Standardized exercise tests in horses : current situation and future perspectives

The purpose of this literature review is to clarify how exercise capacity can be measured in horses and which standardized exercise tests (SETs) exist. In this review, the measurement of the exercise capacity of horses is discussed and the standardized exercise tests (SET) are described. Two main types of SETs are used. Laboratory or treadmill tests are easy to standardize and provide more options to use all kinds of measuring devices, since the horse stays on the treadmill. On the other hand, field tests are conducted under the natural conditions associated with the specific sports discipline, and are easier to implement in the training schedule. However, field tests encompass interfering variables, such as weather conditions, ground surface conditions and the rider or jockey. Several variables are measured in order to calculate the fitness level which may be expressed by different parameters, such as V200 (speed at a heart rate of 200 beats per minute), V1a4 (speed at a blood lactic acid level of 4 mmol/L) and VO2max (maximum oxygen uptake)

Reversible congenital bilateral laryngeal paralysis (grade IV) in a foal

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Generalized sarcoidosis and hypertrophic osteopathy in a Standardbred with poor-performance.

editorial reviewedBackground and objective: Equine sarcoidosis (ES) is a rare but emergent disease of unknown etiology. Body of literature on ES remains limited, especially on the generalized forms associated with hypertrophic osteopathy (HO). This case report describes clinical and imaging findings in a racehorse with exercise intolerance affected by generalized ES and subsequent HO. Material and methods: A 6-year-old Standardbred gelding was presented for sudden exercise intolerance, weight loss, pyrexia, skin lesions, facial and peripheral multifocal swelling. Results: The horse underwent diagnostic imaging of head and limbs. Radiography and ultrasonography of the head revealed periostitis and regional soft tissue swelling of the maxillary bone. Bilateral marked periostitis with palisade-like appearance involving diaphyseal or metaphyseal region was also identified on distal radius and metatarsal bones, suggestive of HO. Computed tomography excluded dental or sinus abnormalities. Due to the appearance (scaling, crusting and exfoliating) of skin lesions on the croup and lower hindlimbs during hospitalization, biopsies were performed revealing granulomatous dermatitis. This finding was consistent with ES, thus explaining HO. Rapidly declining conditions of the horse led to the decision of euthanasia. Post-mortem examination revealed splenomegaly and several pulmonary nodules. Histopathology on different organs confirmed severe granulomatous lesions; PCR on a pool of tissues identified EHV-5. Discussion and conclusions: ES, even in its generalized form, is an emergent disease that should be considered in case of unspecific clinical signs combining exercise intolerance, weight loss, facial/distal limb bone deformities and skin lesions; EHV-5 could play a role in the development of the disease

Effects of aleurone supplementation on glucose-insulin metabolism and gut microbiome in untrained healthy horses

Aleurone, a layer of the bran fraction, is deemed to be responsible for the positive health effects associated with the consumption of whole-grain products. Studies on rodents, pigs, and humans report beneficial effects of aleurone in five main areas: the reduction of oxidative stress, immunomodulatory effects, modulation of energy management, digestive health, and the storage of vitamins and minerals. Our study is the first aleurone supplementation study performed in horses. The aim of this study was to investigate the effect of an increase in the dose levels of aleurone on the postprandial glucose-insulin metabolism and the gut microbiome in untrained healthy horses. Seven adult Standardbred horses were supplemented with four different dose levels of aleurone (50, 100, 200, and 400 g/day for 1 week) by using a Latin square model with a 1-week wash out in between doses. On day 7 of each supplementation week, postprandial blood glucose-insulin was measured and fecal samples were collected. 16S ribosomal RNA (rRNA) gene sequencing was performed and QIIME2 software was used for microbiome analysis. Microbial community function was assessed by using the predictive metagenome analysis tool Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) and using the Metacyc database of metabolic pathways. The relative abundancies of a pathway were analyzed by using analysis of composition of microbiomes (ANCOM) in R. There was a significant dose-dependent increase in the postprandial time to peak of glucose (p = 0.030), a significant delay in the time to peak of insulin (p = 0.025), and a significant decrease in both the insulin peak level (p = 0.049) and insulin area under the curve (AUC) (p = 0.019) with increasing dose levels of aleurone, with a consideration of 200 g being the lowest significant dose. Alpha diversity and beta diversity of the fecal microbiome showed no significant changes. Aleurone significantly decreased the relative abundance of the genera Roseburia, Shuttleworthia, Anaerostipes, Faecalibacter, and Succinovibrionaceae. The most pronounced changes in the relative abundance at phyla level were seen in Firmicutes and Verrucomicrobia (downregulation) and Bacteroidetes and Spirochaetes (upregulation). The PICRUSt analysis shows that aleurone induces a downregulation of the degradation of L-glutamate and taurine and an upregulation of the three consecutive pathways of the phospholipid membrane synthesis of the Archaea domain. The results of this study suggest a multimodal effect of aleurone on glucose-insulin metabolism, which is most likely to be caused by its effect on feed texture and subsequent digestive processing; and a synergistic effect of individual aleurone components on the glucose-insulin metabolism and microbiome composition and function

