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.     

Tillage effects on soil hydraulic properties in space and time: State of the science

Soil tillage practices can affect soil hydraulic properties and processes dynamically in space and time with consequent and coupled effects on chemical movement and plant growth. This literature review addresses the quantitative effects of soil tillage and associated management (e.g., crop residues) on the temporal and spatial variability of soil hydraulic properties. Our review includes incidental management effects, such as soil compaction, and natural sources of variability, such as topography. Despite limited research on space–time predictions, many studies have addressed management effects on soil hydraulic properties and processes relevant to improved understanding of the sources of variability and their interactions in space and time. Whether examined explicitly or implicitly, the literature includes studies of interactions between treatments, such as tillage and residue management. No-tillage (NT) treatments have been compared with various tillage practices under a range of conditions with mixed results. The trend, if any, is for NT to increase macropore connectivity while generating inconsistent responses in total porosity and soil bulk density compared with conventional tillage practices. This corresponds to a general increase in ponded or near-zero tension infiltration rates and saturated hydraulic conductivities. Similarly, controlled equipment traffic may have significant effects on soil compaction and related hydraulic properties on some soils, but on others, landscape and temporal variability overwhelm wheel-track effects. Spatial and temporal variability often overshadows specific management effects, and several authors have recognized this in their analyses and interpretations. Differences in temporal variability depend on spatial locations between rows, within fields at different landscape positions, and between sites with different climates and dominant soil types. Most tillage practices have pronounced effects on soil hydraulic properties immediately following tillage application, but these effects can diminish rapidly. Long-term effects on the order of a decade or more can appear less pronounced and are sometimes impossible to distinguish from natural and unaccounted management-induced variability. New standards for experimental classification are essential for isolating and subsequently generalizing space–time responses. Accordingly, enhanced methods of field measurement and data collection combined with explicit spatio-temporal modeling and parameter estimation should provide quantitative predictions of soil hydraulic behavior due to tillage and related agricultural management.     

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。     

Use of survival analysis as a tool for the genetic improvement of age at first conception in Nellore cattle

Restricted breeding seasons in beef cattle lead to censoring of reproductive data. In this paper, age at first conception (AFC) of Nellore females exposed to the sires for the first time between 11 and 16 months of age, was studied aiming to verify the possibility of genetically advance sexual precocity using a survival model. The final data set contained 6699 records of AFC in days. Records of females that did not calve in the next year following exposure to the sire were considered censored (77.5% of total). The model used was a Weibull mixed survival model including effects of contemporary groups, period (fixed) and animal (random). The effect of the contemporary groups on AFC was important (p < 0.01). Heritabilities were 0.51 and 0.76 in logarithmic and original scales respectively. Results indicate that it is possible to genetically advance sexual precocity, using the outcome of survival analysis of AFC as selection criterion. They also suggest that improvements of the environment could advance sexual precocity too, thus an adequate pregnancy rate for farmers could quickly be achieved.