bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary molybdenum as a putative copper antagonist in the horse
Authors: STRICKLAND K. , SMITH F. , WOODS M. , MASON J.
Published: April 2010

Four horses were stabled and fed a diet of hay ad libitum, and 2 kg oats per animal per day, for a month. The basic diet was then supplemented with molybdenum, at a rate of 20 mg/kg dry matter for 4.5 months. For one month of this period the diet was supplemented also with sulphur at a rate of 1.2 g/kg dry matter. Analyses of jugular blood samples, obtained at intervals varying between two and 20 days, showed no evidence of a decline in total plasma copper or of an increased proportion of trichloroacetic acid (TCA) insoluble copper in plasma over this period. In separate studies, two other horses were given “molybdenum (molybdate, 20 to 28 mg Mo, 4 mCi per animal) per os, initially while being fed the basic diet and later while maintained on the molybdenum supplemented diet. 99Molybdenum appeared rapidly in plasma, but the radioactivity was then quickly cleared (half‐life 7 to 10 h). The 99molybdenum present was identified as (99Mo)‐molybdate. There was no evidence of the persistent, protein‐bound (99Mo)thiomolybdates which appear in ruminants. These studies indicate that increased dietary molybdenum is unlikely to interfere with copper metabolism in horses.
Use of a novel non‐steroidal anti‐inflammatory drug in the horse
Authors: HIGGINS A. J. , LEES P. , SEDGWICK A. D. , BUICK A. R. , CHURCHUS R.
Published: April 2010

In a two‐part cross‐over experiment in six ponies, an acute inflammatory reaction was generated by injecting carrageenin solution into subcutaneously‐implanted tissue‐cages lined with fibrovascular granulation tissue. In each part of the cross‐over, half of the ponies received a novel phenylpyrazoline antiinflammatory agent (BW540C) orally and half received a placebo treatment. BW540C inhibited platelet cyclo‐oxygenase for 24 h but the reductions in exudate eicosanoid concentrations were less pronounced. A significant suppression in the rise of surface skin temperature in BW540C‐treated ponies paralleled drug‐induced inhibition of thromboxane B2 bicyclic prostaglandin (PG) E2 concentrations at the inflamed site. The drug had no significant effect on 6‐keto‐PGF1α, migrating leucocytes, lactate dehydrogenase or total protein in exudates. Maximum plasma concentrations of both compounds occurred 2 to 4 h after dosing and maximum exudate levels of drug and metabolite occurred at 12 h. Both compounds penetrated approximately three times less readily into exudate than into plasma.
Qualitative aspects of the incorporation of equine cancellous bone grafts
Authors: KOLD S. E. , HICKMAN J. , MELSEN F.
Published: April 2010

The incorporation of autogenous cancellous bone graft was studied in eight yearling ponies. The site for the defect to be grafted was chosen so that the effect on the graft, of both the host cortical and trabecular bone, could be assessed. To obtain information concerning the vitality of the graft and the dynamic aspects of the modelling and remodelling processes of graft incorporation, a double and treble tetracycline intravital labelling technique was used. Radiographs of the graft and host tissues of all ponies were obtained regularly, but were of little assistance in assessing graft incorporation. The ponies were destroyed humanely at regular intervals between nine and 241 days after installation of the graft, followed by histological examination of undecalcified sections. The study revealed that all installed graft trabeculae showed signs of non‐vitality at nine days after installation and gradually disintegrated. Two processes of new bone formation were observed. First, finger‐like projections of immature new trabeculae were found to originate from the graft/host interfaces. Second, a gradual process of accretion of osteoid and woven bone upon disintegrating graft trabeculae occurred uniformly throughout the graft. The graft adapted to the structure of opposing host bone by corticalisation and trabecularisation. The present study confirmed clinical observations relating to convalescence time following grafting of large osseous defects in horses and indicated that equine bone reacts to autogenous bone grafts in a similar manner to other mammals.
Preliminary study of quantitative aspects and the effect of pulsed electromagnetic field treatment on the incorporation of equine cancellous bone grafts
Authors: KOLD S. E. , HICKMAN J. , MELSEN F.
Published: April 2010

The quantitative aspects of equine cancellous bone graft incorporation and the possibility of influencing graft incorporation by daily exposure to a pulsed electromagnetic field (pemf) was studied in eight yearling ponies. In order to be able to quantify formative aspects of graft remodelling, a double and treble tetracycline intravital labelling technique was used. Intravital radiographs were obtained at regular intervals throughout the trial, but were found to be of little assistance in assessing any differences between stimulated and non‐stimulated grafts. The ponies were humanely destroyed at regular intervals between nine and 241 days after installation of the graft. Light microscopy and fluorescent light microscopy were used to evaluate quantitative aspects of graft incorporation and to compare pemf‐stimulated grafts with control grafts. There was a small but statistically significant effect of pemf‐stimulation on cancellous bone graft incorporation. In view of this, these observations can only be considered as indicative of a possible trend, but should encourage further studies using different signal modalities.
Social relationships in a herd of 11 geldings and two female ponies
Authors: WOOD‐GUSH D. G. M. , GALBRAITH FRANCES
Published: April 2010

