Prevalence and significance of extracellular myelin‐like material in canine cerebrospinal fluid

Background: Myelin‐like material in canine cerebrospinal fluid (CSF) specimens has been attributed to demyelinating or myelomalacic conditions. In our experience, myelin‐like material is observed frequently, especially in lumbar samples, and in a variety of disease conditions. Objectives: The objective of this study was to determine if there are associations between the presence of myelin‐like material and CSF collection site, body weight, underlying disease, and patient outcome. Methods: Wright–Giemsa‐stained cytocentrifuged specimens of CSF from the cerebellomedullary cistern (n=51) and lumbar cistern (n=47) of 98 dogs with neurologic disease were evaluated retrospectively for the presence and amount of extracellular myelin‐like material. Results were compared based on collection site, body weight, type of neurologic disease, and outcome. Results: Myelin‐like material was observed in 20/98 (20%) samples and was more frequently observed in lumbar (17/47, 36%) than cerebellomedullary samples (3/51, 6%) (P=.0028). Samples from dogs <10 kg were more likely to contain myelin (14/36, 39%) compared with dogs ≥10 kg (5/60, 8%) (P=.0052). Larger amounts of myelin‐like material were observed in CSF from dogs with intervertebral disk disease compared with other diseases (P=.045). No association was found between myelin‐like material and outcome. Conclusion: The association of extracellular myelin‐like material in canine CSF samples with sampling site and body weight suggests it is more often an artifact of collection technique and anatomy rather than the result of neurologic disease. Myelin‐like material in CSF is not associated with a poorer prognosis.     

Effects of misty‐fan cooling and supplemental rbST on rumen function and milk production of crossbred Holstein cattle during early,mid and late lactation in a tropical environment

Two groups of five crossbred 87.5% Holstein cattle were housed in normal shade only (NS) as non‐cooled cows and in shaded housing with misty‐fan cooling (MF) as cooled cows. The cows were treated with recombinant bovine somatotropin (rbST) in early, mid and late lactation with three consecutive injections of rbST in every 14 days. Ambient temperatures and the temperature humidity index in the NS barn were significantly higher than those of the MF barn, whereas relative humidity in MF was higher than that of NS barn. The DMI of cooled cows were higher than those of non‐cooled cows, and cooled cows exhibited more response to rbST treatment. Exogenous rbST significantly increased milk yield throughout lactation. The rbST‐treated cows had higher total ruminal fermentation products as volatile fatty acid and ammonia nitrogen than the non‐rbST treated cows and associated changes were greater in cooled animals in all stages of lactation. Exogenous rbST increased the concentrations of milk urea nitrogen in both groups. These results suggest that the changes in ruminal fermentation with greater production of total VFA and NH₃N in response to rbST in crossbred cows whether under misty‐fan cooling or not, is in part through an increase in feed intake, thereby making more substrate available to the mammary gland for milk synthesis.     

CONTRAST‐ENHANCED MAGNETIC RESONANCE ANGIOGRAPHY FOR DIAGNOSIS OF PORTOSYSTEMIC SHUNTS IN 10 DOGS

Computed tomography angiography, sonography, scintigraphy, and portography can be used to evaluate the portal vasculature to evaluate for a portosystemic shunt (PSS). Time‐of‐flight magnetic resonance angiography (TOF‐MRA) and contrast‐enhanced MRA (CE‐MRA) are other potentially useful techniques. The aim of this study was to evaluate CE‐MRA in 10 dogs suspected of having a PSS. Noncontrast MR images of the abdomen were obtained using a Siemens Symphony MR‐scanner (1.5 T) and a T1‐weighted FLASH‐3D sequence with a very short scan time (about 20 s). After injection of contrast medium, the initial sequence was repeated five times. The sequence with the best contrast medium filling of the portal vasculature was selected subjectively, subtracted from the initial survey image series, and a maximum intensity projection (MIP) of the subtraction data, in multiple views, was created. The cross‐sectional and MIP images were evaluated for abnormal portosystemic vasculature. A single PSS was identified and confirmed at surgery in all dogs. A portocaval shunt was found in five dogs, a portophrenic shunt in three dogs, a portoazygos shunt in one, and a central divisional intrahepatic shunt in one other dog. Based on our results, CE‐MRA is a useful tool for imaging abdominal and portal vasculature and for the diagnosis of a PSS.     

