2018 - 87 (5)

The expression survival of the fittest most often has a misleading connotation in contemporaryears and minds not familiar with genetics and the scientific basis of breeding. Among live organisms,heritable variation is a prerequisite for survival of a species in changing conditions of life.Variants fitting best into new conditions survive and will have the greatest chances to reproducethemselves. This is the meaning of fit in the well-known expression ‘survival of the fittest’, coinedby Herbert Spencer on Darwin’s idea of ‘natural selection’. In order to understand this, a shortlinguistic description is given, starting with to vet, meaning ‘to examine thoroughly’, a relativelyrecent expression (19th century), which at first sight seems to originate from the examinationsdone by veterinarians (vets) on racing horses, before they are allotted to certain categories in theraces. Nowadays the term is especially used in the context of checking persons applying for jobs,business takeover bids and similar situations involving a certain degree of trustworthiness. To fithas a much older pedigree. The earliest attestations are found in mediaeval texts relating militaryor fighting episodes in which the adversaries are considered to be of equal power. This survivedlater on in horse racing competitions and gradually acquired the sense of fitting one thing intoanother, or to fit into a category. For living organisms, to fit into prevailing conditions of life isof utmost importance. It was only in the previous century that the meaning of fit changed intohealthy and strong, possibly also influenced by the use of this term in racing competitions.

Laryngeal hemiplegia is a progressive upper airway dysfunction in the horse. It is not onlyseen in thoroughbred racehorses but also in warmblood horses, draft horses and in ponies. Thecondition is most frequently seen on the left side. The left laryngeal recurrent nerve graduallyloses function and the function of the left cricoarythenoideus dorsalis muscle is compromised.This condition is most often idiopathic. It possibly leads to exercise intolerance but a respiratorynoise is often the primary complaint of the owner. Right sided laryngeal hemiplegia is almostalways related to other pathologies causing the nerve to malfunction. The diagnosis is not alwayseasy because of the restricted availability of endoscopy in the field. A better understanding oflaryngeal ultrasound examination might offer a new possibility in diagnosing laryngeal hemiplegia.If abnormal inspiratory sound is the only problem, laser treatment alone can be satisfactory.If the horse shows clear signs of exercise intolerance, further treatment is needed. If correctlyexecuted, the outcome of laryngoplasty is good. Other techniques, like nerve grafting and pacemakers,are being explored and might even be regarded as better alternative treatments in thefuture, as these are more physiologic compared to laryngoplasty. In sporthorses presented withidiopathic laryngeal neuropathy without postoperative complications, the prognosis is good.

In this case report, the course of a bovine viral diarrhea virus infection (BVDV) type 2 in a Belgiandairy herd is described. Within a period of fourteen days, seventeen adult dairy cows died of acute diarrheaand dehydration. A BVDV infection was suspected from the beginning but this suspicion couldnot be confirmed by testing. Only during the next thirty-four months at different time points, BVDVtype 2a could be identified.

A three-month-old, female, entire, Labrador retriever was presented after being referred becauseof a suspected congenital heart disorder. The dog did not show any symptoms, but on clinical examination,there was a loud continuous heart murmur with a thrill present (grade 5 out of 6), located atthe left heart base. Echocardiographic examination revealed the presence of a patent ductus arteriosus(PDA) and pulmonic stenosis (PS). One and a half month after initial presentation, the PDA was surgicallyclosed. The PS was treated with the ß-blocker atenolol and followed up to evaluate the responseto therapy and the potential need for a balloon valvuloplasty. This case demonstrates the necessity ofa qualitative and complete echocardiographic evaluation in young dogs with a heart murmur. Even ifthe cause of the heart murmur can easily be identified, in the present case patent ductus arteriosus, it isimportant to screen for additional abnormalities, as in this case pulmonic stenosis.

An eight-year-old Thoroughbred mare was presented with acute colic symptoms. Clinicaland ultrasonographic examination revealed a suspicion of diaphragmatic hernia, which wasconfirmed during an emergency midline laparotomy performed the same day. Patients withdiaphragmatic hernia pose a challenge for the surgeon and the anesthesiologist, because of thedisturbed function of the diaphragm and the displacement of the abdominal organs into the thoraciccavity. Achieving optimal ventilation and oxygenation without causing damage to the lungsis not simple. In this case, assisted-controlled, intermittent positive pressure ventilation with alow tidal volume, low pressure and relatively high respiratory rate was applied. Alongside thedifficulties during ventilation, the patient was cardiovascularly compromised. Due to the extentand position of the hernia, euthanasia was performed after obtaining the owner’s consent duringsurgery.

While mature coastal bermudagrass hay is strongly associated with ileal impaction in theSoutheastern United States, stabling on flax bedding has anecdotally been associated with thiscondition in Europe. The aim of this retrospective study was to investigate the association betweenileal impaction and the use of flax shives compared to straw as bedding in horses withcolic. Medical records of 2336 referral cases evaluated for abdominal pain between January 2008and May 2017 at the Department of Large Animal Internal Medicine, Ghent University werereviewed. Diagnosis, date of admission, age, breed, gender, body weight and stable bedding wererecorded. Conditional logistic regression analysis was used to assess the association between ilealimpaction and each individual variable. Odds ratios (OR) and 95% confidence intervals (CI)were determined. Predictors with a value of P < 0.2 were included in a multivariable Cox regressionmodel and Wald’s test was used to assess parameter estimate significance. Further, the associationbetween survival to discharge and type of bedding or type of treatment (medical versussurgical) was analyzed for horses with ileal impactions. The proportion of colic cases stabled onflax bedding at home was 11.3%. The overall prevalence of ileal impaction was 4.2%. In the flaxgroup, the prevalence of ileal impaction was 9.4% as opposed to 3.6% within the straw group.The OR of 2.8 (95% CI 1.7-4.7; P < 0.001) in the multivariable logistic regression model indicatedthat horses stabled on flax shives were approximately three times more likely to have ileal impactionsthan horses stabled on straw. There was no significant association found between ilealimpaction and the period of admission, age, gender or body weight in a multivariable logisticregression model. The odds for having ileal impaction is approximately six times (OR 6.3; 95%CI 2.4-16.4; P < 0.001) higher in draft horses than in warmbloods in the multivariable logisticregression model. No significant association was found between survival to discharge and type ofbedding or treatment. These results suggest that horses with colic that were housed on flax beddingare more likely to present ileal impactions than horses housed on straw.

Distal sesamoidean ligament (DSL) injury is a recognized cause of lameness in horses. Thepurpose of this study was to describe the contrast-enhanced computer tomography (CE-CT)findings in horses with injury to the DSL compared to a control group without injury to the DSL.Medical records of horses referred for CE-CT between 2008 and 2015 were reviewed. Cases wereselected retrospectively based on a CE-CT imaging finding of injury to the DSL. Three horseshad DSL injury as the only finding, while the remaining horses had one or more concomitant injuries.DSL injury and fetlock trauma and/or suspensory branch desmitis were the most frequentinjury combinations. CE-CT can be of value in diagnosing DSL injury. The high number of concurrentDSL and fetlock and/or suspensory lesions suggests that further investigation should beconsidered when evaluating horses with injuries related to either of these structures.