bluuebunny/crossref_metadata_2025 huggingface dataset:
Scintigraphic identification of skeletal muscle damage in horses 24 hours after strenuous exercise
Authors: MORRIS ELISABETH , SEEHERMAN H. J. , O'CALLAGHAN M. W. , SCHELLING S. H. , PARADIS MARY ROSE , STECKEL R. S.
Published: April 2010

The uptake of the bone‐seeking radiopharmaceutical 99mTc‐MDP by damaged skeletal muscle in horses is evaluated. Twenty‐four hours following strenuous exercise, 109 racehorses with a history of inadequate athletic performance and subtle lameness were imaged using scintigraphic techniques. Ten horses (9.2 per cent) demonstrated abnormal uptake of the radioisotope within skeletal muscles. A muscle biopsy from one of theses horses confirmed that the muscles with increased scintigraphic activity had histologic evidence of rhabdomyolysis. This technique allows localisation and relative quantification of muscle damage and is a valuable aid in the evaluation of the athletic horse.
The isolation, characterisation and quantification of the equine plasma lipoproteins
Authors: WATSON T. D. G. , BURNS LYNN , LOVE S. , PACKARD C. J. , SHEPHERD J.
Published: April 2010

Plasma lipoproteins were isolated from eight Thoroughbred horses and eight Shetland ponies on the basis of particle size by gel filtration chromatography and according to density using rate‐zonal ultracentrifugation. Three major classes corresponding to very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL) were identified and characterised by their lipid and apolipoprotein compositions. The particle size distributions of each class were determined by electron microscopy and non‐denaturing polyacrylamide gradient gel electrophoresis. HDL was found to dominate the equine lipoprotein spectrum, accounting for 61 per cent of the total plasma lipoprotein mass (VLDL 24 per cent, LDL 15 per cent). The VLDL class was isolated as a single population of particles that were triglyceride rich and cholesterol, phospholipid and protein poor. Equine LDL was characteristically cholesterol rich and was found to be polydisperse comprising three subfractions that were discrete with respect to particle size and lipid composition. The HDL class was composed of homogeneous particles that were typically protein rich. Apolipoprotein (apo) B was the major protein of VLDL and LDL, and presented two components on Polyacrylamide gel electrophoresis with molecular weights in the region of human apoB‐100 and a third in VLDL similar to that of apoB‐48. ApoA‐I was the predominant protein in equine HDL. Although there were no breed differences in the physical or chemical properties of each lipoprotein class, the Shetland ponies had higher plasma triglyceride and VLDL concentrations than their Thoroughbred counterparts.
Traumatic injuries involving tendons of the distal limbs in horses: a retrospective study of 55 cases
Authors: FOLAND J. W. , TROTTER G. W. , STASHAK T. S. , MCILWRAITH C. W. , TURNER A. S. , AANES W. A.
Published: April 2010

Fifty‐five horses were presented to Colorado State University Veterinary Teaching Hospital between 1st of January 1980 and 31st of December 1989 for treatment of distal limb lacerations involving flexor tendons (n = 35) or extensor tendons (n = 20). Of the 35 flexor tendon lacerations, 11 horses were killed without treatment and 24 horses were treated. Twenty‐two horses were included in determining outcome. Four (18 per cent) returned to their original level of use, nine (41 per cent) returned to limited riding, seven (32 per cent) returned to breeding or pasture soundness and two (9 per cent) were killed. Eighteen of the 20 horses with extensor tendon lacerations underwent treatment and 15 had sufficient follow‐up to determine outcome. Seven (47 per cent) returned to their original or intended use, five (33 per cent) returned to limited use, one (7 per cent) was used for breeding and two (13 per cent) were killed. Results for horses with extensor tendon lacerations support previous reports that these injuries can be treated successfully. Results for horses having flexor tendon lacerations were better than in previous reports.
Histopathological and ultrastructural changes in simulated large colonic torsion and reperfusion in ponies
Authors: MESCHTER CAROL L. , CRAIG DIANE , HACKETT R.
Published: April 2010

This investigation examines the histological and ultrastructural lesions of the colonic mucosa during terminal experimental infarction and subsequent reperfusion. Four ponies were anaesthetised and subjected to surgical torsion of the colon. Biopsies were collected at hourly intervals for 3 h, at which point the torsions were corrected. Circulation was re‐established for 2 h and the bowel was re‐biopsied at hourly intervals. The ponies were killed while under anaesthesia. During the 3 h experimental infarction, the bowel became macroscopically thickened and dark purple. Histologically, the mucosa degenerated from Grade 0 to Grade 3. Ultrastructurally, there was progressive micro‐vascular distension with erythrodiapedesis and damage to the interstitial cells. Spaces developed between the bases and sides of the columnar epithelial cells and sloughing followed subsequently. During the 2 h reperfusion interval, the mucosa continued to degenerate rapidly to a Grade 5, and was characterised by extensive interstitial damage, oedema, cellular swelling, necrosis and mitochondrial damage. The results showed that the experimentally infarcted colonic mucosa degenerated sequentially. Following circulatory reestablishment, continued rapid mucosal degeneration characteristic of reperfusion injury occurred. Reperfusion injury is probably responsible, at least in part, for the often poor outcome of infarcted bowel in horses following surgical correction.
Desmitis of the accessory ligament of the deep digital flexor tendon: 27 cases (1986–1990)
Authors: DYSON SUE J.
Published: April 2010

