bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of prerace exercise, frusemide, sex and ambient temperature on blood sodium, bicarbonate and pH values in Standardbred horses
Authors: FREY L. P. , KLINE K. H. , FOREMAN J. H.
Published: April 2010

Analysis of data collected at racetracks showed that temperature, the diuretic drug, frusemide, exercise, temperature/exercise interaction and sex/age had significant (P<0.05) effects on pH and bicarbonate ion concentration (P<0.01). Sodium concentrations were significantly (P<0.001) affected by temperature and frusemide. We suggest that the normal range limits for blood sodium, bicarbonate and pH used in prerace testing procedures should be adjusted for ambient temperature and for horses given frusemide and/or prerace exercise. These adjustments should improve the precision of detecting illegal alkalogenic agents and incidence of false positive and false negative test results.
Hoof horn abnormalities in Lipizzaner horses and the effect of dietary biotin on macroscopic aspects of hoof horn quality
Authors: JOSSECK H. , ZENKER W. , GEYER H.
Published: April 2010

This study involved a macroscopic evaluation of hoof quality in 152 Lipizzaner horses (130 from Austria and 22 from other countries) and a controlled double blind trial of the effects of biotin on hoof horn growth and quality over 19 months in 42 stallions from the Spanish Riding School (SRS) in Vienna. Using a grading system that incorporated evaluation of horn wall, white line, sole and frog, the macroscopic study revealed the following: 90% of the Austrian Lipizzaners had soft white lines and crumbling, fissured horn at the bearing border of the walls; 39% of the stallions of the SRS, >4‐years‐old, had medium to severe hoof horn changes. Daily administration of 20 mg biotin to a test group of horses (n=26) and a placebo to a control group (n=16) showed that after 9 months the test group had significantly improved compared to the beginning of the trial and the placebo group (P<0.01). In the test group, further improvement was observed during the following 5 months and, subsequently, the same good level of hoof condition was maintained over 3 further years of observation. Growth rate of the horn wall was equal in the biotin and placebo group, being 7 mm/28 days, giving a wall renewal period of 11 months. Mean plasma biotin level of untreated horses was 350 ng/l; plasma levels of biotin supplemented horses were > 1000 ng/l. It was concluded that continuous dietary supplementation with biotin at a daily dose of 20 mg is indicated to improve and maintain hoof horn quality in horses with less than optimum quality hoof.
Confidential enquiry of perioperative equine fatalities (CEPEF‐1): preliminary results
Authors: JOHNSTON G. M. , TAYLOR POLLY M. , HOLMES M. A. , WOOD J. L. N.
Published: April 2010

The Confidential Enquiry into Perioperative Equine Fatalities (CEPEF‐1) is an observational multi‐institutional prospective study of recovery outcome at 7 days post operatively, as called for by Steffey (1991). Data from 6,255 general anaesthetics (February 91‐March 93) were submitted confidentially by 62 clinics. The outcomes of 333 cases which were subjected to euthanasia and which were not classified ‘alive’ or ‘died’ at 7 days, were excluded from the analysis. The remaining 5922 cases were analysed to identify risk ratios (RR) between survivors and nonsurvivors for a variety of factors. These preliminary results indicate an overall death rate, for equine patients dying or being subjected to euthanasia within 7 days of a general anaesthetic because of perioperative complications, of 102/6255 (1.6%). This mortality rate decreased to 46/5220 (0.9%) when all colic surgery and delivery of foals under general anaesthesia were excluded.

There was an increased risk for mares in the last trimester of pregnancy (RR=6.4). Patients undergoing emergency abdominal procedures (colic patients and pregnant mares undergoing controlled or caesarean section delivery of foals) under general anaesthesia were at increased risk (RR=12.9) compared to ear, nose and throat surgery. Within orthopaedic surgery, patients requiring internal fixation were at increased risk (RR=3.2) compared to those undergoing miscellaneous orthopaedic surgery. There was no difference in risk between breeds. Patients not placed in dorsal recumbency were at reduced risk (RR=0.3‐0.5) compared to those which were in dorsal recumbency. Lack of a sedative premedication and use of xylazine were associated with a RR of 6.2 and 2.1 respectively, compared to patients given only detomidine for sedative premedication. However, 90% of all induction regimes were at similar risk, except inhalation with halothane (RR=4.8) and guaiphenesin and ketamine combination (RR=4.3) compared to guaiphenesin and thiopentone combination. There was a reduction in risk for surgeries carried out in the last quarter of the year (RR=0.3), compared to surgery carried out in the first three‐quarters. Patients younger than 1‐week‐old (RR=20.6) and between 1‐week and 1‐month‐old (RR=4.3) and patients older than 12 years old (RR=3.1) were at increased risk, compared to patients age 2–4 years. The likelihood of death increased as the duration of anaesthesia increased beyond 61 min, with the greatest being operations lasting longer than 241 min (RR=7.6). Surgery performed outside of 0900–1700 h had increased risk, worst between 1801–2000 h (RR=9.9), compared to surgeries carried out between 0801–1300 h.
Age related changes in biochemical markers of bone metabolism in horses
Authors: PRICE JOANNA S. , JACKSON B. , EASTELL R. , GOODSHIP A. E. , BLUMSOHN A. , WRIGHT I. , STONEHAM SARAH , LANYON L. E. , RUSSELL R. G. G.
Published: April 2010

