bluuebunny/crossref_metadata_2025_split huggingface dataset:
Muscle characteristics in Standardbreds of different ages and sexes
Authors: RONÉUS MERIKE 
Published: April 2010

SummaryBiopsy samples were taken from the middle gluteal muscle in 107 healthy Standardbred horses. The horses were separated according to sex and divided into 4 age groups (1, 2, 3 and 4–6 years). The proportion of Type I fibres increased with age (from 16 to 20%), irrespective of sex. The proportions of Type IIA and IIB fibres varied with age and differed between stallions and mares. Type IIA fibres increased in mares from 37 to 47% and in stallions from 40 to 48% and Type IIB fibres decreased from 49 to 34% in mares, and from 43 to 30% in stallions. Mares and stallions did not differ in enzyme activities, which changed with age. The activity of citrate synthase increased from 30 to 62 mmol/kg/min and that of lactate dehydrogenase decreased from 1,930 to 1,565 mmol/kg/min. The relative area of each fibre type was measured in biopsy samples from 7 mares and 7 stallions aged 1 year and 7 mares and 11 stallions aged 4–6 years. The relative areas of Type IIA and IIB fibres changed with age and differed between sexes. The relative area of Type IIA fibres increased in mares from 30 to 35% and in stallions from 33 to 47% and that of Type IIB fibres decreased in mares from 63 to 54% and in stallions from 55 to 38% between the ages of 1 and 4–6 years. This study shows that age influences enzyme activities, the relative number of Type I fibres, the Type IIA/IIB fibre ratio and the relative areas of Type IIA and IIB fibres in the middle gluteal muscle of Standardbreds. It also shows that stallions have a higher Type IIA/IIB fibre ratio and a higher relative area of Type IIA fibres and a smaller relative area of Type IIB fibres compared with mares.
Effect of stabling on bronchoalveolar cells obtained from normal and COPD horses
Authors: TREMBLAY G. M. , FERLAND CLAUDINE , LAPOINTE J.‐M. , VRINS A. , LAVOIE J. P. , CORMIER YVON 
Published: April 2010

SummaryBronchoalveolar lavages (BAL) were performed before and after 3 weeks of housing in 5 horses suffering from COPD and 5 normal horses. In the two groups, the total number of cells recovered remained unchanged after stabling. The most common cell populations in BAL fluid of control animals were alveolar macrophages (46.4%) and lymphocytes (44.9%). The percentage of neutrophils increased after stabling from 8.7% to 27.6%. In COPD horses, lymphocytes predominated (40.7%) in animals at pasture with neutrophils increasing from 29.4% to 71.6% after stabling. After fractionation by Percoll density gradient, alveolar macrophages and neutrophils from normal and COPD horses had a similar density distribution. After stabling, these cells from normal horses were increased in the low density layers, while those from COPD horses were predominantly in the hyperdense layers. Therefore, BAL cells obtained from COPD animals at pasture and after stabling differ from those of control horses in the same environment, not only in their populations but also in their buoyant densities. These differences could be related to different states of cellular activation and perhaps be responsible for disease activity in the COPD horses.
Clinical and pathological features of thoracic neoplasia in the horse
Authors: MAIR T. S. , BROWN P. J. 
Published: April 2010

SummaryThirty‐eight horses with confirmed thoracic neoplasia included 28 (37.7%) with lymphosarcoma, 4 (10.5%) with metastatic renal cell carcinoma, 2 (5.3%) with primary lung carcinoma, 2 (5.3%) with secondary squamous cell carcinoma from the stomach, 1 (2.6%) with pleural mesothelioma, and 1 (2.6%) with malignant melanoma.The major clinical features included weight loss, inappetence, dyspnoea and coughing, but in cases of lung metastases, they related more to the primary site of tumour formation. Haematological and serum biochemical abnormalities were non‐specific. Specific pre‐mortem diagnosis was made in 14 horses; this was most readily achieved when exfoliated neoplastic cells were present in pleural fluid.
Clinical syndrome and diagnosis of hyperkalaemic periodic paralysis in Quarter Horses
Authors: NAYLOR J. M. , JONES V. , BERRY S‐L. 
Published: April 2010