Desmitis of the accessory ligament of the deep digital flexor tendon (ALDDFT) was diagnosed in 27 horses between September 1986 and December 1990. The first observed clinical sign in four horses was localised swelling in the proximal metacarpus. Twenty horses became lame suddenly during a work period and most developed swelling within 24 h of exercise. The injury was confirmed by ultrasonographic examination. Ten of 13 horses with uncomplicated desmitis of the ALDDFT resumed full work, within three to nine months of the onset of clinical signs, without recurrence of clinical signs in the period of follow‐up (nine months to four years). Three horses presented with concurrent acute desmitis of the ALDDFT and superficial digital flexor (SDF) tendonitis and two horses had a history of SDF tendonitis; none of these resumed full work.
Therapeutic management of ocular squamous cell carcinoma in the horse: 43 cases (1979–1989)
Authors: KING TRACEY C. , PRIEHS D. R. , GUM G. G. , MILLER T. R.
Published: April 2010

The records of 50 horses with ocular squamous cell carcinoma (OSCC) presented to the University of Florida Veterinary Medical Teaching Hospital over an 11 year period were reviewed to determine the influence of therapy on the outcome of the case. Follow‐up information was obtained for 43 of the 50 cases. The disease was more prevalent in the light horse breeds; however, the draft breeds also were at risk. There was no sex predisposition and the average age was 11.8 years. Tumour recurrence was significant when surgery alone was performed. The eyelid and nictitating membrane were the primary sites for tumor recurrence. Cases in which adjunctive therapy was used correlated with a lower rate of recurrence.
The body condition of feral ponies on Assateague island
Authors: RUDMAN REBECCA , KEIPER R. R.
Published: April 2010

The summer body condition of 47 adult feral ponies on Assateague Island (off the coast of Maryland, USA) was assessed in June 1988 using a visual body condition scoring system. Winter body condition for 36 of the ponies was assessed in February and March, 1989. The ponies were categorised by gender, reproductive status and location on the island, and body condition scores of the ponies in each category were then compared by statistical analyses. No significant seasonal differences were found in the body conditions of the ponies. However, body condition of stallions was better than that of mares. Also, lactating mares had lower body condition scores than non‐lactating mares. Finally, in the summer, ponies on the southern part of the island were in better condition than those on the northern end where food and other resources were more limited. Thus gender, reproductive status and habitat, according to the criteria of this study, all had an effect on the body condition of Assateague Island feral ponies, whereas seasonal effects were not evident. Future studies could clarify the correlation between the condition of the mares during the breeding season and birth rate and survival of foals the following spring.
Measurement of cardiac dimensions with two‐dimensional echocardiography in the living horse
Authors: VOROS K. , HOLMES J. R. , GIBBS C.
Published: April 2010

Two‐dimensional echocardiography (2DE) was performed on 22 unsedated Thoroughbred and part Thoroughbred horses weighing between 411 and 650 kg to establish normal reference values for 2DE measurements. Animals stood during examinations performed with a 3.5 MHz mechanical sector transducer using various transducer positions and tomographic planes. Right ventricular diameter (RVD), ventricular septal thickness (VSTh), aortic diameter (AoD), area of the chordal lumen of the left ventricle (CTA), left ventricular diameter (LVD) and left atrial diameter (LAD) were determined at ventricular end‐diastole (Ed) and/or end‐systole (Es). Fractional shortening (FS) of the left ventricle and end‐systolic left atrial to aortic ratio (LADEs: AoD‐Es) also were calculated. Echocardiographic data were related to body weight by linear regression analysis. Intra‐observer variability was checked in five horses by measuring each parameter during each of 10 consecutive cardiac cycles. The 2DE data were compared with M‐mode values in published reports. In the 18 horses whose weight did not exceed 551 kg, repeatable recordings of good quality were obtained, and 2DE measurements could be made using intra‐cardiac reference points. Increasing body weight proved to impose substantial limitations on measurements taken with the available machine and transducer. This problem might be overcome by using probes of lower frequency or equipment with higher quality image display at greater depth. The following parameters correlated significantly to body weight: VSTh‐Es (r = 0.69; P<0.01). AoD‐Es (r = 0.64; P<0.01) and CTA‐Es (r = 0.84; P<0.001). However, technical limitations prevented determination of the relationship between bodyweight and CTA‐Ed and LVD‐Ed. For each parameter, good reproducibility of values was found because the mean coefficient of variation (CV) varied between 2.6 and 7.2. In this study, 2DE provided reliable qualitative and quantitative assessment of cardiac anatomy and function, but its limitations also must be considered and it should be used in conjunction with other clinical procedures.
Equine synovial tendon sheaths and bursae: a transmission electron microscope study
Authors: HAGO B. E. D. , VAUGHAN L. C. , PLUMMER J. M.
Published: April 2010

A transmission electron microscope study was undertaken to investigate the details of the synovial tendon sheath and bursal lining in horses. The lining cells appeared to be fibroblasts and were buried in a finely granular ground substance. Generally these cells had poor cytoplasmic organelles, sparse short profiles of rough endoplasmic reticulum (RER), few scattered ribosomes and, occasionally, a poorly developed Golgi complex. However, a few lining cells appeared more active, having pronounced RER with dilated cisternane. The surface of the lining cells, particularly those with dilated RER, had filipodia of different shapes, which in some instances appeared to surround a detached matrix. This feature might indicate that these cells are capable of phagocytosis. In young animals, the lining was more or less akin to that of the adult. However, the lining cells were virtually indistinguishable from the fibroblasts in the subconnective tissue.
An immunoperoxidase method applied to the diagnosis of equine herpesvirus abortion, using conventional and rapid microwave techniques
Authors: WHITWELL KATHERINE E. , GOWER SUSAN M. , SMITH K. C.
Published: April 2010

