bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiographic changes in Thoroughbred yearlings. Part 2: Associations with racing performance
Authors: KANE A. J. , McILWRAITH C. W. , PARK R. D. , RANTANEN N. W. , MOREHEAD J. P. , BRAMLAGE L. R. 
Published: April 2007

SummaryReasons for performing study: Although the radiographic examination of yearlings has become commonplace at some large Thoroughbred sales, there are few data to support the decisions facing veterinarians who are asked to evaluate future racing potential.Objectives: To identify radiographic changes in the fetlocks, proximal sesamoid bones, carpi, tarsi, stifles and fore feet of Thoroughbred yearlings associated with future racing performance during ages 2 and 3 years.Methods: Radiographs from routine pre‐ and post sale examinations of 1162 yearlings were used to identify individual radiographic changes in sale yearlings. Starting a race, the percent of starts placed, money earned and earnings per start were used to assess racing performance and examined for associations with the radiographic changes observed.Results: Overall 946 (81%) yearlings started at least one race during ages 2 or 3 years. Fourteen of 24 (58%) yearlings with moderate or extreme palmar supracondylar lysis of the third metacarpus, 8 of 14 (57%) of those with enthesophyte formation on the proximal sesamoid bones and 19 of 30 (63%) of those with dorsal medial intercarpal joint disease started a race. The oDs of starting a race when age 2 or 3 years were 3 times lower for yearlings with these changes (P<0.01) compared with yearlings that did not have these changes. Twenty‐five of 36 (69%) yearlings with proximal dorsal fragmentation of the first phalanx in the hind fetlock started a race and these yearlings were also less likely (OR = 0.51, P = 0.07) to start a race. Yearlings with enthesophyte formation on hind proximal sesamoid bones placed in a smaller percentage of starts (16%, P = 0.01) earned less money ($987 US, P = 0.02) and had lower earnings per start ($252 U S, P = 0.03) compared to starters without this change.Conclusions: Although many of the changes observed on radiographs of sale yearlings do not appear to influence future racing performance, some are associated with reduced performance.Potential relevance: The results of this study are best applied in parallel with the clinical impressions of veterinarians experienced in examining radiographs of sale yearlings. Some findings support those established in the literature as incidental findings and others suggest new areas for concern not previously reported as a problem in Thoroughbred sale yearlings.
Effects of alpha‐2 adrenoceptor agonists during recovery from isoflurane anaesthesia in horses
Authors: SANTOS M. , FUENTE M. , GARCIA‐ITURRALDE P. , HERRAN R. , LOPEZ‐SANROMAN J. , TENDILLO F. J. 
Published: April 2007

SummaryReasons for performing study: Recovery from inhalant anaesthesia in the horse is a critical and difficult period to manage; however, several factors could help to obtain a calm recovery period including choice of anaesthetic and analgesic procedure used and the conditions under which anaesthetic maintenance and recovery occur.Objectives: The objective of this study was to evaluate and compare the quality of recovery in horses administered saline, xylazine, detomidine or romifidine during recovery from isoflurane anaesthesia.Methods: Six mature and healthy horses were premedicated with i.v. xylazine and butorphanol, and anaesthesia induced using ketamine. After 2 h of inhalant anaesthesia with isoflurane vaporised in oxygen, saline solution, xylazine (0.1 mg/kg bwt), detomidine (2 μg/kg bwt) or romifidine (8 μg/kg bwt) were administered. The quality of recovery of each horse and the degree of sedation and ataxia were evaluated. Cardiovascular and respiratory parameters were recorded, and arterial blood samples obtained and analysed for pH, PO2and PCO2during recovery.Results: Quality of recovery was better in groups treated with alpha‐2 adrenergic receptors agonists, showing less ataxia. Degree of sedation was greater in the romifidine group.Conclusions: We concluded that the administration of alpha‐2 adrenoceptor agonists during recovery from isoflurane anaesthesia in horses prolonged and improved the quality of recovery without producing significant cardiorespiratory effects.Potential clinical relevance: Administration of alpha‐2 adrenoceptor agonists after inhalent anaesthesia could prevent complications during the recovery period.
Pregnancy rates in mares after a single fixed time hysteroscopic insemination of low numbers of frozen‐thawed spermatozoa onto the uterotubal junction
Authors: MORRIS L. H. A. , TIPLADY C. , ALLEN W. R. 
Published: April 2007