SummaryOf the 16 horses studied, 14 belonged to a family previously shown to be susceptible to hyperkalaemic periodic paralysis (HPP), and 8 were shown to have HPP. Diagnosis of HPP by electromyographic detection of myotonic discharges or by oral administration of KCl to induce clinical signs and hyperkalaemia had similar reliability and gave the same result in 80% of cases. KCl had to be administered at doses up to 0.2 g/kg bodyweight to produce signs in some horses. KCl challenge testing was more time consuming than EMG and resulted in one fatality. Overall, electromyography and potassium challenge testing together gave the most accurate diagnosis. Horses were more likely to manifest signs of HPP if they were immature. There was no sex predisposition. The most frequent sign of HPP was muscle fasciculation. Other signs were sweating, muscle spasm, and weakness. Respiratory rate increased greatly during some attacks. Attacks of muscle fasciculation without hyperkalaemia were observed in 2 HPP‐affected horses. Affected horses had a greater frequency of spontaneous clinical abnormalities, due mainly to trailering problems, traumatic abrasions and episodes of continuous muscle fasciculation. Hyperkalaemia was confirmed in only one of these instances.
Responses of horses affected with chronic obstructive pulmonary disease to inhalation challenges with mould antigens
Authors: McGORUM B. C. , DIXON P. M. , HALLIWELL R. E. W. 
Published: April 2010

SummaryEight control and 8 asymptomatic COPD‐affected horses were given, on separate occasions, inhalation challenges with extracts ofMicropolyspora faeni, Aspergillus fumigatusandThermoactinomyces vulgaris. All horses were also given nebulised phosphate‐buffered saline (PBS) challenges and ‘;natural challenges’ (NCs), i.e. exposure to hay and straw, as control challenges. Responses were assessed by clinical, pulmonary mechanics, arterial blood gas tensions, arterial blood pH and bronchoalveolar lavage fluid cytological examinations.PBS challenges had no effect on control or COPD‐affected horses, while NC induced COPD only in the COPD‐affected horses. Pulmonary disease, similar to naturally occurring COPD, was induced, only in the COPD‐affected horses, byM. faeniandA. fumigatuschallenges, thus implicating these organisms in the aetiology of equine COPD. The role ofT. vulgarisin the aetiology of equine COPD could not, however, be determined because theT. vulgarischallenges, in addition to inducing pulmonary disease in 4 COPD‐affected horses, induced pulmonary disease in 2 control horses which had been unaffected by NC.The absence of pulmonary disease in control horses afterM. faeni, A. fumigatusand NC challenges suggests that equine COPD is a pulmonary hypersensitivity, rather than a non‐specific toxic response.
Clinical pharmacokinetics of amikacin in hypoxic premature foals
Authors: GREEN SHERRIL L. , CONLON P. D. 
Published: April 2010

SummaryThe pharmacokinetics of amikacin, administered iv at 7 mg/kg, every 8 h, were evaluated over the first 48 h of hospitalisation in 7 critically ill hypoxic premature foals and compared with those in 8 full‐term nonhypoxic critically ill neonatal foals. The pharmacokinetic data were used to calculate dosage schedules that would maintain the plasma amikacin concentrations in individual foals within a target range of ≥15 μg/ml but <30 μg/ml for peak values and ≤3 μg/ml for trough values. The results indicated a statistically significant increase in the amikacin serum half‐life (5.39 ± 3.46 h) and smaller elimination rate constant (0.17 ± 0.09 h−1) in premature foals. The pharmacokinetic derangements required increasing the dose to 8.5–10.5 mg/kg bwt in 6 of 7 premature foals and an increase in the dosage interval to 12–24 h in all 7 foals. Overall, the total dosage of amikacin was decreased in the hypoxic, premature foals so that target peaks and troughs could be maintained.Our findings suggest that prematurity and hypoxia are variables related to a prolonged serum half‐life of amikacin in hypoxic, premature foals. Although there was no evidence of amikacin‐induced nephrotoxicity in any of these foals, daily monitoring and tailoring of the dose schedule to the individual foal are strongly advised.
Cardiovascular effects of thoracic compression in horses subjected to euthanasia
Authors: HUBBELL J. A. E. , MUIR W. W. , GAYNOR J. S. 
Published: April 2010