An indirect immunoperoxidase (IMP) technique was applied to cryostat and paraffin sections of liver from ten aborted equine foetuses. Equid herpesvirus type 1 (EHV‐1) had been isolated from seven of them and EHV‐4 from one: the remaining two were virologically negative and were not used as controls. In the eight virus‐infected cases the immunostaining revealed foci of cells exhibiting a distinct brown cytoplasmic and inclusion body pigmentation. No specific signal was present in the non‐infected controls. The method also was adapted for incubation in a microwave oven, which allowed the total length of the procedure to be reduced to a minimum of 35 mins for cryostat sections, without significant loss of signal.
Pathological findings in horses dying during an outbreak of the paralytic form of Equid herpesvirus type 1 (EHV‐1) infection
Authors: WHITWELL KATHERINE E. , BLUNDEN A. S.
Published: April 2010

In 1988 an outbreak of the paralytic form of Equid herpesvirus type 1 (EHV‐1) infection occurred on a stud farm and several animals died. This provided an opportunity to perform detailed pathological investigations to gain insights into the pathogenesis of this spontaneous disease. Two paretic mares, three foals, an aborted foetus and its non‐paretic dam were examined. The endotheliotropism of the virus was clearly demonstrated by the use of an indirect immunoperoxidase (IP) stain. At autopsy, evidence of viral infection was widespread in the foetus and foals, but limited or absent in the mares, probably reflecting differences in their immune status. Vascular lesions were present in the central nervous system (CNS) of the foals as well as the adults; they resulted in minimal neural lesions in the foals. Severe changes in the upper and lower respiratory tracts were a particular feature in the foals, two of which exhibited extensive vasculitis and thrombosis in the lungs. The IP technique was of great value in locating antigen‐containing cells in the CNS of one mare when virus isolation was negative. It also revealed the presence of virus in less well documented sites such as the pancreas, gut, thyroid, uveal tract and the skin of the nares.
Cardiovascular effects and fatalities associated with intravenous administration of doxycycline to horses and ponies
Authors: RIOND J.‐L , RIVIERE J. E. , DUCKETT W. M. , ATKINS C. E. , JERNIGAN A. D. , RIKIHISA Y. , SPURLOCK S. L.
Published: April 2010

Intravenous use of doxycycline in horses is associated with deleterious side effects on the cardiovascular system which may result in fatalities. At dosages and infusion rates used in these studies, supraventricular tachycardia, systemic arterial hypertension, clinical signs of discomfort, collapse and death were observed. Results of the present study suggest that the intravenous use of doxycycline should be avoided in horses.
Effects of induced alkalosis on performance in Thoroughbreds during a 1,600‐m race
Authors: HARKINS J. D. , KAMERLING S. G.
Published: April 2010

There is considerable debate regarding the ergogenic effects of sodium bicarbonate (NaHCO3) on racing performance in horses. Anecdotal evidence suggests that NaHCO3 improves performance by increasing the buffering capacity of the blood and delaying the onset of hydrogen ion‐induced fatigue. In a cross‐over study, 16 Thoroughbred racehorses were given an aqueous solution of NaHCO3 (0.4 g/kg in 1 litre H2O) or a control treatment (1 litre H2O) before a 1600‐m race. Treatments were administered 3 h before the race, which was the time to peak buffering capacity (2.5‐3.0 h) determined in a separate study. Before the race, there was a significant increase in venous HCO3− and pH in the NaHCO3‐treated horses. After the race, there was a significant increase in venous blood pH and lactate in the NaHCO3‐treated horses. Collectively, the data suggest an improved buffering capacity of the blood after NaHCO3 treatment. However, there was no change in race times or venous partial pressure of carbon dioxide. Therefore, the administration of NaHCO3 provided no ergogenic benefit to horses competing in a 1,600‐m race.
Inhibition of interleukin‐1 activity by equine synovial fluid
Authors: MAY S. A. , HOOKE REBECCA E. , LEES P.
Published: April 2010

The presence, in equine synovial fluid, of inhibitors of interleukin‐1 (IL‐1) activity has been investigated by means of an assay involving IL‐1‐mediated production of PGE2 by synovial cells. Inhibitors of IL‐1α and IL‐1β were identified in normal synovial fluid and synovial fluid from two horses with early joint disease. Inhibitors of IL‐1α were also present in synovial fluid from two horses with long‐standing joint disease. However, IL‐1β inhibitory activity was not present in fluid from the horses with more chronic joint disease. The effect appeared to be specific for IL‐1, and not a direct action on PGE2 production, as synovial fluid had no effect on lipopolysaccharide‐mediated PGE2 production. It is suggested that the inhibitory activity may be involved physiologically in the control of IL‐1 activity in the joint, and the loss of IL‐1 inhibition may be at least as important biologically as increased production of IL‐1.
Aerosol pirbuterol: bronchodilator activity and side effects in ponies with recurrent airway obstruction (heaves)
Authors: DERKSEN F. J. , ROBINSON N. E. , BERNEY C. E.
Published: April 2010

