The latest literature on equine medicine and surgery

01 September 2016, at 1:00am

Exercise arrhythmias and sudden death in horses – a review 

Cristobal Navas de Solis, Swiss Institute of Equine Medicine, Berne 

Arrhythmias are a common finding in horses during and immediately after exercise and in many cases are not likely to be clinically relevant. However, there is a presumption of a link between exercising arrhythmias and poor performance and also in cases of sudden cardiac death.

The author reviews the literature on the aetiology, detection and treatment of arrhythmias in horses and draws comparisons with knowledge of the equivalent conditions observed in human athletes. Studies suggest that the risk of sudden death due to cardiac arrhythmias in horses is extremely low at less than 30 cases per 100,000 race starts but those incidents can have catastrophic consequences for the human rider and for public perceptions of welfare in equestrian sport.

He notes that it is impossible to guarantee that a horse is safe to undergo exercise. The clinician’s role should be to estimate the likely risk and to offer appropriate advice to both the individual rider and the racing authorities.

Equine Veterinary Journal 48 (4): 406-414. 

Effect of different bedding materials in stables on equine behaviour 

Agnieszka Kwiatkowska-Stenzel and others, University of Warmia, Poland 

The quality of bedding material in a stable is important for the occupant’s welfare by absorbing moisture and providing an insulating layer. The authors examined whether the type of material used has any effect on behaviour by recording the activities of horses housed on straw, peat moss with shavings or crushed wood pellets. 

They found that using straw bedding resulted in significantly longer periods lying down than the two alternative bedding materials. The longer time spent in recumbency on straw was correlated with a lower incidence of unwanted behaviours such as crib chewing, pacing and overt aggression towards neighbouring horses. 

Journal of Equine Veterinary Science 42 (1): 57-66. 

Abortion in thoroughbred mares after consuming buttercups 

Thomas Swercszek, University of Kentucky, Lexington

Buttercups are known to be toxic in livestock and a potential cause of abortion in cattle but grazing animals will usually avoid eating a plant that they find unpalatable. The author describes an incident involving thoroughbreds grazing pasture in central Kentucky infested with bulbosus buttercups (Ranunculus bulbosus). 

Seven mares aborted and two  fillies with gastrointestinal and neurological signs had to be euthanised. Post-mortem examination showed ulcers and erosions in the stomach and large intestine. The surviving mares recovered after being moved to buttercup-free pasture and all conceived successfully in the next breeding season. 

Journal of the American Veterinary Medical Association 248 (6): 669-672. 

Diagnosis, management and prognosis for haemoperitoneum in the horse

Jan Hawkins, Purdue University, West Lafayette, Indiana 

Haemoperitoneum is a relatively uncommon cause of blood loss anaemia in the horse, usually resulting from abdominal trauma, reproductive abnormalities, post-surgical haemorrhage or abdominal neoplasia. The author outlines a strategy for dealing with such cases, beginning with a full clinical examination and abdominal palpation per rectum, followed by transabdominal and transrectal ultrasound. 

Treatment will require immediate stabilisation with intravenous fluids, followed by surgery to manage the source of the bleeding, ideally using minimally invasive laparoscopic techniques. 

Equine Veterinary Education 28 (7): 364- 366. 

Associations between temperature, pollen levels and asthma in horses 

Michela Bullone and others, University of Montreal, Quebec 

Severe equine asthma or heaves may affect up to 20% of horses living in temperate environments. The risk increases in winter with prolonged stabling and exposure to dust and other airborne pollutants. The authors investigate the effects of higher temperatures on clinical signs of horses with recurrent disease. 

They show that high temperatures and humidity can both exacerbate existing problems. The findings highlight the need to provide temperate conditions for affected horses especially during disease exacerbations or unavoidable exposure to stable antigens. 

Equine Veterinary Journal 48 (4): 479-484. 

Techniques for the assessment of hind limb lameness in horses 

Rhodes Bell and others, University of Missouri, Columbia

Lameness in horses has traditionally been assessed through the subjective judgements of experienced clinicians but there is increasing interest in the use of objective measurements. The authors examine the value of force plate and body-mounted inertial sensor measurements for investigations into hind limb lameness in horses. 

Their study provides preliminary evidence that inertial sensor measurements of asymmetric vertical pelvic movement may provide information relevant to the nature of hind limb lameness (i.e. push off-type versus impact-type lameness). 

