Reference ranges and reliability of transabdominal ultrasonographic renal dimensions in thoroughbred horses

The aims of this study were to establish a normal reference range (mean ± 2 SD) and assess reliability of renal dimensions obtained using transabdominal ultrasonography in Thoroughbred horses (n = 7). A minimum of three ultrasonographic cineloops were obtained from each intercostal space and the left paralumbar fossa by two observers daily for three consecutive days. Renal length, width, and thickness and cortex, medulla, and pelvic dimensions were obtained. Measurements were undertaken by both observers, who were unaware of prior measurements, to assess reproducibility and measured on three separate occasions to evaluate short-term measurement repeatability. Measurements from images obtained by both operators were compared to evaluate image repeatability. The left kidney was consistently identified in the left 15th-17th intercostal space and the paralumbar fossa with maximal length in the 16th intercostal space (12.7 ± 2.0 cm) and maximal width in the paralumbar fossa (7.9 ± 1.1 cm). The right kidney was consistently identified in the right 15th-17th intercostal space with maximal length and maximal width in the 15th intercostal space (16.0 ± 0.7 cm and 7.9 ± 1.0 cm). Reproducibility, image repeatability, measurement repeatability were good to excellent, although were less good for the smaller structures. There were no differences in renal dimensions between horses. Overall renal ultrasonography was reliable and a normal reference range for Thoroughbred horses was established. Renal dimensions vary between rib spaces. As repeatability and reproducibility were excellent for renal length and width, it may be prudent to use those measurements in rib spaces where parameters were maximal.     

Morphological assessment of cat kidneys using computed tomography

There are numerous publications about feline renal imaging information; however, none have established reference values for kidney size using computed tomography (CT). This study aimed to determine renal size and shape as well as the morphology of renal‐related structures in clinically normal cats (Felis catus) that underwent CT. Twenty‐seven healthy cats underwent pre‐ and post‐iodinated contrast‐enhanced CT. Most cat (59%) kidneys were located at the same level. The average pre‐contrast dimensions of the left kidney included a width of 2.46 ± 0.28 cm, a length of 3.52 ± 0.44 cm and a height 2.19 ± 0.31 cm, whereas those of the right kidneys were 2.45 ± 0.27 cm, 3.54 ± 0.46 cm and 2.05 ± 0.23 cm, respectively. After contrast enhancement, kidneys were slightly enlarged though not significantly. Additionally, renal length (LK or RK) was compared with second lumbar vertebra (L2) length and abdominal aorta diameter (AO). AO was significantly larger in male cats whereas L2 length appeared longer in male cats, but was not statistically different from the female cats. The LK/L2 and RK/L2 ratios were 2.29 ± 0.23 and 2.36 ± 0.20, respectively, and the LK/AO and RK/AO were 11.72 ± 1.37 and 12.05 ± 1.47, respectively. Renal vessels were examined. The renal vein was obviously larger than the renal artery, and paired renal veins were observed periodically. This study provides CT information about the feline kidney, which may help to establish reference values and information regarding renal structure prior to surgery in practice.     

REPEATABILITY AND REPRODUCIBILITY OF TRANSABDOMINAL ULTRASONOGRAPHIC INTESTINAL WALL THICKNESS MEASUREMENTS IN THOROUGHBRED HORSES

The aims of this study were to assess the repeatability and reproducibility of transabdominal ultrasonography to assess intestinal wall thickness in adult Thoroughbred horses (n=8). Ultrasonographic cineloops were captured by one examiner from each horse for five consecutive days. During each examination at least three cineloops were obtained for five different intestinal tract locations. Measurements were performed by three separate observers to assess reproducibility and measured on three separate occasions by three observers to evaluate short‐term repeatability. The repeatability of measurements from the duodenum (0.3 ± 0.04 cm), jejunum (0.29 ± 0.05 cm), ventral colon (0.37 ± 0.01 cm), and cecum (0.42 ± 0.03 cm) were good ( P >0.291). The reproducibility of measurements from the duodenum, jejunum, and ventral colon were good ( P >0.394). Reproducibility of measurement of the cecal wall was inadequate ( P =0.01), although the maximum difference between observers was 0.07 cm. It was possible to image all areas on all days, with the exception of the duodenum, which could not be imaged in one horse, on 1 day. Equine intestinal wall measurements are therefore repeatable and reproducible with the exception of reproducibility of the measurements of cecal wall. Although an accepted clinical technique, measurement of cecal wall thickness from intestinal ultrasound images in a clinical setting must be interpreted with care.     

