Quantitative motor unit action potential analysis in 2 paraspinal neck muscles in adult Royal Dutch Sport horses

BACKGROUND: Reference values for quantitative electromyography (QEMG) in neck muscles of Royal Dutch Sport horses are lacking. OBJECTIVE: Determine normative data on quantitative motor unit action potential (QMUP) analysis of serratus ventralis cervicis (SV) and brachiocephalicus (BC) muscle. ANIMALS: Seven adult normal horses (mean age 9.5 standard deviation [SD] +/- 2.3 years, mean height 1.64 SD +/- 4.5 cm, and mean rectal temperature 37.6 SD +/- 0.3 degrees C). METHODS: An observational study on QMUP analysis in 6 segments of each muscle was performed with commercial electromyography equipment. Measurements were made according to formerly published methods. Natural logarithm transformed data were tested with ANOVA and posthoc testing according to Bonferroni. RESULTS: Mean duration, amplitude, phases, turns, area, and size index (SI) did not differ significantly among the 6 segments in each muscle. Mean amplitude, number of phases, and SI were significantly (P < .002) higher in SV than BC, 520 versus 448 muV, 3.0 versus 2.8 muV, and 0.48 versus 0.30 muV, respectively. In SV 95% confidence intervals (CI) for amplitude, duration, number of phases, turns, polyphasia area, and SI were 488-551 muV, 4.3-4.6 ms, 2.9-3.0, 2.4-2.6, 7-12%, 382-448, and 0.26-0.70, respectively; in BC this was 412-483 muV, 4.3-4.7 ms, 2.7-2.8, 2.4-2.6, 4-7%, 393-469, and 0.27-0.34, respectively. Maximal voluntary activity expressed by turns/second did not differ significantly between SV and BC with a 95% CI of 132-173 and 137-198, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: The establishment of normative data makes objective QEMG of paraspinal muscles in horses suspected of cervical neurogenic disorders possible. Differences between muscles should be taken into account.

A whole-genome scan for recurrent airway obstruction in Warmblood sport horses indicates two positional candidate regions

Recurrent airway obstruction (RAO), or heaves, is a naturally occurring asthma-like disease that is related to sensitisation and exposure to mouldy hay and has a familial basis with a complex mode of inheritance. A genome-wide scanning approach using two half-sibling families was taken in order to locate the chromosome regions that contribute to the inherited component of this condition in these families. Initially, a panel of 250 microsatellite markers, which were chosen as a well-spaced, polymorphic selection covering the 31 equine autosomes, was used to genotype the two half-sibling families, which comprised in total 239 Warmblood horses. Subsequently, supplementary markers were added for a total of 315 genotyped markers. Each half-sibling family is focused around a severely RAO-affected stallion, and the phenotype of each individual was assessed for RAO and related signs, namely, breathing effort at rest, breathing effort at work, coughing, and nasal discharge, using an owner-based questionnaire. Analysis using a regression method for half-sibling family structures was performed using RAO and each of the composite clinical signs separately; two chromosome regions (on ECA13 and ECA15) showed a genome-wide significant association with RAO at P < 0.05. An additional 11 chromosome regions showed a more modest association. This is the first publication that describes the mapping of genetic loci involved in RAO. Several candidate genes are located in these regions, a number of which are interleukins. These are important signalling molecules that are intricately involved in the control of the immune response and are therefore good positional candidates.

Association of increased tracheal mucus accumulation with poor willingness to perform in show-jumpers and dressage horses

The objective of this study was to examine the association of pharyngeal lymphoid hyperplasia (PLH), recurrent laryngeal neuropathy (RLN), mucus accumulation (MA) score and tracheobronchial secretion neutrophil percentage (TBS-N) with rider-assessed performance in sport horses. Airway endoscopy scores, tracheobronchial secretion cytology, rider-assessed general impression and willingness to perform were investigated in 171 top-level sport horses. Increased MA appears to be associated with poor willingness to perform in sport horses. Older horses had decreased PLH scores and increased TBS-N. Mucus accumulation scores > or =3 were associated with increased odds (mean 9.92; upper and lower 95% confidence intervals: 1.5-64.6) of poor rather than excellent willingness to perform. A TBS-N of 20-50% compared with <20% was associated with decreased odds (median 0.11; upper and lower 95% CI: 0.02-0.66) of poor rather than excellent willingness to perform. In addition, horses with an RLN grade > or =2 had significantly higher odds for giving a poorer general impression and willingness to perform. This finding, however, must be interpreted with caution, since only two horses had significant RLN (grade > or =3).

