory period, atrial vulnerability and atrioventricular conduction.
Equine thoracoscopy: normal anatomy and surgical technique
Authors: PERONI J. F. , HORNER N. T. , ROBINSON N. E. , STICK J. A.
Published: April 2007

Six normal, healthy horses age 3–10 years underwent left and right thoracoscopic examination using a rigid telescope. A minimum of 30 days was allowed between procedures. Horses were restrained in stocks and sedated with a continuous detomidine infusion. After surgical preparation of the hemithorax elected for surgery, and administration of local or regional anaesthesia of the surgery sites, thoracoscopy was completed during two 15 min pneumothorax periods. During the procedures, the thoracic structures were viewed using a 57 cm, 10 mm diameter, 30° rigid telescope connected to a digital camcorder to allow computer capture of digital images. The telescope was inserted into the thoracic cavity via 3 different intercostal spaces. The 8th, 10th and 12th intercostal spaces were randomly selected and used among horses. The exploration of each hemithorax started from the dorsal‐caudal quadrant continued toward the cranial thorax and was completed by observing the diaphragmatic and caudal pulmonary region.

Collapsed lung, aorta, oesophagus and diaphragm were viewed readily in either hemithorax. On exploration of the right hemithorax, the azygos vein, thoracic duct and pulmonary veins were also identified. Horses tolerated thoracoscopy well. Signs of discomfort, such as increased respiratory rate, coughing and decreased level of sedation, were associated with lung collapse in one horse, with pneumothorax on 2 occasions, and when the thorax was approached through the 8th intercostal space. Surgery performed via the 8th intercostal space was hindered by the rigidity of the 8th and 9th ribs, and by the presence of a greater musculature, which did not allow easy cranial and caudal movements of the telescope.
Equine dysautonomia (grass sickness) is associated with altered plasma amino acid levels and depletion of plasma sulphur amino acids
Authors: MCGORUM B. C. , KIRK J.
Published: April 2007

To determine whether equine dysautonomia (ED) is associated with alterations in plasma amino acid metabolism, plasma amino acid profiles were determined for horses with acute (n = 10), subacute (n = 6) and chronic (n = 7) ED and for healthy cograzing horses (n = 6) and control horses (n = 10). Horses with acute ED had perturbations in plasma amino acid profiles resembling those of severe protein malnutrition. In addition, horses with ED and cograzing healthy horses had depletion of the plasma sulphur amino acids cyst(e)ine and methionine. As similar plasma amino acid perturbations occur in subacute/chronic cyanide toxicity, the role of cyanogenic glycosides in the aetiology of ED warrants further study. Unfortunately, amino acid analysis cannot be used as a definitivepremortemdiagnostic test for ED, since there was overlap in the individual amino acid levels of control, cograzing and ED horses.
Signal decomposition method of evaluating head movement to measure induced forelimb lameness in horses trotting on a treadmill
Authors: KEEGAN K. G. , PAI P. F. , WILSON D. A. , SMITH B. K.
Published: April 2007

In horses at a trot, the head moves up and down twice in one stride. In horses with unilateral forelimb lameness this movement is asymmetric. Computer‐assisted kinematic analysis of vertical head movement can be used to quantify objectively lameness in horses in clinical trials. However, in mild lameness, absolute measurements of vertical head height may not be sensitive enough to detect small differences in lameness, and extraneous head movement by the horse due to curiosity, excitement or nervousness interferes with the accurate measurement of vertical head movement asymmetry. We describe a simple, signal‐decompensation method of evaluating vertical head movement using a model of induced mild foot lameness in 9 horses. The technique assumes that the vertical head movement pattern can be broken down into 3 components; the vertical head movement caused by forelimb lameness (A1), the amplitude of the natural biphasic vertical head movement (A2) and extraneous head movement. Extraneous head movement is mathematically removed from the vertical head movement pat tern.A1andA2are then calculated. After induction of lameness, meanA1increased by 1.63 cm (range 0.10–3.33 cm, P = 0.005). MeanA2did not significantly change after lameness induction. Error in reproduction of the original head movement pattern was 0.3–0.5%. We calculated that a hypothetical clinical trial would require 12 subjects for testing to be 80% certain that this difference would be successfully detected using this method of lameness evaluation.
A study of an electrodiagnostic technique for the evaluation of equine recurrent laryngeal neuropathy
Authors: HAWE C. , DIXON P. M. , MAYHEW I. G.
Published: April 2007