The dose of aerosol pirbuterol that could be administered safely to ponies (weight approximately 200 kg) was determined by observation for sweating, trembling and excitement and measurement of heart and respiratory rates during cumulative administration of the drug. Sweating, trembling and excitement were first observed following a dose of 2,400 μg and became more severe at 3,200 μg. These effects were accompanied by an increase in heart rate but not a change in respiratory rate. When 3200 μg was administered without prior administration of lower doses, side effects were trivial. This dose was therefore tested for its bronchodilator activity. Pulmonary function was evaluated in ponies that developed airway obstruction (‘heaves’) when housed in a barn and fed hay. Measurements were made when ponies were in clinical remission (Period A) and during an acute attack of airway obstruction (Period B). At Period A, pirbuterol had no effect on pulmonary function. Barn housing increased pulmonary resistance and decreased dynamic compliance. At Measurement Period B, pirbuterol administration significantly reduced pulmonary resistance and increased dynamic compliance and minute ventilation. These changes were significant 5 min after drug administration and lasted for the 30 min duration of the study. Vehicle administration had no effect on pulmonary function. It was concluded that aerosol pirbuterol has few undesirable side effects and is an effective bronchodilator in ponies with recurrent airway obstruction.
Spontaneous echocardiographic contrast in the Thoroughbred: high prevalence in racehorses and a characteristic abnormality in bleeders
Authors: MAHONY CHERYL , RANTANEN N. W. , DeMICHAEL J. A. , KINCAID B.
Published: April 2010

Spontaneous echocardiographic contrast is the term used by ultrasonographers to describe particulate material visible in intracardiac blood by ultrasound. The purpose of the present study was to determine the prevalence of spontaneous contrast in a farm population of Thoroughbreds and in the farm's racehorses. The results showed that spontaneous echocardiographic contrast is common in Thoroughbreds, and that the prevalence of contrast is affected by age, male gender, racing and pregnancy. The amount of right‐sided cardiac contrast was quantitated by videodensitometry and was increased in horses with a history of exercise‐induced pulmonary haemorrhage, in comparison with racehorses without a history of bleeding. Since circulating platelet aggregates are known to produce pulmonary haemorrhage in experimental animals and their presence has been associated with echocardiographic contrast, additional studies evaluating platelet aggregates as the aetiologic agent for exercise‐induced pulmonary haemorrhage are warranted.
Hoof and distal limb surface temperature in the normal pony under constant and changing ambient temperatures
Authors: MOGG KARIN C. , POLLITT C. C.
Published: April 2010

Forelimb surface temperatures were continuously monitored in four clinically normal ponies exposed to: (i) constant ambient temperature; (ii) a biphasic change in ambient temperature; and (iii) an incremental increase in ambient temperature. Limb surface temperatures were recorded at the hoof, metacarpus and forearm, and rectal temperature was also measured. Under constant ambient temperature, limb surface temperatures remained relatively constant. A pyrexic episode occurred in one pony under constant ambient temperature conditions and was characterised by an onset phase in which rectal temperature gradually increased while limb surface temperatures concurrently decreased; a plateau phase in which rectal temperature was elevated but essentially constant although limb surface temperatures rose dramatically; and a febrilytic phase in which limb surface temperatures remained elevated while rectal temperature gradually decreased. A biphasic change in ambient temperature produced corresponding changes in limb surface temperature, but limb surface temperatures were less stable at the lower ambient temperatures. Surface temperature responses to incremental increases in ambient temperature were dependent on the baseline ambient temperature (before increase), and dramatic, spontaneous increases in limb surface temperatures were observed. Rectal temperatures in the normal animals remained relatively constant under all three ambient temperature regimens.

It was concluded that clinical interpretation of limb surface temperatures in ponies required an awareness of ambient temperature conditions. For evaluation of vasodilator agents, constant ambient temperatures of at least less than 18°C are suggested, and constant ambient temperatures exceeding 20°C are recommended for the evaluation of vasoconstrictor agents.
Factors associated with the risk of developing sarcoid tumours in horses
Authors: MOHAMMED H. O. , REBHUN W. C. , ANTCZAK D. F.
Published: April 2010

A retrospective case‐control study was conducted to identify risk factors in horses associated with the development of the common skin tumours known as sarcoids. The study involved 503 sarcoid cases diagnosed (January 1980‐December 1989) at New York State College of Veterinary Medicine and a similar number of controls (non‐sarcoid cases). Data on age, breed and sex of cases and controls were obtained from computerised records. Multiple logistic regression analysis was used to identify risk factors. Separate data were obtained for the same 10‐year period from the Veterinary Medical Data Program to determine the proportional morbidity rate at different veterinary colleges in North America. Appaloosa, Arabian and Quarter horses were at a higher risk of developing sarcoid tumours than were Thoroughbred horses. Standardbred horses had a lower risk of developing sarcoids. Geldings were at a higher risk of developing sarcoids in comparison with stallions. There was no significant difference in the risk of developing sarcoids between stallions and mares. The risk of developing sarcoid increased with age up to 15 years and then declined. The proportional morbidity rate of sarcoids among the veterinary colleges ranged between 0 and 14 per 1,000 cases, with an average of 6 per 1,000.
Improved insulin sensitivity in hyperinsulinaemic ponies through physical conditioning and controlled feed intake
Authors: FREESTONE J. F. , BEADLE R. , SHOEMAKER K. , BESSIN R. T. , WOLFSHEIMER K. J. , CHURCH C.
Published: April 2010

Ten hyperinsulinaemic ponies divided into conditioned (N = 5) and rested (N = 5) groups were evaluated for their insulin and glucose response following oral glucose administration at Weeks 0, 2, 4, and 6. All ponies received a controlled intake of a pelleted ration during the study.