Biochemical markers of bone metabolism were analysed in serum samples obtained from 60 horses with no history of orthopaedic disease (age 3 months‐20 years). Serum levels of the carboxyterminal propeptide oftype Iprocollagen (PICP), a marker of bone formation and the pyridinoline cross linked telopeptide domain oftype Icollagen (ICTP), a putative marker of bone resorption, were measured by radioimmunoassay (RIA). Serum levels of the bone specific isoenzyme of alkaline phosphatase (BALP), another marker of bone formation, were measured by a wheatgerm agglutinin affinity (WGA) method. Total alkaline phosphatase levels were also determined. Serum levels of PICP were significantly correlated with bone ALP (r=0.78, P<0.0001) and ICTP (r=0.87, P<0.0001). ICTP levels also correlated significantly with bone ALP (r=0.81, P<0.0001). However, total alkaline phosphatase did not correlate significantly with PICP, ICTP and BALP in horses over 1 year of age. There was an inverse correlation between serum levels of all biochemical markers and age of animals, with the most significant changes seen over the first 2 years. In animals less than 1 year of age, the reference ranges (mean ± s.d. 1.96) were as follows: PICP 1216–2666 μg/l, ICTP 13.8–26.7 μg/l, bone ALP 134–288 u/l and total ALP 223–498 u/l. In 2‐year‐olds, the equivalent reference ranges were: PICP 550–1472 μg/l, ICTP 7.96‐22.8 μg/l, bone ALP 32.7–125 u/l and total ALP 134–238 u/l. Assays for bone ALP and antigens that reflect collagen metabolism display significant potential as sensitive non invasive methods of evaluating bone metabolism in the horse.
Induction of intra‐articular tumour necrosis factor during acute inflammatory responses in equine arthritis
Authors: BILLINGHURST R. C. , FRETZ P. B. , GORDON J. R.
Published: April 2010

Synovial fluid (SF) was collected at 2, 12 and 26 h post racing from 5 Thoroughbred horses (6 joints) with degenerative joint disease. The effects of serial arthrocentesis on SF TNFα levels were controlled for by testing, in parallel, site‐ and time‐matched samples from clinically normal horses (i.e. without arthritis). A significant induction in TNFα bioactivity was detected in SF from arthritic joints (compared to the control joints) over the 26 h following racing. After subtraction of values for the arthrocentesis control SF, TNFα and protein levels and WBC and mononuclear cell numbers each peaked at 12 h in the SF from the degenerative joints, although there were no statistically significant correlations between any of these parameters. The presence in the SF of TNFα, as well as immunoreactive IL‐1β and IL‐6, was confirmed through use of specific anti‐human cytokine IgG antibodies in neutralisation and slot‐blot radioimmunoassays. TNFβ was not detected in the SF by slot‐blot radioimmunoassay. These results suggest that a significant increase in intra‐articular TNFα occurs during acute inflammatory arthritis in horses. The lack of correlation between infiltrating inflammatory cells and SF TNFα levels further suggests that the source of TNFα may be resident cells of the joint, as opposed to infiltrating cells found within the joint fluids. SF from clinically normal and arthritic joints of racing and hospitalised horses were also screened for bioactive TNFα. No statistically significant differences were found in the TNFα levels of the normal (29.46 ± 3.15 u/ml) vs. degenerative (21.64 ± 3.39 u/ml) joints, although significant elevations were noted in the arthritic joints for SF protein levels and WBC and RBC counts. However, when grouped by arthropathy, there were significant differences from normal in the SF TNFα levels in cases of synovitis and major intra‐articular fractures.
Transection of the accessory ligament of the superficial digital flexor tendon for treatment of tendinitis: long term results in 61 Standardbred racehorses (1985–1992)
Authors: HOGAN PATRICIA M. , BRAMLAGE L. R.
Published: April 2010

Medical records and lifetime race results were obtained for 61 Standardbred racehorses treated consecutively from 1985 to 1992 with transection of the accessory ligament of the superficial digital flexor tendon (AL‐SDF) for tendinitis of one or both forelimbs. A clinical diagnosis of tendinitis was confirmed in all cases by ultrasonographic examination. After surgery, 50 (82%) horses raced and 42 (69%) completed 5 or more starts. Eight horses (13%) failed to start and/or complete 5 or more races due to a recurrence of tendinitis. Six (10%) horses did not start and/or complete 5 or more starts for reasons unrelated to tendinitis and 5 (8%) horses were lost to follow‐up. The median time between surgery and the first post operative start was 39 weeks. Fifty‐seven per cent of those horses to start after surgery completed 20 or more starts and 40% raced on 40 or more occasions. Of the 42 horses to complete 5 or more races, the median number of post operative starts was 37 at time of follow‐up. Thirty‐two of 50 (64%) horses to start after surgery established or lowered lifetime racemarks. Thirty‐six horses had raced prior to surgery. Thirty‐one of 36 (86%) horses returned to racing after treatment of SDF tendinitis with accessory desmotomy (AD) and 27 horses (75%) completed 5 or more starts. Median earnings per start decreased 25% after surgery. Twenty‐five horses had not raced prior to surgery. Nineteen (76%) horses in this group were age 2 years at time of injury. Nineteen of 25 (76%) horses started after surgery and 15 horses (60%) completed 5 or more starts.