State-of-the-art diagnostic methods to diagnose equine spinal disorders, with special reference to transcranial magnetic stimulation and transcranial electrical stimulation

Spinal cord disorders are a common problem in equine medicine. However, finding the site of the lesion is challenging for veterinarians because of a lack of sensitive diagnostic methods that can assess neuronal functional integrity in horses. Although medical imaging is frequently applied to help diagnose corticospinal disorders, this approach does not reveal functional information. For the latter, transcranial magnetic stimulation (TMS) and more recently transcranial electrical stimulation (TES) can be useful. These are brain stimulation techniques that create either magnetic or electrical fields passing through the motor cortex, inducing muscular responses, which can be recorded either intramuscularly or extramuscularly by needle or surface electrodes. This permits the evaluation of the functional integrity of the spinal motor tracts and the nerve conduction pathways. The interest in TES in human medicine emerged these last years because unlike TMS, TES tends to bypass the motor cortex of the brain and predominantly relies on direct activation of corticospinal and extrapyramidal axons. Results from human medicine have indicated that TMS and TES recordings are mildly if not at all affected by sedation. Therefore, this technique can be reliably used in human patients under either sedation or full anesthesia to assess functional integrity of the corticospinal and adjunct motor tracts. This opens important new avenues in equine medicine

Relation entre la valeur seuil du cycle (Ct) d'une qPCR de Salmonella spp. effectuée sur les matières fécales et les signes cliniques et l'issue chez les chevaux.

peer reviewedThe objective of this retrospective study was to evaluate the clinical significance of fecal quantitative real-time polymerase chain reaction (qPCR) Salmonella results when taking the cycle threshold values (Ct) into account. The study included 120 Salmonella qPCR-positive fecal samples obtained from 88 hospitalized horses over a 2-year period. The mean Ct of the qPCR test was evaluated in regard to (1) clinical outcome and (2) systemic inflammatory response syndrome (SIRS) status (no SIRS, moderate SIRS, or severe SIRS) of the sampled horses. An ROC analysis was performed to establish the optimal cut-off Ct values associated with severe SIRS. The mean ± SD Ct value was significantly lower in samples (1) from horses with a fatal issue (27.87 ± 5.15 cycles) than in surviving horses (31.75 ± 3.60 cycles), and (2) from horses with severe SIRS (27.87 ± 2.78 cycles) than from horses with no (32.51 ± 3.59 cycles) or moderate (31.54 ± 3.02 cycles) SIRS. In the ROC analysis, the optimal cut-off value of Ct associated with a severe SIRS was 30.40 cycles, with an AUC value of 0.84 [95% confidence interval 0.76-0.91] and an OR of 0.64 [0.51-0.79]. Results suggest that including the Ct value in the interpretation of fecal qPCR results could improve the diagnostic value of this test for clinical salmonellosis in horses

Effect of oral aleurone supplementation on glucose and insulin dynamics of horses in training

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State-of-the-Art Diagnostic Methods to Diagnose Equine Spinal Disorders, With Special Reference to Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation

Spinal cord disorders are a common problem in equine medicine. However, finding the site of the lesion is challenging for veterinarians because of a lack of sensitive diagnostic methods that can assess neuronal functional integrity in horses. Although medical imaging is frequently applied to help diagnose corticospinal disorders, this approach does not reveal functional information. For the latter, transcranial magnetic stimulation (TMS) and more recently transcranial electrical stimulation (TES) can be useful. These are brain stimulation techniques that create either magnetic or electrical fields passing through the motor cortex, inducing muscular responses, which can be recorded either intramuscularly or extramuscularly by needle or surface electrodes. This permits the evaluation of the functional integrity of the spinal motor tracts and the nerve conduction pathways. The interest in TES in human medicine emerged these last years because unlike TMS, TES tends to bypass the motor cortex of the brain and predominantly relies on direct activation of corticospinal and extrapyramidal axons. Results from human medicine have indicated that TMS and TES recordings are mildly if not at all affected by sedation. Therefore, this technique can be reliably used in human patients under either sedation or full anesthesia to assess functional integrity of the corticospinal and adjunct motor tracts. This opens important new avenues in equine medicine

