Observer agreement for detection of cardiac arrhythmias on telemetric ECG recordings obtained at rest, during and after exercise in 10 warmblood horses

Reasons for performing study: Frequent supraventricular or ventricular arrhythmias during and after exercise are considered pathological in horses. Prevalence of arrhythmias seen in apparently healthy horses is still a matter of debate and may depend on breed, athletic condition and exercise intensity. Objectives: To determine intra- and interobserver agreement for detection of arrhythmias at rest, during and after exercise using a telemetric electrocardiography device. Materials and methods: The electrocardiogram (ECG) recordings of 10 healthy Warmblood horses (5 of which had an intracardiac catheter in place) undergoing a standardised treadmill exercise test were analysed at rest (R), during warm-up (W), during exercise (E), as well as during 0–5 min (PE0–5) and 6–45 min (PE6–45) recovery after exercise. The number and time of occurrence of physiological and pathological ‘rhythm events’ were recorded. Events were classified according to origin and mode of conduction. The agreement of 3 independent, blinded observers with different experience in ECG reading was estimated considering time of occurrence and classification of events. Results: For correct timing and classification, intraobserver agreement for observer 1 was 97% (R), 100% (W), 20% (E), 82% (PE0–5) and 100% (PE6–45). Interobserver agreement between observer 1 vs. observer 2 and between observer 1 vs. 3, respectively, was 96 and 92.6% (R), 83 and 31% (W), 0 and 13% (E), 23 and 18% (PE0–5), and 67 and 55% (PE6–45). When including the events with correct timing but disagreement for classification, the intraobserver agreement increased to 94% during PE0–5 and the interobserver agreement reached 83 and 50% (W), 20 and 50% (E), 41 and 47% (PE0–5), and 83.5 and 65% (PE6–45). The interobserver agreement increased with observer experience. Conclusions: Intra- and interobserver agreement for recognition and classification of events was good at R, but poor during E and poor-moderate during recovery periods. These results highlight the limitations of stress ECG in horses and the need for high-quality recordings and adequate observer training

High-speed cinematographic evaluation of claw-ground contact pattern of lactating cows

To evaluate the manner in which a cow's claws make contact with the ground at the walk, the gait, and in particular the claw-ground contact pattern, were studied in 12 healthy, lactating dairy cows, using high-speed cinematography (500frames/s) while the animals were walking on a treadmill. The results showed that the limbs were advanced around the contralateral limbs in a sigmoid curve. The feet contacted the ground with the foot axis and the tips of the claws rotated slightly outwards. In all cows the lateral claws contacted the ground before the medial claws in the hindlimbs, and in 10/12 cows in the forelimbs. The heel of the lateral claws was the region of initial contact with the ground in the hindlimbs of all cows and in the forelimbs in 9/12 cows. Lateral 'heel first' contact in the fore and hindlimbs appeared to be the normal gait pattern in these animals. Compared with a previous study of heifers, lactating cows had a larger step width in the hindlimbs and a smaller step width in the forelimbs. These ground contact patterns offer an explanation for the predisposition to claw disorders of the lateral claw of the hindlimb. The results of this study reinforce the suggestion that soft floor surfaces should be provided for cattle to prevent mechanical injury to the claws

Hoof conformation in Icelandic competition horses and its interrelationship with hoof pathologies and tölt performance

In order to improve the four-beat-rhythm and forelimb action of the tölt in Icelandic horses (ICE), special shoeing techniques are applied particularly in the front hooves by increasing hoof length and height, or by adding weight to the distal limbs. Although regulations limit dorsal hoof wall length (LDHW) in competition ICE, their shoeing often deviates from a biomechanically optimal distal limb conformation. This study aimed to qualitatively and quantitatively describe current shoeing practices of ICE in competition. Moreover, the influence of LDHW on the occurrence of deviations from a standard hoof conformation, as well as on tölt performance was investigated. At four European competition sites, hoof dimensions of 133 randomly selected ICE were measured manually, and limb conformation and hoof balance were described. Dorsopalmar/-plantar and lateromedial radiographs of the left front and hind hooves were taken of each horse. Various parameters related to hoof dimensions and balance were measured on radiographs using the Metron-Hoof-Pro software. Flares of the dorsal hoof wall had the highest prevalence of all investigated hoof deformities. Multiple logistic regression analysis revealed that longer LDHW was associated with the occurrence of toe flares (P = 0.045), a broken hoof pastern axis (P = 0.003), and asymmetry of the quarter wall heights (P = 0.015). However, horses with a longer LDHW achieved higher scores in competition. In spite of its positive effect on tölt performance, a long LDHW is not recommendable as it may be associated with a higher prevalence of certain hoof deformities

Evaluation of skin sensitivity after shock wave treatment in horses

Objective: To evaluate the effects of shock wave treatment on cutaneous nerve function, compared with the effects of local nerve block and sedation. Animals: 18 clinically sound Swiss Warmbloods. Procedure: Horses were randomly allocated to 3 groups and received different amounts and types of shock waves (extracorporeal shock wave treatment [ESWT] or radial pressure wave treatment [RPWT]). Horses were sedated with xylazine and levomethadone. Shock waves were applied to the lateral palmar digital nerve at the level of the proximal sesamoid bones on 1 forelimb. Skin sensitivity was evaluated by means of an electrical stimulus at the coronary band before and 5 minutes after sedation and at 4, 24, and 48 hours after application of ESWT or RPWT. On the contralateral forelimb, skin sensitivity was tested before and 10 minutes after an abaxial sesamoid nerve block. Results: No significant changes in skin sensitivity were detected, regardless of the shock wave protocol applied. Mean reaction thresholds after sedation were more than twice the baseline thresholds. After the abaxial sesamoid block, no reaction was recorded in any of the horses. Conclusions and Clinical Relevance: Application of ESWT or RPWT to the palmar digital nerve had no effect on cutaneous sensation distal to the treated region for at least 2 days after application. The analgesic effect of sedation on reaction to electrical stimuli was distinct but varied among horses