bluuebunny/crossref_metadata_2025 huggingface dataset:
Spinal accessory nerve biopsy as an ante mortem diagnostic test for equine motor neuron disease
Authors: JACKSON C. A. , DE LAHUNTA A. , CUMMINGS J. F. , DIVERS T. J. , MOHAMMED H. O. , VALENTINE B. A. , HACKETT R. P.
Published: April 2010

The effectiveness of spinal accessory nerve branch biopsy evaluation as a means to confirm the diagnosis of equine motor neuron disease (EMND) was investigated. Sixteen horses with histories and clinical signs suggestive of EMND and 16 control horses with neither histories nor clinical signs of any neurological disorder, were subjects of the study. Biopsy samples of the ventral branch of the spinal accessory nerve were obtained either surgically, under general anaesthesia or post mortem immediately after euthanasia. Evaluation was done on the spinal cord of all horses to serve as the definitive diagnostic indicator of EMND.

Results indicate that biopsy of the ventral branch of the spinal accessory nerve is a reliable ante mortem diagnostic test for EMND. Histological evidence of the degeneration of myelinated axons is present in both acute and arrested cases. The ventral branch of the spinal accessory nerve is easy to approach surgically and biopsy of the nerve causes no disfigurement of the sternocephalicus muscle. The use of semi‐thin Epon sections is an excellent method of sample preparation. Formalin fixation and routine paraffin embedment may prove more accessible and provide good quality preparations for reliable interpretation. In the hands of an experienced pathologist, the sensitivity and specificity reliability coefficients for spinal accessory nerve branch biopsy are 94%, making this technique an extremely valuable diagnostic tool for the ante mortem diagnosis of EMND.
Chronic tenosynovitis of the carpal extensor tendon sheaths in 15 horses
Authors: PLATT D. , WRIGHT I. M.
Published: April 2010

The history, clinical features, radiological findings, treatment and outcome of 15 horses with chronic tenosynovitis of the carpal extensor tendon sheaths are reported. The condition was seen most commonly in horses used for jumping and penetration of the tendon sheaths by thorns was the most common aetiology. Treatment involved surgical resection of the hyperplastic synovial membrane, and adhesions within the tendon sheath, with primary closure. When combined with early postoperative physiotherapy this was found to be an effective method of treatment. All horses in this series were not lame at follow‐up, with 14 horse returning to their former level of athletic performance.
Measurement of cardiac output in standing horses by Doppler echocardiography and thermodilution
Authors: BLISSITT KAREN J. , YOUNG LESLEY E. , JONES R. S. , DARKE P. G. G. , UTTING J.
Published: April 2010

Measurements of cardiac output by Doppler echocardiography were compared to simultaneous measurements by thermodilution in 9 conscious horses. In the Doppler technique, mean blood flow velocities for estimation of cardiac output were recorded from the aorta and pulmonary artery. The flow area of each vessel was calculated from the vessel diameter, measured from a 2‐dimensional ultrasound image. Differences in the site and method of measuring the vessel diameter altered the estimation of cardiac output by the Doppler method. Cardiac output was modified by the i.v. infusion of 4 μg/kg bwt/min dopamine and 4 μg/kg bwt/min dobutamine and by the i.v. administration of 10 μg/kg bwt detomidine and 20 μg/kg bwt butorphanol.

Doppler measurements of cardiac output correlated closely with measurement by thermodilution. Measurements from the aortic outflow correlated more closely with thermodilution, than those from the pulmonary artery (r = 0.89 and r = 0.77, respectively). Doppler measurements agreed most closely with thermodilution measurements when the mean flow velocity was recorded from the aorta and the flow area was measured from the ascending aorta using the leading edge method. There was no significant bias between the 2 techniques when Doppler flow velocities were recorded by this method and the limits of agreement were narrow (±12.26 l/min). The differences between the 2 methods increased with increasing cardiac output.

Doppler echocardiography is a safe noninvasive method of measuring cardiac output in horses. The agreement between Doppler echocardiography and thermodilution in this study is similar to that reported in man and is similar to that reported between thermodilution and other techniques in man.
Visual outcome and ocular survival following Iris prolapse in the horse: a review of 32 cases
Authors: CHMIELEWSKI N. T. , BROOKS D. E. , SMITH PATRICIA J. , HENDRIX DIANE V. H. , WHITTAKER C. , GELATT K. N.
Published: April 2010

The medical records of 32 horses treated for iris prolapse (IP) during an 8 year period, at the University of Florida Veterinary Medical Teaching Hospital, were reviewed. Iris prolapse was associated with perforated corneal ulcers in 15 horses (47%), ruptured stromal abscesses in 2 horses (6%), and full thickness corneal lacerations in 15 horses (47%). Initial ophthalmic examinations revealed IP with severe iridocyclitis in all eyes and keratomalacia in 8 eyes with corneal ulcers, one with a stromal abscess and 1 with a corneal laceration. Hyphema was present in 7 eyes with corneal lacerations.

Thirty horses were managed with combined medical and surgical therapy. Two horses were only treated medically with topically administered antibiotics. Of the 24 perforations surgically repaired, 21 were closed primarily and 13 were then covered with a conjunctival graft. After combined therapy and a minimum of 4 months of follow‐up, vision was retained in 6 of the horses (40%) with perforating corneal disease and 5 of the horses (33%) with perforating corneal lacerations. Post operatively, of the 11 (37%) horses blind at discharge, 6 (55%) subsequently developedphthisis bulbi.Enucleations were performed in 4 cases with extensive keratomalacia and/or endophthalmitis, 2 cases with limbal rupture and total hyphema, and one case with a chronic IP. One horse was subjected to euthanasia after 3 surgical treatments failed to stabilise stromal melting.

