bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prolonged effect of a single injection of human chorionic gonadotrophin on plasma testosterone and oestrone sulphate concentrations in mature stallions
Authors: COX J. E. , REDHEAD PATRICIA H. 
Published: April 2010

SummaryThe long term effect of a single injection of 6,000 iu of human chorionic gonadotrophin (hCG) was studied in two pony stallions. Peripheral plasma samples were anlaysed for testosterone and oestrone sulphate. Testosterone concentrations were markedly elevated for five days after injection in both stallions. No adverse effects of these high concentrations were observed on concentrations later in the experiment. There was an initial increase in oestrone sulphate in one stallion, after which concentrations decreased to below pre‐injection levels. The other stallion (whose initial oestrone sulphate concentrations were somewhat higher) showed no rise in response to hCG but did show a significant decline from five days after injection. Whether this suppression is an effect of the high testosterone concentrations remains to be determined.
Pharmacokinetic studies of cimetidine hydrochloride in adult horses
Authors: SMYTH G. B. , DURAN S. , RAVIS W. , CLARK C. R. 
Published: April 2010

SummaryHistamine type II (H2) antagonists inhibit gastric acid secretion and are useful in treating gastric and duodenal ulcer disease. To provide some information on the pharmacokinetics of the H2 antagonist cimetidine, adult horses were given 3.3 mg/kg cimetidine intravenously (iv) or 3.3 and 10 mg/kg orally. Plasma cimetidine concentrations after 3.3 mg/kg orally were too low to measure. Following 33 mg/kg iv, cimetidine displayed two‐compartment characteristics with a t1/2 of 0.083±0.039 h and t1/2 of 2.23±0.64 h. The total body clearance was 0.443±0.160 litre/h/kg and the mean residence time was 2.74±1.11 h. This clearance and t1/2 are similar to that in man. The volume of distribution (VSS) and volume of the central compartment (VC) were 1.138±0.230 and 0.276±0.102 litre/kg, respectively. After a single oral dose of 10 mg/kg as crushed tablets, peak plasma concentration of 1.81±0.82 μg/ml occurred at approximately 1.4 h. Oral absorption of cimetidine appeared variable and slow with an extent of absorption of 0.296±0.183 and a mean residence time for absorption of 1.99±0.79 h. This was less than in man. Based on a desired average steady state plasma concentration of 1.0 μg/ml, 11.0 mg/kg/day iv and 48 mg/kg/day orally can be recommended in adult horses.
Pharmacokinetics of trimethoprim‐sulphamethoxazole in two‐day‐old foals after a single intravenous injection
Authors: BROWN M. P. , McCARTNEY J. H. , GRONWALL R. , HOUSTON A. E. 
Published: April 2010

SummarySix healthy two‐day‐old foals (3 pony foals and 3 horse foals) were given a single intravenous (iv) injection of trimethoprim (TMP) ‐ sulphamethoxazole (SMZ) at a dosage of 2.5 mg of TMP/kg bodyweight (bwt) and 12.5 mg of SMZ/kg bwt. Serum TMP and SMZ concentrations were measured serially during a 24 hour period. The overall elimination rate constant (K) for TMP in the pony and horse foals was 0.45/h, whereas the K values for SMZ for the pony and horse foals were 0.12/h and 0.07/h, respectively (no significant difference; P > 0.05). Based on published minimum inhibitory concentration values for equine pathogens (Adamsonet al1985), the primary indication for the use of TMP/SMZ in foals may be in the treatment of infections caused by gram‐positive bacteria. A dosage of 2.5 mg of TMP/kg bwt and 12.5 mg of SMZ/kg bwt, given iv at 12 h intervals would be appropriate.
Ancient origins of horsemanship
Authors: McMIKEN D. F. 
Published: April 2010

