Proximal hindlimb flexion in the horse: Effect on movement symmetry and implications for defining soundness

Reasons for performing the study: Flexion tests are a common tool during the prepurchase and clinical lameness examination, yet studies quantifying the effect of flexion, apart from distal forelimb flexion in sound horses, are sparse. Objectives: To investigate the effect of proximal hindlimb flexion on perceivable and measurable changes in movement symmetry in horses with objective movement symmetry falling within the margins of ‘sound’. Methods: Thirteen horses, selected based on objective movement symmetry, were instrumented with inertial sensors on left and right tuber coxae and over the os sacrum. Vertical movement symmetry was quantified at trot before and after proximal hindlimb flexion, with a repeat of flexion after 5 min. Video recordings of the horses were assessed visually. Results: Proximal hindlimb flexion introduced additive changes in movement symmetry to the individual baseline movement, with a tendency towards smaller effects with increasing stride number. The main systematic effect was a decrease in upward movement of the os sacrum following mid‐stance of the flexed limb and an increase in upward movement following mid‐stance of the nonflexed limb, also manifesting in a ‘hip hike’ of the flexed limb; these findings reflected increased movement asymmetry following flexion. Depending on individual baseline asymmetry, flexion can also increase movement symmetry. Conclusions: Proximal hindlimb flexion can exacerbate subtle asymmetry when performed carefully. Variation in measured symmetry following flexion within and between horses showed that the individual response to flexion is highly variable. Potential relevance: Proximal hindlimb flexion may elevate the asymmetry of a slightly lame limb above the threshold for visibility, thus assisting in the clinical gait examination. Further work is needed to examine the causes for a positive response to flexion and possible differences between sound and lame horses as well as horses of different athletic disciplines.     

Four multistate outbreaks of human Salmonella infections associated with live poultry contact, United States, 2009

Outbreaks of human salmonellosis associated with live poultry contact have been reported since 1955. Multiple Salmonella serotypes have been associated with these outbreaks, and specific outbreak strains have been repeatedly linked to single hatcheries over multiple years. During 2009, four multistate outbreaks of human Salmonella infections associated with direct and indirect exposure to live poultry purchased from mail-order hatcheries and agricultural feed stores were identified, resulting in 165 culture-confirmed cases in 30 states. This report describes the epidemiologic, environmental and laboratory investigations conducted by state and local health departments, state departments of agriculture, the U.S. Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS), National Poultry Improvement Plan (NPIP) and National Veterinary Services Laboratories (NVSL), and the Centers for Disease Control and Prevention (CDC). Case-patients were identified through PulseNet, the national molecular subtyping network for foodborne disease surveillance, and interviewed using the CDC standard live poultry contact questionnaire that asks about poultry-related exposures during the 7 days before illness onset. These outbreaks highlight the need to focus efforts on strategies to decrease and prevent human illness associated with live poultry contact through comprehensive interventions at the mail-order hatchery, agricultural feed store and consumer levels. Additional consumer education and interventions at mail-order hatcheries and venues where live poultry are sold, including agricultural feed stores, are necessary to prevent transmission of Salmonella from poultry to humans.     

The influence of temperature and age on the T1 relaxation time of the equine distal limb

The extent of fat suppression using short tau inversion recovery (STIR) imaging is variable between horses. Our aim was to determine if patient's age and/or hoof temperature have an influence on the T(1) relaxation time of bone marrow in the equine distal limb, thereby affecting the suppression of fat signal. Magnetic resonance imaging was conducted on standing horses and cadaver samples using a low-field magnet (0.27 T). The hoof temperature was measured at the lateral side of the coronary band. A modified inversion recovery fast spin-echo (IR-FSE) sequence was used to measure the signal intensity for a range of inversion times (TIs) at six different regions of interest (ROI): (1) distal aspect of the proximal phalanx, (2) proximal aspect of the middle phalanx, (3) distal aspect of the middle phalanx, (4) navicular bone, (5) proximal aspect of the distal phalanx, and (6) distal aspect of the distal phalanx. The T(1) of the bone marrow in the equine distal limb was calculated from the results and was found to increase by 3.13 ± 0.08 (SE) ms/°C. There was no significant effect of age (2-16 years) but the T(1) values measured from the limbs of young (< 1 year) animals were considerably longer (32.6 ± 1.7 (SE) ms). Similar effects of temperature and age were found for all measured ROIs but there were significant differences in the mean values of T(1) , ranging from +7.7 (distal aspect of the distal phalanx) to -13.2 ms (distal aspect of the proximal phalanx).     