Horses presented with ulcerative keratitis of fewer than 15 days duration, or horses with corneal lacerations less than 15 mm in length, tended to have a favourable visual outcome. Keratomalacia, hyphema, corneal lacerations longer than 15 mm and lacerations extending to, along, or beyond the limbus, adversely influenced visual outcome. Iridectomy did not appear clinically to exacerbate anterior uveitis or adversely affect visual outcome. Ocular survival following combined therapy was 80% (12/15) in horses with corneal lacerations and 67% (10/15) in horses with ulcerative keratitis.
A survey for antibodies to equine arteritis virus in donkeys, mules and zebra using virus neutralisation (VN) and enzyme linked immunosorbent assay (ELISA)
Authors: PAWESKA J. T. , BINNS M. M. , WOODS P S. A. , CHIRNSIDE E. D.
Published: April 2010

A seroepidemiological survey of donkeys in South Africa (n = 4300) indicated a wide distribution and increasing prevalence of antibodies to equine arteritis virus (EAV). Donkey sera inhibited equine arteritis virus infection in virus neutralisation (VN) tests and in ELISA specifically bound to a recombinant antigen derived from the Bucyrus isolate of EAV. These results suggest that donkeys have been exposed to the same serotype of this virus as circulates among horses. A good correlation existed between EAV neutralising antibody titres and ELISA absorbance values (0.8631); the ELISA was sensitive and specific (99.2% and 80.3% respectively) for donkey sera when compared to the VN test and the recombinant ELISA antigen did not cross‐react with sera positive for common African equine pathogens. VN+ ELISA+ donkeys were also found in Morocco and Zimbabwe and seropositive mules in both South Africa and Morocco. No seropositive zebra (n = 266) were detected from game reserves or zoos in 9 countries. The results confirm that in addition to horses and donkeys, mules are naturally infected with EAV.
Prevalence of fetal maldispositions in equine referral hospital dystocias
Authors: FRAZER G. S. , PERKINS N. R. , BLANCHARD T. L. , ORSINl J. , THRELFALL W. R.
Published: April 2010

A retrospective investigation was performed to determine the population characteristics of horses presented for dystocia at 2 equine referral hospitals and the types of fetal maldispositions among these horses. The study population consisted of a similar number of Thoroughbreds (25%), Standardbreds (24%) and draft horses (22%). Most of the current literature pertaining to equine obstetrics is based on a predominately draft horse population (63%). The latter population appeared to have more transverse presentations (P = 0.06), possibly because of the higher number of draft mares. In our study, 43% (6/14) of the transverse presentations occurred in draft breeds. Furthermore, 18% of the draft mare dystocias (6/33) were transverse presentations whereas only 8% (6/73) of the 2 major light breeds (Thoroughbred n = 3; Standardbred n = 3) had transverse presentation dystocias. Despite the significant breed differences between the 2 populations (P<0.001), the prevalence of all other fetal maldispositions was not different from those previously reported. Severe dystocia was often multifactorial, with 86% of cases involving malposture and over half (58%) of these involving more than one extremity. Head and/or neck deviation were a major reason for referral. In 30% of cases malposition was a factor, and abnormal presentation was involved in 24% of referrals.
Genetic markers in Standardbred trotters susceptible to the rhabdomyolysis syndrome
Authors: COLLINDER E. , LINDHOLM A. , RASMUSON MARIANNE
Published: April 2010

The equine rhabdomyolysis syndrome (RHA) is believed to be multifactorial in origin; and could be caused by an interaction between genetic and environmental factors. In order to analyse its genetic background an association study was undertaken. Two sample groups of Standardbreds (Stb) which had suffered from RHA were compared to the total population of Swedish Standardbred trotters using recorded polymorphic genetic markers. The results showed that gene frequencies for several markers in the RHA groups differed significantly from those estimated for the total population. A rhabdomyolysis risk group could be characterised using 4 or 5 genetic marker loci.
Comparison of collagen fibril populations in the superficial digital flexor tendons of exercised and nonexercised Thoroughbreds
Authors: PATTERSON‐KANE J. C. , WILSON A. M. , FIRTH E. C. , PARRY D. A. D. , GOODSHIP A. E.
Published: April 2010

This study was undertaken to test the hypothesis that collagen fibrils, the submicroscopic units of strength in tendon, would hypertrophy in response to a specific defined training programme. Fibril diameters were measured in central and peripheral regions of superficial digital flexor tendon (SDFT) samples from five 18‐month‐old horses which underwent a subsequent 18 month training programme and 6 age‐ and sex‐matched controls.