SummarySix horses scheduled for euthanasia were instrumented for the measurement of blood flow by thermodilution, pulmonary arterial, right atrial and arterial blood pressures and collection of arterial blood for pH and blood gas analysis. The horses were anaesthetised with intravenous (iv) thiamylal sodium (10 mg/kg) and placed in right lateral recumbency. After euthanasia with an overdose of pentobarbitone sodium (100 mg/kg, iv) and loss of the electrocardiogram and arterial pulse pressure, thoracic compression at rates of 40, 60 and 80 compressions/min was instituted. Thoracic compression was accomplished by an investigator who delivered a blow to the chest wall with his knee while dropping from a standing or crouching position. Compression rates of 40, 60 and 80/min produced blood flows of 5.65 ± 0.5, 6.33 ± 1.11 and 8.28 ± 2.16 litres/min, respectively. Compression rates of 80/min produced significantly (P<0.05) greater blood flows and mean arterial blood pressures than did slower rates. The blood flows produced by 80 thoracic compressions/min were approximately 50% of those reported for deeply anaesthetised horses and while not sufficient to sustain life might be used to prolong life in order to facilitate distribution of resuscitative drugs to vital tissues.
Characterisation of osseous bodies of the distal phalanx of foals
Authors: KANEPS A. J. , O'BRIEN T. R. , REDDEN R. F. , STOVER S. M. , POOL R. R. 
Published: April 2010

SummaryThe distal phalanx and metacarpal physis of both forelimbs of 32 Thoroughbred foals 3–32 weeks of age were radiographed to identify those limbs with osseous bodies at a palmar process (PP) of the distal phalanx. Osseous bodies (ossicles) were identified radiographically in 19% of the foals. Sixteen of the 32 foals were selected for microradiographic and histological evaluation: 6 foals with radiographic evidence of ossicles and 10 foals without. Fourteen ossicles of the PP were observed radiographically. Ossicles were either a triangular bone fragment at the palmar aspect of the distal angle of the PP, or an oblong bone fragment separated from P3 by a radiolucent line extending 1–3 cm from the incisure of the PP to the solar margin. One foal had radiographic evidence of bilateral distal metacarpal physitis.Seventeen of 35 PPs examined microradiographically were considered normal, in that the dorsal and solar cortices were thin with trabecular bone orientated parallel to the cortical surfaces, and there was a depression in the dorsal cortical surface (i.e. parietal sulcus). Abnormal microradiographic findings in the other 18 PPs included a fracture line extending from the dorsal cortical surfaces and trabecular bridging of the fracture gap. The fracture line was often continuous with the parietal sulcus. Microradiographic evidence of a fracture was found in 75% of foals evaluated.Normal histological findings in 16 PPs included thin dorsal and solar cortices with trabeculae orientated parallel to the cortical surfaces, parallel‐fibred dense connective tissue attachments of the deep digital flexor tendon to the solar cortical surface, and a neurovascular bundle associated with the parietal sulcus. Abnormal histological findings of the other 20 PPs included: a fracture line extending from the dorsal to solar cortical surfaces, trabecular bridging of the fracture gap, and fibrocartilage which was within the fracture gap and orientated parallel to the longitudinal axis of the gap. Histological findings consistent with a fracture were found in 69% of foals evaluated.It was concluded that ossicles of the PP in foals 3–32 weeks of age are fractures, not all of which are visible radiographically.
The airway response of horses with recurrent airway obstruction (heaves) to aerosol administration of ipratropium bromide
Authors: ROBINSON N. E. , DERKSEN F. J. , BERNEY C. , GOOSSENS L. 
Published: April 2010

