Publications by authors named "Daniel G Kenney"

16 Publications

  • Page 1 of 1

Case-Control Comparison of Cervical Spine Radiographs From Horses With a Clinical Diagnosis of Cervical Facet Disease With Normal Horses.

J Equine Vet Sci 2020 Sep 20;92:103176. Epub 2020 Jun 20.

Oberbichler Equine Services, Wellesley, ON, Canada.

The accuracy of using radiographs to diagnose cervical facet osteoarthritis (CFA) in horses is undetermined. Further investigation is required to determine the clinical significance of radiographic evidence of CFA, the prevalence of radiographic changes in horses without clinical signs, and the long-term efficacy of intra-articular CFA treatment. The objectives of this study is to compare degenerative changes of the cervical facet joints of the cervical vertebrae on radiographs of horses with clinical signs of CFA with healthy cohort-matched horses, to compare clinical findings between groups, and to obtain follow-up information on the long-term outcome in treated horses. This is a retrospective case-control cohort-matched comparison study of horses treated for cervical facet disease versus horses with no clinical signs of cervical facet disease. Horses diagnosed with CFA and treated with intra-articular injection of corticosteroids were included. Follow-up information on recovery from treatment was obtained via telephone survey of owners/trainers. Healthy horses with no clinical signs of CFA were matched to treated horses by breed, sex, age, and sport as the control group. Two blinded radiologists reviewed cervical spine radiographs for each horse and recorded CFA score and intravertebral/intervertebral measurements. Clinical and radiographic parameters were compared between treatment and control groups. There was a significant difference in CFA grades for C5-6 and C6-7 between horses with presence of clinical signs and healthy horses. However, interobserver agreement between radiologists for grading CFA was moderate and only 56% of values were identical for both observers. Atrophy of the neck was present on clinical examination in most cases in the treatment group. Dressage horses were overrepresented. Overall, 64% of horses returned to their previous level of performance after treatment. Clinical examination data collected for the treatment group were retrospective and were obtained by different clinicians. Eight owners/trainers were not able to be reached for the survey. There was a significant difference in CFA grades for C5-6 and C6-7 between horses with presence of clinical signs and healthy horses. Despite these statistical differences, the clinical diagnosis of CFA based on radiographic grading alone is questionable because of the lack of agreement between the radiologists. To strengthen the diagnosis, clinical signs of facet disease, in particular atrophy of the neck muscles, need to be present to make this diagnosis. Intra-articular corticosteroid injection was effective at allowing most treated horses to return to athletic use..
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http://dx.doi.org/10.1016/j.jevs.2020.103176DOI Listing
September 2020

Normograde nasolacrimal placement of an ocular-lavage system for treatment of equine eye diseases.

Can Vet J 2019 Jul;60(7):744-748

Ontario Veterinary College - Health Sciences Centre, Department of Clinical Studies, University of Guelph, Guelph, Ontario N1G 2W1.

The standard placement of a subpalpebral lavage system may not be feasible in some horses with eyelid disease. We describe placement of a commercially available, indwelling nasolacrimal lavage system that circumvents eyelid perforation. This novel approach provided for effective delivery of drugs to 1 horse with periocular and corneal disease.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6563880PMC
July 2019

Klossiella equi Infecting Kidneys of Ontario Horses: Life Cycle Features and Multilocus Sequence-Based Genotyping Confirm the Genus Klossiella Belongs In the Adeleorina (Apicomplexa: Coccidia).

J Parasitol 2019 02;105(1):29-40

1 Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada.