Central region fibrils from the trained horses had a mass‐average diameter (MAD) of 105.3 nm, which was significantly lower (P<0.01) than that of 131.7 nm for the same region in the control horses. This reduction in fibril diameter in the region of tendon which is predisposed to injury was interpreted as evidence of microtrauma, as it implies the region is weakened by the training regimen. Repeated episodes of microtrauma may accumulate and eventually result in degenerative lesions and clinical tendonitis.
Severe polysaccharide storage myopathy in Belgian and Percheron draught horses
Authors: VALENTINE B. A. , CREDILLE K. M. , LAVOIE J.‐P , FATONE S. , GUARD C. , CUMMINGS J. F. , COOPER B. J.
Published: April 2010

A severe myopathy leading to death or euthanasia was identified in 4 Belgian and 4 Percheron draught horses age 2–21 years. Clinical signs ranged from overt weakness and muscle atrophy in 2 horses age 2 and 3 years, to recumbency with inability to rise in 6 horses age 4–21 years. In 5 horses there was mild to severe increases in muscle enzyme levels. Clinical diagnoses included equine motor neuron disease (2 horses), post anaesthetic myopathy (2 horses), exertional myopathy (2 horses), myopathy due to unknown (one horse), and equine protozoal myelitis (one horse). Characteristic histopathology of muscle from affected horses was the presence of excessive complex polysaccharide and/or glycogen, revealed by periodic acid‐Schiff staining in all cases and by electron microscopy in one case. Evaluation of frozen section histochemistry performed on 2 cases indicated that affected fibres wereType 2glycolytic fibres. Subsarcolemmal and intracytoplasmic vacuoles were most prominent in 3 horses age 2–4 years, and excessive glycogen, with little or no complex polysaccharide, was the primary compound stored in affected muscle in these young horses. Myopathic changes, including fibre size variation, fibre hypertrophy, internal nuclei, and interstitial fat infiltration, were most prominent in 5 horses age 6–21 years, and the accumulation of complex polysaccharide appeared to increase with age. Mild to moderate segmental myofibre necrosis was present in all cases.
Cortisol concentrations in post competition horse urine: A French and British survey
Authors: POPOT M. A. , HOUGHTON E. , GINN A. , JONES M. , TEALE P. , SAMUELS T. , LASSOURD V. , DUNNETT N. , COWAN D. A. , BONNAIRE Y. , TOUTAIN P. L.
Published: April 2010

The purpose of the present report was to estimate the population parameters of cortisol concentrations in urine, an endogenous hormone used as a ‘doping’ agent and for which an international threshold (1.0 μg/ml) has been proposed. Two data bases (French and UK) corresponding to 112 and 142 samples, respectively were considered. Urine was collected under specific post competition conditions. Cortisol concentrations were obtained by validated methods (HPLC for the French samples, and GC‐MS for UK samples). No difference was observed between the 2 data sets and statistical analyses were carried out on the two merged flies. The overall geometric mean cortisol concentration was 48 ng/ml. Distribution was not Gaussian. A log‐normal distribution was not rejected (for P>0.05). Using the log‐normal distribution, it was calculated that the probability of exceeding a cortisol concentration in urine of 1.0 μg/ml was 1.1 times 10−4. It was concluded that the actual international threshold is specific i.e. robust with regard to the risk of erroneously declaring an unmedicated horse as positive.
An outbreak of abortion in mares associated with Salmonella abortusequi infection
Authors: MADIĆ J. , HAJSIG D. , SOSTARI B. , ĆURIĆ S. , SEOL BRANKA , NAGLIĆ T. , CVETNIĆ Z.
Published: April 2010

An abortion outbreak occurred in a herd of 38 horses, 26 of which were pregnant mares. Twenty‐one mares aborted between 5–10 months of gestation. In no case were there indications of impending abortion. Pathoanatomical, histopathological, virological and bacteriological examinations were carried out on 4 aborted fetuses. Histopathology identified Gram‐negative bacteria compatible with salmonella in all 4 placentae. By subsequent bacteriological examination Salmonella abortusequi was isolated as the single causative agent in each case. Nonmotile Salmonella abortusequi with antigenic formula 4,12:‐:‐ was isolated from one of the 4 fetuses. The described episode of equine abortion clearly indicates that Salmonella abortusequi has not been eradicated from Europe as previously thought.
Cellular heterogeneity in cathepsin D distribution in equine articular cartilage
Authors: HERNANDEZ‐VIDAL G. , JEFFCOTT L. B. , DAVIES M. E.
Published: April 2010

The distribution of cathepsin D in normal equine growth cartilage has been examined immunocytochemically using an antiserum raised against human cathepsin D. The cross‐reactivity and specificity of the antiserum for equine cathepsin D was confirmed, and its lysosomal localisation was demonstrated in horse skin fibroblasts by confocal scanning microscopy. Cultured horse chondrocytes were heterogenous in their expression of cathepsin D. Heterogeneity of distribution of the enzyme was also seen in chondrocytes in cartilage from different anatomical sites. A high level of cathepsin D was observed in the deep layer of cartilage from the lateral trochlear ridge of the distal femur. Cathepsin D was absent in the hypertrophic zone of the distal radial growth plate.
Clostridium difficileassociated with acute colitis in mature horses treated with antibiotics
Authors: BÄVERUD V. , GUSTAFSSON A. , FRANKLIN A. , LINDHOLM A. , GUNNARSSON A.
Published: April 2010

Clostridium (C.) difficile, or its cytoxin, was demonstrated in faecal samples from 10 of 25 (40%) mature horses investigated with acute colitis treated primarily with antibiotics for disorders other than diarrhoea.C. difficilewas not found in faecal samples from 140 horses without signs of enteric disorders, from 21 nondiarrhoeic horses treated with antibiotics, nor from 22 horses with colitis untreated with antibiotics. Except forC. difficileneitherSalmonellanor any other investigated intestinal pathogen was isolated in any of the diarrhoeic horses. The findings strongly support some earlier reports thatC. difficileis associated with acute colitis in mature horses treated with antibiotics.

