AAEP / EVJ supplement 2013

Field: Veterinary (Health Sciences)

The articles in this year's supplement reflect both the breadth and depth of the analytical clinical and basic research studies being performed on areas of importance in equine practice, namely issues relating to the musculoskeletal, respiratory and reproductive systems and the critical care of horses and foals. In the area of the musculoskeletal system, Maliye et al. 1 reported that inertial sensor-based systems can assist veterinarians in the accurate detection of the effects of nerve blocks on gait symmetry in horses with forelimb lameness. Similarly, in an effort to compare the effects of different track surfaces on horses' gaits, Crevier-Denoix et al. 2 analysed foot and limb motion during the swing and support phases of the stride at the canter on dirt and synthetic track surfaces. They detected significant differences in foot position in the lead limb compared with the opposite limb and evidence that the synthetic surface appeared to be more forgiving than the dirt track. In the final musculoskeletal study, Foreman and Ruemmler 3 used a well-established model of foot pain to create temporary lameness in horses and then demonstrated that administration of meperidine hydrochloride provided a short-term decrease in heart rate and improvement in gait. An area of intense research activity in the past decade has been pneumonia caused by Rhodococcus equi. A common rationale for work in this area is that early detection of R. equi pneumonia has been a challenge for many practitioners working with foals on farms with endemic disease. Using a novel and noninvasive approach, Crowley et al. 4 describe early identification of infected foals. Based on their initial findings, additional field studies are warranted to determine whether the technique is accurate and practical before recommendations for widespread implementation in equine practice can be made. In this supplement, two articles address important topics in reproduction, one being related to mares and the other to stallions. As reproductive technologies such as intracytoplasmic sperm injection have become more common in clinical practice, questions have arisen regarding the optimal means of transporting oocytes to centres offering these advanced services. To address these questions, Foss et al. 5 compared a variety of oocyte transport protocols on blastocyst rates after intracytoplasmic sperm injection. Their article provides new practical information regarding the transport of equine oocytes that should allow wider use of this technique. Although the adverse effects of endophyte-infected tall fescue on reproduction in mares have been known for many years, few studies have examined the impact of such exposure on stallions. To address this question, Fayrer-Hosken et al. 6 performed controlled studies in which stallions were exposed to endophyte-infected fescue. The results of that study indicate that such exposure resulted in no detectable changes in most seminal parameters. Four of the articles in this supplement reflect the increasing focus on critical care of horses and foals in recent years. Because gastrointestinal dysfunction occurs commonly in horses after elective anaesthesia, Nelson et al. 7 reviewed case records to identify risk factors associated with colic or delayed faecal output with the goal of implementing measures to prevent or at least reduce the occurrence of these problems in the future. It is common practice for blood samples to be collected serially from critically ill horses to monitor alterations in clinicopathological parameters. This is primarily done by collecting blood from the jugular vein. Unfortunately, these patients often are at increased risk for the development of thrombophlebitis. To provide a basis for circumventing the use of the jugular vein in these cases, Hunter et al. 8 compared values obtained for the most commonly monitored parameters (packed cell volume, total solids and lactate) from samples collected simultaneously from the jugular vein and transverse facial venous sinus of critically ill horses. Their results support the use of the transverse facial venous sinus for repeated blood sampling in these horses. There is evidence that monitoring of serial blood lactate concentrations is of prognostic value in critically ill human patients. However, there have been no large multicentre prospective studies regarding the utility of determining serial blood lactate concentrations in critically ill neonatal foals. To address this need, Borchers et al. 9 performed a study involving more than 600 foals at 13 university and private equine referral hospitals. Based on the results of that study, lactate metabolism is impaired in nonsurviving and septic foals and monitoring changes in blood lactate concentrations can be used to identify foals at high risk for mortality. It is not uncommon for veterinarians to encounter horses with haematuria of undetermined origin. Because haematuria may occur as a result of upper urinary tract disorders and identification of these disorders may lead to improvements in therapy, Pasquel et al. 10 developed the techniques necessary to examine the equine renal pelvis and terminal recesses endoscopically. The results of this study provide the basis for advanced diagnostic imaging and assessment of renal function in horses.