The social behaviour of a small herd of 10 Exmoor geldings, two Exmoor mares and one Highland pony gelding was studied in order to see whether any specific associations existed between ponies and, if so, whether these applied to all or only some of the ponies' main activities of grazing, eating hay and sleeping. Such relationships were found but only in a small number of cases did they apply to all activities. The results are discussed in relation to the individual histories of these ponies and in relation to the welfare of horses.
Specific serum protein changes associated with primary and secondary Strongylus vulgaris infections in pony yearlings
Authors: KENT JOYCE E.
Published: April 2010

The concentrations of haptoglobin, immunoglobin (Ig)G(T) and IgG were measured in the serum of four previously parasite‐free pony yearlings following a single dose of 700 (Group H) or 200 (Group L) stage three Strongylus vulgaris larvae (L3) and following a reinfection with the same doses 34 weeks later. The results are compared with an uninfected control pony. The haptoglobin concentration increased during Weeks 1 to 6 and 14 to 17 after infection in the serum of the ponies receiving 200 L3, but in only one pony dosed with 700 L3 (during Weeks 1 to 16). The serum haptoglobin also increased during the first seven weeks after the second infection, in three of the four ponies following the second dose of larvae. The serum IgG(T) concentration started to increase from Week 6 or 9 in the ponies given 700 L3, reaching peaks of 44 and 32 g/litre respectively, eight to nine weeks later, compared with a peak of 16 g/litre 20 to 22 weeks after infection in ponies dosed with 200 L3. The IgG(T) concentration increased to a maximum of 25 g/litre in the serum of only one of the four ponies after the reinfection. The serum IgG concentration in all ponies increased nearly twofold during the first eight weeks after both the primary and secondary dose of larvae. It is concluded that the measurement of specific proteins is more reliable and quicker than the electrophoretic separation and quantitation of protein bands, in tracing changes in serum proteins following the artificial infection of ponies with S vulgaris larvae.
Control of breeding in the mare
Authors: COLQUHOUN K. M. , ECKERSALL P.D. , RENTON J. P. , DOUGLAS T. A.
Published: April 2010

Six mares were studied over a period of two years under varying conditions of lighting from total darkness to normal ambient lighting. The mares continued to cycle during the winter under natural lighting and also when kept in total darkness. Circulating melatonin, progesterone and oestrogen concentrations were determined and related to clinical changes in the reproductive tract.
Exercise‐induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. II. Gross lung pathology
Authors: O'CALLAGHAN M. W. , PASCOE J. R. , TYLER W. S. , MASON D. K.
Published: April 2010

Gross post mortem examinations were performed on the lungs of 26 Thoroughbred horses of known exercise‐induced pulmonary haemorrhage (EIPH) status. The most consistent finding was a variable degree of bilaterally symmetrical, dark discolouration of the dorsocaudal regions of the caudal lung lobes. In more severely affected lungs, the stained areas extended cranially along the dorsal surfaces of the lungs, and in some cases affected approximately one third of the lung surface. Discoloured areas of lung were denser than normal, collapsed less readily, often contained trapped air and were slow to inflate. The subpleural bronchial arteries were more prominent in the discoloured regions. Pleural adhesions were noted in two horses but were not related to the discoloured lung regions. It was concluded that the discoloured lesions have a complex pathogenesis and were related directly to previous bouts of EIPH. Associated with them were signs indicating probable partial small airway obstruction, decreased tissue compliance and direct involvement of the bronchial arterial circulation.
Exercise‐induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. V. Microscopic observations
Authors: O'CALLAGHAN M. W. , PASCOE J. R. , TYLER W. S. , MASON D. K.
Published: April 2010

Lungs from 19 Thoroughbred racehorses with a history of exercise‐induced pulmonary haemorrhage (EIPH) were studied using several forms of microscopy. Light microscopy of paraffin sections revealed three lesions in the caudodorsal region of the lungs from each horse. These correspond with the location of blue to brown stains seen at necropsy. These lesions include sequelae of bronchiolitis, hemosiderophages and increased connective tissue. Much of each of the lungs appeared normal, especially the more cranial or ventral portions. Foci of eosinophil infiltration were found in seven of the 19 lungs examined. With two exceptions, these eosinophilic foci had a different distribution to the three lesions. In areas of severe bronchiolar changes and fibrosis, vascular lesions typical of hypertension were found occasionally. Transmission electron microscopy was used to confirm cell types seen by light microscopy and to examine arterioles for changes characteristic of neovascularisation. Areas of enlarged airspaces from the vascular injected right lungs were examined by scanning electron microscopy. The balance of fibrosis and destruction varied in these areas, but none were as extensive as those seen in chronic obstructive pulmonary disease. The authors hypothesise that bronchiolitis and related neovascularisation are essential components of the aetiology of EIPH.
Exercise‐induced pulmonary haemorrhage in the horses: results of a detailed clinical, post mortem and imaging study. VII. Ventilation/perfusion scintigraphy in horses with EIPH
Authors: O'CALLAGHAN M. W. , HORNOF W. J. , FISHER P. E. , PASCOE J. R.
Published: April 2010