Horses that had not started prior to sustaining injury had significantly (P<0.05) less total earnings per horse and earnings per start after surgery than those horses that had previously raced. Horses that had started before surgery achieved significantly faster post operative lifetime racemarks than horses that had not raced before surgery. Horses that were age 2 years at time of injury did not differ statistically from horses older than 2 years in any post operative variable evaluated. There was no statistical difference in rate of recurrence of tendinitis between horses undergoing AD in one or both limbs for treatment of tendinitis occurring in one limb. This study suggests that transection of the AL‐SDF allows a high percentage of Standardbred horses with tendinitis to race and earn money without recurrence of tendinous injury. Horses that have not raced prior to tendinous injury may be expected to earn less money and achieve lower lifetime racemarks after surgery than horses that have raced prior to sustaining tendinous injury.
Ventilatory and timing parameters in normal horses at rest up to age one year
Authors: KOTERBA ANNE M. , WOZNIAK J. A. , KOSCH P. C.
Published: April 2010

The purpose of the study was to document the developmental changes in the ventilatory and timing parameters associated with quiet breathing at rest in awake, standing horses during the first yearpost partum. Tidal volume (VT), breathing frequency, airflow, mechanical timing intervals and minute ventilation (V̇E) were measured serially in foals age 24 h‐1 year. In the growing foal, V̇Eincreased due to a progressive rise in VT, in spite of a pronounced decrease in respiratory frequency. When normalised to body weight (bwt), V̇E7kg declined with maturation in a curvilinear fashion, from mean ± s.d. 848 ± 231 ml/min/kg in the 24 h‐old foal, to 155 ± 15 ml/kg/min in the 1‐year‐old foal. Tidal volume normalised to bwt remained relatively constant during the study period, with the exception that at age 3 weeks and from 2–6 months, VT/kg was significantly lower than the value recorded at age 1 week. The decrease in frequency resulted from prolongation of both inspiratory (TI) and expiratory (TIE) time but there was a disproportionately larger increase in TEcompared to TI, which resulted in a significantly lower ratio of TI/TEin older foals. The allometric equation relating VTto bwt suggested that lung growth in the horse is dysanaptic, with increases in overall body size exceeding lung growth in the maturing foal during the first yearpost partum.
Rheumatoid factor, anti‐heat shock protein (65 kDa) antibodies and anti‐nuclear antibodies in equine joint diseases
Authors: CARTER S. D. , OSBORNE ANNE C. , MAY S. A. , BENNETT D. ,   Arthritis Research Group
Published: April 2010

To consider the hypothesis that autoimmune mechanisms may contribute to the pathology of equine joint diseases, 3 autoimmune responses were assayed in sera and synovial fluids. IgM‐rheumatoid factor and antibodies to heat shock protein 65 kDa were determined by ELISA; anti‐nuclear antibodies were assayed by indirect immunofluorescence to whole cell nuclear components. All parameters showed only modest increases, if any and not in a pattern related to disease, although some statistically significant increases were detected.

Group analysis showed significantly elevated synovial fluid IgM‐rheumatoid factor (IgM‐RF) in horses with OA (P<0.01), traumatised joints (P<0.01) and articular fractured bones (P<0.001). There was no significantly increased IgM‐RF in the sera of horses with joint disorders compared to control horses. Significantly raised anti‐heat shock protein molecular weight 65 kDa (HSP65) antibodies were only found in the synovial fluids of the horses with traumatised joints (P<0.001). No correlations were found between the synovial fluid and sera levels of IgM‐RF or anti‐HSP65 antibodies. Synovial fluid anti‐HSP65 antibody and IgM‐RF levels positively correlated in the OCD (P<0.001), fracture (P<0.01) and synovitis (P<0.05) groups. As antibodies to HSP65 correlated with IgG concentrations in synovial fluids, it is not possible to draw conclusions on HSP roles in joint disease pathogenesis. No serum anti‐nuclear antibodies (ANA) were detected by immunofluorescence using rat liver and a human epithelial cell line (HEp‐2) as substrates.

Compared with autoimmune responses in human and canine arthropathies, the low levels of autoimmune reactivity detected in this study can only suggest a minor contributory role to joint disease pathology in the horse. These results have 2 important implications. Firstly, other pathogenetic mechanisms should be considered and secondly, autoimmune mechanisms cannot be used to monitor disease progress and therefore should not be targetted for treatment.
Effects of ketoprofen and phenylbutazone on chronic hoof pain and lameness in the horse
Authors: OWENS JANE G. , KAMERLING S. G. , STANTON S. R. , KEOWEN M. L.
Published: April 2010

The analgesic effects of the nonsteroidal anti‐inflammatory drugs, ketoprofen (2.2 and 3.63 mg/kg bwt) and phenylbutazone (4.4 mg/kg bwt) were compared in 7 horses with chronic laminitis. Hoof pain was quantified objectively by means of an electronic hoof tester and lameness was subjectively graded on a modified Obel scale. Ketoprofen at a dose of 3.63 mg/kg bwt (phenylbutazone equimolar dose) reduced hoof pain and lameness to a greater extent than the 2.2 mg/kg dose and phenylbutazone. These effects were still present at 24 h in 3 of the 4 pain tests, including lameness grade. These data suggest that ketoprofen at the dosage rate of 1.65 times the recommended therapeutic dose was more potent than phenylbutazone in alleviating chronic pain and lameness in horses.
Photic headshaking in the horse: 7 cases
Authors: MADIGAN J. E. , KORTZ G. , MURPHY C. , RODGER LYNN
Published: April 2010

Seven horses with headshaking are described. No physical abnormalities were detected in any of the cases. Six of these horses had onset of clinical signs in the spring. The role of light was assessed by application of a blindfold or dark grey lens to the eyes, covering the eyes with a face mask and observing the horse in total darkness outdoors. Cessation of headshaking was observed with blindfolding (5/5 horses), night darkness outdoors (4/4 horses) and use of grey lenses (2/3 horses). Outdoor behaviour suggested efforts to avoid light in 4/4 cases. The photic sneeze in man is suggested as a putative mechanism for equine headshaking. Five of 7 horses had improvement with cyproheptadine treatment (0.3 mg/kg bwt b.i.d.). Headshaking developed within 2 calendar weeks of the same date for 3 consecutive years in one horse. Neuropharmacological alterations associated with photoperiod mechanisms leading to optic trigeminal summation are suggested as possible reasons for spring onset of headshaking.
Localisation of 15‐hydroxy prostaglandin dehydrogenase (PGDH) and steroidogenic enzymes in the equine placenta
Authors: HAN X. , ROSSDALE P. D. , OUSEY JENNIFER , HOLDSTOCK NICOLA , ALLEN W. R. , SILVER MARIAN , FOWDEN ABIGAIL L. , McGLADDERY A. J. , LABRIE F. , BELANGER A. , ENSOR C. M. , TAI H‐H. , CHALLIS J. R. G.
Published: April 2010