SummaryArchaeological evidence of horse domestication dates from 4000 BC in the Eurasian Steppes of the Ukraine. There, Indo‐Europeans rode horses and herded them for meat. This had profound social and economic consequences which led to the development of nomadic equestrian cultures. The earliest direct evidence of riding is from Mesopotamian plaques, and correspondence of the Kings of Mari (2000 BC). Indo‐Europeans brought the horse to the Near East and there, outside its natural habitat, used specialised knowledge to raise and train horses on a large scale for military use. Hittite instructions on training chariot horses are contained in the Kikkuli text from Anatolia (1350 BC). Systematic conditioning, grain feeding and elements of ‘interval training’ are notable. Equine prescriptions were also recovered from Ugarit (Syria) which indicate a rational approach to veterinary medicine in the same era. With the evolution of effective training and tools, chariots, metal bits, and the recurve bow, horses became formidable weapons of war. Mounted bowmen succeeded chariots in warfare, particularly nomadic Scythians who dominated Central Asia (1000‐500 BC). In the Middle East (Iraq), Assyrians assembled a powerful military empire and employed a vast and skilled cavalry (900‐612 BC). The first surviving text on training cavalry mounts is by the Athenian General Xenophon (400 BC) who reveals a sensitive understanding of the horse. Although the horse has been used for herding, transportation and sport, a recurring stimulus for horsemanship throughout history has been its military role.
Ultrasound as an aid to diagnosis of granulosa cell tumour in the mare
Authors: HINRICHS KATRIN , HUNT P. R. 
Published: April 2010

SummaryThe ultrasonic appearance of seven cases of granulosa cell tumour is described, and compared with an ovarian haematoma and an ovarian serous cystadenoma. The granulosa cell tumours varied from being uniformly dense to having one or several large fluid filled cysts. Some tumours resembled the haematoma or cystadenoma and also, in some aspects, normal ovarian structures such as corpora haemorrhagica or follicles in early pregnancy. There was no typical ultrasonographic appearance of the granulosa cell tumours which enabled definitive diagnosis. However, ultrasound may be a diagnostic aid when used in conjunction with the history and findings on rectal palpation.
Changes in plasma progesterone concentrations from Days 17 to 42 of gestation in mares maintaining or losing pregnancy
Authors: IRVINE C. H. G. , SUTTON P. , TURNER J. E. , MENNICK P. E. 
Published: April 2010

SummaryPlasma progesterone concentrations were measured in 179 mares bled on alternate days commencing with a positive pregnancy diagnosis on Days 17 to 18 after ovulation and concluding on Days 42 to 45. During this period 17 mares (10 per cent) lost their pregnancies, 11 before Day 25. In 15 mares the timing of the pregnancy loss could be determined with adequate accuracy; in only one did a decline in progesterone precede the loss. Thus pregnancy loss between Days 17 and 42 was rarely caused by a fall in plasma progesterone.
Arthrography of the equine shoulder joint
Authors: NIXON A. J. , SPENCER C. P. 
Published: April 2010

SummaryTechniques and normal radiographic anatomy for positive and double contrast shoulder arthrography in horses were evaluated. General anaesthesia was used for most radiographic projections of the shoulder. The mediolateral projection provided the most information during arthrography, although the supinated mediolateral view occasionally allowed better definition of the cartilage surfaces on the medial aspects of the humeral head. The craniocaudal mediolateral oblique and caudocranial projections provided limited additional information. Water soluble non‐ionic contrast agents, such as metrizamide and iohexol, were suitable for shoulder arthrography; iohexol resulted in less synovitis and lameness. Arthrography in cases of osteochondrosis and osteochondritis dissecans allowed better evaluation of cartilage attachment to subchondral bone, better evaluation of the length and depth of cartilage lesions and more accurately defined the site and shape of osteocartilaginous free bodies. Cartilage thickening without detachment from the subchondral bone could only be determined by arthrography. Although these thick cartilage regions may later dissect from the subchondral bone, most cases where the cartilage was firmly adherent were not candidates for surgical debridement and carried a favourable prognosis. The determination of a free flap by arthrography indicated the need for surgery. Extensive humeral and glenoid cavity lesions were better defined by arthrography, allowing a rational decision between surgical debridement or euthanasia. Using arthrography, evaluation of the size and patency of the communicating canal to a subchondral cystic defect better separated cases with long, narrow and poorly patent canals for conservative rather than surgical therapy.
Osteochondral fragmentation of the distal aspect of the patella in horses
Authors: MclLWRAITH C. WAYNE 
Published: April 2010