Validation of a new LMS (lactate minimum speed) exercise test for optimal assessment of the aerobic window of sport horses

Standardized exercise tests (SETs) are golden standard to provide training advise. However, they require maximum intensity exercise, increasing injury risk. Our aim is to validate a modified LMS-test and to compare it with a SET. Standardbreds ( , 3-4 years, n=6) were trained in standardized conditions. A SET and LMS-test were executed on Week0 and Week8. Tests encompassed respectively: for SET: incremental steps (4km/h; 3 min/step; 20-40 km/h); for LMS-test: first 3 min trot (36-40 km/h until blood lactate (BL) >5mmol/L), followed by incremental steps (start 20 km/h; 3min; 2 km/h, max34 km/h). GPS, heartrate (Polar®) and BL were monitored. Speed vs BL values were plotted. Curve parameters (R core team, 3.6.0) were: (For SET) VLa1.5/2/4 and (For LMS) AUCLMS and LMS. LMS validation entailed: >10 km at LMS and 110% LMS. Curve parameters and aerobic window (AW) were assessed for both tests and compared (paired T-test, except for LMS: paired Wilcoxon test; Significance p<0.05). Training induced a significant increase in VLa1.5/2/4 (P=0.003; 0.004; 0.006)(exponential curve) and a significant decrease in LMS (P=0.008), AUCLMS (P=0.008)(flattening of the parabola curve). BLmax was significantly lower for LMS vs SET (p<0.0001). No BL increase (>1mmol/L) occurred during validation at LMS, however did at 110%LMS. AW assessment showed significant overestimation for SET. Post training the LMS BL equilibrium is reached earlier and maintained longer. This modified LMS-test allows for a more robust assessment of the aerobic window at lower speed and BL when compared to SET

Comparison of shifts in skeletal muscle plasticity parameters in horses in three different muscles, in answer to 8 weeks of harness training

Training-induced follow-up of multiple muscle plasticity parameters in postural stability vs. locomotion muscles provides an integrative physiological view on shifts in the muscular metabolic machinery. It can be expected that not all muscle plasticity parameters show the same expression time profile across muscles. This knowledge is important to underpin results of metabolomic studies. Twelve non-competing Standardbred mares were subjected to standardized harness training. Muscle biopsies were taken on a non-training day before and after 8 weeks. Shifts in muscle fiber type composition and muscle fiber cross-sectional area (CSA) were compared in the m. pectoralis, the m. vastus lateralis, and the m. semitendinosus. In the m. vastus lateralis, which showed most pronounced training-induced plasticity, two additional muscle plasticity parameters (capillarization and mitochondrial density) were assessed. In the m. semitendinosus, additionally the mean minimum Feret's diameter was assessed. There was a significant difference in baseline profiles. The m. semitendinosus contained less type I and more type IIX fibers compatible with the most pronounced anaerobic profile. Though no baseline fiber type-specific and overall mean CSA differences could be detected, there was a clear post-training decrease in fiber type specific CSA, most pronounced for the m. vastus lateralis, and this was accompanied by a clear increase in capillary supply. No shifts in mitochondrial density were detected. The m. semitendinosus showed a decrease in fiber type specific CSA of type IIAX fibers and a decrease of type I fiber Feret's diameter as well as mean minimum Feret's diameter. The training-induced increased capillary supply in conjunction with a significant decrease in muscle fiber CSA suggests that the muscular machinery models itself toward an optimal smaller individual muscle fiber structure to receive and process fuels that can be swiftly delivered by the circulatory system. These results are interesting in view of the recently identified important fuel candidates such as branched-chain amino acids, aromatic amino acids, and gut microbiome-related xenobiotics, which need a rapid gut–muscle gateway to reach these fibers and are less challenging for the mitochondrial system. More research is needed with that respect. Results also show important differences between muscle groups with respect to baseline and training-specific modulation