15‐hydroxy prostaglandin dehydrogenase (PGDH) is the critical enzyme that determines metabolism of primary prostaglandins. Its expression is determined in part by steroid hormones, particularly progesterone, formed from Δ5 steroids through 3β‐hydroxysteroid dehydrogenase (3β‐HSD) activity. To assess whether the regulation of PGDH might occur in a paracrine, autocrine or intracrine fashion, we used immunohistochemistry (IHC) to determine the localisation of key steroidogenic enzymes in the equine placenta and compared these patterns to the distribution of immunoreactive (IR‐) PGDH. Placental tissue was obtained from pony or Thoroughbred mares at about Days 150, 250–280 and >300 of pregnancy (term 320–360 days; n=5–8 each group). IR‐PGDH, 3β‐HSD, cholesterol side chain cleavage enzyme (P450scc) and 17‐hydroxylase/lyase (P450c17) were localised using specific antibodies and the avidin‐biotin peroxidase technique and visualised using diaminobenzidine as substrate. IR‐P450scc was present in trophoblast cells, but not in maternal tissues of the microcotyledons or elsewhere in the endometrium. Specific staining for P450C17 was not detected in either maternal or fetal tissues at any stage of gestation studied. IR‐3β‐HSD was present in trophoblast cells, but not in maternal tissues of the microcotyledons. In contrast, at Days 150 and 280, IR‐PGDH was present in maternal epithelial and interstitial cells in the microcotyledons, but was not detected in trophoblast epithelium, chorioallantois or endometrial glands. After Day 300, IR‐PGDH was present in the maternal epithelium and interstitial cells of the placenta and it was also present in trophoblast cells in some specimens. We conclude that the equine placenta has the enzymes necessary to produce C21Δ4 steroids from C27Δ5 substrates in trophoblast cells by Day 150 of gestation. The localisation of these enzymes is compatible with paracrine regulation of PGDH by products of 3β‐HSD activity for most of pregnancy, although autocrine or intracrine regulation of placental PGDH may also be possible nearer to term.
Modulation of 3β‐hydroxysteroid dehydrogenase (3β‐HSD) activity in the equine placenta by pregnenolone and progesterone metabolites
Authors: CHAVATTE PASCALE M. , ROSSDALE P. D. , TAIT A. D.
Published: April 2010

The purpose of this study was to measure 3β‐HSD activity in the equine placenta and to assess the effect of fetal and maternal blood plasma progestagens on 3β‐HSD activity in vitro. 3β‐HSD activity was measured in 8 late gestation (collected by caesarian section at 250 to 320 days) and 7 term (collected at birth) equine placentae using a tritium release assay with [3α‐3H] pregnenolone as substrate. Mean ± s.d. Kmapp and Vmax for term placentae were in general higher than for late gestation placentae (0.129 ± 0.217 μmol/l and 23.85 ± 9.1 nmol/mg/h respectively vs. 0.016 ± 0.048 μmol/l and 17.36 ± 20.9 nmol/mg/h) but there was no statistical difference between them. Inhibition studies were performed on 3 term placentae and 3 late gestation ones. Steroid concentrations used for inhibition studies were close to blood plasma concentrations (0.5 to 2 μmol/l). 3β‐hydroxy compounds (5α‐pregnane‐3β, 20β‐diol, 5α‐pregnane‐3β, 20α‐diol and 3β‐hydroxy‐5α‐pregnan‐20‐one) showed noncompetitive or mixed inhibition. Mean Kiapp ranged from 0.47 μmol/l to 1.55 μmol/l. Noncompetitive inhibition was found for 5‐pregnene‐3β,20β‐diol with a mean Kiapp of 0.7 μmol/l. Inhibition was competitive with 20α‐hydroxy‐5α‐pregnan‐3‐one with a mean Kiapp of 0.1 μmol/l. Progesterone was found to be a weak noncompetitive inhibitor of equine 3β‐HSD actitvity (mean Kiapp=1.2 umol/l) and no consistent inhibitory action was found with 5α‐pregnane‐3,20‐dione.

These data demonstrate that a marked inhibition of 315‐HSD activity is caused by 5‐pregnenes and 5α‐pregnanes in the range of blood plasma concentrations in the pregnant mare. It is probable that a cumulative effect of these compounds could lead to a further decrease in the enzyme activity in the term placenta, which may be of significance in the onset of parturition.
Descriptive epidemiological study of equine laminitis
Authors: SLATER MARGARET R. , HOOD D. M. , CARTER G. K.
Published: April 2010

A descriptive and matched case‐control study of laminitis was conducted in 7 private practices and at the Texas Veterinary Medical Centre (TVMC) between May 1992 and July 1993. Out of 108 horses with laminitis, 19 acute (49%) and 20 chronic (51%) cases were seen in private practice and 16 acute (23%) and 53 chronic (77%) cases at the TVMC. Gastrointestinal disease was the most common problem in 19/35 horses (54%), occurring just prior to the onset of acute laminitis in all hospitals. Among all horses in the study, most commonly used drugs were phenylbutazone (68%), acepromazine (34%), dimethyl sulphoxide (DMSO) (27%), antibiotics of various types (19%) and flunixin meglumine (19%). Acepromazine, DMSO and flunixin meglumine were used more commonly in acute cases of laminitis compared to chronic cases. In acutely affected horses, DMSO and flunixin meglumine were used significantly more often at the TVMC. In chronic cases, phenylbutazone and antibiotics were used more often in private practice. Shoeing and trimming were more commonly part of the treatment protocol for chronic cases. There were no significant associations between age, breed, sex or weight and the occurrence of acute laminitis. Horses with chronic laminitis were significantly older (P=0.04) and more females tended to be affected (P=0.08).
Small intestinal herniation through the epiploic foramen: 53 cases (1987–1993)
Authors: VACHON ANNE M. , FISCHER A. T.
Published: April 2010