Species in the genus Klossiella Smith and Johnson, 1902 are unique among the suborder Adeleorina because they are monoxenous in mammals exclusively, whereas all other reported members of the Adeleorina use invertebrates as definitive hosts. Unlike other coccidia, all members of the Adeleorina undergo syzygy, the association of microgamonts and macrogamonts before maturation to gametes and syngamy. After fertilization, many members of the Adeleorina produce thin-walled polysporocystic oocysts. Despite being biologically similar to other members of the Adeleorina, the phylogenetic placement of the genus Klossiella has been questioned based on its unique host affinity. In the present study, 2 cases of Klossiella equi were reported from the kidneys of horses in Ontario. Details of the life cycle as well as mitochondrial and nuclear 18S ribosomal DNA ( 18S rDNA) sequences were analyzed to provide both morphological and molecular evidence for the phylogenetic placement of K. equi. Initially, various stages of the life cycle were identified in histological slides prepared from the kidney tissue, and DNA was isolated from the infected tissue. Polymerase chain reaction and Sanger sequencing were used to generate a complete mitochondrial genome sequence (6,569 bp) and a partial 18S rDNA sequence (1,443 bp). The K. equi 18S rDNA sequence was aligned with various publicly available apicomplexan 18S rDNA sequences. This alignment was used to generate a phylogenetic tree based on Bayesian inference. Multiple K. equi stages were identified including meronts, microgamonts, and macrogamonts associating in syzygy as well as thin-walled oocysts in various stages of sporogonic development. The 18S rDNA sequence of K. equi positioned within the monophyletic Adeleorina clade. The mitochondrial genome of K. equi contained 3 coding sequences for cytochrome c oxidase I, cytochrome c oxidase III, and cytochrome b as well as various fragmented ribosomal sequences. These components were arranged in a unique order that has not been observed in other apicomplexan mitochondrial genomes sequenced to date. Overall, it was concluded that there were sufficient morphological and molecular data to confirm the placement of K. equi and the genus Klossiella among the Adeleorina. The biological and molecular data obtained from these cases may assist with future studies evaluating the prevalence and life history of this seemingly underreported parasite and better define the impact of K. equi on the health of domestic and wild equids.
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February 2019

Copy number variation in the horse genome.

PLoS Genet 2014 Oct 23;10(10):e1004712. Epub 2014 Oct 23.

Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, College Station, Texas, United States of America.

We constructed a 400K WG tiling oligoarray for the horse and applied it for the discovery of copy number variations (CNVs) in 38 normal horses of 16 diverse breeds, and the Przewalski horse. Probes on the array represented 18,763 autosomal and X-linked genes, and intergenic, sub-telomeric and chrY sequences. We identified 258 CNV regions (CNVRs) across all autosomes, chrX and chrUn, but not in chrY. CNVs comprised 1.3% of the horse genome with chr12 being most enriched. American Miniature horses had the highest and American Quarter Horses the lowest number of CNVs in relation to Thoroughbred reference. The Przewalski horse was similar to native ponies and draft breeds. The majority of CNVRs involved genes, while 20% were located in intergenic regions. Similar to previous studies in horses and other mammals, molecular functions of CNV-associated genes were predominantly in sensory perception, immunity and reproduction. The findings were integrated with previous studies to generate a composite genome-wide dataset of 1476 CNVRs. Of these, 301 CNVRs were shared between studies, while 1174 were novel and require further validation. Integrated data revealed that to date, 41 out of over 400 breeds of the domestic horse have been analyzed for CNVs, of which 11 new breeds were added in this study. Finally, the composite CNV dataset was applied in a pilot study for the discovery of CNVs in 6 horses with XY disorders of sexual development. A homozygous deletion involving AKR1C gene cluster in chr29 in two affected horses was considered possibly causative because of the known role of AKR1C genes in testicular androgen synthesis and sexual development. While the findings improve and integrate the knowledge of CNVs in horses, they also show that for effective discovery of variants of biomedical importance, more breeds and individuals need to be analyzed using comparable methodological approaches.
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http://dx.doi.org/10.1371/journal.pgen.1004712DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4207638PMC
October 2014

Methicillin-resistant Staphylococcus aureus in a neonatal alpaca.

Can Vet J 2012 Jun;53(6):670-2

Department of Pathobiology, Ontario Veterinary College, University of Guelph, Ontario, Canada.

A 6-hour-old alpaca was presented for evaluation of respiratory difficulty. As part of routine surveillance, methicillin-resistant Staphylococcus aureus (MRSA) was identified from a nasal swab taken upon admission to the hospital. No signs of MRSA infection were noted. The MRSA strain recovered was a human epidemic clone that has been associated with horses. Methicillin-resistant S. aureus colonization can occur in camelids, and the potential animal and public health risks require consideration.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3354829PMC
June 2012

Removal of a nasogastric tube fragment from the stomach of a standing horse.

Can Vet J 2012 Jan;53(1):83-5

Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1.

An 82-cm fragment of nasogastric tube was removed from the stomach of an adult horse under standing sedation by use of an endoscope and electrocautery snare. This is the first report of successful non-surgical removal of a nasogastric tube fragment from the stomach of a horse.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3239156PMC
January 2012

Influence of electrode position on cardioversion energy requirements during transvenous electrical cardioversion in horses.

Am J Vet Res 2011 Sep;72(9):1193-203

BSC (Hons) Program, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.