Of the 10 horses, 4 proved positive forC. difficileboth in culture and in the cytotoxin test, 4 in culture only and 2 only in the cytotoxin test. Eight of 10 horses positive for C. difficile were or had recently been hospitalised, indicating thatC. difficilemay be a nosocomial infection in horses. All horses positive forC. difficilewere treated with β‐lactam antibiotics.

The authors are grateful to A. Hellander‐Edman, B. Green and J. Skidell for fruitful cooperation and for providing specimens and to G. Holmström, G. Sigstam and H. Ljung for excellent technical assistance. This research was supported by ATG (the Swedish Horserace Totalizator Board) and the AGRIA Foundation for Research.
Pulmonary vascular pressures of strenuously exercising Thoroughbreds after administration of varying doses of frusemide
Authors: MANOHAR M. , GOETZ T. E. , SULLIVAN EILEEN , GRIFFIN R.
Published: April 2010

The frusemide dose‐response for attenuation of exercise‐induced pulmonary capillary hypertension was studied in 7 healthy, exercise‐conditioned Thoroughbred horses using previously described haemodynamic procedures. Four different doses of frusemide were tested: 250 mg regardless of bodyweight (amounting to 0.56 ± 0.03 mg/kg bwt), 1.0 mg/kg bwt, 1.5 mg/kg bwt and 2.0 mg/kg bwt. Frusemide was administered i.v., 4 h before exercise. Haemodynamic data were obtained at rest and during treadmill exercise performed at 14.2 m/s on a 3.5% uphill grade; this workload elicited maximal heart rate of horses. Airway endoscopy was performed post exercise to detect exercise‐induced pulmonary haemorrhage (EIPH). In standing horses, frusemide administration resulted in a significant (P<0.05) decrease in mean pulmonary arterial, pulmonary capillary and pulmonary artery wedge pressures, but significant differences among the various frusemide doses were not observed. In the control experiments, exercise caused significant increments in the right atrial as well as pulmonary arterial, wedge, and capillary pressures, and all horses experienced EIPH. Following frusemide administration, the exercise‐induced rise in right atrial and pulmonary vascular pressures was significantly attenuated, but significant differences between the frusemide doses of 250 mg, 1.0 mg/kg, and 1.5 mg/kg were not discerned and all horses remained positive for EIPH. Although a further significant (P<0.05) attenuation of the exercise‐induced rise in pulmonary capillary blood pressure occurred when frusemide dose increased from 250 mg to 2.0 mg/kg bwt, all horses still experienced EIPH. It is concluded that a linear response to increasing frusemide dosage in terms of attenuation of the pulmonary capillary hypertension does not exist in strenuously exercising Thoroughbred horses.
Tachykinin receptors in the equine pelvic flexure
Authors: SONEA IOANA M. , WILSON DEBORAH V. , BOWKER R. M. , ROBINSON N. E.
Published: April 2010

Tachykinins, of which substance P (SP) is the prototype, are neuropeptides which are widely distributed in the nervous systems. In the equine gut, SP is present in enteric nerves and is a powerful constrictor of enteric muscle; in other species, SP is also known to have potent vasodilatory and proinflammatory effects. The specific effects of SP are determined by the subtype of receptor present in the target tissue. There are 3 known subtypes of tachykinin receptors, distinguished by their relative affinities for SP and other tachykinins. The distribution of SP binding sites in the equine pelvic flexure was determined using125I‐Bolton Hunter SP (I‐BHSP) autoradiography. Most I‐BHSP binding sites were determined to be saturable and specific, therefore presumably representing tachykinin receptors. The greatest degree of I‐BHSP binding occurred over very small vessels, and over themuscularis mucosae; I‐BHSP binding was also intense over the circular muscle of themuscularis externaand mucosa, and present, although less intense, over the longitudinal muscle of themuscularis externa. Competition of I‐BHSP with specific receptor agonists for binding sites in the equine pelvic flexure were used to determine the subtypes of tachykinin receptors present. The neurokinin‐1 receptor subtype predominated in the equine pelvic flexure, followed by the neurokinin‐3 receptor subtype.
The association of erythromycin ethylsuccinate with acute colitis in horses in Sweden
Authors: GUSTAFSSON A. , BÄVERUD V. , GUNNARSSON A. , RANTZIEN M. HORN , LINDHOLM A. , FRANKLIN A.
Published: April 2010

In Sweden there are several reports of mares developing acute colitis while their foals were being treated orally forRhodococcus equipneumonia with the combination of erythromycin and rifampicin. In this study 6 adult horses were given low oral dosages of these antibiotics, singly or in combination. Within 3 days post administration of erythromycin, in one case in combination with rifampicin, 2 horses developed severe colitis (one fatal).Clostridium difficilewas isolated from one of the horses, whereas no specific pathogens were isolated from the other. Both horses had typical changes in blood parameters seen in acute colitis.Clostridium difficilewas also isolated from the faeces of a third horse given an even lower dosage of erythromycin in combination with rifampicin. This horse developed very mild clinical symptoms and recovered spontaneously. In the fourth horse given erythromycin only, very high numbers ofClostridium perfringenswere isolated. The horses given rifampicin only did not develop any clinical symptoms and there were no major changes in their faecal flora. In conclusion, it has been demonstrated that low dosages of erythromycin ethylsuccinate can induce severe colitis in horses associated with major changes of the intestinal microflora.Clostridium difficilehas been demonstrated as a potential aetiological agent in antibiotic‐induced acute colitis.
Effect of acepromazine and butorphanol on halothane minimum alveolar concentration in ponies
Authors: DOHERTY T. J. , GEISER D. R. , ROHRBACH B. W.
Published: April 2010