The incidence of epiploic entrapment of the small intestine in horses undergoing celiotomy for colic was 5%. The condition was more prevalent in older (mean 9.81 years) gelding and Thoroughbred horses. Preoperative peritoneal protein level was a good prognostic indicator as it was significantly greater in the nonsurvivor (39.4 ± 5.10) group than in the survivor group (26.6 ± 14.0) (P<0.05). Abdominal ultrasonography allowed earlier diagnosis and surgical intervention in nonpainful cases with inconclusive rectal findings. Surgery was completed in 46 horses and 44 horses recovered from anaesthesia. Nine horses were either subjected to euthanasia in surgery (7 horses) or died in recovery (2 horses). Repeat laparotomies were pursued in 27% (12/44) of the horses. Seven horses (16%) showed post operative adynamic ileus which was the most common post operative complication. The incidence (6%) of adhesion formation was lower than previously reported. Other post operative complications included gastric ulceration, liver disease, diarrhoea and weight loss. Short and long term survival rates were 79% (35/44) and 70% (31/44) respectively. Improved rates were attributed to earlier referral and diagnosis and prompt surgical intervention. The aggressive use of repeat celiotomy and a more effective treatment of the endotoxic horse in the perioperative period contributed to survival.
Equine pulmonary disease: a case control study of 300 referred cases. Part 1: Examination techniques, diagnostic criteria and diagnoses
Authors: DIXON P. M. , RAILTON D. I. , McGORUM B. C.
Published: April 2010

Three‐hundred adult horses, referred from 1990 to 1993 inclusively, for pulmonary examination were assessed using standardised history taking and clinical, intrapleural pressure, arterial blood gases and pH, bronchoscopic and tracheal and broncho‐alveolar lavage fluid (BALF) cytological examinations. Two‐hundred and thirty‐five cases were referred with overt signs of pulmonary disease and the remaining 65 cases were referred for pulmonary examination because of reduced exercise (usually racing) performance or prolonged dyspnoea after racing.

No pulmonary disease was detected in 30 cases. The 270 horses with pulmonary disease included 148 cases (54.8%) of chronic obstructive pulmonary disease (COPD), 45 (16.7%) of infectious or post infectious pulmonary disease, 7 (2.6%) ofStreptococcus zooepidemicuspulmonary infection, 7 (2.6%) of lungworm infection, 16 (5.9%) of primary exercise induced pulmonary haemorrhage (EIPH), 9 (3.3%) of chronic idiopathic hypoxaemia, 20 (7.4%) of miscellaneous identified pulmonary disorders and 18 (6.7%) of undifferentiated pulmonary disorders. Two cases of primary summer associated obstructive pulmonary disease (SPAOPD) were observed, but 9.5% of COPD affected horses additionally suffered from SPAOPD.
Equine pulmonary disease: a case control study of 300 referred cases. Part 3: Ancillary diagnostic findings
Authors: DIXON P. M. , RAILTON D. I. , McGORUM B. C.
Published: April 2010

The majority of 270 adult horses with chronic pulmonary diseases had excessive volumes of respiratory secretions (RS) present in their trachea, elevated tracheal RS neutrophil ratios and lowered arterial oxygen partial pressures. Some control horses, had inexplicably elevated tracheal RS neutrophil ratios. Only the chronic obstructive pulmonary disease (COPD) affected group had significantly elevated bronchoalveolar lavage fluid (BALF) neutrophil ratios. Maximal intrapleural pressure changes (max dPpl) were raised in 48% of COPD cases and rarely with other pulmonary disorders. Arterial pH or carbon doxide partial pressures values were seldom altered with any pulmonary diseases. Tracheal RS and BALF eosinophil ratios were raised with lungworm infection and idiopathic pulmonary eosinophilia.
Corneal stromal abscesses in the horse: a review of 24 cases
Authors: HENDRIX DIANE V. H. , BROOKS D. E. , SMITH PATRICIA J. , GELATT K. N. , MILLER T. R. , WHITTAKER C. , PELLICANE CHRISTINA , CHMIELEWSKI NOELLE
Published: April 2010

The medical records of 24 horses with corneal stromal abscesses were reviewed. Twenty of the horses initially presented with a corneal ulcer, corneal opacity, or evidence of ocular pain. All of the horses were treated with topical antibiotics prior to referral. Most had also been treated with topical atropine sulphate and systemic flunixin meglumine. Ophthalmic examinations revealed focal, yellow‐white corneal opacities, corneal vascularisation and evidence of iridocyclitis. Nine of the horses were treated primarily medically as the initial response to topical and systemic medication was rapid. Fifteen horses were treated both medically and surgically. Surgical treatment was undertaken when corneal rupture was imminent, the iridocyclitis was intractable or when there was minimal response to intensive medical therapy. The surgical procedure performed in most cases was a deep keratectomy with a conjunctival pedicle flap. Intraoperative specimens for cytology, culture, and/or histopathology contributed to the aetiological diagnosis in 5 of 8 cases in which preoperative cytology and cultures were nondiagnostic. All horses, excluding one that was enucleated at presentation for iris prolapse, had vision at discharge.
Near infrared spectroscopy of pedal haemodynamics and oxygenation in normal and laminitic horses
Authors: HINCKLEY K. A. , FEARN S. , HOWARD B. R. , HENDERSON I. W.
Published: April 2010