SummaryA condition characterised by osteochondral fragmentation of the distal aspect of the patella in 15 horses is described. The problem was unilateral in six horses and bilateral in nine. There were eight Quarterhorses, three Thoroughbreds, two American Saddlebreds, one American Paint and one Warmblood‐Thoroughbred cross. A previous medial patellar desmotomy had been performed on 12 of the 15 horses. The condition manifested as hindlimb lameness and stiffness ranging from mild to severe. There was fibrous thickening in the stifle area in the 12 cases with a previous medial patellar desmotomy, and synovial effusion in seven of 12 cases. Synovial effusion was present in two of the three cases in which a previous medial patellar desmotomy was not performed. The radiographic changes included bony fragmentation, spurring (with or without an associated subchondral defect), subchondral roughening and subchondral lysis of the distal aspect of the patella. All horses were treated with arthroscopic surgery. The lesions at arthroscopy varied from flaking, fissuring, undermining or fragmentation of the articular cartilage to fragmentation or lysis of the bone at the distal aspect of the patella. The subchondral bone was involved in all cases that had a previous medial patellar desmotomy. Of the 12 horses that had a previous medial patellar desmotomy, eight became sound at their intended use, one was sold in training without problems, one is in early training without problems, one never improved and one is in convalescence. Of the three that did not have a patellar desmotomy, two performed their intended use well but one was unsatisfactory.
Reduced efficacy of anthelmintics in young compared with adult horses
Authors: HERD R. P. , GABEL A. A. 
Published: April 2010

SummaryStudies on a Thoroughbred breeding farm in Ohio from 1982 to 1988 demonstrated the value of three anthelmintic pastes (ivermectin, oxibendazole, pyrantel pamoate) in controlling benzimidazole resistant cyathostomes (small strongyles) in adult horses. However, a comparison of drug efficacy in suppressing faecal egg counts for the full period between treatments showed a significant reduction in efficacy of all drugs in yearling horses compared with adults. Mean faecal egg counts of adult horses were generally kept below 100 eggs per gram (epg) of faeces when using oxibendazole or pyrantel pamoate at four to five week intervals and ivermectin at eight week intervals. By contrast, mean counts of young horses rose as high as 655 epg (oxibendazole), 729 epg (pyrantel pamoate) and 852 epg (ivermectin) within the same time period after treatment. Individual counts of treated yearlings sometimes exceeded 3,000 epg. Three distinct mechanisms appeared to be involved in the poor results in young horses. These were 1) anthelmintic refuge, 2) anthelmintic resistance, and 3) anthelmintic avoidance.
A tracheoscopic technique for obtaining uncontaminated lower airway secretions for bacterial culture in the horse
Authors: DARIEN B. J. , BROWN C. M. , WALKER R. D. , WILLIAMS M. A. , DERKSEN F. J. 
Published: April 2010

SummaryTranstracheal aspirate (TTA) aerobic microbiology culture results from 30 ponies were compared to protected catheter brush (PCB) culture results obtained from the same ponies. The PCB procedure resulted in significantly fewer (P<0.05) isolates than those obtained by the TTA procedure and the PCB procedure resulted in significantly more samples with no bacteria growth than the TTA procedure. To address the possibility that the volume of tracheobronchial secretion obtained by PCB was insufficient as a microbiological sample, a sterile, double‐sheathed, protected aspiration catheter (PAC) was developed. Comparisons were made between TTA and PAC aerobic microbiology culture results from 18 pneumonic foals and weanlings. There were no significant differences between the PAC and TTA procedures with respect to the number of bacteria isolates. It was concluded that the PAC technique may be used as an alternative to TTA for isolation of equine pulmonary bacteria and may be the preferred procedure because of the reduced risk of complications associated with the TTA.
Variation in conformation of Swedish Warmblood horses and conformational characteristics of élite sport horses
Authors: HOLMSTRÖM M. , MAGNUSSON L.‐E. , PHILIPSSON J. 
Published: April 2010

SummaryThe variation in conformation of 356 Swedish Warmblood horses is described, using a quantitative method of measuring horses. Thirty‐three of the horses were élite dressage horses, 28 were élite showjumpers, 100 were riding school horses and 195 were unselected four‐year‐olds. Most horses had a long body form. The average height at the withers was 163.4 cm. Sixty per cent of the horses had a bench knee conformation, 50 per cent had a toe‐in conformation of the forelimbs and 80 per cent had outwardly rotated hind limbs. The majority of these deviations were mild or moderate. Conformation was influenced by sex and age. Mares were smaller and had longer bodies and shorter limbs. The élite dressage horses and showjumpers had larger hock angles and more sloping scapulas than other horses. The showjumpers also had smaller fetlock angles in the front limbs. It is suggested that the larger hock angles among the elite horses may be because hocks with small angles are more prone to injury, and because small hock angles may negatively influence the ability to attain the degree of collection necessary for good performance in advanced classes.
Plasma theophylline concentration and lung function in ponies with recurrent obstructive lung disease
Authors: McKIERNAN B. C. , KORITZ G. D. , SCOTT JACQUELINE S. , BERNEY CATHY , ROBINSON N. E. 
Published: April 2010