The electrodiagnostic measurement of the thoracolaryngeal reflex (TLR) (‘slap test’) latency was compared to 5 other diagnostic techniques used for evaluation of laryngeal function, namely laryngeal muscle palpation, resting and immediately postexercise endoscopic examinations, and palpable and endoscopic responses to the TLR. Compared to resting endoscopy, the electrodiagnostic measurement of TLR latency was not found to be an accurate test for the evaluation of recurrent laryngeal neuropathy (RLN), nor was laryngeal muscle palpation or the endoscopic response to the TLR. Twenty‐five (71%) of 35 Clydesdale horses examined were affected by RLN; 16 (46%) had mild, 5 (14%) moderate, 3 (9%) severe hemiparesis and 1 (3%) had total laryngeal paralysis. Within these 35 horses, physical traits such as height orneck length did not correlate with the incidence or severity of RLN. Ten control ponies showed no evidence of abnormal laryngeal function.
Plasma pharmacokinetics and faecal excretion of ivermectin, doramectin and moxidectin following oral administration in horses
Authors: GOKBULUT C. , NOLAN A. M. , MCKELLAR Q. A.
Published: April 2007

The present study was carried out to investigate whether the pharmacokinetics of avermectins or a milbemycin could explain their known or predicted efficacy in the horse.

The avermectins, ivermectin (IVM) and doramectin (DRM), and the milbemycin, moxidectin (MXD), were each administered orally to horses at 200 μg/kg bwt. Blood and faecal samples were collected at predetermined times over 80 days (197 days for MXD) and 30 days, respectively, and plasma pharmacokinetics and faecal excretion determined. Maximum plasma concentrations (Cmax) (IVM: 21.4 ng/ml; DRM: 21.3 ng/ml; MXD: 30.1 ng/ml) were obtained at (tmax) 7.9 h (IVM), 8 h (DRM) and 7.9 h (MXD). The area underthe concentration time curve (AUC) of MXD (92.8 ng.day/ml) was significantly larger than that of IVM (46.1 ng.day/ml) but not of DRM (53.3 ng.day/ml) and mean residence time of MXD (17.5 days) was significantly longer than that of either avermectin, while that of DRM (3 days) was significantly longer than that of IVM (2.3 days). The highest (dry weight) faecal concentrations (IVM: 19.5 μg/g; DRM: 20.5 μg/g; MXD: 16.6 μg/g) were detected at 24 h for all molecules and each compound was detected (≥ 0.05 μg/g) in faeces between 8 h and 8 days following administration.

The avermectins and milbemycin with longer residence times may have extended prophylactic activity in horses and may be more effective against emerging and maturing cyathostomes during therapy. This will be dependent upon the relative potency of the drugs and should be confirmed in efficacy studies.
Effects of intravenous lidocaine overdose on cardiac electrical activity and blood pressure in the horse
Authors: MEYER G. A. , LIN H. C. , HANSON R. R. , HAYES T. L.
Published: April 2007

This study aimed to identify blood serum lidocaine concentrations in the horse which resulted in clinical signs of intoxication, and to document the effects of toxic levels on the cardiovascular and cardiopulmonary systems. Nineteen clinically normal mature horses of mixed breed, age and sex were observed. Lidocaine administration was initiated in each subject with an i.v. loading dose of 1.5 mg/kg bwt and followed by continuous infusion of 0.3 mg/kg bwt/min until clinical signs of intoxication were observed. Intoxication was defined as the development of skeletal muscle tremors. Prior to administration of lidocaine, blood samples for lidocaine analysis, heart rate, mean arterial blood pressure, systolic blood pressure, diastolic blood pressure, respiratory rate and electrocardiographic (ECG) data were collected. After recording baseline data, repeat data were collected at 5 min intervals until signs of intoxication were observed.

The range of serum lidocaine concentrations at which the clinical signs of intoxication were observed was 1.85–4.53 μg/ml (mean ± s.d. 3.24 ± 0.74 μg/ml).

Statistically significant changes in P wave duration, P‐R interval, R‐R interval and Q‐T interval were observed in comparison to control values, as a result of lidocaine administration. These changes in ECG values did not fall outside published normal values and were not clinically significant. Heart rate, blood pressures and respiratory rates were unchanged from control values. This study establishes toxic serum lidocaine levels in the horse, and demonstrates that there were no clinically significant cardiovascular effects with serum lidocaine concentrations less than those required to produce signs of toxicity.
Wedge‐shaped conformation of the dorsolateral aspect of the third tarsal bone in the Thoroughbred racehorse is associated with development of slab fractures in this site
Authors: BAIRD D. H. , PILSWORTH R. C.
Published: April 2007

Anecdotal evidence suggested that many cases of third tarsal bone (T3) fracture encountered clinically were associated with an abnormal shape to this bone. The radiographs of 10 normal horses and 10 horses affected with slab fracture of T3 were therefore examined to ascertain if any pre‐existent radiological abnormality was present in cases of fracture. Measurement of the maximum and minimum width between the proximal and distal articular surfaces of the dorsolateral aspect of this bone was carried out on a standardised dorso‐50° medial‐palmarolateral radiographic projection of the tarsus of each horse. To avoid artefacts produced by possible image magnification, ratios of these values were used for comparison between horses. The results showed that wedge shaped conformation of T3, in which the articular surfaces of the bone converge and then diverge again on the dorsolateral aspect, was over‐represented in the population of horses sustaining T3 fracture when compared to controls. This information may be important in making judgements on the suitability of horses during prepurchase examination for racing.
Factors influencing blood flow in the equine digit and their effect on uptake of 99m technetium methylene diphosphonate into bone
Authors: DYSON S. , LAKHANI K. , WOOD J.
Published: April 2007