In both groups body weight had decreased from baseline by Week 4 and remained low. After 2 weeks of exercise, ponies in the conditioned group had significantly decreased insulin and glucose indices, including peak insulin response, area under the insulin curve from 0 to 210 min (TIS), and the TIS value: area under the glucose curve from 0 to 210 min. By Week 4 of conditioning, although the insulin and glucose indices continued to decrease in the exercised ponies, there was no significant difference between the groups. Over the first 6 weeks of the study all ponies improved their insulin sensitivity accompanied by a loss of body weight.

The conditioned ponies were further evaluated during deconditioning at Weeks 8, 10 and 12. The improved insulin sensitivity was maintained during deconditioning.
Inflammatory effects of platelet activating factor (PAF) in equine skin
Authors: FOSTER A. P. , CUNNINGHAM F. M. , LEES P.
Published: April 2010

Intradermal administration of PAF (0.001 −1 μg/site), but not lyso‐PAF (10 μg/site), in the horse caused an increase in cutaneous vascular permeability which was maximal by 32 min. Responses to PAF and histamine were reduced by coadministration of the histamine 1 receptor antagonist chlorpheniramine, although only the inhibition of histamine‐induced responses was dose‐related and statistically significant. The cyclo‐oxygenase inhibitor indomethacin was without effect on PAF‐induced increases in vascular permeability. These findings suggest that the actions of PAF on equine skin microvasculature may be partly due to histamine release but not to prostanoid formation. Coadministration of prostaglandin (PG) E2 enhanced the oedematous responses to both PAF and histamine, although PGE2 failed to exert direct permeability‐increasing activity. In addition, and in contrast to PAF and histamine, PGE2 increased cutaneous blood flow and skin surface temperature. PAF, but not lyso‐PAF, also caused neutrophil infiltration into the skin which was maximal at 2 h. No significant effects on eosinophil or mononuclear cell numbers were apparent up to 24 h after injection of PAF. These results are consistent with the concept that PAF may be a mediator of inflammatory disorders of the skin in the horse.
Microwave thermography: a non‐invasive technique for investigation of injury of the superficial digital flexor tendon in the horse
Authors: MARR CELIA M.
Published: April 2010

Microwave thermographs were recorded from 77 normal horses. In 51% the lowest temperature was recorded in the mid‐metacarpal region, and in 41% it was in the distal metacarpal region. The mean temperature of the normal limbs rangesd from 25.04 to .37.4°C. Maximum temperature differences between symmetrical points in both forelimbs ranged from 0 to 5.33°C and differences in mean limb temperatures between both forelimbs ranged from 0 to 2.91°C.

In 48 horses with acute (<4 weeks' duration) injury of the superficial digital flexor tendon (SDFT) (36 unilateral, 12 bilateral) and 12 horses with acute injury of the soft tissues of the palmar metacarpal region other than the SDFT (all unilateral) 66% of forelimbs had acute SDFT injury, and 50% of those with other soft tissue injuries, had elevations of the temperature in the mid‐ or distal metacarpal region. Abnormal values for mean limb temperature, difference in mean limb temperature and maximum temperature difference between locations in opposite forelimbs were detected in 75% of the horses with SDFT injury and in only 16% of the horses with other soft tissue injury. The sensitivity of microwave thermography for the detection of SDFT injury was 81% and the specificity 74%.

When 30 horses in National Hunt training were examined weekly for 5 weeks, 2 horses sustained SDFT injury during that period. The microwave thermographs recorded from these 2 horses, at 1 and 2 weeks before the onset of clinical signs, were abnormal. However, 16 horses which did not develop tendon injury also displayed thermographic abnormalities.
Videoendoscopic evaluation of the mare's uterus: I. Findings in normal fertile mares
Authors: BRACHER VERENA , ALLEN W. R.
Published: April 2010

The new generation of videoendoscopes uses an electronic, instead of an optical, system for image transmission. Advantages over conventional fibre‐optic endoscopes include increased image quality, handling robustness and direct display of the image on a TV monitor for multiple simultaneous viewing. In the present study, hysteroscopy was performed on 14 normal fertile Welsh Pony and Thoroughbred mares at various times during the annual and ovarian breeding cycles. Oestrus was characterised by an oedematous, relaxed cervix lying on the floor of the vagina, diffuse oedema of the endometrium and the occasional accumulation of small amounts of clear secretions in the uterine lumen. In dioestrus, the cervix appeared tight and pale and was located in the centre of the vaginal fornix. The endometrium appeared thinner due to the reduction in interstitial fluid, which allowed the underlying blood vessels to become visible, but it still had a glistening surface as a result of endometrial gland secretions. The appearance of the uterotubal papillae reflected the changes in the cervix, being relaxed, pinkish and oedematous during oestrus but remaining pale, tight and erect in dioestrus (between Days 7 and 12 after ovulation).