TRANSRECTAL ULTRASONOGRAPHY OF THE LEFT ADRENAL GLAND IN HEALTHY HORSES

Little information is available on medical imaging of the adrenal glands in horses. We investigated the feasibility of transrectal ultrasonography to characterize the normal equine adrenal gland. Transrectal ultrasonography was performed in 25 healthy horses using a 7.5 MHz linear array probe at a displayed depth of 8 cm. Transrectal ultrasonography of the right adrenal gland was not feasible. For the left adrenal gland, the left kidney, the abdominal aorta, the left renal artery, the left renal vein, and the cranial mesenteric artery were used as landmarks. The size of the left adrenal gland was variable, but it generally appeared as a long, flat structure with a hyperechoic medulla surrounded by a hypoechoic cortex. The most cranial part of the gland could not be delineated appropriately in 11 horses (44%). The mean (±SD) thickness of the gland and medulla was 0.66±0.15 cm (n=25) and 0.28±0.09 cm (n=25) near the caudal pole, 0.87±0.25 cm (n=14) and 0.40±0.18 cm (n=12) near the cranial pole, and 0.89±0.18 cm (n=25) and 0.36±0.13 cm (n=25) in the middle of the gland, respectively. The mean (±SD) length of the entire adrenal gland and of the medulla was 6.22±0.77 cm (n=14) and 5.45±0.71 cm (n=6), respectively. Transrectal ultrasonography allowed adequate visualization of the left adrenal gland in horses.     

Urinary tract ultrasonography in normal rams and in rams with obstructive urolithiasis

We determined the position, dimensions, and structure of the kidneys, ureters, bladder, and urethra in 20 healthy, adult rams by use of ultrasonography. The findings were compared with those of seven rams with obstructive urolithiasis, thus establishing criteria for the diagnosis of urolithiasis via ultrasonography. A 5.0 MHz convex transducer was placed over the right paralumbar fossa to examine the kidneys, and a 5.0 MHz linear rectal transducer was used to examine the bladder and urethra transrectally. All examinations were performed on standing rams. The left kidney had a length of 8.4 ± 0.3 cm (mean ± SD), a width of 4.7 ± 0.3 cm, and a depth of 4.4 ± 0.3 cm. The diameter of the renal sinus of the left kidney was 1.5 ± 0.2 cm. The circumference of the medullary pyramids measured 2.8 ± 0.3 cm. Similar ultrasonographic measurements were obtained for the right kidney. The mean diameter of the bladder of 12 rams was 7.5 ± 2.8 cm. The diameter of the bladder could not be determined in the remaining eight rams because it was greater than 10 cm and therefore beyond the penetration depth of the scanner. The only part of the urethra which could be visualized ultrasonographically was the internal urethral orifice. It had a diameter of 0.2 ± 0.1 cm.

Ultrasonographic examination of seven rams with obstructive urolithiasis revealed a markedly dilated urethra and urinary bladder. Due to severe cystitis, the contents of the urinary bladder appeared as multiple, tiny, uniformly distributed echoes. The renal pelvis and medullary pyramids of both kidneys were dilated in four rams. In two rams, uroperitoneum and accumulation of urine in the abdomen were diagnosed via ultrasonography. In one ram this was due to a ruptured ureter and in one to a ruptured bladder. The results of this study indicate that ultrasonography is a useful aid in the diagnosis of obstructive urolithiasis.