Detailed post mortem examination of the lungs of horses with exercise‐induced pulmonary haemorrhage (EIPH) has demonstrated significant small airway disease and intense bronchial arterial proliferation in the dorsocaudal lungfields. The purpose of this study was to investigate ventilation and perfusion distribution in the lungs of a similar group of horses to compare changes in the live animal with the previously reported post mortem findings. Thoracic radiography and ventilation/perfusion (V/Q) scintigraphy were performed on five racing Thoroughbreds with recent histories of EIPH. Parametric images of V/Q ratios for left and right lungfields were also generated from the scan images. In all horses, ventilation and perfusion deficits were demonstrated in the dorsocaudal areas of the lung corresponding closely to the observed radiographic lesions. In particular, the perfusion images and V/Q ratio displays indicated that, in affected areas of lung, pulmonary arterial perfusion was the more seriously impaired. This finding appears to confirm the post mortem evidence of reduced pulmonary arterial perfusion and bronchial arterial dominance in these areas. Ventilation deficits in the same areas also confirmed the likelihood of partial airway obstruction consistent with the small airway disease noted in previous post mortem observations. These results suggest that the vascular and airway lesions demonstrated in detailed post mortems of horses with EIPH are also functionally important in affected horses, even at rest. As a consequence of the apparent persistent, insidious and progressive nature of the lesions associated with EIPH there are serious long term implications for management of the condition.
Technique for assessing respiratory health hazards from hay and other source materials
Authors: CLARKE A. F. , MADELIN THERESA
Published: April 2010

This paper describes and compares three techniques of categorisation of hay, straw and other feeds and beddings collected from stables. A hand‐held sampler was used to categorise samples according to the presence of plant material, fungal spores and dust mites. An Andersen sampler was used to categorise samples according to the thermotolerances of fungi and actinomycetes. An aerodynamic particle sizer was used to categorise samples according to respirable particle release rates. The highest burden of respirable particles was associated with the presence of thermophilic and thermotolerant actinomycetes and fungi. The portable slit sampler proved to be an accurate, quick and simple semiquantitative method of assessing the mould contamination of source materials. This latter technique requires only a microscope and the sampler, and is thus ideal for veterinary practices and small diagnostic laboratories.
Survey of the designs of racehorse stables in the south west of England
Authors: JONES R. D. , McGREEVY P. D. , ROBERTSON A. , CLARKE A. F. , WATHES C. M.
Published: April 2010

The design of 96 racehorses stables in the south west of England were surveyed. The ‘typical’ racehorse is kept in a loose box, bedded on straw and remains indoors while the stable is cleaned. It is given a floor area of 12 m2 and shares its airspace of 39 m3 with seven other horses. Overall, the predicted minimum rate of air change by natural convection in calm winds is 6.6 air changes/h but this is reduced to 2.2 if the top door of the stable is closed. On balance, racehorse stables in use today are based on designs which are worse overall than the best available in the 19th century.
Radiographic examination of the facial, nasal and paranasal sinus regions of the horse: I. indications and procedures in 235 cases
Authors: LANE J. G. , GIBBS CHRISTINE , MEYNINK SARAH E. , STEELE FIONA C.
Published: April 2010

The radiographic procedures used for examination of the facial area and paranasal sinuses of 235 horses are reported. Clinical indications for these examinations and the diagnoses made are reviewed. Unilateral nasal discharge was the commonest reason for radiography, accounting for about one third of cases, most of which had radiological signs of paranasal sinus disease recognisable on erect lateral films. Oblique projections were required to obtain further information about the maxillary dental arcades and ventro‐dorsal views demonstrated sinus expansion and extension of disease into the nasal cavity. In 24 horses with bilateral nasal discharge, the origin was usually shown to be in the lower respiratory tract and radiographic abnormalities were found in only 20 per cent of cases. Facial swelling was a feature of 25 per cent of cases; the commonest causes were premolar periapical disease, best shown on oblique views with the patient recumbent, and suture periostitis, easily demonstrated on erect lateral films. Other causes of facial swelling, which required multiple radiographic projections for evaluation, were sinus cysts and tumours and peripheral soft tissue masses. Epistaxis for which no cause could be found in the lower respiratory tract was the indication for radiography in a further 10 per cent of cases. In almost half of these a radiopaque shadow representing an ethmoid haematoma could be seen on an erect lateral film. A sinus cyst and a tumour were also recorded but most other causes of epistaxis failed to produce radiographic signs. Radiography contributed to determining the cause of nasal airway obstruction in the majority of 13 cases and was also useful in evaluating radicular involvement in animals with gross visible dental crown defects and discharging sinus tracts. Contrast medium was used to delineate atretic nasolacrimal ducts in horses with epiphora. Of 13 cases with facial trauma six presented with epistaxis and/or facial deformity and the remainder had developed complications as a result of injury and were showing signs of nasal discharge, obstruction or facial swelling. Radiography of 24 horses with behavioural or neurological disturbances was consistently unrewarding.
Radiographic examination of the facial, nasal and paranasal sinus regions of the horse. II. Radiological findings
Authors: GIBBS CHRISTINE , LANE J. G.
Published: April 2010