Summary Reasons for performing study: To compensate for the wide variation in the freezability of stallion spermatozoa, it has become common veterinary practice to carry out repeated ultrasonography of the ovaries of oestrous mares in order to be able to inseminate them within 6–12 h of ovulation with a minimum of 300–500 × 106 frozen‐thawed spermatozoa. Furthermore, in order to achieve satisfactory fertility, this requirement for relatively high numbers of spermatozoa currently limits our ability to exploit recently available artificial breeding technologies, such as sex‐sorted semen, for which only 5–20 × 106 spermatozoa are available for insemination. Objectives: This study was designed to evaluate and compare the efficacy of hysteroscopic vs. conventional insemination when low numbers of spermatozoa are used at a single fixed time after administration of an ovulation‐inducing agent. Methods: In the present study, pregnancy rates were compared in 86 mares inseminated once only with low numbers of frozen‐thawed spermatozoa (3–14 × 106) at 32 h after treatment with human chorionic gonadotrophin (hCG), either conventionally into the body of the uterus or hysteroscopically by depositing a small volume of the inseminate directly onto the uterotubal papilla ipsilateral to the ovary containing the pre‐ovulatory follicle. Results: Pregnancy rates were similarly high in mares inseminated conventionally or hysteroscopically with 14 × 106 motile frozen‐thawed spermatozoa (67% vs. 64%). However, when the insemination dose was reduced to 3 × 106 spermatozoa, the pregnancy rate was significantly higher in the mares inseminated hysteroscopically onto the uterotubal junction compared to those inseminated into the uterine body (47 vs. 15%, P<0.05). Conclusions: When inseminating mares with <10 × 106 frozen‐thawed stallion spermatozoa, hysteroscopic uterotubal junction deposition of the inseminate is the preferred method. Potential clinical relevance: Satisfactory pregnancy rates are achievable after insemination of mares with frozen‐thawed semen from fertile stallions 32 h after administration of human chorionic gonadotrophin (Chorulon)1. Furthermore, these results were obtained when mares were inseminated with 14 × 106 progressively motile frozen‐thawed spermatozoa from 2 stallions of proven fertility.
Uptake of 5‐hydroxytryptamine by equine digital vein endothelial cells: inhibition by amines found in the equine caecum
Authors: BAILEY S. R. , WHEELER‐JONES C. , ELLIOTT J. 
Published: April 2007

SummaryReasons for performing study: 5‐hydroxytryptamine (5‐HT; serotonin) is a potent vasoconstrictor of equine digital blood vessels and has been implicated in the pathogenesis of acute laminitis.Objectives: The aims of this study were firstly to examine whether cells of the digital blood vessel wall exhibited an active uptake mechanism for 5‐HT and to characterise its efficiency; and secondly, to study the potential inhibitory effect on this process of other amines, produced in the equine caecum.Methods: Confluent monolayers of equine digital vein endothelial cells (EDVEC) and equine digital vein smooth muscle cells (EDVSMC) were incubated with [3H]5‐HT (0.1–250 μmol/l) and the total and active uptake calculated. Equine pulmonary vein endothelial cells (EPVEC) were used as a positive control.Results: Both EDVEC and EDVSMC showed uptake of [3H]5‐HT by nonfaci litated diffusion; however, only EDVEC showed evidence of saturable facilitated uptake mechanism, with a Kmof 41.6 ± 9.3 μmol/l, which was significantly higher than that of EPVEC (9.9 ± 2.1 μmol/l). All 6 caecally‐derived amines examined (tyramine, spermine, isoamylamine, tryptamine, phenylethylamine and isobutylamine) inhibited the total uptake of [3H]5‐HT in a concentration‐dependent manner, tyramine having the lowest IC50(3.7 × 10−6mol/l).Conclusions: These data suggest that facilitated uptake into the endothelium could play a role in moderating the vasoconstrictor response to 5‐HT in the equine digital circulation.Potential clinical relevance: The vasoconstrictor action of 5‐HT could be potentiated by gut‐derived amines, providing a feasible link between GI disturbances and the pathophysiology of laminits.
Systemic concentrations of antioxidants and biomarkers of macromolecular oxidative damage in horses with grass sickness
Authors: McGORUM B. C. , WILSON R. , PIRIE R. S. , MAYHEW I. G. , KAUR H. , ARUOMA O. I. 
Published: April 2007