     

Assessment of the accuracy of computed tomography for measurement of normal equine pituitary glands

OBJECTIVE: To describe the anatomic features of the pituitary gland region in horses via computed tomography (CT) and determine the accuracy of CT for estimating normal equine pituitary gland dimensions. ANIMALS: 25 adult horses with no clinical signs of pituitary disease. PROCEDURE: Transverse CT images and gross transverse tissue sections were compared in 2 horses. Contrast-enhanced CT of the pituitary gland region was performed postmortem in 23 horses with 4 slice thickness and interval settings (10-mm contiguous or overlapping slices and 4-mm contiguous or overlapping slices). Gross and CT estimates of pituitary gland dimensions were compared via ANOVA. Accuracy of CT estimates was calculated with gross pituitary gland measurements as the known value. RESULTS: Pituitary glands were located between the temporomandibular joints and had contrast enhancement. Mean gross dimensions were length, 2.11 cm; width, 2.16 cm; height, 0.98 cm; and volume, 2.66 cm3. Gross measurements and CT estimates of pituitary gland length from 10-mm contiguous and overlapping slices did not differ. Gross measurements and CT estimates of pituitary gland width from 4-mm contiguous and overlapping slices did not differ. Estimates of height and volume from all CT techniques differed from gross measurements. Accuracies for CT estimates were length, 88 to 99%; width, 81 to 92%; height, 58 to 71%; and volume, 43 to 55%. CONCLUSIONS AND CLINICAL RELEVANCE: Accuracy of estimates of pituitary gland dimension in horses varied with CT scanning technique; via CT estimates of length and width of glands were more accurate than estimates of height or volume.     

A Cross-Sectional Survey of Forelimb Hoof Conformation and the Prevalence of Flat Feet in a Cohort of Thoroughbred Racehorses in New Zealand

Racehorses in New Zealand predominantly train counter clockwise. This training pattern has been associated with between forelimb differences in bone mineral density profile and asymmetrical limb loading after training. At present, there is limited data on the hoof conformation of these racehorses. Distal forelimb and digital hoof conformation data were collected from 75 Thoroughbred racehorses (2–5 years old) from two training yards. Digital conformation was subjectively graded, and multiple hoof measurements were made with a modified tire gauge (sole and sulci depth) and from digital photographs. All the horses were shod by two registered master farriers within a median of 15 (interquartile range [IQR], 1–25) days before measurement. There were few distal limb conformation abnormalities scored. Most (62/75) horses presented with some deviation from normal hoof parameters, with 2 (IQR, 1–3) abnormalities reported per horse. The most common hoof abnormality was uneven sulci, which was identified in 43 horses and 59 affected hooves, followed by higher medial hoof wall height in 38 horses and 53 affected hooves. Many of the linear and hoof angle measurements and their ratios were within the bounds reported within the literature and indicative of a balanced foot. The length and width measurements increased with horse age. The dorsal hoof wall (DHW) length:heel length ratios were consistently less than 3:1, and the absolute difference between toe and heel angle was generally greater than 5°. Between limb hoof variation was identified for a number of the morphologic measurements including frog length and sole length and the ratio of sole width:sole length. Flat feet (lack of concave solar surface) were identified in 21/75 (28%) horses and in 28/150 (19%) forelimb hoofs. More horses had a flat left foot (10/75) than right foot (4/75), but seven horses had both feet classified as being flat. Flat feet had 2.4 (1.1–5.6, P = .036) greater odds of presenting with uneven sulci. These data indicate that uneven sulci depth and flatter hooves with may be a typical presentation of Thoroughbred feet. Asymmetry in measurements between limb may reflect the greater loading of the left forelimb when race training counter clockwise.     

Refractive state of the Spanish Thoroughbred horse: a comparison with the crossbred horse

Objective To assess the refractive state of the equine eye utilizing retinoscopy. To compare the refractive state of Spanish Thoroughbred horses with the refractive state of Crossbred horses. Procedures The refractive state of 135 horses (264 eyes) was assessed utilizing streak retinoscopy. Two perpendicular meridians were examined in order to assess astigmatism at a working distance of approximately 67 cm. A group of 81 Spanish Thoroughbred horses was compared with a group of 54 Crossbred horses. Cyclopentolate ophthalmic solution was instilled in the eyes of a group of 18 horses to determine if accommodation has any influence on the assessment of the refractive state. Results Mean ± SE refractive state of all horses examined was ?0.17 ± 0.04 D. The mean refractive state of the Spanish Thoroughbred was ?0.28 ± 0.06 D while that of the Crossbred was ?0.01 ± 0.05 D. The refractive state of the Spanish Thoroughbred was found to be statistically different to that of the Crossbred. The most prevalent refractive state was emmetropia in all cases, followed by hyperopia for the Crossbred, and myopia for the Spanish Thoroughbred. Astigmatism ≥0.50 D present in both eyes from the same individual was found in 21.7% of all horses examined. Anisometropia ≥1.00 D was diagnosed in 4 out of 129 horses with both visual eyes. Cycloplegia did not statistically affect the refractive state of the evaluated eyes. Conclusions The equine eye has a refractive state close to emmetropia. Myopia is higher among Spanish Thoroughbred horses than among Crossbred horses.     