A survey on the feeding of eventing horses during competition

This study aims at the comparison of the actual feeding of horses with the recommendations from the literature, and it studies the effects of feeding and exercise on several blood metabolic parameters before and after exercise. Blood samples were collected from 25 horses during one-star eventing competitions and evaluated for blood glucose, insulin, lactate, free fatty acids and triglyceride levels. Questionnaires on the feeding practices of the horses were evaluated. The questionnaires revealed that during training, and on tournament days, horses received on average 4.3 kg of concentrate per day (min. 1.54 kg, max. 8 kg). The statistical analysis showed no significant effect of the amount of concentrate fed before exercise on the measured blood values. Oil was supplied as a supplementary energy source to 30% of the horses, but most of them only received very small quantities (0.02–0.4 l/day). Five horses (20%) had no access to salt supplements at all, and eleven horses (45%) had no access to salt on tournament days. Fifteen horses (60%) were supplied with mineral feed. Twenty-one horses (84%) had daily access to pasture during the training period. During competition, 55% of the horses received roughage ad libitum, compared with 37% during training. The majority of the horses received less roughage on days before the cross-country competition. It could not be ascertained whether feeding a large amounts of roughage had a beneficial effect on performance, because only a few horses in this study were fed with very restrictive roughage. Feeding of most of the horses was in agreement with the recommendations from the literature, except the need for sodium and chloride. The sodium and chloride need for sport horses may be overestimated in literature and needs to be re-evaluated.

The use of electromyography interference pattern analysis to determine muscle force of the deep digital flexor muscle in healthy and laminitic horses

BACKGROUND: In equine laminitis, the deep digital flexor muscle (DDFM) appears to have increased muscle force, but evidence-based confirmation is lacking. OBJECTIVES: The purpose of this study was to test if the DDFM of laminitic equines has an increased muscle force detectable by needle electromyography interference pattern analysis (IPA). ANIMALS AND METHODS: The control group included six Royal Dutch Sport horses, three Shetland ponies and one Welsh pony [10 healthy, sound adults weighing 411 ± 217 kg (mean ± SD) and aged 10 ± 5 years]. The laminitic group included three Royal Dutch Sport horses, one Friesian, one Haflinger, one Icelandic horse, one Welsh pony, one miniature Appaloosa and six Shetland ponies (14 adults, weight 310 ± 178 kg, aged 13 ± 6 years) with acute/chronic laminitis. The electromyography IPA measurements included firing rate, turns/second (T), amplitude/turn (M) and M/T ratio. Statistical analysis used a general linear model with outcomes transformed to geometric means. RESULTS: The firing rate of the total laminitic group was higher than the total control group. This difference was smaller for the ponies compared to the horses; in the horses, the geometric mean difference of the laminitic group was 1.73 [geometric 95% confidence interval (CI) 1.29-2.32], and in the ponies this value was 1.09 (geometric 95% CI 0.82-1.45). CONCLUSION AND CLINICAL RELEVANCE: In human medicine, an increased firing rate is characteristic of increased muscle force. Thus, the increased firing rate of the DDFM in the context of laminitis suggests an elevated muscle force. However, this seems to be only a partial effect as in this study, the unchanged turns/second and amplitude/turn failed to prove the recruitment of larger motor units with larger amplitude motor unit potentials in laminitic equids.

Clinical and echocardiographic features of mild mitral valve regurgitation in 108 horses

The clinical and echocardiographic characteristics of 108 horses with echocardiographically confirmed mild mitral valve regurgitation (MR) were investigated along with its clinical progression. Follow-up consisted of a re-examination of 28 horses and questionnaires were used to obtain information on a further 43 cases. Thirty-seven horses with mild MR were lost to follow-up. Horses with mild MR were re-examined between 2 and 9 years (3.8+/-1.8 years) following first presentation, with mild MR still present and a small, but statistically significant (P=0.049) increase of left ventricular diameter in end-diastole. These results suggested that mild MR has a good mid-term prognosis in sport and pleasure horses.

Lesions of the gastric mucosa in adult horses of different disciplines: a review

The prevalence of gastric mucosal lesions in the thoroughbred race horse has been the subject of numerous studies. The frequency of gastric ulcer diseases in the adult horse of other sport disciplines are less well investigated. Recent data show that gastric mucosal lesions in non thoroughbred racehorses occur considerably more frequently than previously thought. Prevalences of up to 93 % in endurance horses, of up to 87 % in standardbreds, of 40 % in western horses, of 63 % in show-jumping horses, of 71 % in broodmares and of 53 % in leisure horses are reported. Since the introduction of gastroscopy in equine medicine in the 1990s, numerous scoring-systems to describe the number, the severity and the localisation of the lesions have been used. Unfortunately, no standardized scoring system is generally accepted to date. A direct comparison of results from different studies is therefore difficult. Comparison and interpretation of data is further hampered by the heterogenicity of the study populations which consist of horses of different age-groups, breeds and exercise intensity.

The association between extra-curricular sport participation and social anxiety symptoms in children

Social anxiety is a common psychological complaint that can have a significant and long-term negative impact on a child’s social and cognitive development. In the current study, the relationship between sport participation and social anxiety symptoms was investigated. Swiss primary school children (N = 201), parents, and teachers provided information about the children’s social anxiety symptoms, classroom behavior, and sport involvement. Gender differences were observed on social anxiety scores, where girls tended to report higher social anxiety symptoms, as well as on sport activity, where boys engaged in more sport involvement. MANCOVAs with gender as covariant showed no differences in social anxiety symptoms between children involved in an extracurricular sport and those not engaged in sport participation. Nevertheless, children engaged in team sports displayed fewer physical social anxiety symptoms than children involved in individual sports.