A flexible polythene cannula was passed into the uterine lumen through the working channel of the endoscope for directed collection of uterine fluid for cytological and bacteriological examinations. Site‐directed biopsies of the endometrium were taken, with flexible forceps inserted through the working channel of the endoscope, or with rigid forceps passed through the cervix alongside the endoscope. Both methods enabled accurate visual selection of the sampling area but the rigid forceps were preferred due to the larger size of the piece of endometrium recovered.
Radiographic anatomy of soft tissue attachments in the equine metacarpophalangeal and proximal phalangeal region
Authors: WEAVER J. C. B. , STOVER SUSAN M. , O'BRIEN T. R.
Published: April 2010

The sites of bony attachment of the tendons, ligaments, and fibrous portion of the joint capsules of the equine metacarpophalangeal (fetlock) joint region were determined by gross dissection. These sites were transposed to standard radiographic views of the fetlock joint to yield illustrations that can be used as an aid in the diagnosis of soft tissue pathology from radiographs. Evidence of direct attachment of the common digital extensor tendon to the proximal phalanx was not found. Branches of the superficial digital flexor tendon were found to insert only on the middle phalanx. The recently described sites of insertion of the branches of the superficial digital flexor tendon to the proximal phalanx were found to be sites for attachment of the deep abaxial palmar ligaments of the proximal interphalangeal joint.
Plasma lipids, lipoproteins and post‐heparin lipases in ponies with hyperlipaemia
Authors: WATSON T. D. G. , BURNS L. , LOVE S. , PACKARD C. J. , SHEPHERD J.
Published: April 2010

The metabolic origins of equine hyperlipaemia were investigated by analysing the concentration and composition of plasma lipoproteins in 18 ponies with the condition. The mean concentrations of cholesterol, triglyceride and very low density lipoproteins (VLDL) were increased by 4‐, 52‐ and 19‐fold, respectively, compared with a control group of 18 healthy ponies. These increases were due to the appearance of a buoyant VLDL fraction (VLDL1) not present in healthy ponies. The mean diameter of VLDL1particles was 44% greater than control VLDL, and the particles were enriched in triglyceride and free cholesterol and depleted of cholesteryl esters, phospholipid and protein. The apolipoprotein (apo) B‐100 content of VLDL1was reduced and the ratio of apoB‐100 to apoB‐48 particles was 1:1, compared with 2:1 in control VLDL. The VLDL1was also enriched in apoE, but had normal complements of apoC‐II and apoC‐III. The conventional VLDL (called VLDL2), LDL and HDL fractions were moderately enriched with triglyceride, and HDL contained increased amounts of apoE, apoC‐II and apoC‐III. The activities of lipoprotein lipase and hepatic lipase, the enzymes responsible for the catabolism of VLDL and their remnants, were increased by 2‐ and 3‐fold, respectively, in response to the increased concentrations of their substrates. The composition of VLDL1suggested that the liver was maximising the secretion of triglyceride by producing larger number of VLDL particles that accommodated a greater mass of triglyceride by having apoB‐48 rather than apoB‐100 as their structural protein. Plasma free fatty acid (FFA) concentrations were elevated in 17 of the 18 ponies, suggesting that increased FFA flux might be the stimulus for hepatic triglyceride synthesis and VLDL secretion. We conclude that overproduction, rather than defective catabolism, of VLDL was the cause of the hyperlipidaemia and that lipid lowering agents which reduce VLDL synthesis, by decreasing adipose lipolysis and FFA flux, are candidates for the management of hyperlipaemia.
Increase in plasma progestagen concentrations in the mare after foetal injection with CRH, ACTH or betamethasone in late gestation
Authors: ROSSDALE P. D. , McGLADDERY A. J. , OUSEY JENNIFER C. , HOLDSTOCK NICHOLA , GRAINGER L. , HOUGHTON E.
Published: April 2010

Maternal plasma progestagen concentrations increase about 20 days before parturition. The major contributors to the increase are reduced metabolites (ie 5α‐pregnanes). Precocious increases (ie < 310 days of gestation) in these metabolites may occur in abnormal pregnancies. The effects of CRH, ACTH or betamethasone administered to the foetus at gestational ages ranging from about 250 to 320 days were examined. Sixteen healthy pony mares were used for foetal injection employing aseptic techniques. Water or normal saline were used as controls. Maternal plasma progestagen concentrations were measured using a commercial radioimmunoassay (RIA) progesterone kit and results were confirmed using gas chromatography‐mass spectrometry (GC‐MS). Results demonstrated clearly that an increase in maternal plasma progestagen concentrations occurred after injection of ACTH, CRH or betamethasone to the foetus, irrespective of gestational age. A comparable increase was not observed in the control animals. Of the 16 mares in which the foetus was injected, 13 produced viable foals at gestational ages ranging from 307 to 339 days whereas 3 mares delivered non‐viable foals at 284 to 306 days gestation. The results support the hypothesis that the pre‐parturient rise in progestagens occurring in the mare is the result of foetal adrenocortical activity.
Substance P in the synovial membrane and fluid of the equine middle carpal joint
Authors: CARON J. P. , BOWKER R. M. , ABHOLD R. H. , TOPPIN D. S. , SONEA I. M. , VEX K. B.
Published: April 2010