Short-term cast immobilisation is effective in reducing lesion propagation in a surgical model of equine superficial digital flexor tendon injury

Reasons for performing the study: Larger superficial digital flexor tendon (SDFT) injuries have a poorer prognosis than smaller lesions. During the inflammatory phase enlargement of the initial lesion is frequently noted, with biomechanical loading being recently proposed to play an important role. Objectives: To evaluate the effect of lower limb cast immobilisation on tendon lesion propagation in an equine model of surgically induced SDFT injury. Methods: Core lesions were surgically induced in both front SDFTs of 6 young mature horses. At the end of surgery, one leg was randomly placed in a lower limb cast and the other leg (control) was bandaged for 10 days. Computerised ultrasonographic tissue characterisation performed at Days 10, 15, 21, 28, 35 and 42 allowed measurement of lesion length (cm) and width (expressed as a percentage of whole tendon cross‐section). On Day 42 horses were subjected to euthanasia and both SDFTs were sectioned every centimetre to assess the lesion length macroscopically. Statistics were performed to compare cast vs. control legs with significance set at P<0.05. Results: When all time points were combined, lesion length was 19% shorter (P<0.0001) and lesion width 57% smaller (P = 0.0002) in the cast legs (6.13 ± 0.12 cm; 6.90 ± 0.64%) than in the control legs (7.30 ± 0.21 cm; 10.85 ± 1.22%). On Day 42 the lesion length on macroscopic evaluation was 19% shorter (P = 0.04) in the cast (7.00 ± 0.36 cm) than in the control legs (8.33 ± 0.33 cm). Conclusions: Cast immobilisation for 10 days effectively reduced lesion propagation (length and width) compared to bandaging in an in vivo model of artificially‐induced tendon lesions. Potential relevance: A short period of cast immobilisation during the early phase of tendon healing may be an easy and cost‐effective way to reduce the initial enlargement of lesion size and hence to improve prognosis.     

ULTRASONOGRAPHIC EVALUATION OF RENAL SIZE IN DOGS WITH ACUTE ALLOGRAFT REJECTION

The purpose of this study was to determine the best method to ultrasonographically monitor renal size changes associated with acute allograft rejection in dogs. Qualitative changes in renal cortical and medullary echogenicity were also evaluated, although this was not a major focus of the study. Four unrelated, mixed-breed dogs underwent bilateral nephrectomies and heterotopic renal allograft transplantation. Ultrasound examinations of transplanted kidneys were initiated at 3 days after surgery and continued at 2–3 day intervals until death (38±2 days). Ultrasound measurements of kidney length, width, height, cross-sectional area, and estimated volume were used to assess relative changes in renal size associated with transplantation and rejection. Transplanted kidneys had a rapid increase in volume and cross-sectional area that averaged 103% and 83% above baseline levels, respectively, by 17 days after transplantation. The increased size was attributed to a combination of hypertrophy and acute rejection, the latter of which was confirmed at postmortem. Kidney volume decreased to approximately 35% above baseline volume by day 34 as rejection became more advanced. Qualitative changes associated with rejection included medullary enlargement with decreased echogenicity early in the study, followed by increased cortical thickness and echogenicity with poor cortical medullary definition in the latter stages of the survival period. It was concluded that relative changes in renal allograft size can be easily monitored with ultrasound. In regard to linear measurements, changes in renal width were more pronounced than changes in height or length with acute rejection. Therefore measurements that incorporate the width, namely volume or cross-sectional area, appear to be the most sensitive for monitoring changes in allograft size. Renal cross-sectional area measurements are preferred because they are simple to perform using the automated calculation capability of most newer ultrasound units.     