SummarySix ponies with recurrent obstructive lung disease were studied during two separate 60 min periods while receiving constant equal volume infusions of either aminophylline or sterile water. Dynamic lung compliance, pulmonary resistance, respiratory rate, tidal volume, blood gas tensions and heart rate were measured. Plasma samples were obtained for determination of theophylline concentrations before, and at 10 min intervals during, the infusion period. Excitability was assessed subjectively at these same time periods. The plasma theophylline concentrations in ponies were well predicted by a previously published model of theophylline pharmacokinetics in the horse. Sterile water had no effect on lung function. Aminophylline produced significant changes in lung function compared to baseline values, including a decrease in resistance at 30 min when the mean plasma theophylline concentration was 59 ± 14 μmol/litre and an increase in compliance at 60 mins at a mean plasma theophylline concentration of 102 ± 23 μmol/litre. Excitement was noted between 40 and 50 mins in all ponies (mean plasma theophylline concentration 74 ± 20 and 84 ±24 μmol/litre, respectively). Heart rate increased at 50 mins. The therapeutic range for intravenous (iv) theophylline concentration in ‘heavey’ ponies therefore appears to be between 59 and 84 μmol/litre when aminophylline is administered iv. Below 59 μmol/litre there was no consistent bronchodilator activity and above 84 μmol/litre excitement and tachycardia limited the usefulness of the drug.
Specific immunotherapy in the treatment ofCulicoideshypersensitive horses: A double‐blind study
Authors: BARBET JOY L. , BEVIER DIANE , GREINER E. C. 
Published: April 2010

SummaryFourteen privately owned horses completed a six month, controlled, double‐blind trial to assess the efficacy of immunotherapy using an aqueous extract of whole, unfedCulicoides variipennisin the treatment ofCulicoideshypersensitivity. Selected horses had a history of a seasonal, pruritic dermatitis, clinical signs and distribution compatible withCulicoideshypersensitivity, failed to improve in response to ivermectin therapy, and reacted to several dilutions ofCulicoidesextracts without significant reactivity to other possible allergens including insects, moulds and feeds. One horse from the control group (n=8) and one from the test group (n=6) improved. Statistically, there was no significant difference between horses onCulicoidesantigen and control horses. In each group, four owners thought that their horses had improved.
Naloxone‐induced abdominal distress in the horse
Authors: KAMERLING S. G. , HAMRA JENA G. , BAGWELL CLEO A. 
Published: April 2010

SummaryEndogenous opioid peptides have been implicated in the regulation of pain perception, behaviour, gastrointestinal activity and other physiological responses. However, the functional role of these peptides in the horse has yet to be elucidated. The opioid antagonist, naloxone, is often administered to infer endogenous opioid effects. In the present study, naloxone (0.75 mg/kg bodyweight) was administered to eight Thoroughbred racehorses and a number of behavioural and autonomic responses were measured. Naloxone produced rapid onset diarrhoea, restlessness, abdominal checking, tachycardia, tachypnoea, paradoxical yawning and diaphoresis. These responses described an acute abdominal distress syndrome similar to spasmodic colic. Results from this study suggest that, in the horse, endogenous opioids: 1) influence behaviour, 2) modify intestinal activity and sensation, and 3) if perturbed, may be involved in pathophysiology of colic.
The excretion of theobromine in Thoroughbred racehorses after feeding compounded cubes containing cocoa husk ‐establishment of a threshold value in horse urine
Authors: HAYWOOD P. E. , TEALE P. , MOSS M. S. 
Published: April 2010