It was hypothesised that exercise may promote perfusion of the distal part of the limbs and enhance uptake of radiopharmaceutical into bone, but bandaging and lameness would have no effect. Two hundred and two horses undergoing routine nuclear scintigraphic examination for assessment of lameness or poor performance between November 1998 and November 1999 were assigned randomly to one of 4 groups: no bandages and no exercise (NB/NE); bandages and no exercise (B/NE); no bandages and exercise (NB/E); bandages and exercise (B/E). In the bandage groups, the distal forelimbs were bandaged for at least 16 h prior to injection of radiopharmaceutical. In the exercise groups, horses were lunged for 15 min at trot and canter prior to injection. Quantitative values for perfusion of the front feet and uptake of the radiopharmaceutical into the bones of the distal limb were obtained from scintigraphic measurements during the vascularand bone phases of radiopharmaceutical distribution. Perfusion of the front feet was classified as good in 60% of limbs, reduced in 21% and poor in 19%. There was a strong positive relationship between exercise and both perfusion of the front feet and uptake of the radiopharmaceutical into bone. Bandaging had no effect. There was a relationship between environmental temperature and both perfusion and uptake of the radiopharmaceutical into bone. Estimation of foot surface temperature using thermography was helpful in predicting perfusion of the distal limbs. There was no relationship between lameness and uptake of the radiopharmaceutical into bone. It is therefore recommended that, whenever possible, horses are exercised for 15 min prior to injection of radiopharmaceutical if nuclear scintigraphy of the distal parts of the limb is to be performed.
Systemic antibodies to Clostridium botulinum type C: do they protect horses from grass sickness (dysautonomia)?
Authors: HUNTER L. C. , POXTON I. R.
Published: April 2007

The aetiology of equine grass sickness (EGS) is still unknown. There is increasing evidence that toxicoinfection with Clostridium botulinum type C is involved. Epidemiological evidence shows that resistance to EGS can occur in older horses and those that have been on a particular pasture for longer or have been in prior contact with the disease. This resistance may be in the form of an immune response to the aetiological agent. Levels of systemic antibodies to the surface antigens of C. botulinum type C (using the closely related and safe C. novyi type A as a phenotypic marker) and to the botulinum type C neurotoxin (BoNT/C) were investigated in horses with and without EGS.

Horses with grass sickness were found to have significantly lower levels of systemic IgG to both surface antigens and BoNT/C. Horses with low levels of systemic immunity to these antigens may be more susceptible to developing EGS. There were no significant differences in antibody levels between the different categories of EGS, suggesting systemic immunity to C. botulinum type C does not play a significant role in influencing the severity of the disease. However, horses that had been in contact with EGS or that were grazing land where it had occurred frequently in the past had significantly higher antibody levels to these antigens. These horses may have been exposed to subclinical doses of C. botulinum type C and BoNT/C, resulting in the production of a protective immune response against the putative aetiological agent. This finding is of potential significance for the prospect of prevention of EGS by vaccination against C. botulinum type C.
Effect of romifidine on gastrointestinal motility, assessed by transrectal ultrasonography
Authors: FREEMAN S. L. , ENGLAND G. C. W.
Published: April 2007

A technique of transrectal ultrasonography was developed to investigate the effects of romifidine 80 and 120 μg/kg bwt on intestinal motility in the horse. Motility of the small intestine, caecum and left ventral colon were assessed following injection of romifidine and a saline control, using a blinded, cross‐over study design in 6 horses. Measurements were taken at 15, 30, 60, 120, 180 and 240 min after drug administration. There was a slight nonsignificant decrease in motility in the control group over the 4 h study period. Both doses of romifidine produced a marked decrease in gastrointestinal motility and were associated with the presence of reduced (nonpropulsive) contractions. Transrectal ultrasonography proved suitable for monitoring changes in the type and frequency of intestinal motility in the horse.
Application of a constant blood withdrawal method in equine exercise physiology studies
Authors: BARAGLI P. , TEDESCHI D. , GATTA D. , MARTELLI F. , SIGHIERI C.
Published: April 2007