The effect of i.v. acepromazine (0.05 mg/kg bwt), butorphanol (0.05 mg/kg bwt) and a combination of acepromazine and butorphanol on halothane minimum alveolar concentration (MAC) was determined in 7 mixed‐breed ponies. Ventilation was controlled, and blood pressure and temperature were maintained within normal limits. Following the determination of baseline MAC, treatments were administered to each pony in a random manner. The control treatment was normal saline. The baseline halothane MAC for the control group was 0.91 ± 0.04%, and no significant change occurred after saline administration. Acepromazine decreased (P = 0.0001) the halothane MAC from mean ± s.e. 0.92 ± 0.02% to 0.58 ± 0.04%, and the combination of acepromazine and butorphanol, decreased (P = 0.003) halothane MAC, from mean ± s.e 0.95 ± 0.04% to 0.59 ± 0.06%. This represents a decrease of 36.9 and 37.8%, respectively. However, the difference between these 2 treatments was not significant. Butorphanol did not significantly change the mean group value for MAC; nevertheless, 3 ponies had an increase, one a decrease, while the MAC did not change in the remaining 3 ponies following butorphanol treatment.
Pharmacokinetics of enrofloxacin in horses after single intravenous and intramuscular administration
Authors: KAARTINEN LIISA , PANU SARI , PYÖRÄLÄ SATU
Published: April 2010

Pharmacokinetic behaviour of enrofloxacin was studied in 6 horses after intravenous (i.v.) or intramuscular (i.m.) administration of enrofloxacin (5 mg/kg bwt). Concentrations of enrofloxacin and ciprofloxacin were measured by high performance liquid chromatography in serum. Antimicrobial activity of the samples was determined with an agar‐diffusion technique. Reactions at the site of i.m. injection were monitored clinically and by determination of serum creatine kinase (CK) activity.

After i.v. administration, elimination half‐life of enrofloxacin was 4.4 h and volume of distribution was 2.3 1/kg bwt. Enrofloxacin was rapidly metabolised to ciprofloxacin. The half‐life of ciprofloxacin parallelled that of the parent drug, its concentration in serum reached 20–35% of that of the parent drug. After i.m. administration, elimination half‐life of enrofloxacin was longer (9.9 h) than after i.v. administration. Mean absorption time of enrofloxacin was also long (9.9 h).

No statistically significant differences were found when half‐life and mean residence time of antimicrobial activity were compared with those of enrofloxacin and ciprofloxacin from chemically analysed data.

Intramuscular injection of enrofloxacin was found to be very irritating. After i.m. administration, CK activity in serum, compared with pre‐injection levels, increased over 10‐fold. CK activity also stayed high during the 32 h follow‐up period. Clinical reactions, such as swelling or tenderness at the i.m. injection sites, were observed in 2 horses.
Aerosol deposition in equine lungs following ultrasonic nebulisation versus jet aerosol delivery system
Authors: VOTION DOMINIQUE , GHAFIR YASMINE , MUNSTERS K. , DUVIVIER DOMINIQUE H. , ART TANIA , LEKEUX P.
Published: April 2010

Therapeutic aerosols play an increasing role in the treatment of equine respiratory disorders. This route of delivery permits concentration of significant amounts of drugs at the site of action without unwanted high systemic concentration and resultant side effects. The efficiency of such a topical therapy depends on the quantity of inhaled drugs deposited in the lungs and, for some drugs, on the proportion retained in specific parts of the lungs.

The objective of this study was to define and to compare quantitative (dose deposited) and qualitative (regional distribution) deposition of an aerosol in the equine lungs, using either an ultrasonic nebuliser (UN) currently used in human medicine or a high pressure jet nebuliser (JN) especially developed for the equine species. This comparison was possible owing to gamma‐scintigraphy, a noninvasive technique ideally suited to give information about both total and regional deposition of inhaled drugs in the respiratory tract.

The quantitative study did not point out any difference between the 2 systems concerning the activity released from the nebuliser proportionally to the initial loaded dose (mean ± s.d. 45.95 ± 4.93% for the UN vs. 46.47 ± 8.49% for the JN). By contrast, the percentage of the dose released reaching the lungs was significantly lower with the UN compared to the JN (5.09 ± 0.66% vs. 7.35 ± 1.96 %). The qualitative analysis did not show any significant difference in size of aerosol deposition image between the 2 nebulisers. However peripheral deposition was significantly higher with JN compared to UN.

In conclusion, both nebulisers may be used for aerosol therapy in the equine species. The ultrasonic and pneumatic nebulisation achieved drug deposition in the peripheral part of the lungs (i.e. small airways and lung parenchyma).
Bacterial endocarditis in horses: ten cases (1984–1995)
Authors: MAXSON ABBY D. , REEF VIRGINIA B.
Published: April 2010

A retrospective study of 10 horses with bacterial endocarditis was performed in order to describe the echocardiography findings in horses with bacterial endocarditis, in conjunction with clinical signs andpost mortemfindings, and to evaluate the usefulness of echocardiography in the diagnosis of bacterial endocarditis and the formulation of a prognosis. Echocardiographic andpost mortemexaminations were performed in 7 horses.Post mortemexamination alone was performed in 2 horses and echocardiographic examination alone performed in one horse.