This preliminary study was designed to determine whether the neurotransmitter substance P was present in the middle carpal synovial membrane of the normal horse and whether the neuropeptide could be identified in the synovial fluid of normal horses and those with joint diseases. Immunocytochemistry on middle carpal synovial membrane biopsies from fresh cadavers was used to demonstrate substance P‐containing neural elements. Substance P was most abundant in the subintimal portion of the membrane, with occasional filaments coursing via synovial fronds to the intimai portion. Radioimmunoassay techniques were used on acidified acetonitrile‐preserved synovial fluid samples to measure substance P concentrations. Fluid from 9 joints of 5 normal horses and 6 joints of 4 horses with joint diseases were analysed. Disease conditions included acute and chronic osteoarthritis and osteochondrosis. Synovia from normal horses contained a mean concentration of substance P significantly less than that of horses with joint diseases (P < 0.05). Elevated concentrations of neurotransmitters in diseased joints suggests a potential contribution to the pathophysiology of joint disorders in horses.
Idiopathic muscular hypertrophy of the equine small intestine: 11 cases (1980–1991)
Authors: CHAFFIN M. K. , FUENTEABLA I. CARMEN , SCHUMACHER J. , WELCH R. D. , EDWARDS J. F.
Published: April 2010

The medical records of 11 horses with idiopathic muscular hypertrophy (MH) of the small intestine were reviewed to determine the clinical and pathological features of the disease. The median age of affected horses was 10.0 years (range 5–18 years). No breed or sex predisposition was apparent. Ten horses (91%) had chronic (23 days to 2.4 years) signs of mild, intermittent colic, and 1 horse had signs of severe colic of only 3 days' duration. Partial anorexia and chronic weight loss of variable duration (1–6 months) were prominent historical findings in 5 (45%) horses. Diagnostic tests, with the exception of exploratory caeliotomy, were ineffective for definitive diagnosis of intestinal MH as a cause of colic. In 2 horses, however, a thickened, rigid ileum was detected by palpationper rectum, and in 5 horses, multiple loops of distended small intestine were detected by palpationper rectum. Hypertrophy of both the circular and longitudinal layers of muscularis was determined as the cause of intestinal thickening in all horses. Muscular hypertrophy of the ileum was present in 9 (82%) horses. Two horses (18%) had MH of a section of jejunum only, and 4 (36%) horses had MH of the ileum in combination with MH of other sections of small intestine. Two (18%) horses had MH of the entire small intestine. In 9 (82%) horses, intestinal MH resulted in narrowing of the luminal diameter at the site of MH. Small diverticula were present on the mesenteric border of the hypertrophied ileum of 5 (45%) horses. Five linear (up to 150‐cm) diverticula were present in the hypertrophied jejunum of 1 (9%) horse. Haemomelasma ilei was present on the antimesenteric serosal surface of affected intestine of 8 (73%) horses. Full‐thickness rupture of the ileum with subsequent diffuse, septic peritonitis occurred in 3 (27%) horses.
Comparison of two grafting methods in 4.0‐mm drill defects in the third metacarpal bone of horses
Authors: HANIE ELIZABETH. A. , SULLINS K. E. , POWERS B. E. , NELSON P. R.
Published: April 2010

In 6 horses, bilateral metacarpal vertical series of three 4.0‐mm unicortical drill holes were made. At random, one of each series of 3 holes was filled using a sternal 4.0‐mm cancellous bone cylinder or a slurry of cancellous bone injected into the hole or left as an empty control. All horses had lateral metacarpal xeroradiographs at monthly intervals. Three horses (6 metacarpi) were examined post mortem after 4 months and 3 others after 6 months.

Immediate through 4‐month post‐operative xeroradiographs demonstrated increased density in the holes with cancellous cylinders and no difference could be seen between the untreated controls and holes injected with slurry. From 5 months, no radiographic difference could be seen between the treatment groups. No consistent histological difference between treatment groups could be detected. In conclusion, no justification for clinical grafting of 4.0‐mm unicortical dorsal metacarpal drill holes could be found.
Septic arthritis in 15 Standardbred racehorses after intra‐articular injection
Authors: LAPOINTE J. M. , LAVERTY SHEILA , LAVOIE J. P.
Published: April 2010

Case histories, results of synovial fluid analyses, treatment regimens and outcome are described for 15 adult Standardbred horses with confirmed post‐injection septic arthritis. Joint sepsis followed injection of corticosteroids, hyaluronic acid, polysulphated glycosaminoglycan, or local anaesthetic. The median interval from injection to appearance of clinical signs was 2.5 days, and median interval from injection to referral was 9 days. The median initial synovial leucocyte count on admission was 57 times 109/litre, but there was a wide range of values (18–258 times 109/litre). The median synovial neutrophil percentage was 95% (77–99%). All bacterial isolates were Gram‐positive cocci, 86% of which were staphylococci. All treated horses (12/15) initially received broad‐spectrum parenteral antibiotic therapy, and the articulations of all horses except one were lavaged, either with non‐surgical through‐and‐through techniques only (N=3), or surgically with arthrotomy (N=1) or arthroscopy (N=7). The owners of all treated horses were contacted and racing records were consulted. Eleven of 12 horses returned to racing. Outcome was judged as either satisfactory (3/12) if the horse had returned to racing levels similar to or better than before treatment, or unsatisfactory (9/12) if the horse had poorer performance or could not return to racing. The 3 horses with satisfactory follow‐up had been treated with arthroscopy and post‐surgical closed suction drainage. The results of bacterial cultures suggest that the initial antimicrobial agents used should be effective against penicillin‐resistant staphylococci.
A retrospective study of 192 horses affected with septic arthritis/tenosynovitis
Authors: SCHNEIDER R. K. , BRAMLAGE L. R. , MOORE R. M. , MECKLENBURG LINDA M. , KOHN CATHERINE W. , GABEL A. A.
Published: April 2010