The radiographic findings in 167 horses subjected to radiography of the facial area, nasal cavity and paranasal sinuses are recorded. Cases were grouped according to clinical diagnosis and the common and disparate radiographic features between and within groups are discussed. Dental disease occurred most frequently and accounted for about 30 per cent of cases, most of which had periapical infection. This disorder presented as two distinct clinical entities in almost equal numbers affected teeth with roots rostral to the maxillary sinus usually produced facial swelling, whereas those with roots within the sinus were generally associated with nasal discharge as a result of secondary sinusitis. In the former group periapical changes could readily be identified on radiographs, but in the latter group affected teeth could be recognised with confidence in only about half the cases. Primary sinusitis was the commonest specific condition recorded and accounted for 32 cases, three of which were mycotic. Using lateral erect projections, comparison of the radiographic features of primary sinusitis and sinusitis secondary to dental disease showed some useful differentiating signs. In four ponies, rhinitis associated with sinusitis led to disruption of the intra‐nasal structures but mycotic rhinitis, nasal ulceration and an intra‐nasal foreign body produced no radiographic abnormalities. Sixteen cases of suture periostitis were recorded, with varying degrees of new bone formation, and of 13 animals presented for evaluation of trauma, pre‐diagnosed fractures were demonstrated in 10 and complications due to sinusitis in three. Twelve cases of paranasal sinus cysts and three of 10 progressive ethmoidal haematomas showed non‐specific radiographic changes within the spectrum of those recorded in sinusitis, while the remaining ethmoidal haematomas produced distinctive clearly defined opacities, four of which were within paranasal sinuses. Four tumours were confirmed histologically, but other neoplastic lesions are probably also included in a group of 10 cases of undiagnosed cysts or masses. Other conditions, which occurred sporadically, are of anecdotal interest only. The incidence of wolf teeth among a group of 134 horses was 33 per cent.
Immunocytochemical localisation of carbonic anhydrase isozyme III in equine skeletal muscle
Authors: NISHITA T. , MATSUSHITA H. , KAI M.
Published: April 2010

The location of carbonic anhydrase III (CA‐III) in frozen sections of biopsies of Thoroughbred horse skeletal muscle was studied. Fibre types were determined by ATP‐ase and succinate dehydrogenase staining. CA‐III isozyme was detected using a peroxidase conjugated anti‐CA‐III antibody. CA‐III was found to be localised in slow twitch oxidative fibres (ST), but was also present in fast twitch oxidative (FTH) fibres in small amounts. Fast twitch glycolytic (FT) fibres were stained lightly compared with control sections. The concentrations of CA‐III in muscle and liver were 70 μg/mg protein and 4 μg/mg protein, respectively. CA‐I and CA‐II were not found in muscle extracts by the double immunodiffusion method.
The relationship of air hygiene in stables to lower airway disease and pharyngeal lymphoid hyperplasia in two groups of Thoroughbred horses
Authors: CLARKE A. F. , MADELIN THERESA M. , ALLPRESS R. G.
Published: April 2010

The relationship between air hygiene within two types of identically managed horse housing and the incidence of covert respiratory disease (as revealed by endoscopic examination) of their inhabitants was assessed. The horses were all under the supervision of the same trainer. In one yard the design ensured the boxes were well ventilated in still air conditions. In the other yard the boxes were insulated and there was little provision for natural ventilation in still air conditions. There was heavy fungal and actinomycete contamination of wood shavings in the heavily insulated, poorly ventilated housing but not in the shavings of better ventilated boxes. There was increased incidence and severity of mucopus in the tracheas of horses stabled in the contaminated environment over that seen in the other group. There was no such association between the incidence or degree of pharyngeal lymphoid hyperplasia and the two environments or between the degree of tracheal mucopus and PLH found in the 72 horses examined in this study.
Chromosome anomalies and infertility in the mare
Authors: LONG SUSAN E.
Published: April 2010

Nine reproductively normal mares, 25 infertile mares and one set of heterosexual twins were examined cytogenetically using conventional giemsa staining, C‐banding and G‐banding. It was concluded that G‐banding was necessary to identify even gross anomalies. Three (12 per cent) of the infertile mares, but none of the controls, had a chromosomal anomaly. One was 63,XO, one a 63,XO/64,XX mixoploid and one a 64,XY sex reversed male. It is argued that a cytogenetic examination is a useful diagnostic technique but that routine screening of the whole population would be uneconomic.
Determination and repeatability of maximum oxygen uptake and other cardiorespiratory measurements in the exercising horse
Authors: EVANS D. L. , ROSE R. J.
Published: April 2010

A rapid incremental treadmill exercise test was used to determine the repeatability of the following measurements in exercising horses: maximal oxygen consumption (V̇o2max), maximal heart rate (HRmax), velocity at a heart rate of 200 beats/min (V̇‐200), oxygen consumption at a heart rate of 200 beats/min (V̇o2‐200), oxygen consumption at HRmax (V̇o2‐HRmax), work rate at a heart rate of 200 beats/min (W‐200), work rate at HRmax (W‐HRmax) and treadmill velocity at HRmax (V‐HRmax). Six Standardbred geldings were exercised on three separate occasions on a treadmill set at an inclination of 6°. The exercise protocol was that each horse was exercised for 2 mins at 3 m/sec, after which the treadmill speed was increased by 1 m/sec every 60 secs, until the horse could no longer maintain its speed. A minimum of 24 h was allowed between repeated tests. No significant differences were found between the three means of any of the eight cardiorespiratory variables with repeated measurement. Variables with high coefficients of variation (>10 per cent) included V‐HRmax, W‐HRmax and V̇o2‐HRmax. The V‐200, W‐200 and V̇o2‐200 showed less variation. The V̇o2max showed good reproducibility, there being coefficients of variation ranging from 1.4 to 9.0 per cent. The individual horse values for V̇o2max ranged from 104 to 169 ml/kg bodyweight/min. Maximal heart rate was also highly reproducible and the coefficients of variation were less than or equal to 2.7 per cent in all horses. It is concluded that the measurement of V̇o2max has good reproducibility, but other estimates of maximal aerobic capacity are less precise.
Sudden and unexpected death in horses and ponies: an analysis of 200 cases
Authors: BROWN C. M. , KANEENE J. B. , TAYLOR R. F.
Published: April 2010

