Journal of Equine Veterinary Science最新文献

Nutrigenomics defines the interaction between the nutrients in our food and the genes in our body. Examples from human medicine of diseases and associated genes include lactose intolerance (genetic variants in LCT lactase), hypercholesteremia (low density lipoprotein receptor, LDLR) and caffeine sensitivity (adenosine A2A receptor, ADORA2A). In horses, examples include Hyperkalemic Periodic Paralysis (HYPP), where clinical signs of disease are managed through maintaining a diet low in potassium and Polysaccharide Storage Myopathy Type 1 (PSSM1), where low starch and high fat diets are recommended to prevent episodes of rhabdomyolysis. Personalized nutrition tailors nutrition advice for an individual based on their genetic makeup. In humans and in horses, there is a wide range of individual response to vitamin E supplementation. Some horses obtain very high serum vitamin E concentrations with minimal intake, whereas others require high doses of supplementation to remain in the normal range. In humans, the efficiency of vitamin E absorption is widely variable and is affected by dietary factors, such as food matrix, and genetic polymorphisms in genes related to vitamin E intake, distribution and metabolism. In horses, the efficiency of vitamin E absorption is also related to diet; however, genetic variation has not been yet evaluated. With over 200 genetic variants identified in and surrounding vitamin E candidate genes in horses, future genetic profiling of vitamin E response in horses should be performed.

Long before the concept of social license to operate came to the forefront of equestrian sports, veterinarians have always had a responsibility to advocate for the welfare of the horse. For performance horses this often means helping to ensure that the horse is performing positively and comfortably for its intended use. A horse that is struggling to perform at an optimal level may be doing so for a multitude of reasons, but regardless of the underlying cause, it often presents as any number of behavioral issues. This review explores various underlying physical causes of behavioral issues in performance horses in order to highlight the fact that most "behavioral issues" are not behavioral at all.

Background: Foals, that receive poor-quality colostrum, are exposed to a risk of failure of transfer of passive immunity. The Brix refractometer can be used for the estimation of the immunoglobulin (IgG) concentration of mare colostrum, yet there is a scarce literature available on Brix refractometer thresholds for use in the detection of mare colostra with high and low IgG concentrations.

Aim: This study aimed to assess the diagnostic accuracy of the Brix refractometer in determining mare colostra with IgG concentrations of <50g/L, <60g/L, >80g/L, >100g/L and >125g/L.

Materials and methods: Two hundred and seventeen Arabian mares had colostral IgG concentrations measured with the radial immunodiffusion assay and estimated with the Brix refractometer. Brix thresholds were determined by performing a receiver operating characteristics analysis.

Results: The mean colostral IgG concentration was 83.73±2.46g/L and colostral IgG concentrations had a high correlation (Pearson's r=0.78) with Brix percentages. The optimal refractometer thresholds for the determination of colostral IgG concentrations of <50, <60, >80, >100 and >125g/L were ascertained to be <19.6%, <20.1%, >21.6%, >23.6% and >27.3%, respectively. The sensitivity and specificity of the Brix refractometer for the determination of colostral IgG concentrations of <50, <60, >80, >100 and >125g/L were found to be 89.3%(95%CI:71.8-97.7%) and 83.8%(95%CI:77.5-89.0%); 82.0%(95%CI:68.6-91.4%) and 88.1%(95%CI:81.8-92.8%); 85.3%(95%CI:76.9-91.5%) and 73.7%(95%CI:63.9-82.1%); 84.8%(95%CI:73.0-92.8%) and 76.1%(95%CI:68.2-82.8%); and 75.0%(95%CI:53.3-90.2%) and 90.4%(95%CI:85.1-94.3%), respectively.

Conclusion: the digital Brix refractometer showed a good performance in determining mare colostra with low and high IgG concentrations.

Athlete horses' contraction and conduction of the healthy heart influences racing performance. Gene expression patterns in the horse heart are not yet fully investigated. We aimed to evaluate the gene expression from the four chambers of the heart overall and with focus on genes involved in the electrophysiology of the heart in Thoroughbred racehorses with no clinical cardiac abnormalities. Tissue was collected from the left atrium (LA), right atrium (RA), left ventricle (LV), and right ventricle (RV). Total RNA was analysed by microarray technique. We compared gene expression in the heart chambers by contrasting atrial against ventricular chambers (chamber related differences), and by contrasting left side to right side (left-to-right related differences). The pathway analyses revealed that RA was characterised by significantly lower expression of genes related to energy derivation and metabolism in comparison to both ventricles and left atria. LA, on the other hand, was characterised by higher expression of genes related to cardiac conduction, and less expression of cardiac morphogenesis, compared to ventricles. The left-to-right related comparisons indicated wider differences between the atria than between the ventricles. Mapping of the genes specifically involved in cardiac conduction and contraction indicated clear chamber related differences. Some potassium channels, KCNE1 and KCNJ2,3 and 4, showed distinct atrial-ventricular specificity and genes involved in calcium regulation were, as a group, more abundant in both atria compared to ventricles. Our results provide a general overview of the gene expression pattern in the healthy racehorse, with particular focus on the cardiac ion channels.