The present study applies near infrared spectroscopy (NIRS) to the haemodynamics of the pedal circulation in normal and laminitic horses. NIRS is a noninvasive technique which uses changes in light absorption at 4 wavelengths to provide information on the changes in cytochrome aa3 (cyt aa3) reduction‐oxidation (redox) status, and changes in the tissue concentration of oxyhaemoglobin (O2Hb), deoxyhaemoglobin (HHb) and therefore total haemoglobin (tHb). Other studies have shown NIRS to be sensitive to changes in tissue oxygenation and perfusion in human cerebral and limb circulation. In this study, the NIRS sensor was applied to the dorsal surface of horses' hooves. Normal and laminitic animals (acute and chronic) were subjected to manoeuvres (cuff tourniquet; digital vessel occlusion at the palmar surface of the pastern; lifting of contralateral limb) predicted to change pedal haemodynamics. The procedures produced changes in pedal haemodynamics and oxygenation, which were similar to those observed in the ischaemic/reperfused human forearm. Laminitic differed from normal horses: return of HHb to baseline was slower and the change in cyt aa3 more rapid than normal in cases of chronic laminitis, taken to indicate reduced O2stores as a result of compromised basal perfusion. In acute laminitis, baseline values did not fluctuate following any of the manoeuvres, suggesting haemostasis in the diseased hoof. NIRS is a useful noninvasive method to assess pedal vascular function in normal and laminitic horses.
Lymphocyte subsets in the endometrium of genitally normal mares and mares susceptible to endometritis
Authors: Watson Elaine D. , Thomson S. R. M.
Published: April 2010

The density and distribution of MHC Class II positive cells and subpopulations of lymphocytes were studied in the endometrium of genitally normal mares and mares susceptible to endometritis. In genitally normal mares, more MHC Class II positive cells were present in the epithelium and stratum compactum during oestrus than dioestrus. Significantly more CD4+ and CD8+ lymphocytes were present in the stratum compactum than in the stratum spongiosum. CD4+ lymphocytes were present in greater numbers than CD8+ lymphocytes in the stratum compactum but approximately equal numbers were present in the stratum spongiosum and in lymphoid aggregates. Occasional CD4+ and CD8+ cells were seen in the luminal and glandular epithelium. Infrequently, B cells were present in the endometrium and were not observed in the epithelium. Numbers of T and B cells did not appear to be affected by cycle stage. In mares with endometritis, the densities of CD4+, CD8+ and B cells were significantly increased. Large aggregates of lymphoid cells which contained approximately twice as many CD4+ cells as CD8+ cells were present in the endometrium of these mares and all 3 subclasses of lymphocyte were seen occasionally in luminal and glandular epithelium.
Evaluation of pulse oximetry in anaesthetised foals using multiple combinations of transducer type and transducer attachment site
Authors: CHAFFIN M. K. , MATTHEWS NORA S. , COHEN N. D. , CARTER G. K.
Published: April 2010

A commercially available pulse oximeter was evaluated in anaesthetised foals to determine its accuracy for estimating arterial haemoglobin saturation (SaO2). Five different transducer/transducer attachment site (TIAS) combinations were evaluated; 1–3) a fingertip transmission transducer attached to the foal's ear, lip and tongue, 4) an adhesive transmission transducer positioned on the foal's ear and 5) a forehead reflectance transducer placed on the ventral aspect of the foal's tail‐base.

Eight normal, Quarter Horse foals (age 5–10 days) were studied while under general anaesthesia. Alterations in arterial carbon dioxide tension (PaCO2) were produced by changing the level of ventilation. At each level of ventilation, alterations of arterial haemoglobin saturation (SaO2) were produced by varying the inspired fraction of oxygen (FIO2). At each level of ventilation and each level of FIO2, arterial blood samples were obtained for blood gas analysis while pulse oximeter readings were recorded simultaneously for each TTAS combination. Arterial blood oxygen saturation (SaO2) was calculated from arterial blood gas values and the equine blood oxygen dissociation curve.

Pulse oximeter readings from each TTAS combination were compared with SaO2values with linear regression analyses. Bias and precision values were determined and the sensitivity and specificity of each TTAS combination for detecting desaturation (SaO2<90%) were determined.

Linear regression analyses indicated significant (P<0.05) linear correlation between oxygen saturation determined by pulse oximeter (SpO2) and SaO2for each of the 5 TTAS combinations. The combinations TTAS‐1, TTAS‐3 and TTAS‐4 tended slightly to underestimate SaO2at high SaO2ranges, but overestimated SaO2at low ranges of SaO2. Combination TTAS‐2 overestimated SaO2over all ranges of SaO2. Combination TTAS‐5 consistently underestimated SaO2at all ranges of SaO2. In general, accuracy and precision of each TTAS combination decreased at lower SaO2ranges. All TTAS combinations, except TTAS‐2 and TTAS‐4, had good sensitivity for detecting SaO2less than 90%. All TTAS combinations except TTAS‐5 demonstrated good specificity.