An analysis was made of the causes of death in horses and ponies over one year of age which died suddenly (Group 1) or were found dead but were considered normal when last seen (Group 2). There were 49 animals in Group 1. Thoroughbreds were overrepresented, but there were no ponies in this group. No cause of death was found in 30.6 per cent of cases and 16.3 per cent died from each of the following causes: haemorrhage in the respiratory system, central nervous system, and adverse drug reactions. Cardiovascular lesions were the cause of death in 14.4 per cent and the remaining 3.1 per cent had lesions of the gastrointestinal system. Racehorses mostly died suddenly from severe haemorrhage in various sites, particularly the thorax. In Group 2 there were 151 animals, and in 33.1 per cent no cause of death was determined. Gastrointestinal lesions were considered the cause of death in 39.2 per cent of cases and respiratory lesions killed 8.6 per cent. Lesions of both the central nervous system and cardiovascular system were considered the cause in 4.6 per cent of cases. The remaining 9.9 per cent of animals had miscellaneous lesions. Toxicological studies were performed in 46 of the total 200 cases, and only two had positive results; lead in one and nicotine in the other.
Effects of age, sex, and post mortem interval on intestinal lengths of horses during development
Authors: SMYTH G. B.
Published: April 2010

Lengths of small intestine, caecum, ascending colon and descending colon were measured in intestinal tracts from 103 foetuses, foals and adult horses. Intestinal tracts from 21 of the horses were measured at varying intervals after death. Total intestinal length increased markedly from mid‐gestation to one year of age, then showed little increment up to 35 years. Small intestinal length increased most rapidly in the first month of life. Caecal length increased most rapidly from one to six months and length of ascending colon increased most rapidly between one week and one year. Descending colon length increased gradually after birth. Periods of rapid increase in length of various intestinal segments and alterations in the percentage of total intestinal length were associated with periods of rapid body growth and changes in dietary compositon. Sex and post mortem interval did not affect intestinal length significantly.
Dose related effects of the kappa agonist U‐50, 488H on behaviour, nociception and autonomic response in the horse
Authors: KAMERLING S. , WECKMAN T. , DONAHOE J. , TOBIN T.
Published: April 2010

Current opiate receptor theory suggests that kappa agonists should provide good analgesia without producing marked central nervous system stimulation. U‐50,488H is an experimental narcotic analgesic that is a selective kappa agonist. In the present study, U‐50,488H produced good analgesia in horses using both the skin twitch and hoof withdrawal reflex assays. Further, the analgesia was relatively long lasting (120 mins) compared to other μ‐agonists tested in horses. The locomotor response to U‐50,488H was less than observed with ethylketazocine and butorphanol, and has yielded the smallest locomotor response of any of the narcotic analgesics tested to date. Other work showed that the autonomic responses to U‐50,488H were less than those of other narcotic analgesics, and that the analgesic response to this drug was blocked by naloxone. Based on its ability to produce analgesia with little other stimulatory action, U‐50,488H shows promise of becoming a useful narcotic analgesic in equine medicine.
Surgical treatment of acquired inguinal hernia in the horse: A review of 51 cases
Authors: van der VELDEN M.A.
Published: April 2010

During a seven year period, 51 cases of acquired inguinal herniation in 50 stallions were treated surgically. In 25 cases the herniated loop was ileal, in the other 26 it was jejunal. In cases of strangulation, the vaginal ring was enlarged by incising the peritoneum and transverse fascia. Closure of the superficial inguinal ring was advisable to prevent the hernia recurring. In all cases unilateral castration was performed. Laparotomy was carried out in 33 cases; 22 required intestinal resection and in four cases a bypass was made. Follow‐up at least six months postoperatively indicated that surgery had been successful in 76 per cent of the cases treated.
Body temperature and behaviour of mares during the last two weeks of pregnancy
Authors: SHAW EVE B. , HOUPT KATHERINE A. , HOLMES DOROTHY F.
Published: April 2010

Average daily core body temperature and behavioural patterns of pregnant mares were studied, in search of definitive signs of parturition within 24 h of the event. Nineteen pony mares were sampled twice daily for core body temperature. A significant temperature drop, averaging 0.1°C (0.2°F) was observed during the day prior to parturition. Between 18.00 h and 06.00 h, during the two weeks before parturition, Thoroughbred and Standardbred mares (n=52) spent an average 66.8 per cent of their time standing, 27.0 per cent eating, 4.9 per cent lying in sternal recumbency, 1.0 per cent lying in lateral recumbency, and 0.3 per cent walking. On the night before parturition, mares spent significantly less time lying in sternal recumbency than on previous nights and on the night of parturition all behaviour patterns except eating were significantly different from the nights of the two weeks before parturition. There was an increase in walking (5.3 per cent), lying in sternal recumbency (8 per cent) and lying in lateral recumbency (5.3 per cent) whereas standing (53.3 per cent) was decreased. In 58 observed pregnancies, 54 mares (97 per cent) foaled in a recumbent position and 50 mares (86 per cent) foaled between 18.00 h and 06.00 h.
Increased local IgA production in chronic obstructive pulmonary disease
Authors: MAIR T. S. , STOKES C. R. , BOURNE F. J.
Published: April 2010