SummaryThe airway response to aerosol administration of the anticholinergic agent ipratropium bromide was determined in 8 horses with recurrent airway obstruction (heaves). The reversibility of airway obstruction was confirmed by measuring lung function before and during stabling; and by determining the response to atropine administration (0.02 mg/kg bwt intravenously). The dose‐response to ipratropium bromide was determined using a Williams square design experiment in which 25, 50 or 75 μg ipratropium bromide/ml (4 ml/100 kg bwt) or the same volume of vehicle was administered to each horse by nebulisation. Lung function was measured before and 1 and 4 h after nebulisation. Vehicle had no effect on lung function. Ipratropium decreased the maximal change in pleural pressure during tidal breathing (ΔPplmax) and pulmonary resistance (RL) and increased dynamic compliance (Cdyn). At the 1 h measurement period, the effect on RLand Cdynwas dose‐dependent. A separate experiment demonstrated that the duration of action of ipratropium was between 4 and 6 h.
Paravertebral thoracolumbar anaesthesia in 10 horses
Authors: MOON PAULA F. , SUTER C. M. 
Published: April 2010

SummaryThe caudal border of the last rib was used as a reliable point of orientation while performing paravertebral thoracolumbar anaesthesia (PTLA) on 10 horses undergoing standing flank laparotomy. The local anaesthetic in all horses was 2% lidocaine. The PTLA procedure was completed in 9.8±1.8 mins (mean ± sd). Sedation was provided by a combination of intravenous morphine with xylazine or detomidine. Overall analgesia, provided by the combination of PTLA and sedation, was rated as excellent in 2 horses and good in 6 horses. In the remaining 2 horses, overall analgesia was rated as fair because of incomplete analgesia at the ventral portion of the incision. Total time, from start of PTLA to end of surgery was 143.5±24.2 mins. Five horses responded mildly to suturing of the ventral portion of the incision. Apart from 1 horse which developed transient, unilateral hindlimb weakness intraoperatively, no other complications were noticed. We conclude that PTLA can easily be performed in the horse and, combined with systemic sedation, is an effective and safe method of providing analgesia for standing flank laparotomy.
In‐vitro susceptibility to antimicrobial drugs of bacterial isolates from horses in The Netherlands
Authors: ENSINK J. M. , VAN KLINGEREN B. , HOUWERS D. J. , KLEIN W. R. , VULTO A. G. 
Published: April 2010

SummaryMinimum inhibitory concentrations (MICs) of 30 antimicrobial agents (including the hitherto unreported antimicrobial agents doxycycline, minocycline, vanomycin, 3 quinolones and 3 combinations of antimicrobial agents) for isolates ofSalmonellaspp. (20),Escherichia coli(17),Klebsiellaspp. (8),Proteusspp. (7),Pseudomonas aeruginosa(7),Actinobacillus equuli(5),Rhodococcus equi(4),Streptococcus zooepidemicus(23),Streptococcus equisimilis(6),Streptococcus equi(4), coagulase‐positiveStaphylococcusspp. (20) andTaylorella equigenitalis(19) were determined using the agar dilution method. All isolates were of equine origin.MICs were compared with recommended MIC breakpoints. The results indicate that, for some of the pathogenic bacteria evaluated, susceptibility testing of isolates from the individual patient is essential to determine an appropriate antimicrobial treatment.
Measurement of 24‐h gastric pH using an indwelling pH electrode in horses unfed, fed and treated with ranitidine
Authors: MURRAY M. J. , SCHUSSER G. F. 
Published: April 2010