Summary Reasons for performing study: The aetiopathogenesis of equine grass sickness (EGS) is unknown. The role of free radical‐mediated neuronal damage has not previously been investigated in this condition. Objectives: To investigate the potential contribution of oxidative damage and antioxidant status to neurodegeneration in EGS. Methods: Systemic levels of surrogate biomarkers were determined in 10 horses with acute EGS and in 2 control populations; 10 healthy horses co‐grazing with the 10 EGS horses at the onset of clinical disease, and 10 healthy mares grazing where EGS has not been reported. Results: EGS horses had alterations in levels of several antioxidants, consistent with oxidative stress, the acute phase response and/or the secondary metabolic complications of EGS. EGS horses had elevated plasma dihydroxyphenylalanine (DOPA) levels. Conclusions: The elevated DOPA levels probably reflected a generalised disturbance of catecholamine metabolism rather than increased DOPA production via free radical‐mediated oxidation of tyrosine. However, there was no evidence of systemic macromolecular oxidative damage. Potential clinical relevance: Further work is required to determine whether macromolecular oxidative damage occurring at the neuronal level contributes to EGS.
Equine melanoma in a population of 296 grey Lipizzaner horses
Authors: SELTENHAMMER M. H. , SIMHOFER H. , SCHERZER S. , ZECHNER P. , CURIK I. , SÖLKNER J. , BRANDT S. M. , JANSEN B. , PEHAMBERGER H. , EISENMENGER E. 
Published: April 2007

SummaryReasons for performing study: Equine melanomas occur most commonly in grey horses at age 5 years or more. Generally, benign and malignant melanomas are distinguished by microscopy, but a more distinct classification would be helpful.Objectives: The objectives of this study were to gain further evidence concerning the occurrence of melanotic tumours, and to evaluate the impact of heredity on melanoma development.Methods: A clinical study was conducted on a defined population of 296 grey horses of Lipizzaner breed. Individuals were classified according to theirstage of disease using a 0–5 scale. Heritability was estimated on a sample of 296 grey horses with pedigrees traced back as far as 32 generations.Results: Of the 296 horses, dermal melanomas were present in 148 horses (50%), 68 of which were more than age 15 years; 51 of these were melanoma‐bearing. In 75.6% of cases, melanotic tumours were detected underneath the tail. Although melanoma‐bearing grey horses were encountered up to stage 4, none of the affected individuals suffered any severe clinical effect or was handicapped in performance. Statistical analysis revealed highly significant effects of stud and age (P<0.0001), explaining 28% of the total variability.Conclusions: In contrast to melanomas in solid‐coloured horses characterised by early metastases, melanomas in grey horses showed less malignancy. Affected individuals often had encapsulated nodules or structures similar to human blue nevi. Grey horse‐specific genetic factors inhibiting metastatic processes may be responsible for this phenomenon.Potential clinical relevance: Although the obtained heritability estimate of 0.36 with a standard error of 0.11 indicates a strong genetic impact on the development of melanoma in ageing grey horses, a possible influence of the genes with large effects was also suggested. Therefore, further analysis is required of melanoma development in the ageing grey horse.
Tenosynovitis of the digital flexor tendon sheath and annular ligament constriction syndrome caused by longitudinal tears in the deep digital flexor tendon: a clinical and surgical report of 17 cases in Warmblood horses
Authors: WILDERJANS H. , BOUSSAUW B. , MADDER K. , SIMON O. 
Published: April 2007

Summary Reasons for performing study: Inflammation of the digital flexor tendon sheaths is a chronic and nebulous condition often unresponsive to medical and surgical treatment. Objectives: To evaluate the incidence of longitudinal tears (LT) as the underlying cause of chronic tenosynovitis and annular ligament constriction syndrome (ALCS) in warmblood horses. Methods: The records of 25 horses with chronic tenosynovitis and ALCS in which tenoscopical inspection of the digital flexor tendon sheath (DFTS) was performed between 1999–2000 were reviewed. Of 25 horses, 17 were diagnosed with an LT in the deep digital flexor tendon (DDFT). All horses had a history of distension of the DFTS and/or signs of an ALCS. All cases presented typical signs of a chronic inflamed DFTS on ultrasonography and 11 horses showed ultrasonographic changes (echogenic material or an irregular outlining) at the lateral or medial border of the DDFT. The diagnosis of LTs of the DDFT was established in all cases by tenoscopy. Surgical treatment consisted of removal of the torn collagen fibrils using a mechanical resector and decompressing the fetlock canal by a transection of the palmar annular ligament (PAL) using a hook knife under tenoscopic control. Results: Ten horses became sound and resumed their previous level of work, 3 horses remained lame, 4 horses returned to previous level of work but needed intrasynovial treatment of the DFTS and reduced competition frequency to remain sound. Conclusions: Horses presented with chronic inflamed DFTS and/or ALCS might sufferfrom LTs in the DDFT; however, the diagnosis cannot be established with absolute certainty using only ultrasonography. Longitudinal tears should be suspected if ultrasonographic changes are present lateral or medial to the border of the DDFT but tenoscopical examination of the tendon sheath is essential to establish an accurate diagnosis and an effective treatment. Potential relevance: The presence of these LTs might explain why some cases of chronic tenosynovitis of the digital flexor tendon sheath and/or ALCS do not respond on surgical transection of the PAL alone without tenoscopy.
Spectral analysis of respiratory noise in horses with upper airway disorders
Authors: FRANKLIN S. H. , USMAR S G. , LANE J. G. , SHUTTLEWORTH J. , BURN J. F. 
Published: April 2007