The aim of the present study was to test a constant blood withdrawal method (CBWM) to collect blood samples from horses during treadmill exercise. CBWM was performed in 4 Standardbreds and 5 Haflinger horses. A peristaltic pump was used to control blood aspiration from an i.v. catheter via an extension line. Blood was collected using an automatic fractions collector, with a constant delay time between the drawing of blood and sample collection. Blood withdrawal using CBWM was made during a treadmill standardised exercise test (SET). A blood flow of 12 ml/min was used and samples collected every 60 s during the entire period of exercise. The volume of blood collected in each sample tube was 12.1 ± 0.2 ml, with a delay time of mean ± s.d. 25.3 ± 0.8 s. Plasma lactate kinetics based on measurement of lactate in each fraction showed an exponential increase during the first 13 min of exercise (10.5 min of SET and 2.5 min recovery). The peak plasma lactate concentration was observed between 2.5 and 5.5 min after the end of SET. CBWM permits the kinetics of lactate and other blood‐borne variables to be studied over time. This method could be a valuable aid for use in studying equine exercise physiology.
Measurement of serum amyloid A in the neonatal foal using a latex agglutination immunoturbidimetric assay: determination of the normal range, variation with age and response to disease
Authors: STONEHAM S. J. , PALMER L. , CASH R. , ROSSDALE P. D.
Published: April 2007

This paperdescribes the use of a latex agglutination assay to measure serum amyloid A (SAA) in the neonatal foal. The normal range and response to clinical disease was determined. This retrospective study evaluated SAA concentrations over the first 3 dayspostpartumof 226 Thoroughbred foals judged to be clinically healthy. The normal range for each day was determined; levels were found to be significantly highest on Day 2 (Day 1 vs. Day 2 P<0.0001). The 95th percentile for Days 1–3 was 27.1 mg/l.

Clinical records of 133 foals, presented as first or second opinion cases, were evaluated. Foals were divided into 4 groups; septicaemia (S), focal infection (FI), failure of passive transfer (FPT) and noninfectious disease (NI). There was a statistically significant difference (P<0.0001) between SAA concentrations of control foals compared toGroups SandFI.There was no statistically significant difference between controls andGroups FPTandNI.WhenGroup NIwas compared toGroups SandFI, there was a statistically significant difference (P<0.0001).

The authors suggest that SAA determined by this latex agglutination assay might be a helpful aid in the diagnosis of septicaemia and focal infection in neonatal foals; levels >100 mg/l are highly suggestive of infection in young foals.
Effects of an external nasal strip and frusemide on pulmonary haemorrhage in Thoroughbreds following high‐intensity exercise
Authors: GEOR R. J. , OMMUNDSON L. , FENTON G. , PAGAN J. D.
Published: April 2007

The purpose of this study was to examine the effects of an external nasal strip (NS), frusemide (FR) and a combination of the 2 treatments (NS + FR) on exercise‐induced pulmonary haemorrhage (EIPH) in Thoroughbred horses. It was hypothesised that both the NS and FR would attenuate EIPH as assessed by red blood cell count in bronchoalveolar lavage fluid. In random order, 8 horses completed each of 4 sprint exercise tests on a treadmill: 1) NS; 2) FR (0.5 mg/kg bwt i.v., 4 h pre‐exercise); 3) NS + FR; and 4) control (C; no treatment). After a 5 min warm‐up (4.5 m/s), horses completed 2 min running at 120% maximum oxygen consumption (Vo2max) with the treadmill set at 3° incline. Mean ± s.d. running speed was 14.2 ± 0.2 m/s. In the FR and NS + FR trials, horses carried weight equal to that lost as a result of frusemide administration. During exercise at 120%V̇O2max, oxygen consumption (Vo2) and carbon dioxide production (Vco2) were measured at 15 s intervals. Plasma lactate concentration was measured in samples collected before exercise, at the end of the sprint and after 5 min cooldown at the trot. Thirty minutes after the run, bronchoalveolar lavage (BAL) was performed and the red cell count in the fluid quantified. Vo2and Vco2were significantly lower in NS and NS + FR trials than in the C and FR trials at the end of the sprint exercise protocol. However, plasma lactate concentrations did not differamong treatments. Compared with the C trial (61.1 ± 30.5 × 106red blood cells/ml BAL fluid), pulmonary haemorrhage was significantly (P<0.05) decreased in both the NS (15.9 ± 4.0 × 106RBC/ml) and FR (12.2 ± 5.8 × 106RBC/ml) trials. EIPH in the NS + FR trial (7.9 ± 1.0 × 106RBC/ml) was further diminished (P<0.05) compared to the NS trial, but not different from the FR trial. We conclude that both the external nasal strip and frusemide attenuate pulmonary haemorrhage in Thoroughbred horses during high‐speed sprint exercise. The external nasal strip appears to lowerthe metabolic cost of supramaximal exertion in horses. Given the purported ergogenic effects of frusemide, the external nasal strip is a valuable alternative for the attenuation of EIPH.
Effect of partial replacement of oats with sugar beet pulp and maize oil on nutrient utilisation in horses
Authors: LINDBERG J. E. , KARLSSON C. PALMGREN
Published: April 2007

The objective of the present work was to assess the influence of partial replacement of oats with dried unmolassed sugar beet pulp (SBP) and/or maize oil on nutrient utilisation in horses fed a traditional hay and concentrate diet.