Objective: To evaluate influence of electrode position on cardioversion energy (CE; energy delivered in the shock at which cardioversion was achieved) during transvenous electrical cardioversion (TVEC) in horses with atrial fibrillation.

Animals: 37 horses with atrial fibrillation (41 cardioversion events).

Procedures: Records were reviewed to identify horses that underwent TVEC for treatment of atrial fibrillation. Signalment and CE were recorded. Electrode positions in the right atrium and pulmonary artery were identified on intraoperative radiographs. An orthogonal coordinate space was created, and electrode y- and z-axis coordinates and shadow lengths were determined. Trigonometric modeling was used to estimate x-axis electrode positions that resulted in observed shadows. Postmortem casts of catheterized horses were used to assess electrode paths and anatomic relationships. Model assumptions were tested by use of these and a theoretical data set. Relationships between signalment, electrode position, and CE were assessed via multivariate analysis.

Results: Sex and y-axis differences between electrode positions were significant predictors of CE. Population stratification based on examination of residuals improved model strength; populations differed in z-axis variables and in CE. Decreasing distance between electrodes and pulmonary artery electrode positions ventral to the right atrium were associated with increased CE. Agreement between estimated and actual x-axis coordinates was poor.

Conclusions And Clinical Relevance: Optimal electrode positioning can reduce the energy requirement for successful TVEC and may eventually support application of TVEC under short-term IV anesthesia and potentially increase chances of treatment response. Further investigation into these relationships is warranted.
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http://dx.doi.org/10.2460/ajvr.72.9.1193DOI Listing
September 2011

Management and complications of anesthesia for transvenous electrical cardioversion of atrial fibrillation in horses: 62 cases (2002-2006).

J Am Vet Med Assoc 2007 Oct;231(8):1225-30

Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.

Objective: To describe management of anesthesia for transvenous electrical cardioversion (TVEC) in horses and report perianesthetic complications.

Design: Retrospective case series.

Animals: 62 horses with atrial fibrillation and without underlying cardiac disease and 60 horses without atrial fibrillation.

Procedures: Medical records of horses with atrial fibrillation anesthetized for TVEC were reviewed, as were records of horses without atrial fibrillation anesthetized for magnetic resonance imaging (MRI). The TVEC group horses were compared with MRI group horses for incidence of intraoperative bradycardia and use of inotropic drugs. Data obtained included patient signalment, weight, duration of anesthesia, heart rate and arterial blood pressure during anesthesia, anesthetic drugs administered, mode of ventilation, perioperative complications, and quality of recovery.

Results: The TVEC group horses were > 1 year of age and were predominantly Standardbreds. The TVEC group horses underwent a total of 76 anesthetic episodes. For 40 (52.6%) anesthetic episodes, horses received xylazine only for premedication, and for 26 (34.2%) anesthetic episodes, horses received xylazine and butorphanol. Induction of anesthesia consisted of ketamine administration in various combinations with diazepam and guaifenesin for 74 (97.4%) anesthetic episodes and ketamine alone for 2 (2.6%). Bradycardia in horses was encountered during 15 of 76 (19.7%) anesthetic episodes. Minor signs of possible postanesthetic myopathy occurred following 6 (7.9%) anesthetic episodes. No significant difference was found between TVEC and MRI group horses regarding incidence of bradycardia and inotropic drug administration.

Conclusions And Clinical Relevance: Short-duration anesthesia for TVEC of atrial fibrillation in horses without underlying cardiac disease was a safe procedure.
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http://dx.doi.org/10.2460/javma.231.8.1225DOI Listing
October 2007

Use of somatic cell nuclear transfer to study meiosis in female cattle carrying a sex-dependent fertility-impairing X-chromosome abnormality.

Cloning Stem Cells 2007 ;9(1):118-29

Department of Biomedical Science, University of Guelph, Guelph, Ontario, Canada.