SummaryReasons for performing study: It has long been recognised that the production of abnormal respiratory sounds by horses during exercise is frequently associated with upper airway obstructions. Respiratory acoustic measurements have shown promise in investigation of upper airway disorders in man and, more recently, in horses with experimentally‐induced obstructions.Objectives: To evaluate sounds from exercising horses with naturally occurring dynamic obstructions of the upper respiratory tract and to compare these with those from normal horses in order to determine whether different obstructions produce characteristic spectral patterns.Methods: The audio signal, airflow and videoendoscopic images were recorded simultaneously during an incremental exercise test on a high‐speed treadmill.Results: Spectral analysis of the audio signal showed marked differences between control and clinically afflicted horses. Dorsal displacement of the soft palate was characterised by a narrow low frequency (20–80 Hz) peak during expiration. Horses with dynamic laryngeal collapse produced inspiratory sounds characterised by a broad band high frequency spectral component in the range 1.1–2.7 kHz.Conclusions and potential relevance: Spectral analysis of respiratory sounds in horses has potential as a diagnostic technique for field use especially when facilities for highspeed treadmill assessment are not practicable.
Management of drug‐resistant cyathostominosis on a breeding farm in central North Carolina
Authors: LITTLE D. , FLOWERS J. R. , HAMMERBERG B. H. , GARDNER S. Y. 
Published: April 2007

Summary Reasons for performing study: Possible anthelmintic resistance on a breeding farm where a rapid rotation anthelmintic programme had been implemented for 9 years was investigated. Cyathostomins resistant to fenbendazole and pyrantel were documented by faecal worm egg count reduction test (FWECRT). Objectives: To 1) manage small strongyle transmission in a herd of horses in which resistance to both pyrantel pamoate and fenbendazole was identified and thereby reduce the risk of clinical disease in the individual animal, 2) monitor the change in resistance patterns over time and 3) monitor the efficacy of ivermectin over the study period. Methods: Targeted ivermectin treatment of horses on the farm was instituted formature horses with faecal worm egg counts (FWEC) >200 eggs/g (epg) and for horses <age 2 years with FWEC >100 epg. Results: Over a 30 month period, targeted ivermectin treatment achieved acceptable control in mares, as judged by FWEC, and improved control of patent cyathostome infection in consecutive foal crops. Egg reappearance time (ERT) after treatment with ivermectin was <8 weeks in mares and foals more frequently in the second year of the study than in the first year. Numbers of anthelmintic treatments were reduced by 77.6 and 53.3% in the mare and foal group, respectively. Conclusions: Targeted ivermect in treatment may be an economically viable method of managing multiple drug resistant cyathostominosis. Potential relevance: Use of ivermectin should be monitored closely for development of resistance.
Are the material properties and matrix composition of equine flexor and extensor tendons determined by their functions?
Authors: BATSON E. L. , PARAMOUR R. J. , SMITH T. J. , BIRCH H. L. , PATTERSON‐KANE J. C. , GOODSHIP A. E. 
Published: April 2007