The total tract digestibility of nutrients, urinary excretion and plasma parameters were studied in a 4 × 4 Latin‐square design experiment with purebred Arabian geldings. Horses fed the SBP diets responded with a reduced (P<0.05) apparent digestibility of crude protein and feeding of maize oil resulted in an increased (P<0.05) apparent digestibility of crude fat. The apparent energy digestibility was unaffected by the replacement of oats with SBP, but increased (P<0.05) when maize oil replaced part of the oats. The urinary excretion of nitrogen increased (P<0.05) when maize oil replaced oats and the excretion of energy was higher (P<0.05) on the diets where oats were replaced by maize oil and SBP.

There was a significant (P<0.05) effect across treatments of postprandial blood sampling time on plasma glucose and insulin concentrations. Also, plasma concentrations of glucose and insulin tended to be higher on the oats than on the SBP diets.

In conclusion, the limited effects on the digestibility of nutrients and energy suggest that it should be possible to partially replace oats with maize oil and/or SBP in diets for horses without any impairing effects on the overall nutrient utilisation. However, the dietary‐induced changes in the urinary excretion of energy and on plasma glucose and insulin levels, indicate a possible influence of dietary carbohydrate composition on nutrient utilisation at the organ level, which requires further study.
Effect of GnRH immunisation on hormonal levels, sexual behaviour, semen quality and testicular morphology in mature stallions
Authors: MALMGREN L. , ANDRESEN Ø. , DALIN A.‐M.
Published: April 2007

The aim of this study was to investigate the effect of gonadotrophin‐releasing hormone (GnRH) immunisation on mature stallions that had been used for breeding. Four Standardbred stallions were used in the study: 3 experimental animals and 1 control animal. Semen was collected regularly, i.e. twice/week, during the 4 months prior to the experimental period. The stallions were immunised against GnRH with a GnRH‐BSA conjugate. Equimune was used as the adjuvant. The stallions were immunised on 5 occasions, 4 at 2 week intervals, and the fifth 4 weeks after the fourth. Blood samples were taken once a week for analysis of GnRH antibody titre and every third week for testosterone and oestrone sulphate analyses. Semen was collected once a week, and libido and sexual behaviour were observed. Ejaculate volume, sperm concentration, total number of sperm in the ejaculate, sperm motility and sperm morphology were evaluated. Testicular size was measured once a week. At the end of the study, the stallions were castrated, and a histological examination of the testes performed.

All immunised stallions produced antibodies against GnRH, and plasma testosterone concentration decreased. However, the effect of immunisation varied between stallions. In 2 of the stallions, high levels of antibodies were found, while in the third, the level was moderate. Four weeks after the first immunisation, a decrease in libido was observed. Two months after the first immunisation, marked changes in semen quality were observed in the 2 stallions with high antibody titres. Fourteen weeks after the first immunisation, the total number of sperm/ejaculate had decreased from >8.6×109 to<2.7×109, sperm motility from >59 to<10% and the frequency of morphological normal spermatozoa had decreased from >60 to<14%. The dominating abnormalities were abnormal head shapes, proximal cytoplasmic droplets and detached heads. In the third stallion, only slight changes in semen quality were found. No changes were observed in the control stallion.

Decreases in testicular size were noted in all of the experimental stallions. Pronounced histological alterations in the testes were observed in 2 of the stallions.

It is concluded that the vaccine was effective in stimulating production of GnRH antibodies and in suppressing testicular function and androgen secretion. However, there was an individual variation in the responses among the stallions and, further, libido was not totally suppressed.
Contact areas and pressure distribution on the proximal articular surface of the proximal phalanx under sagittal plane loading
Authors: BRAMA P. A. J. , KARSSENBERG D. , BARNEVELD A. , van WEEREN P. R.
Published: April 2007

The objective of this study was to map topographically contact areas and pressure distributions on the proximal articular surface (PAS) of the proximal phalanx (PI) under various clinically relevant loading conditions. Left and right forelimbs of 13 mature horses were transected halfway down the radius and loaded in a position mimicking the weightbearing attitude close to the midstance phase. Five loads were used which corresponded with loads that can be expected in different gaits or during athletic performance (stance: 1800 N, walk: 3600 N, trot: 5400 N, gallop: 10,500 N and jumping: 12,000 N). Contact areas and pressure distributions at the PAS of PI were determined using a methylene blue dye staining technique and 2 pressure sensitive films (low pressure: range 2.5–10 MPa and medium pressure: range 10–50 MPa).