A Novel Equine Hoof Lamellar Tissue Biopsy Technique

This study aims to validate the efficacy of a new device specifically developed for equine lamellar biopsy. Nine adult horses were used. Under sedation and digital nerve perineural anesthesia and after keratinized tissue thinning, a sample from the dorsal lamellar stratum was obtained using an instrument called Falcão-Faleiros' lamellotome. Hoof pain sensitivity was evaluated for 60 days, and horses were monitored for 6 months. Lateromedial radiographic images to analyze the spatial relationship between the distal phalanx and the hoof capsule were obtained before and 30 days after the biopsy. The effect of time on the variables was statistically analyzed (P < .05). On average (±SD), the biopsies produced samples that were 2.32 (±0.64) cm in length, 0.48 (±0.09) in width, and 0.51 (±0.11) cm in depth. A mean of 69 of intact primary epidermal lamellae was obtained per biopsy sample. Lameness and sensitivity to hoof testers were evident during the first 4 days postbiopsy but returned to basal levels after the fifth day. Minimal radiographic changes were observed, and the horses completely returned to their regular activities after 60 days. All biopsied hoofs grew normally during the 6-month period, making the dorsal wall defects reach the ground level. The use of the lamellotome for equine hoof lamellar biopsy produced an adequate quality and quantity of tissue for histology and allowed for full clinical recovery of the horses.     

Ultrasonographic aspects and biometry of Striped owl’s eyes (Rhinoptynx clamator)

Objective To report the biometric values and ultrasonographic aspects of the normal eye of the Striped owl (Rhinoptynx clamator). Sample population Twenty‐seven healthy, free‐living, adult Striped owls from the Ecological Park of Tiete Veterinary Ambulatory (Sao Paulo, Brazil). Procedures Both eyes of all owls underwent B‐mode ultrasonographic examination and biometry was performed for lens axial length (WL), depth of the anterior (AC) and vitreous (VC) chambers, axial length of the globe (LB) and the pecten oculi (LP) of both eyes, using a 12 MHz probe. The owls were manually restrained without sedation and the eyes were topically anesthetized. Results Biometric and statistical findings were as follows: in the left eye, the means and standard deviations were: LB = 23.76 ± 0.92 mm, WL = 7.79 ± 0.27 mm, AC = 4.27 ± 0.47 mm, VC = 11.36 ± 0.29 mm and LP = 5.69 ± 0.50 mm; in the right eye, the values were: LB = 24.25 ± 0.79 mm, WL = 8.03 ± 0.40 mm, AC = 4.56 ± 0.52 mm, VC = 11.40 ± 0.25 mm, and LP = 5.68 ± 0.41 mm. No significant differences were found between left and right eyes measurements of LB, WL, AC, VC, and LP dimensions. Conclusions Ocular ultrasound aspects and biometric values of the Striped owl are reported. The study’s results provide means for various ocular measurements. The ultrasound is an easy and safe exam to be performed in the Striped owl’s eyes.     

Catastrophic scapular fractures in Californian racehorses: pathology, morphometry and bone density

Reasons for performing study: To enhance understanding of the nature and pathogenesis of scapular fractures in racehorses. Hypothesis: Scapular fractures in racehorses have a consistent configuration related to sites of pre‐existing stress modelling and remodelling. Methods: Fractured and intact scapulae collected post mortem were examined visually and with computed tomography (CT). Scapular fracture configuration, bone modelling changes and standardised CT morphometry and density measurements were recorded. Statistical comparisons were made between fractured, nonfractured contralateral and control scapulae. Results: Thirty‐nine scapulae from 10 Thoroughbred (TB) and 10 Quarter Horse (QH) racehorses were obtained. All 14 fractured scapulae (from 12 horses) had a consistent comminuted fracture configuration. A complete fracture coursed transversely through the neck of the scapula at the level of the distal aspect of the spine (8.9 ± 0.9 cm proximal to the lateral articular margin of the glenoid cavity). The distal fragment of 13 fractured scapulae was split into 2 major fragments by a fracture in the frontal plane that entered the glenoid cavity (2.8 ± 0.4 cm caudal to the cranial articular margin). Focal areas of periosteal proliferation and/or radiolucency were present in the distal aspect of the scapular spine of all fractured and intact contralateral scapulae, but less commonly (P<0.01) in intact scapula from horses without a scapular fracture. Fractured scapulae had 7–10% lower mean density and 46–104% greater density heterogeneity in the spine adjacent to the transverse fracture compared to control scapulae (P<0.03). Conclusions and clinical relevance: Thoroughbred and QH racehorses have a characteristic scapular fracture configuration that is associated with pre‐existing pathology of the distal aspect of the spine. This location is consistent with scapular stress fractures diagnosed in lame TB racehorses. Catastrophic fracture is the acute manifestation of a more chronic process. Consequently, there are opportunities for early detection and prevention of fatalities.     