Animal models have played an important part in establishing our knowledge base on reproduction, development, and the occurrence and impact of chromosome abnormalities. Translocations involving the X chromosome and an autosome are unique in that they elicit sex-dependent infertility, with male carriers rendered sterile by synaptic anomalies during meiosis, whereas female carriers conceive but repeatedly abort. Until now the limited access to relevant fetal oocytes has precluded direct study of meiotic events in female carriers. Because somatic cell nuclear transfer (SCNT) circumvents meiotic problems associated with fertility disturbances in translocation carriers, we used SCNT to generate embryos, fetuses, and calves from a cell line derived from a deceased subfertile X-autosome translocation carrier cow to study the meiotic configurations in carrier oocytes. Data from 33 replicates involving 2470 oocyte-donor-cell complexes were assessed for blastocyst development and of these, 42 blastocysts were transferred to 21 recipients. Fourteen pregnancies were detected on day 35 of gestation. One of these was sacrificed for ovary retrieval on day 94 and three went to term. Features of oocytes from the fetal ovary and from the newborn ovaries were examined. Of the pachytene spreads analyzed, 16%, 82%, and 1.5% exhibited quadrivalent, trivalent/univalent, and bivalent/univalent/univalent structures, respectively, whereas among the diakinesis/metaphase I spreads, 16% ring, 75% chain, and 8.3% bivalent/bivalent configurations were noted, suggesting that the low fertility among female carriers may be related to synaptic errors in a predominant proportion of oocytes. Our results indicate that fibroblasts carrying the X-autosome translocation can be used for SCNT to produce embryos, fetuses, and newborn clones to study such basic aspects of development as meiosis and to generate carriers that cannot easily be reproduced by conventional breeding.
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http://dx.doi.org/10.1089/clo.2006.0036DOI Listing
June 2007

Adverse extrapyramidal effects in four horse given fluphenazine decanoate.

J Am Vet Med Assoc 2006 Jul;229(1):104-10

Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada.

Case Description: 4 racehorses were examined because of markedly abnormal behavior following administration of fluphenazine decanoate.

Clinical Findings: Clinical signs included restlessness, agitation, profuse sweating, hypermetria, aimless circling, intense pawing and striking with the thoracic limbs, and rhythmic swinging of the head and neck alternating with episodes of severe stupor. Fluphenazine was detected in serum or plasma from all 4 horses. The dose of fluphenazine decanoate administered to 3 of the 4 horses was within the range (25 to 50 mg) routinely administered to adult humans.

Treatment And Outcome: In 2 horses, there was no response to IV administration of diphenhydramine hydrochloride, but the abnormal behavior in these 2 horses appeared to resolve following administration of benztropine mesylate, and both horses returned to racing. The other 2 horses responded to diphenhydramine administration. One returned to racing. The other was euthanized because of severe neurologic signs, respiratory failure, and acute renal failure.

Clinical Relevance: Findings indicate that adverse extrapyramidal effects may occur in horses given fluphenazine decanoate. These effects appear to be unpredictable and may be severe and life threatening. Use of fluphenazine decanoate as an anxiolytic in performance horses is not permitted in many racing and horse show jurisdictions, and analytic procedures are now available to detect the presence of fluphenazine in serum or plasma.
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http://dx.doi.org/10.2460/javma.229.1.104DOI Listing
July 2006

Inflammatory aural polyp in a horse.

Can Vet J 2006 Jan;47(1):65-6

Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario.

An inflammatory aural polyp was identified in a 1-year-old standardbred filly, which presented with otorrhea and head rubbing. The polyp was removed by traction-avulsion, and the filly showed no subsequent signs of otorrhea. Aural polyps have not been reported in horses, but they are commonly seen in companion animals and humans.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1316124PMC
http://dx.doi.org/10.4141/cjas67-009DOI Listing
January 2006

How to perform transvenous electrical cardioversion in horses with atrial fibrillation.

J Vet Cardiol 2005 Nov 15;7(2):109-19. Epub 2005 Nov 15.

Veterinary Teaching Hospital, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.

Electrical cardioversion of atrial fibrillation is a well-established technique for restoration of sinus rhythm in humans. While transthoracic cardioversion is more commonly used, transvenous electrical cardioversion (TVEC) has been reported as having higher efficacy at substantially lower energy levels. In horses, treatment of atrial fibrillation has essentially been limited to the administration of quinidine salts either orally or intravenously. TVEC provides an alternative to quinidine salts, especially for those animals in which quinidine is neither effective nor tolerated. The present report details this technique in horses, discusses possible complications of the procedure, and provides guidance for successful outcome. Still and video images are used to illustrate details with regard to TVEC techniques in horses. Please view supplemental material for the videos.
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http://dx.doi.org/10.1016/j.jvc.2005.09.001DOI Listing
November 2005

Transvenous electrical cardioversion of equine atrial fibrillation: technical considerations.

J Vet Intern Med 2005 Sep-Oct;19(5):695-702

Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.