The immunoglobulin (Ig) content of serum and tracheal lavage fluid was measured in 50 horses suffering from chronic obstructive pulmonary disease (COPD) and 40 control horses. The mean immunoglobulin: albumin ratios of the lavage fluids of both groups were significantly higher than the corresponding values for serum, which indicates significant local production of immunoglobulins in the lower respiratory tract. The IgA: albumin ratio of lavage fluid was significantly higher in diseased compared with normal horses, which implies increased local production of IgA in this disease. The IgG: albumin and IgM: albumin ratios of lavage fluid were not significantly different in the Iwo groups of horses. These results reveal an involvement of the respiratory mucosal immune system in COPD.
A morphological study on the obliteration processes of the ductus arteriosus in the horse
Authors: MACHIDA N. , YASUDA J. , TOO K. , KUDO N.
Published: April 2010

The obliteration processes of the ductus arteriosus of equine foetuses and newborn foals were studied morphometrically and histologically. The length, internal and external diameters and circumference of the ductus in equine foetuses increased progressively and linearly up to 310 days with advancing foetal age, but the values, especially the internal diameter, decreased from 320 to 330 days. After birth, the ductal measurements decreased gradually and ductal closure was found in three of 14 foals examined on the first day post partum, in two of six on the second day and in nine of nine on the third day or later, suggesting that the ductus arteriosus closes physiologically within three days after birth. Microscopical findings of the ductus arteriosus were characterised by the rearrangement of smooth muscle cells in the inner media and intimai thickening in foetuses, and by the central displacement of the intima in newborn foals. It was concluded that the ductus arteriosus begins to undergo preparatory modifications during intrauterine life, when the vessel is still functional, and that the most significant starting point of change in the obliteration processes is the rearrangement of smooth muscle cells in the inner media, which occurs during pre‐ and post natal life.
The foramen ovale of the foetal and neonatal foal
Authors: MACDONALD A. A. , FOWDEN ABIGAIL L. , SILVER MARIAN , OUSEY JENNIFER , ROSSDALE P. D.
Published: April 2010

Hearts from 24 foals were studied; 10 were from foetuses ranging in gestational age from 230 to 322 days and 14 were from newborn and young foals aged between birth and 17 days. The foramen ovale and associated vena caval and atrial structures were examined by scanning electron microscopy. Additional observations were made by light and transmission electron microscopy. A tube‐like flap of tissue was observed, extending from the aperture in the caudal vena cava to the lumen of the left atrium. In the younger foetuses, the distal end of this tube was covered with a thread‐like network of tissue. In animals nearer to term, the network was replaced by distal fenestrations. Protrusions were seen on the rim of the opening of the tube as it entered the atrium. The role that these may play, together with the significance of cardiac muscle and non‐elastic connective tissue in the wall of the tube, were discussed with respect to possible mechanisms of closure of the foramen ovale.
A morphometric study of foetal and newborn cardiac growth in the horse
Authors: MACHIDA N. , YASUDA J. , TOO K.
Published: April 2010

A morphometric study of hearts in 81 equine foetuses, ranging in age from 190 to 330 days of foetal age, and in 26 newborn foals is reported. The mean weight, external dimensions, ventricular wall thickness and circumference of the atrio‐ventricular orifice were measured. Features of the main associated vessels of the heart were also recorded. All cardiac measurements of foetuses increased linearly throughout the latter half of pregnancy and were highly correlated with foetal age. This linear growth pattern was also found in the parameters of the associated arterial trunks. The ratio of the right ventricular weight to the total ventricular weight in the equine foetuses increased gradually from 0.27 (Day 190) to 0.34 (full term), but in newborn foals, this ratio began to decrease soon after birth, declining from 0.32 to 0.28 by 11 days of age. The interventricular septum was thickest followed by the right ventricular wall, and the left ventricular wall was thinnest during the period of gestation studied. The right ventricle was 3.2 per cent to 31.5 per cent thicker than the left ventricle.
Amyloid in the horse: A report of nine cases
Authors: van ANDEL A. C. J. , GRUYS E. , KRONEMAN J. , VEERKAMP J.
Published: April 2010

Out of approximately 16,000 horses referred for clinical examination, nine had amyloidosis. Six of these horses had localised amyloid deposits in the wall of the nasal meatus and ventral turbinates associated with epistaxis. Horse 1 also developed malignant histiolymphocytic lymphosarcomas. The amyloid deposits were potassium permanganate‐resistant and tryptophan‐positive. Gel filtration of solubilised amyloid fibrils from Horse 1 revealed a major retarded fraction with an apparent molecular weight of 20 kD. This protein had an amino acid composition similar to human AL‐amyloid proteins and horse immunoglobulin light chains. On Western blot a strong cross‐reaction was observed between horse IgG2alight chains and the Horse 1 amyloid. Horses 7 to 9 had suppurative verminous aneurysm, tuberculosis and an adrenal cortical adenoma, respectively, and had generalised amyloid deposits in liver and spleen. These amyloid deposits were found to be potassium permanganate‐sensitive and positive for tryptophan. Gel filtration of solubilised amyloid fibrils from Horse 8 revealed a major retarded fraction (protein AA) with an apparent molecular weight of 10 kD. Immunoperoxidase‐antiperoxidase staining showed the localised deposits to be negative or only weakly positive with antisera against bovine, hamster, dog and human protein AA and to be positive with anti‐horse‐one amyloid protein. The generalised deposits were found to be positive with the antisera against allogenic protein AA. The results of the potassium permanganate incubation, biochemistry, immunoblotting and immunochemistry, indicate that the localised amyloid of Horse 1 and most likely the amyloid of Horses 2 to 6, is of the AL‐type. The generalised amyloid deposits were found to be of the AA type.
Use of iohexol for myelography in the horse
Authors: MACLEAN A. A. , JEFFCOTT L. B. , LAVELLE R. B. , FRIEND S. C. E.
Published: April 2010