No breed or sex predilection was obvious. Mean age ± s.d. was 2.12 ± 3.32 years. Predominant clinical signs and abnormal clinical pathology data were fever, cardiac murmur, tachycardia, tachypnoea, hyperfibrinogenaemia, anaemia and leucocytosis.Pasteurella/Actinobacillusspp. andStreptococcusspp. were most commonly cultured. Vegetative lesions were found most frequently on the mitral valve and secondarily on the aortic valve. The location and number of lesions identified with echocardiography in the horses accurately described the lesions found onpost mortemexamination.

Medical treatment was attempted in 50% of the horses. Serial echocardiography was used to assess the response to treatment in 2 horses. All horses with vegetative lesions of the mitral and/or aortic valve died or were subjected to euthanasia due to the severity of their cardiac disease. Both horses with tricuspid valve endocarditis were cured of the infection; one horse returned to racing after antimicrobial therapy and the other was subjected to euthanasia due to severe laminitis.
Chronic colic in the mature horse: A retrospective review of 106 cases
Authors: MAIR T. S. , HILLYER M. H.
Published: April 2010

The clinical features of 106 horses presenting with chronic colic examined over a 5 year period were reviewed. Chronic colic was defined as colic signs observed, daily for 3 days or longer, except when masked by analgesics. The diagnosed causes of chronic colic included colonic impaction (31%), peritonitis (16%), enteritis/colitis (7%), colonic displacement/torsion (6%) and lymphosarcoma (4%). A variety of other diseases were diagnosed in a small number of cases, including intestinal adhesions, ileal obstructions, grass sickness, liver disease, caecal impactions, thromboembolic disease, intussusceptions etc. No diagnosis was reached in 8% of cases. Diagnosis was relatively easily achieved in most cases of colonic impaction and peritonitis by results of transrectal palpation and evaluation of peritoneal fluid. Specific clinical features, transrectal palpation, abdominal paracentesis and laboratory evaluations of blood were helpful in the diagnosis of some of the other diseases, but exploratory laparotomy remained necessary in a few cases to achieve a diagnosis.
Recurrent colic in the mature horse: A retrospective review of 58 cases
Authors: HILLYER M. H. , MAIR T. S.
Published: April 2010

The clinical features of 58 horses presenting with recurrent colic examined over a 5 year period were reviewed. The horses were categorised into 3 groups on the basis of the history of colic episodes. Recurrent transient colic Group 1 was characterised by 3 or more episodes of transient colic (of apparently similar type) occurring within one month. Recurrent transient colic Group 2 was characterised by 3 or more episodes of transient colic occurring within one year. Recurrent prolonged colic was characterised by 3 or more episodes of prolonged colic occurring within one year.

Fifteen horses were classified as recurrent transient colic Group 1. This group had the highest mortality rate 53%. They included 3 horses with lymphosarcoma, 2 with intussusceptions, 2 with thromboembolic disease/verminous arteritis and 2 with partial ileal obstructions. The recurrent transient colic Group 2 comprised 27 cases with a mortality rate of 4%. Nine of these horses were affected by spasmodic colic. The recurrent prolonged group involved 16 horses with a mortality rate of 31%. These included 3 cases of recurrent colonic impaction and 2 cases each of lymphosarcoma, 2 thromboembolic disease, 2 partial ileal obstructions and 2 intestinal adhesions.
Effects of omeprazole on healing of naturally‐occurring gastric ulcers in Thoroughbred racehorses
Authors: MURRAY M. J. , HAVEN MICHELLE L. , EICHORN EVELYN S. , ZHANG DONGHUI , EAGLESON JANE , HICKEY G. J.
Published: April 2010

Seventeen Thoroughbred horses with moderate to severe gastric ulceration were purchased from a race track within 10 days of racing and were treated once daily with either omeprazole (9 horses) or vehicle (8 horses) and evaluated gastroscopically for ulcer healing. Horses were administered omeprazole (1.5 mg/kg bwt/day) or vehicle by nasogastric tube once daily. Gastroscopic examination was performed on Days 0, 4, 7, 11, 14, 17, 21, 24 and 28, until lesions healed completely. Selected images of gastric lesions were captured by computer at each endoscopic examination, with a measuring caliper included in captured images. The area and perimeter of lesions were measured by computer and healing rates of specific lesions were determined by calculating the rate of linear advance of the margins toward the centre of the lesion. Additionally, the number of days to complete healing of the entire gastric squamous mucosa was compared between treatment groups. Gastric lesions healed at a significantly faster rate in horses receiving omeprazole than in vehicle‐treated horses (P<0.001). Complete healing of the entire stomach occurred in 10–21 days in omeprazole‐treated horses, and 14–28 days in 3 of 8 vehicle‐treated horses, with the remaining vehicle‐treated horses having unhealed lesions on Day 28. In addition, 5 vehicle‐treated horses developed new lesions in the squamous epithelial mucosa during the trial; no new lesions were observed in the omeprazole‐treated group.
Prospective study of equine colic risk factors
Authors: TINKER MARY K. , WHITE N. A. , LESSARD P. , THATCHER C. D. , PELZER K. D. , DAVIS BETTY , CARMEL D. K.
Published: April 2010