The contact area of PI was positively correlated (r = 0.86; P<0.01) with the applied load. The contact area increased from 63% at 1800 N to 95% at 12,000 N and gradually shifted to include more of the edges of the articular surface, but especially the dorsal articular margin of PI. Pressure distribution patterns were similar under the different loading conditions. Pressure was less at the palmar margin and in the central depression and highest at the dorsal articular margin. With increasing load, the highest peak pressures were measured at sites of the dorsal articular margin that are not loaded in the standing or walking horse. The results of this study suggest that the frequent occurrence of osteochondral lesions at the dorsal articular margin of PI is caused by the combination of the intermittent character and the high absolute values of loads at this site as they occur during athletic performance.
Abdominal radiography in monitoring the resolution of sand accumulations from the large colon of horses treated medically
Authors: RUOHONIEMI M. , KAIKKONEN R. , RAEKALLIO M. , LUUKKANEN L.
Published: April 2007

This retrospective study consisted of 14 horses (age 6 weeks–12 years) with radiographically evident sand accumulations cranioventrally in the abdomen and clinical signs suggestive of sand enteropathy. The horses were treated medically and resolution of sand was monitored radiographically. Routine treatment consisted of psyllium mucilloid, combined with magnesium sulphate and/or mineral oilif needed. Initially, the number, size and shape of the sand accumulations showed large variation and the response to therapy was not predictable based on the initial appearance of the accumulation. In 2 foals, some of the sand was passed and the rest was mixed with other intestinal contents within 2–4 days. Even large accumulations disappeared in 2–4 days with psyllium alone or combined with mineral oil in 4 horses. In another 4 horses, the size of the accumulations decreased but varying amounts remained approximately at the same site, despite treatment for 1–4 weeks, and all these horses also had either gastric or large colon impaction. Three horses had a limited response to psyllium treatment, but the accumulation resolved with repeated doses of magnesium sulphate, with or without mineral oil. One horse did not respond to prolonged laxative treatment but the accumulation resolved on pasture. Clinical improvement was not necessarily related to the resolution of sand. Radiography of the cranioventral abdomen was found to be a useful means for monitoring the resolution of sand and confirming the effect of medical treatment in removing sand from the large colon in the horse.
Age‐related changes in the testes of horses
Authors: FUKUDA T. , KIKUCHI M. , KUROTAKI T. , OYAMADA T. , YOSHIKAWA H. , YOSHIKAWA T.
Published: April 2007

Atrophy of seminiferous tubules and interstitial fibrosis are frequently observed in aged horses. Samples from 8 male Thoroughbreds, age 4–24 years, were subjected to histological, electron microscopical and immunohistochemical examination and statistical analysis. There were statistically significant increases in collagen fibres in the lamina propria of seminiferous tubules and testicular interstitium in 3 horses age 23 and 24 years compared with 5 horses age 4–20 years (P<0.001). Lamina propria surrounding atrophic tubules was thickened by an increase in collagen type IV and elastic fibres and by proliferation of bizarre myoid cells. Basal lamina was also thickened but had decreased reactivity for collagen type IV. Some myoid cells changed morphologically to a swollen and irregular shape and contained abundant cytoplasmic organelles. Laser scanning microscopy revealed that cytoplasmic actin filaments were decreased; the remaining filaments were positive for α‐smooth muscle actin and vimentin, and matrix metalloproteinase‐2 was secreted. These myoid cells transformed into myofibroblasts. The changes are interpreted as evidence of injured structure and function of the lamina propria and basal lamina and may explain the functional decline of the blood‐testis barrier. Myoid cells may play an important role in the progression of testicular fibrosis.
Surgical and postoperative factors influencing short‐term survival of horses following small intestinal resection: 92 cases (1994–2001)
Authors: MORTON A. J. , BLIKSLAGER A. T.
Published: April 2007

Although short‐term survival rates following small intestinal resection reportedly range from 48–88%, there is little information on predicting which horse may or may not survive small intestinal (SI) resection and anastomosis. The aim of this study was to identify factors that contribute to nonsurvival in horses following small intestinal resection. Medical records of horses which recovered from anaesthesia following SI resection were reviewed. Clinical and surgical variables were evaluated for their association with short‐term survival using logistic regression and were reported as odds ratios (OR), including the 95% confidence interval (CI), indicating the likelihood of horses not surviving to hospital discharge. Ninety‐two records met the criteria for inclusion. Thirty‐six (81.8%) of the horses that underwent jejunojejunostomy (JJ) and 34 (70.8%) of the horses that underwent jejunocaecostomy (JC) survived to discharge. Multiple logistic analysis indicated that postoperative ileus (OR = 29.7; 95% CI 2.5–354.6), repeat celiotomy (OR = 18; CI 1.7–187.6), and an elevated heart rate of ≥ 60 beats/min (OR = 5.6; CI 1.5–20.6) were the principal factors associated with nonsurvival. A low total plasma protein of <55 g/l (OR = 1.8; CI 0.5–7.6) was incorporated in the final model because its inclusion improved the overall validity of the model Clinicians should be aware of the factors associated with the greatest likelihood of nonsurvival following small intestinal resection, so that they can institute aggressive treatment and accurately inform owners on the likelihood of survival.
The effects of cyclo‐oxygenase inhibitors on bile‐injured and normal equine colon
Authors: CAMPBELL N. B. , JONES S. L. , BLIKSLAGER A. T.
Published: April 2007