SummaryThoroughbred geldings were fed racehorse cubes containing a predetermined concentration of theobromine in the form of cocoa husk. They were offered 7 kg of cubes per day, divided between morning and evening feed, and food consumption was monitored. Urinary concentrations of theobromine were determined following the consumption of cubes containing 11.5, 6.6, 2.0 and 1.2 mg per kg of theobromine, to verify whether or not such concentrations would produce positive urine tests. Pre‐dose urine samples were collected to verify the absence of theobromine before each experiment. It became apparent from the results of the first three administrations that the limit of detection of theobromine, using such procedures, would be reached at a feed level of about 1 mg per kg theobromine. Therefore the final administration, using cubes containing 1.2 mg per kg theobromine, was singled out for additional analytical work and quantitative procedures were developed to measure urinary concentrations of theobromine. It was anticipated that the results would form a basis for discussions relating to the establishment of a threshold value for theobromine in horse urine. The Stewards of the Jockey Club subsequently gave notice that they had established a threshold level for theobromine in urine of 2 μg/ml.
The stress response to anaesthesia in ponies: barbiturate anaesthesia
Authors: TAYLOR POLLY M. 
Published: April 2010

SummaryInformation on the equine stress response to anaesthesia and surgery is sparse but offers a promising approach to elucidating the high anaesthetic risk in this species. Previous work has shown that halothane anaesthesia induces substantial metabolic and endocrine changes. This paper reports the effects of barbiturate anaesthesia. Anaesthesia was induced with thiopentone in six ponies and no further agents were given. They stood within 30 mins. On another occasion, these animals, and three further ponies, were anaesthetised with pentobarbitone and anaesthesia was maintained for 2 h. No surgery was performed on either occasion. Plasma concentrations of glucose, lactate, non esterified fatty acids, cortisol, insulin, catecholamines and adrenocorticotrophic hormone were measured at the same time intervals in both groups before, during and after anaesthesia. There were no significant changes in hormones or metabolites during either period of anaesthesia and normotension was maintained. This was in marked contrast to the substantial stress response and hypotension under halothane anaesthesia in the same ponies. These results suggest that barbiturates may induce less of a stress response than halothane in horses. Recovery after 2 h of pentobarbitone anaesthesia was poor, precluding its clinical use. The need for a non‐cumulative intravenous agent or a non‐hypotensive volatile agent for use in equine anaesthesia is discussed.
Metabolic and hormonal changes associated with arthroscopic surgery in the horse
Authors: ROBERTSON SHEILAH A. , STEELE CYNTHIA J. , CHEN CHAO‐LING 
Published: April 2010

SummaryThe effect of general anaesthesia and arthroscopic surgery on blood glucose and lactate, plasma non‐esterified fatty acids, insulin, beta‐endorphin and cortisol was investigated in seven horses. Animals were premedicated with xylazine and anaesthesia was induced with guaifenesin and sodium thiamylal and maintained with halothane vaporised in oxygen. Blood samples were collected in the pre‐, intra‐ and post operative period. Induction of anaesthesia was associated with a transient hyperglycaemia and a significant rise in plasma insulin levels. Plasma insulin values fell during surgery but showed a significant increase post operatively. Surgery stimulated a small but significant rise in plasma beta‐endorphin and cortisol values but these had returned to baseline values in the early post operative period. No changes in blood lactate were recorded.
Effect of low‐dose butorphanol on halothane minimum alveolar concentration in ponies
Authors: MATTHEWS NORA S. , LINDSAY S. L. 
Published: April 2010

SummaryMinimum alveolar concentration (MAC) for halothane was measured before and after administration of intravenous butorphanol (0.022 and 0.044 mg/kg in bodyweight in nine yearling Shetland ponies. Arterial blood pressure, heart rate, respiratory rate, expired CO2and rectal temperature was also measured. Even though mean MAC values decreased 10 and 9 per cent after the low and high doses respectively, they were not statistically different from those measured prior to butorphanol. Halothane MAC values increased after butorphanol in two ponies, both animals increasing locomotor activity and demonstrating apparent central nervous system stimulation. No significant differences were seen in any variable measured after butorphanol administration.
A scanning electron microscopic study of the equine upper respiratory tract
Authors: PIRIE MYRTLE , PIRIE H. M. , WRIGHT N. G. 
Published: April 2010

SummaryThe surface features of the upper respiratory tract of 20 clinically normal horses of various ages and types were studied with scanning electron microscopy. In the rostral part of the nasal cavity, there was a wide zone of non‐ciliated epithelium whereas, caudally, the surface was well ciliated. This latter type of epithelium extended into the nasopharynx and guttural pouches although scattered areas of non‐ciliated microvillous cells were also found.