SummaryA glass combined pH‐reference electrode was placed in the stomachs of 5 adult horses and pH was recorded every 6 mins for 24 h while (1) feed and all bedding materials were withheld for 24 h (unfed), (2) horses had free access to Timothy grass hay for 24 h (fed), and (3) horses had free access to Timothy grass hay and were treated with ranitidine, 6.6 mg/kg body weight, orally, every 8 h for 48 h (fed + ranitidine). There was a significant (P= 0.007) difference in median 24‐h gastric pH amongst the 3 protocols, the value being 3.1 in fed horses and 1.55 in unfed horses (P= 0.05) and 4.6 in fed + ranitidine horses (P= 0.05 compared with fed horses).The percentage of pH readings <2.0 was significantly greater (P= 0.05) in unfed (76%) than in fed (30%) horses, and in fed horses than in fed + ranitidine (9%) horses. The percentage of readings >2.0, 3.0, 4.0, 5.0 and 6.0 were each significantly (P= 0.05) greater in fed + ranitidine horses than in fed horses, and in fed than in unfed horses. There was no difference (P= 0.13) between median gastric pH values from different times of day in unfed horses (00:00 to 06:00 h, 1.5; 06:00 to 12:00 h, 1.6; 12:00 to 18:00 h, 1.7; and 18:00 to 24:00 h, 1.5).We conclude that gastric acidity is greatest when horses do not have access to feed material and that ranitidine effectively suppresses gastric acidity in horses under conditions of free access to hay.
Retrospective analysis of the results of 151 exploratory laparotomies in horses with gastrointestinal disease
Authors: PHILLIPS T. J. , WALMSLEY J. P. 
Published: April 2010

SummaryOf 149 horses that underwent 151 exploratory laparotomies for gastrointestinal disorders from September 1987 to May 1991, 107 (72%) were discharged from the hospital: 100 (66%) survived for >7 months, 94 of which returned to their intended use. Survival rate (64/80) for horses with caecum/large colon obstruction was significantly (P=0.003) higher than for horses with small intestinal obstruction (33/64). Prolonged surgery was associated with significantly (P<0.001) lower survival rates than short surgical time. In the large intestine, survival rate (15/29) for strangulated obstructions was significantly (P<.0.001) lower than for simple obstructions (52/58). Generalised septic peritonitis (9 horses) and bowel obstruction associated with adhesions (8 horses) were the most frequent fatal post‐operative complications. The rate (6/44) of post‐operative adhesions after small intestinal obstruction was significantly (P=0.006) higher than that (2/68) following large intestinal obstruction. The rate (8/55) of post‐operative adhesion formation in horses that required enterotomy/enterectomy was significantly (P=0.003) higher than that (0/57) in horses that did not require gut wall incisions. Incisional suppuration developed in 42 horses and occurred with a significantly (P=0.028) higher rate (32/72) after caecum/large colon lesions than after obstruction at other sites, (10/42) but was not associated with known contamination at the time of surgery (P=0.806).
Diagnosis and prediction of cervical vertebral malformation in Thoroughbred foals based on semi‐quantitative radiographic indicators
Authors: MAYHEW I. G. , DONAWICK W. J. , GREEN S. L. , GALLIGAN D. T. , STANLEY E. K. , OSBORNE J. 
Published: April 2010

SummaryOver a period of 5 years on a central Kentucky Thoroughbred stud farm 132 foals were evaluated for the presence of cervical vertebral malformation (CVM). Lateral cervical vertebral radiographs were obtained on 70 standing foals. These radiographs were evaluated semi‐quantitatively and scored numerically for the presence of stenosis of the vertebral canal, enlarged physeal growth plates, caudal extension of the dorsal border of the orifice of the vertebral canal, angular fixation, delayed ossification of bone and degenerative joint disease. From these scores a total CVM score was given for each set of radiographs. All foals were repeatedly examined for clinical signs of neurological disease. Foals with no clinical signs of CVM had maximal total CVM scores (mean ± sd) of 5.7 ± 2.8 and foals affected with CVM had maximal total CVM scores of 17.0 ± 2.8. Determination of the total CVM score was non‐invasive, inexpensive and a very accurate procedure for predicting and diagnosing the presence of CVM in Thoroughbred foals up to 1 year of age.
Correlation of racing performance with blood lactate and heart rate after exercise in Thoroughbred horses
Authors: EVANS D. L. , HARRIS R. C. , SNOW D. H. 
Published: April 2010