A potential adverse effect of cyclo‐oxygenase (COX) inhibitors (nonsteroidal anti‐inflammatory drugs [NSAIDs]) in horses is colitis. In addition, we have previously shown an important role for COX‐produced prostanoids in recovery of ischaemic‐injured equine jejunum. It was hypothesised that the nonselective COX inhibitor flunixin would retard repair of bile‐injured colon by preventing production of reparative prostaglandins, whereas the selective COX‐2 inhibitor, etodolac would not inhibit repair as a result of continued COX‐1 activity. Segments of the pelvic flexure were exposed to 1.5 mmol/l deoxycholate for 30 min, after which they were recovered for 4 h in Ussing chambers. Contrary to the proposed hypothesis, recovery of bile‐injured colonic mucosa was not affected by flunixin or etodolac, despite significantly depressed prostanoid production. However, treatment of control tissue with flunixin led to increases in mucosal permeability, whereas treatment with etodolac had no significant effect. Therefore, although recovery from bile‐induced colonic injury maybe independent of COX‐elaborated prostanoids, treatment of control tissues with nonselective COX inhibitors may lead to marked increases in permeability. Alternatively, selective inhibition of COX‐2 may reduce the incidence of adverse effects in horses requiring NSAID therapy.
Case control study to identify risk factors for simple colonic obstruction and distension colic in horses
Authors: HILLYER M. H. , TAYLOR F. G. R. , PROUDMAN C. J. , EDWARDS G. B. , SMITH J. E. , FRENCH N. P.
Published: April 2007

A case control study was performed to identify risk factors for colic caused by simple colonic obstruction and distension (SCOD) in the horse. Case horses were recruited from 2 veterinary school clinics. Control horses were population based and matched by time of year. A number of risk factors were considered in the following areas: general carer and premises information; exercise information; husbandry information (housing‐ and pasture‐related); feeding information; breeding information; behavioural information; travel information; preventive medicine information and pevious medical information. All variables with a P value of <0.2 in the univariable analysis were considered for possible inclusion in a multivariable model. A final model, produced by a forward stepwise method, identified crib‐biting or windsucking, an increasing number of hours spent in a stable, a recent change in a regular exercise programme, the absence of administration of an ivermectin or moxidectin anthelmintic in the previous 12 months and a history of travel in the previous 24 h as associated with a significantly increased risk of SCOD. An alternative final model, produced by a backwards elimination method, identified the same variables as the forward model with, in addition, a history of residing on the current establishment for less than 6 months, a history of a previous colic episode and the fewer times per year the teeth were checked/treated as associated with a significantly increased risk of SCOD. Three of the risk factors in this model were associated with a large increase in risk: stabling for 24 h/day, crib‐biting/windsucking and travel in the previous 24 h.
Reliability of ultrasonography compared to radiography in revealing intestinal sand accumulations in horses
Authors: KOROLAINEN R. , RUOHONIEMI M.
Published: April 2007

In order to investigate the reliability of ultrasonography in revealing intestinal sand accumulations, the cranioventral parts of the abdomen of 32 horses (age 3–20 years) with signs suggestive of gastrointestinal sand were examined radiographically and ultrasonographically. The amount of sand and its localisation, relative to the ventral abdominal wall, were evaluated radiographically and graded (scale 0–4). Motility of the intestine and whether it was lying against the ventral abdominal wall were evaluated ultrasonographically and the findings summed and graded (scale 0–3) to express the likelihood of the presence of sand. The ultrasonographic and radiographic grades were significantly associated. Out of 14 horses with a moderate or large ventral sand accumulation radiographically, 13 (92.9%) had a positive sand finding ultrasonographically. Out of 8 horses with no signs of sand radiographically, 7 were considered negative for sand ultrasonographically. The specificity of ultrasonography in detecting sand accumulations was 87.5% (7/8) and the sensitivity 87.5% (21/24). Small and more dorsally located accumulations were more difficult to detect ultrasonographically. Of the horses with a small or moderate amount of sand relatively ventrally or only a small part of sand close to the ventral abdominal wall, 70% (7/10) were considered suggestive or positive for sand ultrasonographically. The ventral aspect of sand accumulations was hyperechoic, causing varying acoustic shadowing and the intestine had decreased or absent motility. Ultrasonography revealed the length of the accumulations but gave very limited information of their height. Ultrasonography is a practical and reliable method for detecting sand accumulations but it cannot replace radiography.
Factors associated with development of ileal impaction in horses with surgical colic: 78 cases (1986–2000)
Authors: LITTLE D. , BLIKSLAGER A. T.
Published: April 2007