A1 year prospective study was conducted on 31 horse farms to identify risk factors for equine colic. Farms were randomly selected from a list from 2 adjacent counties of Virginia and Maryland, USA. The association between colic and farm or individual horse risk factors related to management, housing, pasture, use, nutrition, health and events was first examined by univariate statistical analysis. Individually significant (P<=0.25 for farm factors, P<=0.10 for horse factors) variables were used in a stepwise multivariable forward logistic regression to select explanatory factors (P<=0.05). Analysis was conducted at 2 levels: farm and individual horse with farm specified as a random effects variable. No farm‐level variables were significant Significant horse‐level variables included: age, odds ratio (OR)=2.8 for horses age 2–10 years compared to <2 years; history of previous colic, OR=3.6 relative to no colic; changes in concentrate feeding during the year (1 per year, OR=3.6, more than 1, OR=2.2) relative to no changes; more than 1 change in hay feeding during the year, OR=2.1 relative to no changes; feeding high levels of concentrate (>2.5 kg/day dry matter, OR=4.8, >5 kg/day dry matter, OR=6.3) relative to feeding no concentrate; and vaccination with monocytic ehrlichiosis vaccine during the study, OR=2.0 relative to no vaccination. Feeding a whole grain with or without other concentrate components reduced risk, OR=0.4, relative to feeding no whole grain. Results of the study suggest that diet and changes in diet are important risks for colic in a population of horses on farms.
The effect of age and diet on the oral glucose tolerance test in ponies
Authors: MURPHY D. , REID S. W. J. , LOVE S.
Published: April 2010

To evaluate the effects of age and diet on the oral glucose tolerance test (OGTT) in healthy ponies, OGTTs were performed on 2 groups of British native breed ponies (Group A: 7 foals [6–9 months],Group B: 7 mature individuals [6–13 years]) when maintained on either a high fibre pelleted ration only (Groups AandB) or a hay only diet (Group B). Plasma glucose response, following oral glucose administration, forGroup A(basal plasma glucose concentration [Glu0] 4.6 ± 0.4 mmol/1 (mean ± s.d.) increasing to 11.5 ± 1.3 mmol/1 at 90 min) was significantly different (P<0.05) from that observed forGroup B(Glu0of 4.3 ± 0.2 mmol/1 increasing to 6.8 ± 1.3 mmol/1 at 90 min), when fed the same diet. ForGroup Bponies, the plasma glucose response, following oral glucose administration, was significantly different (P<0.05) when fed hay only (Glu04.6 ± 0.4 mmol/1 increasing to 9.6 ± 2.1 mmol/l at 150 min) compared to when fed the high fibre pelleted ration. These results indicate that both age and diet have a significant effect on plasma glucose concentrations measured during an OGTT.
Technical validation of a face mask adapted for dry powder inhalation in the equine species
Authors: DUVIVIER D. H. , VOTION D. , VANDENPUT S. , ART T. , LEKEUX P.
Published: April 2010

Development of dry powder inhalation (DPI) for horses requires the use of an adapted face mask.In experiment 1, 4 masks (A, B, C and D) were tested and factors influencing the delivery of the dry powder were determined. Mask A was one which is commercially available for metered‐dose inhalation. Mask B had the same shape as Mask A but an airtight rubber seal was added for the connection between the mask and horse's head. Mask C was a prototype adapted for DPI with connection for the DPI device between the nostrils, airtight expiratory valves in front of each nostril and an airtight rubber seal to attach the mask on the horse's head. Mask D was the same as Mask C but the airtight expiratory valve was situated in front of one nostril and the connection for the DPI device was placed in front of the other nostril. Inhalet emptying and peak inspiratory pressure were measured on 5 healthy horses with each face mask. Both Masks A and B gave a low rate of inhalet emptying. Inspiratory pressures created in Masks C and D were negative enough to ensure inhalet emptying rates of mean ± s.d. 98.28 ± 1.79% and 100% respectively.

Inexperiment 2, the face masks giving the greatest inhalet emptying were used to test the therapeutic efficacy of ipratropium bromide DPI. This was tested on 6 horses suffering from acute exacerbation of chronic obstructive pulmonary disease (COPD). At a dose of 200 μg/100 kg bwt, ipratropium administered with Mask D improved significantly pulmonary function measurements compared to baseline values and placebo inhalation. With Mask C, a double dose of ipratropium (400 μg/100 kg bwt) was necessary to improve these parameters compared to baseline values. This indicated the importance of locating the DPI device in front of one nostril.

It was concluded that inhalet emptying is correlated to inspiratory pressures measured in the face masks. Secondly, these pressures are in turn dependent on the airtightness of the mask, i.e. airtightness of the expiratory valve and close connection between the horse's head and the mask. Thirdly, position of the DPI device in front of a nostril allows bronchodilation at a dose half that required when the device is placed between the nostrils. Finally DPI using Mask D (EquiPoudre1) is a rapid, effective and well tolerated inhalation treatment for COPD horses.
Ageing of equine articular cartilage: structure and composition of aggrecan and decorin
Authors: PLATT D. , BIRD J. L. E. , BAYLISS M. T.
Published: April 2010

In order to identify the pathological processes involved in the destruction of articular cartilage in arthritic diseases, it is first necessary to characterise the normal homeostasis of cartilage in a healthy joint. In particular, normal age‐related changes in the biochemistry of cartilage complicate any comparisons that are made between diseased and healthy tissue. There are, however, no reports in the literature detailing the influence of ageing on the biochemistry of proteoglycans in equine articular cartilage. This study addresses the absence of such information by investigating the structure of aggrecan and decorin extracted from a wide age‐range of full thickness equine tissue.