SummaryAt 2 and 5 mins after an 800‐m gallop, venous blood was collected from 26 Thoroughbred racehorses for measurement of blood lactate concentration, packed cell volume (PCV) and haemoglobin concentration. In addition, 14 racehorses were given a strenuous submaximal treadmill exercise test. Heart rates during and after exercise at 10 m/sec on a treadmill inclined at 5° were recorded. Blood samples at 2 and 5 mins after exercise were used to measure PCV, blood and plasma lactate and ammonia concentrations. Results of each exercise test were compared with the retrospective performance of horses in races, using Timeform ratings. The results of the field tests were also compared with the performance of each horse in a race 2 days later.There were no significant correlations between any of the measurements taken after the Field test and either subsequent race performance or Timeform rating. Heart rate 4 mins after treadmill exercise was significantly correlated with Timeform rating (r =−0.565, P<0.05). Blood and plasma lactate concentrations 2 and 5 mins after treadmill exercise were all significantly correlated with Timeform. The highest correlations were with blood lactate concentrations 2 and 5 mins after exercise (r =−0.68, P < 0.01). There were no significant correlations between Timeform and heart rate during exercise at 10 m/sec, heart rates at 1, 3 and 5 mins after exercise, PCV and plasma ammonia at 2 and 5 mins, or the differences between lactate concentration in plasma or blood at 2 and 5 mins after exercise. It is concluded that the quality of Thoroughbred race performance is significantly correlated with the blood lactate concentration after strenuous submaximal treadmill exercise.
Immunocytochemical and lectin histochemical study of neuronal lesions in autonomic ganglia of horses with grass sickness
Authors: GRIFFITHS I. R. , KYRIAKIDES E. , SMITH S. , HOWIE F. , DEARY A. W. 
Published: April 2010

SummaryEquine grass sickness (EGS) is a primary dysautonomia characterised pathologically by lesions in autonomic ganglia, enteric plexi and specific nuclei in the CNS. Immunocytochemistry and lectin histochemistry of the autonomic ganglia were used to determine whether abnormalities can be detected in specific proteins or cellular organelles. EGS ganglia contained a mixture of morphologically normal and abnormal neurons, the former appearing identical to cells from control animals. Affected cells showed marked disturbances in neurofilament (NF) proteins and β‐tubulin, major components of the cytoskeleton; in most neurons immunoreactivity was reduced or absent while the distribution was altered in the remainder. Staining for neuron‐specific enolase, a pan‐neuronal marker, was severely reduced or absent, as was reactivity for the catecholaminergic enzyme tyrosine hydroxylase. However, affected neurons showed a marked increase in dopamine‐β‐hydroxylase (DβH), another enzyme associated with noradrenaline synthesis. Wheat germ agglutinin and Griffonia simplicifolia B4 lectin histochemistry was used to label membranes of the Golgi apparatus, which stained as discrete curvilinear perinuclear profiles. All affected neurons showed abnormalities with either complete loss of reaction or amorphous centrally located lectin staining.The results indicate perturbation in a wide variety of cytoplasmic and cytoskeletal proteins. In the majority of instances there is a decrease in stainable protein; the increase in DβH may indicate a failure to be transported down the axon with resultant accumulation in the perikaryon. Loss of a recognisable Golgi structure appears to be an early event in the neuropathology of EGS.