Ileal impaction is prevalent in the south‐eastern USA, where feeding of Coastal Bermuda hay has been implicated as a risk factor. Alternatively, infection with the tapewormAnoplocephala perfoliatahas been identified as a risk factor for ileal impaction in the UK. We hypothesised that feeding Coastal Bermuda hay and failure to administer routinely an anthelmintic with efficacy against tapeworms would place horses at risk of developing ileal impaction in the USA. Seventy‐eight horses, with surgically confirmed ileal impaction and 100 horses admitted for colic that did not have an ileal impaction, were selected retrospectively for logistic regression analysis. Using odds ratios (OR) as an index of risk, feeding Coastal Bermuda hay (OR = 2.9) and failure to administer a pyrantel salt within 3 months of admission (OR = 3.1) placed horses at risk of development of ileal impaction. This study confirms the belief that feeding Coastal Bermuda hay places horses at risk of ileal impaction, although the quality of the hay may also play a role. Periodic administration of anthelmintics with efficacy against tapeworms should be considered to reduce risk of ileal impaction.
Equine surgical colic: risk factors for postoperative complications
Authors: FRENCH N. P. , SMITH J. , EDWARDS G. B. , PROUDMAN C. J.
Published: April 2007

The reason for undertaking this study was that postoperative complications of colic surgery lead to patient discomfort, prolonged hospitalisation and increased cost. Potential risk factors for the 6 most common postoperative complications (jugular thrombosis, ileus, re‐laparotomy, wound suppuration, incisional herniation and colic) were evaluated using multivariable models. Jugular thrombosis was associated significantly with heart rate greater than 60 beats/min and with increased packed cell volume (PCV) at admission. The risk of postoperative ileus also increased with increasing PCV at admission and was higher in horses recovering from pedunculated lipoma obstruction. Incisional herniation was strongly associated with wound suppuration and with increasing heart rate at admission. The emergence of cardiovascular parameters as risk factors for several postoperative complications is consistent with the hypothesis that endotoxaemia is important in the development of these complications. Early referral of colic cases, prior to the development of severe endotoxaemic shock, may minimise the risk of some postoperative complications. Horses that have suffered epiploic foramen entrapment, are more than 4 times as likely to undergo re‐laparotomy than other horses. Horses that have suffered postoperative ileus have a similarly increased risk of undergoing re‐laparotomy. The risk of postoperative colic is significantly associated with horses recovering from large colon torsion (>360°) and with having undergone re‐laparotomy. Hazard ratios (with 95% confidence intervals) for these last two effects are 3.1 (1.7, 5.7) and 3.4 (1.9, 6.2), respectively. Knowledge of the risk factors for postoperative complications allows more accurate prognostication postoperatively and suggests ways in which the risk of postoperative complications can be minimised.
Comparison of endoscopic, necropsy and histology scoring of equine gastric ulcers
Authors: ANDREWS F. M. , REINEMEYER C. R. , McCRACKEN M. D. , BLACKFORD J. T. , NADEAU J. A. , SAABYE L. , SÖTELL M. , SAXTON A.
Published: April 2007

Equine gastric ulcer syndrome (EGUS) represents a major health problem in performance horses. Much debate exists regarding endoscopic gastric ulcer scoring systems and their ability accurately to predict severity or depth of gastric ulcers. The purpose of this study was to evaluate the ability of an endoscopist to count gastric ulcers and predict gastric ulcer severity or depth using 2 endoscopic scoring systems and compare them to the same gastric ulcers see on necropsy and histopathology. Endoscopic examination of the stomach was performed under general anaesthesia on 23 mixed breed yearling horses, after feed was withheld for 24 h. Gastric ulcers were scored using 2 systems, number/severity‐scoring (N/S) and practitioner simplified (PS) systems. Afterendoscopy, the horses were subjected to euthanasia and the stomach mucosa examined blindly and scored again at necropsy using above scoring systems. Representative gastric ulcers were then placed in 10% formalin and processed routinely for histopathology. The gastric ulcers were scored using a histopathology system (HSS) based on ulcer depth. Number scores in the N/S scoring system and PS on endoscopic and necropsy examinations were compared using Friedman 2 way analysis of variance. Where significant differences between variables were found apost hocanalysis was conducted using a Tukey's Studentised range (HSD) test. Severity scores using the N/S (ENGS) and PS scores recorded for the stomach via endoscopy and scores from HSS were evaluated for significant association using a Mantel‐Haenszel Chi‐square and Pearson moment correlation coefficient analysis. Significance was P<0.05.

All horses had gastric ulcers in the nonglandular mucosa via endoscopic examination and at necropsy examination. Mean nonglandular ulcer number (ENGN) score was significantly (P = 0.0024) lower on endoscopic examination compared to the score at necropsy (NNGN); whereas PS scores were not significantly different on endoscopy when compared to necropsy examination. A significant but weak association was found between ENGS and HSS (3.89, P = 0.048; r = 0.453, P = 0.045) and no correlation was found between PS and HSS (1.2, P = 0.272; r = 0.117; P = 0.622). Only 1/23 horses had glandular ulcers observed via endoscopic examination whereas, 6/23 horses had glandular ulcers at necropsy and on histopathology. The prevalence of EGUS is high in stalled yearling horses. The endoscopist may underestimate the number of gastric ulcers and may not be able accurately to predict the severity or depth of those ulcers present in the nonglandular equine stomach. Furthermore, the endoscopist may miss glandular gastric ulcers.