The use of iohexol as a contrast agent for myelography is reported in two groups of horses. Group 1 (n = 6) were used only for myelography and to assess the clinical and pathological effects of intrathecal administration of iohexol. A volume of 20 ml at a concentration of 300 or 350 mg iodine/ml gave satisfactory myélographie detail with no serious clinical or neurological side effects. Only a minimal inflammatory réponse could be demonstrated in cerebrospinal fluid at four and 14 days after injection. At post mortem examination 14 days after myelography there was no evidence of meningitis nor was any other pathological change detected. Group 2 (n = 19) comprised a series of clinical cases of suspected cervical vertebral malformation. The only untoward sequelae recorded involved two horses in which iohexol was diluted with sterile water prior in intrathecal injection. A progressive necrotising meningitis developed in both cases which necessitated euthanasia. It was concluded that the major advantages of iohexol for use in the horse were its diagnostic quality, safety and low cost.
Oxidative capacity of skeletal muscle fibres in racehorses: histochemical versus biochemical analysis
Authors: VALBERG STEPHANIE , GUSTAVSSON BIRGITTA ESSÉN , WALLBERG HELENA SKOGLUND
Published: April 2010

The oxidative capacity of skeletal muscle fibre types was evaluated histochemically using the nicotinamide dinucleotide diaphorase (NADH‐D) staining, and biochemically by measuring the activity of citrate synthase (CS) in both whole muscle samples and in pools of fibres of identified type. Duplicate determinations of the NADH‐D staining pattern resulted in standard deviations (sd) between duplicates of 6 and 11 per cent for two observers. The NADH‐D pattern was found to differ between observers. Duplicate determinations of CS activity in the same fibre pools resulted in an sd value of 2.9 μ mol/g/min. Measurements of whole muscle CS activity did not provide information about the distribution of oxidative capacity among fibre types. The NADH‐D stain and CS activity in fibre pools both showed that, in general, type I and IIA fibres had a higher oxidative capacity than type IIB fibres. Biochemical techniques also showed, however, that the CS activity in type I and IIA fibres of different horses could vary as much as twofold, whereas the NADH‐D rating showed a high intensity staining for most type I and IIA fibres in all horses. Furthermore, type IIB fibres received a lower NADH‐D rating than the other fibre types even when the CS activities were quite similar. For purposes of research, biochemical measurement of oxidative capacity in individual muscle fibre types provides valuable quantitative and comparative information. The ease of histochemical NADH‐D staining in comparison to fibre dissections makes this technique more practical for routine estimates of the distribution of oxidative capacity among muscle fibres. Since racehorses have a high muscle oxidative capacity, NADH‐D stains should be carefully interpreted and comparative evaluations are best made if quantitative biochemical measurements of whole muscle oxidative capacity are added to histochemical evaluations.
The effect of detomidine (Domosedan) on the maintenance of equine pregnancy and foetal development: ten cases
Authors: KATILA TERTTU , OIJALA MARI
Published: April 2010

Detomidine was administered throughout 10 pregnancies in eight mares. An intravenous injection of 20 pg/kg bodyweight was given weekly from Day 14 to Day 60 of gestation and thereafter every four weeks until parturition. One mare suffered torsion of the large colon and was destroyed on Day 86; the foetus was normally developed. A further mare aborted at 167 days. The remaining eight pregnancies continued to full term. One foal was delivered by caesarean section because of torticollis and, of the seven foals born spontaneously, one had bilateral upward patellar fixation at one month old. Therefore, although only six of the 10 foals developed normally, the other four cases showed no pathological similarities to suggest a common cause. Although these data were based on a small number of mares, they did not suggest that the repeated administration of detomidine had specific adverse effects on the pregnancies.
Cardiorespiratory and sedative effects of a combination of acepromazine, xylazine and methadone in the horse
Authors: NILSFORS L. , KVART C. , KALLINGS P. , CARLSTEN J. , BONDESSON U.
Published: April 2010

Cardiorespiratory and sedative effects of a combination of acepromazine, xylazine and methadone were studied in the horse. Acepromazine and xylazine produced cardiovascular effects whereas methadone mainly affected respiratory rate. Decreases in heart rate, arterial blood pressure and respiratory rate were seen. Sedation was superior to that of acepromazine, xylazine or a combination of these. No serious side effects were seen.
Effect of ovarian steroids on migration of uterine lumenal neutrophils and on chemokinetic factors in uterine secretions from mares
Authors: WATSON E. D.
Published: April 2010