We concluded that pulse oximetry appears to be a valuable method for assessing SaO2and detecting desaturation in anaesthetised foals. Clinicians should be aware that the type of transducer used and the anatomical site to which it is attached can have marked effects on the accuracy of pulse oximetry; and that different TTAS combinations may behave differently over various ranges of SaO2.
The role of computed tomography in evaluation of subchondral osseous lesions in seven horses with chronic synovitis
Authors: HANSON JENNIFER A. , SEEHERMAN H. J. , KIRKER‐HEAD C. A. , O'CALLAGHAN M. W.
Published: April 2010

Seven horses with severe, persistent lameness of sudden onset were evaluated with scintigraphy and/or computed tomography. The lameness was localised to the front fetlock joint in 2 horses and to the tibiotarsal joint in 5 horses. Five of the horses had a history of intra‐articular injections of the involved joint prior to presentation. All horses had effusion of the affected joint and were positive to flexion tests. Intraarticular anaesthesia eliminated or improved the lameness in 4 cases and a nerve conduction block proximal to the affected joint improved the lameness in another. Cytology examination of fluid from affected joints identified normal joint fluid (one horse) or elevations in nucleated cell counts of 0.9 × 109/1–36.8 × 109/l and total protein 20–42 g/l (6 horses). The joint fluid of 2 of these horses cultured positive for bacteria. Initial radiographs were either normal (4 cases) or the changes seen were not sufficient to explain the degree of lameness. In the 6 cases where scintigraphy was performed, intense focal isotope uptake was found in the suspected region, which corresponded to the proximal portion of the first phalanx (2 cases), distal tibia (2 cases), or talus (3 cases). Computed tomography (CT) was performed because occult fracture or osteomyelitis was suspected; and knowledge of the precise anatomical location of the lesion was considered necessary to assess the need for surgery and to plan the surgical approach. Hypodense focal lesions with hyperdense haloes were found in the subchondral bone deep to the sagittal groove of the first phalanx (P1) (2 cases) in the cochlea of the distal tibia (2 cases), and in the intertrochlear portion of the talus (3 cases). Communication between the lesion and the joint space was demonstrated by CT in 5 cases.Post mortemexamination of one case revealed synovitis and a chronic bone abscess (Brodie's abscess) communicating with the joint space.
Hypertrophic osteopathy (Marie's disease) in Equidae: a review of twenty‐four cases
Authors: MAIR T. S. , DYSON SUE J. , FRASER J. A. , EDWARDS G. B. , HILLYER M. H. , LOVE S.
Published: April 2010

The case records of 23 horses and one donkey affected by hypertrophic osteopathy (HO) (Marie's disease) were reviewed. All affected animals presented with limb swellings, which were bilaterally symmetrical and usually involved both fore‐ and hindlimbs. Associated signs included stiffness/lameness and weight loss. Radiological features included periosteal new bone formation over the diaphyses and metaphyses of affected bones. The metacarpal and metatarsal bones were most frequently affected. Articular surfaces remained free of disease. Seventeen animals were destroyed on humane grounds, 3 horses recovered after successful treatment of the primary disease, 3 horses recovered after symptomatic treatment and one horse was lost to follow‐up. Significant primary diseases that were believed to predispose to HO were identified (pre‐ orpost mortem) in 14 cases. In each of these cases, an intrathoracic disease was identified, although co‐existing extrathoracic disease was present in 3 cases. Granulomatous inflammatory lesions were present in 9 of these 14 cases. In 4 horses, which underwent necropsy examination, no significant underlying disease was identified.
Induction of early‐phase endotoxin tolerance in horses
Authors: ALLEN G. K. , CAMPBELL‐BEGGS CINDY , ROBINSON JULIE A. , JOHNSON R J. , GREEN ELEANOR M.
Published: April 2010

Six, clinically healthy horses, of mixed age and sex, were infused via a jugular venous catheter with 100 ml of pyrogen‐free sterile saline (PFSS; 0.9% NaCl). Animals were infused withEscherichia coliO55:B5 endotoxin (total dose = 50 ng/kg bwt), 24 (LPS‐1) and 48 h (LPS‐2) after PFSS infusion. Blood was collected before, and every 15 min after, each infusion for the first 8 h and then every 2 h for the following 14 h. Clinical responses (rectal temperature, heart rate, respiration rate and blood pressure) were determined before and every 4 h after each infusion for 20 h. Geometric mean anti‐endotoxin antibody titres in serum samples, harvested just before each infusion, were unchanged over the course of the experiment. Serum tumour necrosis factor‐alpha (TNFα) activity was estimated using a cytotoxic bioassay and WEHI 164 clone 13 murine fibrosarcoma cells as targets. Mean clinical parameter values and geometric mean serum TNFα activity at given time points were compared across the 3 infusions. Both LPS‐1 and LPS‐2 resulted in elevated mean rectal temperature at 4 h after infusion. However, duration of mean rectal temperature elevation was greater (P<0.05) after LPS‐1 (through 12 h) than after LPS‐2 (through 8 h). More substantial increases in systolic and diastolic blood pressure were observed after LPS‐1 than LPS‐2 and mean systolic blood pressure after LPS‐1 was elevated at 4 h when compared to PFSS (P<0.05). Decreased systolic and diastolic blood pressures were observed at 16 h after both LPS infusions, when compared to PFSS infusion. Heart rate was increased, compared to PFSS, after both LPS‐1 (8–12 h) and LPS‐2 (4–12 h) (P<0.05). No significant elevations in mean respiratory rate were observed after either LPS‐1 or LPS‐2 when compared to PFSS. However, at 4 h post infusion, mean respiratory rate after LPS‐2 was greater (P<0.05) than that after LPS‐1. Serum TNFα activity was not detected after infusion of PFSS, but was detected after both LPS‐1 and LPS‐2. Serum TNFα activity was elevated earlier, was present in higher concentrations and persisted longer after LPS‐1 than after LPS‐2 (P<0.05). The decreased duration of fever and attenuated serum TNFα response subsequent to successive sublethal LPS challenge observed in this study support the conclusion that these horses developed early‐phase endotoxin tolerance (EPET) and, therefore, contributes to the understanding of the role of endotoxaemia in a number of clinical conditions in horses.
Rectal biopsy diagnosis in horses with clinical signs of intestinal disorders: a retrospective study of 116 cases
Authors: LINDBERG R. , NYGREN ANNICA , PERSSON S. G. B.
Published: April 2010