American Journal of Veterinary Research 77 (4): 337-345. 

Evaluation of an implant for use in prosthetic laryngoplasty in horses 

Harry Markwell and Eric Mueller, University of Georgia, Athens 

Laryngeal hemiplegia is a performance- limiting condition that affects up to 35% of horses. Prosthetic laryngoplasty is an accepted surgical treatment for the condition with success rates of up to 78%. The authors describe the results of an ex vivo mechanical evaluation of a proprietary device, a Sternal ZipFix implant, for prosthetic laryngoplasty. 

They conclude that this implant is less suitable for use in such procedures than a single strand of USP 5 braided polyester suture material (TiCron). The implant is considerably stronger and stiffer than the suture material but there is a high risk of arytenoid cartilage fracture during placement.

Veterinary Surgery 45 (4): 450-455. 

Antimicrobial resistance trends among equine Salmonella isolates 

Kevin Cummings and others, Texas A&M University, College Station

Salmonella enterica is an important disease agent in horses, causing diarrhoea, fever, colic, dehydration and septicaemia. Antimicrobial use in horses with salmonellosis is controversial and generally restricted to those cases with severe neutropaenia, persistent pyrexia or an indwelling intravenous catheter.

The authors examined the antimicrobial resistance patterns in 464 salmonella isolates from horses in north-eastern United States between 2001 and 2013. Overall, the results suggest that current antimicrobial use in equine practice is not contributing to the emergence of resistant Salmonella strains.

American Journal of Veterinary Research 77 (5): 505-513. 

Clinical findings in cases of severe hyponatraemia in foals

Niamh Collins and others, Scone Equine Hospital, Scone, New South Wales

Severe hyponatraemia in foals is defined as a serum sodium concentration of less than 122mmol/L. There are several different pathophysiological mechanisms that can be responsible 

for excessive retention of uid or excessive loss of sodium. 

The authors investigated the prevalence of hyponatraemia in foals admitted as medical emergencies to an intensive care unit, and collate the clinical ndings, diagnostic results and clinical findings. They found the prevalence of severe hyponatraemia in 1,718 admissions was 4%, with the majority showing no significant clinical manifestations and most cases having a favourable outcome.

Australian Veterinary Journal 94 (6): 186- 191. 

Bone marrow and adipose tissue stem cells in treating meniscal lesions 

Maria Gonzalez-Fernandez and others, University of Leon, Spain

The meniscus is a semilunar brocartilaginous tissue in the stifle joint, which heals poorly after injury because of its limited blood supply. The authors examined the ability to regenerate an equine meniscus using a collagen repair patch scaffold seeded with mesenchymal stem cells derived from bone marrow or adipose tissue. 

Promising results were obtained using stem cell implants obtained from both tissue sources. They note that these findings may have applications in the treatment of human joint disease. 

American Journal of Veterinary Research 77 (7): 779-788. 

Reduced tongue tone in a case of equine motor neurone disease 

Matthew Robin and others, University of Liverpool

Equine motor neurone disease is a condition characterised by generalised weakness and muscle atrophy, and associated with degeneration of motor neurons in the ventral horns of the spinal cord. The authors describe a case in a seven-year-old Welsh pony gelding, which presented with unusual clinical signs of diffuse neuromuscular weakness and marked accidity of the tongue. 

Their findings were consistent with an atypical form of the disease that should be considered when attempting to differentiate EMND from similar conditions, such as botulism.

Equine Veterinary Education 28 (8): 434- 438. 

Peritoneal fluid immunocytochemistry in the diagnosis of B-cell lymphoma 

Maria Carolina Duran and others, University of Saskatchewan, Saskatoon

A 17-year-old Arabian gelding was admitted to a university equine hospital with signs of dullness and abdominal distension. On physical examination the patient was quiet but alert and the distension only became apparent after removal of the turnout blanket. 

Gastrointestinal neoplasia with suspected diffuse peritoneal metastasis was diagnosed on ultrasonography and peritoneal fluid analysis. The owner elected for euthanasia and declined a post-mortem examination but immunohistochemistry analysis of the peritoneal fluid indicated a case of B-cell lymphoma. 

Canadian Veterinary Journal 57 (6): 601- 604.