A Genome-Wide Association Study for Morphometric Traits in Quarter Horse

A genome-wide association study for morphometric traits was conducted in 184 Quarter Horses, 120 from a racing population, and 64 from a cutting population, which were genotyped using the Illumina EquineSNP50 chip. Association analysis was performed with 42,058 single-nucleotide polymorphisms (SNPs) (after quality control) using Qxpak5 software. The following traits were measured: weight (W), rump length (RL), and body length (BL). These morphometric traits are important for the best performance in race and cutting events. For weight, three SNPs associated (P < .0001) were found on chromosomes (Equus caballus autosomes [ECA]) 2 and 3. For rump length, eight SNPs associated (P < .0001) were found on ECA 2, 3, 6, 7, 9, 21, and 26. On ECA 3 and ECA 8, two SNPs were associated (P < .0001) with body length. So, a total of 13 important chromosomal regions were identified with Q values of 0.53 (SNPs for W), 0.40 (SNPs for RL), and 0.99 (SNPs for BL). Positional and functional candidate genes emerging from this study were WWOX and AAVPR1A. Further studies are required to confirm these associations in other populations.     

Nd:YAG Laser Treatment of a Vestibulovaginal Varicosity in a 15-Year-Old Pregnant Mare

A 15-year-old, pregnant Dutch Warmblood mare was exhibiting intermittent hemorrhage secondary to a large vestibulovaginal varicosity. The vessel was reduced with transendoscopic Nd:YAG laser photocoagulation. This technique is minimally invasive compared with traditional surgical ligation, and significantly decreases the risk of severe hemorrhage, especially with advancing pregnancy. One laser treatment resulted in complete reduction in vessel size and allowed the pregnancy to continue to term without incident or further vaginal hemorrhage.     

Use of Ultrasound In Horses for Diagnosis of Left Dorsal Displacement of the Large Colon and Monitoring its Nonsurgical Correction

During a 28 month period, 82 horses with clinical signs of abdominal pain were examined for left dorsal displacement of the large colon (LDDLC) using percutaneous ultrasound. Left dorsal displacement of the large colon was diagnosed when a gas echo dorsal to the spleen obliterated the dorsal splenic border, or when the colon was observed lateral to the spleen. In 42 horses, ultrasound confirmed a diagnosis of LDDLC and 40 horses had no evidence of LDDLC. There were five false negative results and no false positives. In four horses with LDDLC, the colon was displaced between the spleen and body wall; three of these colic episodes resolved with medical therapy and the fourth required a celiotomy to relieve a sand impaction. The remaining 38 horses had a renosplenic entrapment; surgical correction was elected in 4 horses, 21 horses were corrected by a nonsurgical rolling procedure, 12 were corrected at surgery after an unsuccessful rolling attempt, and one was corrected by rolling but required surgery later because of an additional lesion. Percutaneous abdominal ultrasound was a valuable aid in the diagnosis of LDDLC and in confirming correction of the displacement after a nonsurgical rolling procedure.     

Clinical, Clinicopathologic, and Epidemiologic Features of Anhidrosis in Central Florida Thoroughbred Horses

A group of 834 Thoroughbred horses was surveyed on four central Florida farms for clinical and epidemiologic features of anhidrosis. In addition, comparative analysis was made of serum thyroxine, serum electrolytes, and fractional urinary electrolyte excretion ratios. An overall disease prevalence of 6.12% was observed. Training horses and nonpregnant broodmares had a predilection for the disease. Adolescent horses were infrequently affected. There was no correlation with sex or color. Comparative clinical signs, related to thermoregulatory compromise, included tachypnea and hyperthermia. Long-term effect included focal and generalized alopecia, decreased appetite, and impaired performance. Previously reported hypothyroidism and hypochloremia were not demonstrated; however, fractional urinary chloride excretion ratios indicated a significant relative conservation of chloride.     

Effects of dioctyl sodium sulfosuccinate on hematological values in normal horses

In several horses referred for evaluation of colic, we observed marked leukopenia (attributable to neutrophil counts <2,000/μl) which was inconsistent with the mild nature of abdominal pain, absence of fever, or lack of signs of endotoxemia. In all cases, large bowel impaction has been diagnosed via rectal palpation prior to admission and dioctyl sodium sulfosuccinate (DSS) had been one of the medications administered. To investigate the hypothesis that DSS administration may lead to bowel irritation, margination of neutrophils, and development of leukopenia (neutropenia), the effects of DSS administration (20 mg/kg via a nasogastric tube) on clinical and hematologic values were studied in eight clinically normal horses. No changes were detected in any of the clinical values assessed in these horses and neither leukopenia nor neutropenia was observed following DSS administration. A trend for plasma total protein concentration to increase four hours after DSS administration (in comparison to control data) suggested that DSS may enhance secretion of fluid into the bowel in treated horses. In conclusion, the results did not support the hypothesis that the leukopenia observed in horses with colic could be attributed to DSS administration. Whether DSS has more significant effects in horses with altered bowel motility and mucosal integrity during colic episodes is not known.     

Accuracy of open magnetic resonance imaging for guiding injection of the equine deep digital flexor tendon within the hoof

Lesions of the distal deep digital flexor tendon (DDFT) are frequently diagnosed using MRI in horses with foot pain. Intralesional injection of biologic therapeutics shows promise in tendon healing; however, accurate injection of distal deep digital flexor tendon lesions within the hoof is difficult. The aim of this experimental study was to evaluate accuracy of a technique for injection of the deep digital flexor tendon within the hoof using MRI‐guidance, which could be performed in standing patients. We hypothesized that injection of the distal deep digital flexor tendon within the hoof could be accurately guided using open low‐field MRI to target either the lateral or medial lobe at a specific location. Ten cadaver limbs were positioned in an open, low‐field MRI unit. Each distal deep digital flexor tendon lobe was assigned to have a proximal (adjacent to the proximal aspect of the navicular bursa) or distal (adjacent to the navicular bone) injection. A titanium needle was inserted into each tendon lobe, guided by T1‐weighted transverse images acquired simultaneously during injection. Colored dye was injected as a marker and postinjection MRI and gross sections were assessed. The success of injection as evaluated on gross section was 85% (70% proximal, 100% distal). The success of injection as evaluated by MRI was 65% (60% proximal, 70% distal). There was no significant difference between the success of injecting the medial versus lateral lobe. The major limitation of this study was the use of cadaver limbs with normal tendons. The authors conclude that injection of the distal deep digital flexor tendon within the hoof is possible using MRI guidance.     

QUANTITATIVE ULTRASONIC ASSESSMENT OF LIVER SIZE IN THE DOG

Static and real-time B-mode hepatic ultrasound imaging was performed on 16 anesthetized dogs (7.7–29 kg). Sagittal static B-mode scans were acquired at 1–cm intervals, and transverse scans were made with both static and real-time units. Measurements were made from the surface of the liver to the diaphragm and were tested individually and when added or multiplied together for significant correlation with liver and body weight. Only one of the static B-mode measurements had a significant correlation ( p >0.05), and none of the real-time measurements was dependent on liver weight. Ultrasonographic assessment of canine liver size using these methods was of little value in predicting actual liver weight.     

中国柞蚕微粒子病病原研究续报

对辽宁柞蚕的第３、４种微孢子虫的光镜和电镜观察以及寄生习性的研究结果确定：其一为链孢变形孢虫新种，另一为讷卡变形孢虫，后者在柞蚕上尚属首次发现。