Systemic effects of a prolonged continuous infusion of ketamine in healthy horses

Background: Ketamine as continuous rate infusion (CRI) provides analgesia in hospitalized horses. Objective: Determine effects of prolonged CRI of ketamine on gastrointestinal transit time, fecal weight, vital parameters, gastrointestinal borborygmi, and behavior scores in healthy adult horses. Animals: Seven adult Thoroughbred or Thoroughbred cross horses, with permanently implanted gastric cannulae. Methods: Nonblinded trial. Random assignment to 1 of 2 crossover designed treatments. Ketamine (0.55 mg/kg IV over 15 minutes followed by 1.2 mg/kg/h) or lactated Ringer's solution (50 mL IV over 15 minutes followed by 0.15 mL/kg/h) treatments. Two hundred 3 × 5 mm plastic beads administered by nasogastric tube before drug administration. Every 2 hours vital parameters, behavior scores recorded, feces collected and weighed, and beads retrieved. Every 6 hours gastrointestinal borborygmi scores recorded. Study terminated upon retrieval of 180 beads (minimum 34 hours) or maximum 96 hours. Nontransit time data analyzed between hours 0 and 34. Results: No significant (P < .05) differences detected between treatments in vital signs or gastrointestinal borborygmi. Significant (P = .002) increase in behavior score during ketamine infusion (0.381) from hours 24–34 compared with placebo (0). Ketamine caused significant delay in passage of 25, 50, and 75% of beads (ketamine = 30.6 ± 5.3, 41.4 ± 8.4, 65.3 ± 13.5 hours versus placebo = 26.8 ± 7.9, 34.3 ± 11.1, 45.8 ± 19.4 hours), and significant (P < .05) decrease in fecal weight from hours 22 (12.6 ± 3.2 versus 14.5 ± 3.8 kg) through 34 (18.5 ± 3.9 versus 12.8 ± 6.4 kg) of infusion. Conclusions and Clinical Importance: Ketamine CRI delayed gastrointestinal transit time in healthy horses without effect on vital parameters.     

Ultrasonography of the urinary tract of female sheep.

We determined the position, dimensions, and structure of the kidneys, ureters, bladder, and urethra of 62 female sheep by use of ultrasonography. A 5.0-MHz convex transducer was placed over the right flank to examine the kidneys, and a 5.0 MHz-linear transducer was used to examine the bladder and urethra transrectally. All examinations were performed on sheep in standing position. The left kidney was 7.1 to 8.9 cm long, 3.4 to 5.5 cm wide, and 3.3 to 4.7 cm deep. Diameter of the parenchyma and renal sinus of the left kidney ranged between 1.1 and 1.9 cm and 1.1 and 2.0 cm, respectively. Circumference of the medullary pyramids varied between 2.1 and 3.3 cm. Similar ultrasonographic measurements were obtained for the right kidney. The diameter of the bladder varied between 0.3 and 6.9 cm in 96.8% of the sheep. The diameter of the bladder could not be determined in 32% of the sheep because it was > 10 cm, and, therefore, was beyond the penetration depth of the scanner. The only part of the urethra that could be ultrasonographically visualized was the internal urethral orifice. It had diameter between 0.1 and 0.2 cm. The ureters could not be ultrasonographically visualized in any of the sheep examined. The urinary tract of 8 sheep was examined 10 times within 2 weeks to examine whether measurements were reproducible. The interassay variation coefficient determined ranged from 3.1 to 31.8%, although for most variables, it ranged between 5 and 11%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Accuracy of the TurfTrax Racing Data System for determination of equine speed and position