The histology from rectal biopsy specimens taken 1980–1990 on 131 occasions from 116 horses, age 1–18 years, with clinical signs of intestinal disease was evaluated and classified retrospectively. In 40 horses, autopsy results were studied for comparison. Biopsy specimens (21 horses) andpost mortemrectal tissue (9 horses) from 30 healthy horses, age 4–22 years, were used as controls. In 105 clinical cases, a biopsy was performed on only one occasion, while repeat biopsy was performed in 11 cases. Specimens showed pathological changes in 60 horses. The findings were classified into acute, chronic or chronic active simple proctitis, granulomatous enteritis, eosinophilic granulomatosis/gastroenteritis, eosinophilic‐proctitis, erosive/ulcerative proctitis, pseudomembranous proctitis, proctitis with vasculitis and malignant lymphoma. Mild scattered neutrophil infiltration in thelamina propriawas found in controls, but neutrophils in crypt or surface epithelia were abnormal findings. Depletion or hyperplasia of goblet cells sometimes accompanied inflammation. Simple proctitis occurred in association with malignant lymphoma and various inflammatory disorders of the gastrointestinal tract apparent at autopsy. Eosinophilic granulomatosis/gastroenteritis and granulomatous enteritis were diagnosed from biopsy specimens in 6 of 12 and 4 of 9 cases, respectively, of these diseases confirmed at autopsy. Reduction of acid mucins in goblet cells was a prominent feature of eosinophilic granulomatosis. Rectal biopsy was found to be a useful adjunct for evaluation of intestinal disease in the horse.
Endotoxin induced expression of tumour necrosis factor, tissue factor and plasminogen activator inhibitor activity by peritoneal macrophages
Authors: BARTON MICHELLE HENRY , COLLATOS CHRYSANN , MOORE J. N.
Published: April 2010

Peritoneal fluid was collected aseptically from 30 healthy adult horses and 115 horses with acute gastrointestinal disease and supernatant was separated from cells by centrifugation followed by freezing until assayed for endotoxin and tumour necrosis factor activity. Peritoneal macrophages obtained from healthy horses were incubatedin vitrofor 3, 6, 12 or 24 h in the absence (media control) or presence ofEscherichia coli055:B5 endotoxin (final concentrations of 1, 10, 100 or 1000 ng/ml). Macrophages obtained from horses with acute gastrointestinal disease were incubated for 12 h in the absence (media control) or presence of 100 ng endotoxin/ml. At the conclusion of the incubation, macrophage supernatants were collected and frozen at −70°C until analysed for tumour necrosis factor activity. Macrophage membranes were lysed and frozen at −70°C until assayed for tissue factor and plasminogen activator inhibitortype 2activity.

Compared to cells incubated with media, incubation of macrophages, obtained from healthy horses, with endotoxin significantly increased tumour necrosis factor, tissue factor and plasminogen activator inhibitortype 2activity. These increases were dependent on the endotoxin concentration and the duration of incubation. Compared to cells incubated with media alone, incubation of macrophages, obtained from horses with acute gastrointestinal disease with endotoxin, significantly increased tumour necrosis factor and tissue factor activity. Endotoxin induced tumour necrosis factor activityin vitrowas significantly less for macrophages from horses with acute gastrointestinal disease, as compared to that produced by similarly treated cells obtained from healthy horses. For those horses with acute gastrointestinal disease, macrophages obtained from horses with either endotoxin or tumour necrosis factor activity in the peritoneal fluid supernatant had significantly less endotoxin induced tumour necrosis factorin vitro, as compared to similarly treated cells obtained from horses without endotoxin or tumour necrosis factor activity in the peritoneal fluid supernatant. The results of this study indicate that exposure of equine peritoneal macrophages to endotoxin results in a significant increase in tumour necrosis factor, tissue factor and plasminogen activator inhibitortype 2activity. Afterin vitroexposure to endotoxin, there is significant down‐regulation of inflammatory mediator production by peritoneal macrophages obtained from endotoxaemic horses. These results suggest that these macrophages may exhibit early endotoxin tolerance.
Expression of types II, VI and X collagen in equine growth cartilage during development
Authors: HENSON FRANCES M. D. , DAVIES M. ELISABETH , SCHOFIELD P. N. , JEFFCOTT L. B.
Published: April 2010

The synthesis and expression of collagen types II, VI and X were investigated in growth cartilage selected from a group of 31 horses and ponies in the age range 157 days of gestation to 12 years. Collagen isolation, immunolocalisation and in situ hybridisation techniques were used in order to provide information on the pattern of synthesis of these 3 collagens during endochondral ossification in normal horses. Type II collagen immunoreactivity and mRNA expression was found in each of the 3 zones of growth cartilage chondrocytes in all samples studied, whereas the localisation of both collagen types VI and X varied during cartilage development Type VI collagen in the fetus was present only in the resting and upper proliferative zones and around the cartilage canal blood vessels in both articular/epiphyseal and metaphyseal cartilage, whereas in animals age >2 years it was present throughout all the cartilage studied. Type X collagen immunoreactivity and mRNA expression was detected only in the late hypertrophic zone in articular/epiphyseal cartilage in animals age <6 months and in metaphyseal cartilage in animals <12 months.

These results demonstrated the presence of collagen types VI and X in equine cartilage for the first time. In addition, the pattern of expression of type II mRNA in the cartilage has been established and type VI and X collagens have been shown to differ in their expression during development of the skeleton.