Incubation of blood neutrophils with uterine flushings collected from ovariectomised mares treated with oestradiol, stimulated migration under agarose, whereas flushings from mares treated with progesterone or oily vehicle, inhibited migration. After intra‐uterine infusion of bacteria, however, flushings from oestradiol‐treated and vehicle‐treated mares inhibited migration, whereas progesterone treatment stimulated migration. Migration of uterine‐derived neutrophils under agarose was less than that of blood neutrophils and was not influenced by treatment with ovarian steroids. Uterine susceptibility to infection in progesterone‐treated mares was not, therefore, correlated with the migratory activities of uterine neutrophils or the chemokinetic properties of uterine secretionsin vitro.
A comparison of enterotomies through the antimesenteric band and the sacculation of the small (descending) colon of ponies
Authors: ARCHER R. M. , PARSONS J. C. , LINDSAY W. A. , WILSON J. W. , SMITH D. F.
Published: April 2010

Three pairs of longitudinal enterotomies were performed in the small colon of 10 ponies. Each pair consisted of one enterotomy through the antimesenteric band and one through the sacculation. The ponies were destroyed 96 h after surgery. The enterotomies in the two sites were compared for: speed of surgery, adhesions, bursting wall tension, neovascularisation by micro‐angiography, and histological reaction. Enterotomies made through the antimesenteric band were superior because they were quicker to perform, stronger, more accurately apposed, and had less inflammation than those made through the sacculation.
A method for reproducing fatal idiopathic colitis (colitis X) in ponies and isolation of a Clostridium as a possible agent
Authors: PRESCOTT J. F. , STAEMPFLI H. R. , BARKER I. K. , BETTONI R. , DELANEY K.
Published: April 2010

Severe colitis was induced in two ponies after oral pre‐treatment with clindamycin and lincomycin, followed by intestinal content from two horses which had died from naturally‐occuring idiopathic colitis. Two ponies treated with antibiotic alone, and two ponies treated with intestinal content alone, were unaffected. In a further study, three ponies treated on separate occasions with lincomycin, administered orally, died or were destroyed 67 to 72 h after initial treatment. No established salmonella, yersinia or Campylobacter pathogens were isolated from these ponies, but a Clostridium closely resemblingClostridium cadaveriswas isolated as the predominant Clostridium from them all and from the colonic content of one of six horses which died from naturally‐occuring idiopathic colitis. It was not isolated from six horses with non‐fatal diarrhoea. This Clostridium is a candidate as an agent of some cases of fatal colitis in horses.
Macrophage clearance of125I‐labelled polyvinyl pyrrolidone in the horse: Effect of ovarian steroids and persistent endometritis
Authors: WATSON ELAINE D. , STOKES C. R.
Published: April 2010

The rate of clearance of125I‐labelled polyvinyl pyrrolidone (PVP) from blood was measured in mares as an indicator of macrophage function. In three out of four cycling mares, PVP clearance was slower during oestrus than dioestrus. Similarly, administration of oestrogen to four ovariectomised mares tended to depress PVP clearance compared with clearance from the same mares before they received oestrogen. However, the effect of oestrogen was not statistically significant. Mares susceptible to persistent endometritis had rates of PVP clearance which were similar to those of genitally normal mares.
BCG emulsion immunotherapy of equine sarcoid
Authors: VANSELOW B. A. , ABETZ I. , JACKSON A. R. B.
Published: April 2010

Of 61 horses with sarcoids treated with intralesional injection of a double emulsion incorporating inactivated bacillus Calmette Guérin organisms, 36 (59 per cent) showed complete regression and 11 (18 per cent) showed partial regression. The majority of cases required only one treatment. Not all sarcoids were responsive to this therapy; those not responding were usually large or on horses with multiple sarcoids.
Attempts to prevent equine post neurectomy neuroma formation through retrograde transport of two neurotoxins, doxorubicin and ricin
Authors: CUMMINGS J. F. , FUBINI S. L. , TODHUNTER R. J.
Published: April 2010

Digital neurectomies, performed to relieve pain and lameness, are often complicated postoperatively by formation of painful neuromas. In this study attempts were made to deliver lethal doses of neurotoxin to the cell bodies of the transected digital nerve fibres via long‐distance retrograde axon transport and, thereby, prevent the regenerative changes that lead to neuroma formation. After applying doxorubicin in various ways to the digital nerve stumps of ponies, degenerating or necrotic neurones appeared only sporadically in the spinal ganglia. Although doxorubicin was largely ineffective in retrograde destruction of cell bodies, when absorbed in pledgets on the stumps it exerted a sustained action which prevented Schwann cell proliferation and axon sprouting. Ricin, in contrast to doxorubicin, was effective in retrograde destruction of sensory neurons. Many affected neurons were devoid of polysomes but packed with mitochondria; others had advanced to various stages in cytolysis. Despite its effectiveness, ricin cannot be recommended because of its extreme toxicity. The clinical use of retrograde transport in equine neurectomy will probably depend on future development of hybrid toxins with high neural specificity and low systemic toxicity.
Ectopic ureter managed by unilateral nephrectomy in two female horses
Authors: SULLINS K. E. , McILWRAITH C. W. , YOVICH J. V. , MacHARG MARGARET A. , FESSLER J.
Published: April 2010

Unilateral ureteral ectopia was diagnosed in three‐year‐old and 10‐month‐old fillies exhibiting urinary incontinence since birth. In one case reimplantation of the ureter onto the bladder was planned but considered to be impractical intraoperatively. Unilateral nephrectomy was performed successfully in both cases which alleviated the urinary incontinence. Both horses had normal urinary function postoperatively and became healthy, serviceable animals.