Reasons for performing study: The speed and position data collected by TurfTrax Racing Data Limited during UK Thoroughbred racing have potential to benefit equine science and welfare. The size (the 2006 data set alone consists of 30,932 individual horse starts across 2667 races) and nature (speed and 2D position for each horse at 4 updates per second) of the data make it a unique resource for questions in equine safety, welfare, performance, and animal locomotion. Objective: To determine the accuracy of the TurfTrax tracking system in estimating the speed and position of horses during racing. Methods: Measurements from the TurfTrax wireless tracking system were compared with those of a survey‐grade global positioning system (GPS) receiver. Results: The TurfTrax system was found to give position measurements to within ± 11 and ± 64 cm in the fore‐aft and lateral directions, respectively, averaging ± 38 cm (interquartile range) and speed to within 0.15 m/s. Potential relevance: The data collected by the TurfTrax system are of sufficient accuracy to inform new diagnoses, training regimens and basic locomotor scientific studies. The position data can provide the precise distance, going, inclination, rate of turn and pack positioning through which each horse has raced. The speed profile can be used to examine the level of exertion, effect of training regimens and influence of racecourse features on performance. A first clinical application would be to analyse retrospectively these factors on occurrence of injury to compare with past training regimens, levels of exertion, and/or racecourse conditions.     

Echocardiographic changes in heart size in hypohydrated horses

Background: Hypohydration causes transient echocardiographic changes in pigs, dogs, humans, and cats. These changes mask the diagnosis of some cardiac diseases (valvular regurgitation, dilated cardiomyopathy) and promote the diagnosis of others (hypertropic cardiomyopathy and infiltrative disease), thus inhibiting accurate echocardiographic evaluation. Objectives: To describe the echocardiographic changes associated with hypohydration in normal horses. Animals: Ten adult horses without detectable cardiac disease. Methods: Experimental study. Echocardiographic examinations were performed on horses in the euhydrated and hypohydrated states. Horses were hypohydrated by combined water deprivation and furosemide administration until a 4–7% reduction in bodyweight was achieved. Statistical analyses were performed by paired t‐tests. Results: Hypohydration decreased left ventricular internal diameter in systole (0.8 ± 0.6 cm) and diastole (1.7 ± 0.9 cm), left atrial diameter (1.5 ± 0.4 cm) and left ventricular volume (490 ± 251 mL) (P‐values < .01), and increased septal wall thickness in diastole (0.6 ± 0.3 cm), free wall thickness in diastole (0.5 ± 0.3 cm), mean wall thickness (0.5 ± 0.2 cm) and relative wall thickness (0.2 ± 0.1 cm) (P‐values < .01). Conclusions and Clinical Importance: Hypohydration produces changes in left ventricular and atrial size that could mask or promote the severity of cardiac disease. The thickened, “pseudohypertrophied” appearance of the left ventricle in hypohydrated horses could affect interpretation of echocardiographic variables that are applied to the prediction of athletic performance. Echocardiography may prove a noninvasive method of monitoring volume status and response to fluid therapy in hypovolemic horses.     

Morphological Characteristics of the Placenta and Umbilical Cord of Arabian Mares Foaling in the United Arab Emirates

A total of 127 normal placentas from Arabian mares resident in the United Arab Emirates were examined. The mean linear dimensions of the placenta were, on average, 84% of those previously recorded for the placentas of the Thoroughbred. Significant differences in the size of the allantochorion between primigravid and multiparous mares were seen only in the linear dimensions of the body portion. The pregnant horn was more commonly on the right than left side of the uterus (P = .01; 74/127; 58%). Cord attachment was primarily at the base of the two placental horns (112/127; 88%), with the remainder showing anomalies from this position. The mean (±SEM) total length of the umbilical cords was 62.2 ± 1.2 cm, being composed of the allantoic portion (29.7 ± 0.9 cm) and amniotic portion (32.5 ± 0.6 cm), which averaged 53 ± 0.01% of the total length. The amniotic portion was usually, but not always, longer than the allantoic portion (79/127; 62%). Longer cords were associated with a greater proportion of allantoic length. An enlarged yolk sac remnant (YSR) was present in 16/127 (13%) placentas. Cords with YSRs displayed a significantly longer allantoic portion than those without (P = .02). The total cord length was not correlated with the weight or area of the allantochorion or amnion, any linear measurement of the allantochorion, gestation length, the month of foaling, parity of the dam, or birthweight or sex of the foal. The purpose for which the mare was bred (i.e., racing or showing) influenced the cord length, those of show mares being significantly longer.