Conventional treatment of equine atrial fibrillation (AF) involves administration of quinidine salts. Most uncomplicated cases respond to treatment, but pharmacologic cardioversion involves a range of adverse effects, and some horses are unable to tolerate medication. A study was undertaken to develop transvenous electrical cardioversion (TVEC) as an alternative treatment. Safety issues and catheter placement techniques with catheter-integrated cardioversion electrodes were investigated, and responses to shock application were evaluated. After the premortem catheterization of elective-euthanasia horses, no tissue abnormalities were detected at postmortem examination. To evaluate the response to the application of shocks and appropriate electrode positions, an electrical cardioversion of research horses in chronic AF was then attempted. After catheterization of the right atrium (RA) and pulmonary artery through the right jugular vein, horses were placed under general anesthesia. Biphasic, truncated exponential shock waves were delivered at incremental energies until cardioversion was achieved or until a maximum energy of 300 J was reached. Five treatment events were applied to 3 horses, with cardioversion achieved in one of the treatment events. No adverse effects of cardioversion attempts or general anesthesia were observed. The procedure was then applied to 8 client-owned horses, with cardioversion achieved in 7. No adverse responses to appropriately delivered shocks were observed. No antiarrhythmic medications were administered to any horse at any stage. Catheter design and placement technique evolved throughout the study, with combined ultrasonography and pressure guidance proving most effective in achieving appropriate electrode placement. Results suggest TVEC, as applied in the present study, is a safe, effective, and realistic therapeutic option for equine AF.
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http://dx.doi.org/10.1892/0891-6640(2005)19[695:tecoea]2.0.co;2DOI Listing
January 2006

Transvenous electrical cardioversion in equine atrial fibrillation: technique and successful treatment of 3 horses.

J Vet Intern Med 2003 Sep-Oct;17(5):715-8

Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.

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December 2003

West Nile virus encephalomyelitis in horses in Ontario: 28 cases.

Can Vet J 2003 Jun;44(6):469-73

Department of Clinical Studies, Ontario Veterinary College, Guelph, Ontario N1G 2W1.

West Nile virus encephalomyelitis was diagnosed in 28 horses presented to the Ontario Veterinary College Veterinary Teaching Hospital between August 20 and October 15, 2002. The age range of affected horses was 5 months to 20 years (mean 6.9 years, median 6 years). Clinical signs were highly variable. Duration of hospitalization ranged from < 1 to 12 days (mean 5 days, median 5.4 days). Overall, 16 of the 28 (57%) horses were discharged and, of the 14 from which follow-up information was available, 13 (93%) were reported to be clinically normal 4 to 6 weeks following discharge, while the other horse had markedly improved. This pathogen is emerging as an important cause of neurological disease in Canada.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC340169PMC
June 2003

Binding of radiolabeled porcine motilin and erythromycin lactobionate to smooth muscle membranes in various segments of the equine gastrointestinal tract.

Am J Vet Res 2002 Nov;63(11):1545-50

Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Canada.

Objective: To identify and characterize motilin receptors in equine duodenum, jejunum, cecum, and large colon and to determine whether erythromycin lactobionate competes with porcine motilin for binding to these receptors.

Sample Population: Specimens of various segments of the intestinal tracts of 4 adult horses euthanatized for reasons unrelated to gastrointestinal tract disease.

Procedure: Cellular membranes were prepared from smooth muscle tissues of the duodenum, jejunum, pelvic flexure, and cecum. Affinity and distribution of motilin binding on membrane preparations were determined by use of 125I-labeled synthetic porcine motilin. Displacement studies were used to investigate competition between 125I-labeled synthetic porcine motilin and erythromycin lactobionate for binding to motilin receptors in various segments of bowel.

Results: Affinity of 125I-labeled synthetic porcine motilin for the equine motilin receptor was estimated to be 6.1nM. A significantly higher number of motilin receptors was found in the duodenum than in the pelvic flexure and cecum. The jejunum had a significantly higher number of motilin receptors than the cecum. Erythromycin lactobionate displacement of 125I-labeled porcine motilin from the equine motilin receptor did not differ significantly among various segments of bowel.

Conclusions And Clinical Relevance: Motilin receptors were found in the duodenum, jejunum, pelvic flexure, and cecum of horses. The highest number of motilin receptors was in the duodenum, and it decreased in more distal segments of bowel. Erythromycin lactobionate competed with motilin binding in the equine gastrointestinal tract. This suggests that 1 of the prokinetic actions of erythromycin in horses is likely to be secondary to binding on motilin receptors.
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http://dx.doi.org/10.2460/ajvr.2002.63.1545DOI Listing
November 2002