SummaryReasons for performing study: Injury to the superficial digital flexor tendon (SDFT) is common in competition horses. The SDFT contributes to locomotory efficiency by storing energy; such tendons have low safety margins. Tendons which merely position the limb, including the opposing common digital extensortendon (CDET), are rarely injured. The current failure of strategies to prevent or effectively treat injury to the SDFT indicates the importance of understanding how it differs from tendons which are not injury‐prone.Hypothesis: That the structural and material properties and matrix composition of the SDFT and CDET differ, reflecting their specific functional requirementsin vivo.Methods: Forelimb tendons were harvested from 26 mature horses and loaded to failure prior to matrix composition analysis of specimens.Results: The SDFT had a significantly higher cross‐sectional area, structural stiffness, failure load and failure strain and a lower elastic modulus than the CDET(P < 0.0001).Conclusions: The SDFT has conflicting requirements for strength and elasticity; although as a whole it is a stiffer structure than the CDET, differences in the matrix molecular composition including water and total sulphated glycosaminoglycan contents allow it to remain more elastic as a material.Potential relevance: Further information on how the two tendons attain these different properties may be of use in the development of prevention and treatment strategies for SDFT rupture.
Medetomidine‐ketamine anaesthesia induction followed by medetomidine‐propofol in ponies: infusion rates and cardiopulmonary side effects
Authors: BETTSCHART‐WOLFENSBERGER R. , BOWEN I. M. , FREEMAN S. L. , WELLER R. , CLARKE K. W. 
Published: April 2007

SummaryReasons for performing study: To search for long‐term total i.v. anaesthesia techniques as a potential alternative to inhalation anaesthesia.Objectives: To determine cardiopulmonary effects and anaesthesia quality of medetomidine‐ketamine anaesthesia induction followed by 4 h of medetomidine‐propofol anaesthesia in 6 ponies.Methods: Sedation consisted of 7 μg/kg bwt medetomidine i.v. followed after 10 min by 2 mg/kg bwt i.v. ketamine. Anaesthesia was maintained for 4 h with 3.5 μg/kg bwt/h medetomidine and propofol at minimum infusion dose rates determined by application of supramaximal electrical pain stimuli. Ventilation was spontaneous (FIO2> 0.9). Cardiopulmonary measurements were always taken before electrical stimulation, 15 mins after anaesthesia induction and at 25 min intervals.Results: Anaesthesia induction was excellent and movements after pain stimuli were subsequently gentle. Mean propofol infusion rates were 0.89–0.1 mg/kg bwt/min. No changes in cardiopulmonary variables occured over time. Range of mean values recorded was: respiratory rate 13.0–15.8 breaths/min; PaO229.1–37.9 kPa; PaCO26.2–6.9 kPa; heart rate 31.2–40.8 beats/min; mean arterial pressure 90.0–120.8 mmHg; cardiac index 44.1–59.8 ml/kg bwt/min; mean pulmonary arterial pressure 11.8–16.4 mmHg. Recovery to standing was an average of 31.1 mins and ponies stood within one or 2 attempts.Conclusions: In this paper, ketamine anaesthesia induction avoided the problems encountered previously with propofol. Cardiovascular function was remarkably stable. Hypoxaemia did not occurbut, despite FIO2of >0.9, minimal PaO2in one pony after 4 h anaesthesia was 8.5 kPa.Potential relevance: The described regime might offer a good, practicable alternative to inhalation anaesthesia and has potential for reducing the fatality rate in horses.
The role of electromyography in clinical diagnosis of neuromuscular locomotor problems in the horse
Authors: WIJNBERG I. D. , BACK W. , DE JONG M. , ZUIDHOF M. C. , VAN DEN BELT A. J. M. , VAN DER KOLK J. H. 
Published: April 2007

Summary Reasons for performing study: Systematically performed EMG needle examination of muscles provides essential information about the functional aspects of the motor unit. However, clinical studies in which information is given on the diagnostic and discriminative values of electromyography (EMG) in the horse are scarce. Objectives: To determine to what extent inclusion of EMG analysis in clinical examination contributes to determination of type and localisation of abnormality. Methods: EMG analysis, complete clinical examination and diagnosis of 108 horses (mean ± s.d. age 7.5 ± 3.8 years; bodyweight 548 ± 86 kg; height 1.67 ± 0.07 m) were performed, and results without and with EMG analysis compared. Results: Without EMG, myopathy and neuropathy were diagnosed in 20 and 58 horses, respectively, and with EMG in 17 and 82 horses. EMG changed localisation in myopathy and neuropathy in 12 and 37% of cases, respectively. Lesions in the C1‐T2, T2‐L3 and L3‐S3 segments were, respectively, diagnosed without EMG in 7, 11 and 30%, and with EMG in 27, 7 and 17% of cases. Where no clinical diagnosis could be made prior to EMG, many patients appeared to be suffering from localised cervical lesions (29%) or generalised neuropathy (54%). Conclusions and potential relevance: The assistance of EMG in discriminating between normal, neuropathy and myopathy, and in locating pathology, contributes to diagnosis of neuromuscular problems.