The medical records of 192 horses with septic arthritis/tenosynovitis 1979–1989 were reviewed. Forty‐three horses developed infection after an intra‐articular injection, 46 following a penetrating wound, 25 following surgery, 66 were foals less than 6 months old, and 12 were adult horses without a known aetiology. Haematogenous infection of a joint occurs in adult horses and should be considered as a differential diagnosis in horses with an acute onset of severe lameness. The aetiology of the infection had a significant effect on the type of bacteria identified by culture.Staphylococcuswas cultured from most of the horses that developed infection following a joint injection or surgery, 69% of the horses from which an organism was identified. Horses that developed infection secondary to a penetrating wound frequently provided cultures of more than one organism; Enterobacteriaceae and anaerobes were more frequently isolated in this group. The most common organisms isolated from foals were Enterobacteriaceae;E. coliwas identified in more than 27% of the foals. The hock was the most frequently involved joint. Multiple treatments were used over the 10‐year period of study. Survival rates were lowest in foals; only 45% survived to be released from the hospital. Survival was greater in adult horses; 85% of the horses that were treated were released from the hospital. Survival was significantly greater in horses with septic tenosynovitis; all 14 of the horses that were treated survived. Survival was not significantly affected by the joint involved or by the type of bacteria cultured from the synovial fluid. Follow‐up racing data were obtained for all horses of racing age that were released from the hospital; 56.5% of these horses returned to racing and over 45% of these horses were able to make at least 5 starts. We suggest that if the infection can be eliminated before irreversible damage to the articular cartilage occurs, horses can return to athletic function.
Open drainage, intra‐articular and systemic antibiotics in the treatment of septic arthritis/tenosynovitis in horses
Authors: SCHNEIDER R. K. , BRAMLAGE L. R. , MECKLENBURG LINDA M. , MOORE R. M. , GABEL A. A.
Published: April 2010

Open drainage was used to treat 26 horses with persistent or severe septic arthritis/tenosynovitis. Infected synovial structures were drained through a small (3 cm) arthrotomy incision that was left open and protected by a sterile bandage. Joint lavage was performed in all 26 horses. In addition to systemic antibiotics, 23 of these horses were also treated with intra‐articular antibiotics; amikacin (17 horses), gentamycin (2 horses), cefazolin (2 horses), and 2 horses were injected at different times with gentamycin and amikacin. The infection was eliminated from the involved synovial structures in 25 of 26 horses; 24 survived and were released from the hospital. The arthrotomy incisions healed by granulation in 16 horses; in 9 horses the arthrotomy incision was sutured closed once the infection was eliminated. Seventeen horses returned to soundness and resumed athletic function. Open drainage was an effective method of achieving chronic drainage from a joint or tendon sheath. It is indicated in horses that have established intra‐synovial infections or in horses that do not respond to joint lavage through needles.
Evaluation of progesterone treatment to create a model for equine endometritis
Authors: HINRICHS KATRIN , SPENSLEY M. S. , McDONOUGH P. L.
Published: April 2010

To investigate a model for equine endometritis, 12 mares with normal reproductive tracts were divided into 2 groups. All mares received progesterone in oil, 250 mg im, daily. At 5 days after initiation of progesterone administration, the uteri were inoculated with 106colony forming units ofPseudomonas aeruginosa. The day of inoculation was designated Day 0. On Day 6, endometrial swab samples yieldedP. aeruginosain 5 mares; samples from the other 7 mares yielded heavy growth ofEscherichia coli, Streptococcus zooepidemicus, Klebsiella pneumoniae, Enterobacterspp.,Citrobacter diversus, Staphylococcus epidermidisandStreptococcus morbillorum. On Days 6, 7 and 8, Group A mares received intrauterine infusions of 6 g ticarcillin disodium and 0.2 g clavulanate potassium in 100 ml sterile saline. Group B mares received infusions of saline only. The incidence of swab specimens yielding no bacterial growth was significantly higher in Group A than Group B mares on Days 8 and 13 (4/6 vs 0/6). Swab samples from 5 of the 6 mares in Group A yielded growth of fungi on Days 13 and 19. Mares in Group B were then similarly treated with ticarcillin/clavulanate infusions, on Days 19, 20 and 21. The incidence of swab specimens yielding no bacterial growth was 2/6 and 1/6 on Days 21 and 26, respectively; fungi were not recovered from these mares at any time. The incidence of no‐growth swabs after antibiotic treatment tended to be higher in Group A and incidence of fungal recovery after antibiotic treatment was significantly higher in Group A. Although the progesterone‐treated, uterine‐inoculated mares consistently developed endometritis that, in Group A, responded to intrauterine infusion of antibiotics, it was concluded that the model's problems for studying equine endometritis, include 1) failure of establishment of inoculated bacteria; 2) changing population of bacteria, probably attributable to introduction of organisms at the times of transcervical manipulation; 3) acquisition of fungal infection after intrauterine treatment with antibiotics; and 4) variable response to antibiotic treatment, apparently associated with duration of progesterone administration and/or endometritis.