MAGNETIC RESONANCE IMAGING OF PULP IN NORMAL AND DISEASED EQUINE CHEEK TEETH

A retrospective analysis of 619 upper and lower cheek teeth from 62 horses was performed. Based on clinical findings, as well as radiographic and magnetic resonance (MR) imaging findings, the teeth were classified into five groups. There were 20 teeth with abnormal MR imaging signals as well as clinical alterations and 599 healthy teeth. Using MR imaging, the appearance of pulp in diseased and disease‐free teeth was compared, and the appearance of abnormal pulp was studied. Subsequently, the ability of MR imaging to diagnose pulpitis and pulp necrosis in teeth with normal external appearance was investigated. In horses with clinically verified dental disease, abnormal MR imaging findings were confirmed in the pulp of all affected teeth. An enlarged blurred pulp image with a lower signal intensity was observed only in clinically diseased teeth and was a reliable criterion for diagnosing dental disease on MR imaging. On the other hand, partial or complete absence of pulp in all MR imaging sequences was observed in both diseased and nondiseased teeth. These data demonstrate that pulp changes in equine cheek teeth can be evaluated using MR imaging.     

Sex differences in the response of yearling horses to handling by unfamiliar humans

In adult horses, pronounced sex differences in behavior exist, and many riders prefer male horses to mares. In the present study, we tested the hypothesis that sex differences in the response of horses to handling emerge before puberty, that is, in sexually immature animals. Warm-blooded yearling horses (6 males and 9 females) were exposed to a stationary human test (exposure to an unfamiliar person for 5 minutes) and a tolerance test (haltering and direct contact with the horse) on 5 consecutive days. The horses' behavior and heart rate were recorded. Male yearling horses displayed significantly less exploratory behavior than females during the stationary human test on days 1 and 2 (P < 0.05). Latency to halter and ease with which horses could be haltered were significantly affected by day (P < 0.05), and a significant interaction of day and sex was detected (P < 0.05; e.g., time for haltering: females, day 1: 23.8 ± 7.8 seconds [±standard error of the mean] and day 5: 21.1 ± 1.7 seconds; males, day 1: 53.6 ± 10.4 seconds and day 5: 19.4 ± 2.2 seconds). Heart rate of the horses in response to the test situations was significantly affected by day (P < 0.01) but not by sex. In conclusion, sex differences in behavior do not only exist in adult horses but are already present in young horses before puberty. When exposed to unfamiliar humans for the first time, male yearling horses display more caution than females.     

Cholecalciferol

The primary source of exposure to cholecalciferol in dogs and cats is ingestion of rodenticide baits with vitamin D₃ as the active ingredient. Other sources of this toxin are human medications and rarely, contaminated pet food. Although the reported lethal dose 50% for cholecalciferol is 88 mg/kg, deaths have been seen with an individual exposure of 2 mcg/kg in dogs. Clinical signs are induced by profound hypercalcemia affecting multiple body systems. Clinical presentations may include anorexia, depression, muscle weakness, vomiting, polyuria, polydipsia, dehydration, abdominal pain, hematemesis, melena, and bradycardia. Tissue mineralization may develop if calcium × phosphorous product is greater than 60. Serum testing for hypercalcemia, hyperphosphatemia, and decreased serum parathyroid hormone are confirmatory. Initial treatment relies upon decontamination with emesis induction followed by administration of pulse-dose activated charcoal designed to interfere with the extensive enterohepatic recirculation of toxin. Medical management is designed to decrease serum calcium levels by use of intravenous fluid diuresis with administration of furosemide and prednisolone. Biphosphate pamidronate is used to inhibit calcium release from the bone. Phosphate binders aid in decreasing phosphate availability to interact with calcium. The prognosis is better if treatment is instituted early before development of hypercalcemia and hyperphosphatemia enables tissue mineralization to progress.     

Impact of harvest year on amino acids and sugars in potatoes and effect on acrylamide formation during frying

Acrylamide is formed via the Maillard reaction between reducing sugars and asparagine in a number of carbohydrate-rich foods during heat treatment. High acrylamide levels have been found in potato products processed at high temperatures. To examine the impact of harvest year, information on weather conditions during growth, that is, temperature, precipitation, and light, was collected, together with analytical data on the concentrations of free amino acids and sugars in five potato clones and acrylamide contents in potato chips (commonly known as crisps in Europe). The study was conducted for 3 years (2004-2006). The contents of acrylamide precursors differed between the clones and the three harvest years; the levels of glucose were up to 4.2 times higher in 2006 than in 2004 and 2005, and the levels of fructose were 5.6 times higher, whereas the levels of asparagine varied to different extents. The high levels of sugars in 2006 were probably due to the extreme weather conditions during the growing season, and this was also reflected in acrylamide content that was approximately twice as high as in preceding years. The results indicate that acrylamide formation is dependent not only on the content and relative amounts of sugars and amino acids but also on other factors, for example, the food matrix, which may influence the availability of the reactants to participate in the Maillard reaction.