The total glycosaminoglycan content of articular cartilage from the metacarpophalangeal joint remained relatively constant throughout life. In contrast, specific components such as hyaluronan increased in concentration with advancing age as did the content of a structural epitope present on keratan sulphate chains. There were also significant age‐related changes in the sulphation pattern of chondroitin sulphate chains. The structure of the large aggregating proteoglycan (aggrecan) became more heterogeneous in size with increasing age and each of the subspecies of aggrecan identified in the extracts was shown to carry a hyaluronan binding region (G1) domain. All subspecies of aggrecan also expressed specific epitopes to keratan sulphate, chondroitin‐4‐sulphate and chondroitin‐6‐sulphate glycosaminoglycan chains. The structure of the small nonaggregating proteoglycan decorin and the aggrecan stabilising molecule link protein were demonstrated to be similar in size and charge to that reported for other species.
The effects of partial thyroidectomy on the development of the equine fetus
Authors: ALLEN A. L. , FRETZ P. B. , CARD C. E. , DOIGE C. E.
Published: April 2010

A syndrome of congenital hypothyroidism and dymaturity has been an important cause of reproductive loss and foal mortality in western Canada. The cause and pathogenesis of this syndrome is under investigation. One issue to be addressed is whether all the anomalies present in affected foals are produced concurrently by the same agent, or if affected foals are primarily hypothyroid in utero which induces the associated lesions. This study was designed to document the effects of fetal thyroidectomy, at about 215 days of gestation, on the growth and development of the equine fetus and to compare the anomalies present to those reported in the spontaneously occurring syndrome of foals in western Canada.

Two sham‐operated controls and 4 partially thyroidectomised foals were carried to term following surgery. Sham‐operated control foals were normally developed. Partially thyroidectomised foals were hypothyroid; had hyperplastic thyroid gland remnants; abnormal behaviour and locomotor skills; and numerous, marked deficiencies in their skeletal development. The anomalies present in partially thyroidectomised foals were comparable to those reported in congenitally hypothyroid neonates of other species, including human infants, and were similar to those described in congenitally hypothyroid and dysmature foals reported in western Canada.
Exercise‐related alterations in crimp morphology in the central regions of superficial digital flexor tendons from young Thoroughbreds: a controlled study
Authors: PATTERSON‐KANE J. C. , WILSON A. M. , FIRTH E. C. , PARRY D. A. D. , GOODSHIP A. E.
Published: April 2010

Injury to the core of the mid‐metacarpal region of the superficial digital flexor tendon in Thoroughbred racehorses is a very frequent but poorly understood condition. It has been suggested that subclinical changes induced by galloping exercise weaken the collagen in this region of the tendon, predisposing it to rupture. The longitudinally arranged collagen fibrils in tendon follow a planar waveform, termed the crimp. Fibril bundles with a smaller crimp angle fail at a lower level of strain than those with a larger crimp angle. This study tested the hypothesis that a specific 18 month exercise programme would result in significant reduction of collagen fibril crimp angle and period length in the core region of the superficial digital flexor tendon of young Thoroughbreds (21 ± 1 months), compared to the normal change in these parameters with age. Central region crimp angle and length were significantly lower in exercised horses than in control horses (P<0.05). The crimp angle was significantly lower in this central region than in the peripheral region of the tendon in 4 of the 5 exercised horses, as was the crimp length in 3 of the 4 horses. The crimp angle in the peripheral region was significantly greater in exercised horses than in the controls (P<0.05), which may indicate functional adaptation due to differing mechanical environment between the 2 tendon regions. The results of this study supported previous evidence that galloping exercise modifies normal age‐related changes in crimp morphology in the core of the superficial digital flexor tendon. Such changes are indicative of microtrauma and would be detrimental to tendon strength.
Survey of anthelmintic resistance on Danish horse farms, using 5 different methods of calculating faecal egg count reduction
Authors: CRAVEN J. , BJØRN H. , HENRIKSEN S. A. , NANSEN P. , LARSEN M. , LENDAL S.
Published: April 2010

This study reports on the prevalence of anthelmintic resistance in strongyles of horses in Denmark. Of 5 methods used for the calculation of faecal egg count reduction (FECR) the method recommended by the World Association for the Advancement of Veterinary Parasitology, for the detection of resistance in sheep was the most sensitive procedure for detecting resistance. Using this method benzimidazole resistance was detected on 33 of 42 farms (79%) examined. Pyrantel was tested on 15 farms and FECR tests indicate resistance on 3 (30%) farms. On 2 farms on which resistance to pyrantel was detected resistance to benzimidazoles was also detected. On one of 16 farms examined ivermectin resistance was indicated at Day 14 but not at Day 19. On the 15 remaining farms ivermectin was effective.

Due to the high prevalence of anthelmintic resistance in Danish horse herds it is recommended that tests of anthelmintic efficacy be conducted routinely to monitor the effectiveness of the strongyle control programmes.