EFFECTS OF ANESTHETIC PROTOCOL ON NORMAL CANINE BRAIN UPTAKE OF 18F‐FDG ASSESSED BY PET/CT

The purpose of this study was to assess the effects of four anesthetic protocols on normal canine brain uptake of 2‐deoxy‐2‐[¹⁸F]fluoro‐d ‐glucose (FDG) using positron emission tomography/computed tomography (PET/CT). Five clinically normal beagle dogs were anesthetized with (1) propofol/isoflurane, (2) medetomidine/pentobarbital, (3) xylazine/ketamine, and (4) medetomidine/tiletamine–zolazepam in a randomized cross‐over design. The standard uptake value (SUV) of FDG was obtained in the frontal, parietal, temporal and occipital lobes, cerebellum, brainstem and whole brain, and compared within and between anesthetic protocols using the Friedman test with significance set at P<0.05. Significant differences in SUVs were observed in various part of the brain associated with each anesthetic protocol. The SUV for the frontal and occipital lobes was significantly higher than in the brainstem in all dogs. Dogs receiving medetomidine/tiletamine–zolazepam also had significantly higher whole brain SUVs than the propofol/isoflurane group. We concluded that each anesthetic protocol exerted a different regional brain glucose uptake pattern. As a result, when comparing brain glucose uptake using PET/CT, one should consider the effects of anesthetic protocols on different regions of the glucose uptake in the dog's brain.     

不同饲用燕麦品种生产性能的综合评价

基于熵权赋权法,运用灰色系统理论中的灰色关联度法对26个燕麦品种的生产性能进行综合评价,结果表明,生产性能综合表现较好的是初岛燕麦、青永久409、青永久709及青永久316;青永久18综合评价值最低,生产性能最差,其余品种生产性能表现一般。经逐步回归分析,发现其中的绿叶数、叶长、茎叶比、鲜干比、生长速度、叶面积指数、相对生长速率及生长天数8个指标对饲用燕麦生产性能贡献显著。     

宁夏白芨滩国家级自然保护区苦豆子内生真菌多样性及生态分布

为探索宁夏干旱荒漠区苦豆子（Sophora alopecuroides L.）内生真菌的多样性及区系组成,为苦豆子内生真菌的合理开发和利用提供理论依据。从宁夏白芨滩国家级自然保护区不同植被和土壤类型的6个样区采集苦豆子样品30份,采用组织匀浆法从植株的根、茎、叶和种子中分离内生真菌,根据培养性状、菌落、孢子等形态特征,结合rDNA-ITS序列分析对菌株进行鉴定;根据内生真菌的相对频率、物种多样性指数、丰富度指数和相似性系数分析其区系组成特点。结果表明,从30份样品中共分离得到内生真菌213株,分别属于19个属,其中镰刀菌属（Fusarium）、链格孢属（Alternaria）和茎点霉属（Phoma）为优势属。苦豆子内生真菌的分布具有一定的组织特异性,根部的内生真菌数量高于其他部位,茎部内生真菌多样性指数最高。植被类型中,沙生植被草原（样区Ⅴ）分离的内生真菌物种多样性指数最高,而荒漠草原（样区Ⅲ）最低。荒漠草原（样区Ⅰ）和沙生植被草原（样区Ⅴ）内生真菌群落有密切的相似性。可见,苦豆子蕴含丰富的内生真菌资源,其内生真菌具有很高的宿主特异性,且分布受生境影响。     

覆膜垄沟集雨种植对老芒麦高度和密度的影响

研究了北方农牧交错区垄沟集雨种植措施对老芒麦Elymus sibiricus生长发育的影响。覆膜垄沟集雨种植可以使有限降雨在沟内富集累加,垄面径流效率达到80%左右。老芒麦2008和2009年营养生长阶段,处理间高度差异显著。2008年处理1和CK相比,株高提高33.5%~61.3%;处理2和CK相比,株高提高20.1%~44.1%,处理1与处理2相比,株高提高9.2%~16.2%。2009年处理1与CK相比,株高提高93.2%~116.4%;处理2与CK相比,株高提高65.4%~82.3%;处理1与处理2相比,株高提高12.1%~19.4%。处理1、处理2与CK三者在密度方面差异不尽相同,总体表现出处理2和处理1老芒麦密度高于CK,2008年密度动态变化和单株分蘖数变化保持一致,2009年返青后,呈现出整体略微下降趋势,趋于稳定。     

Surveillance of Parapoxvirus Among Ruminants in Virginia and Connecticut

In 2008, two deer hunters in Virginia and Connecticut were infected with a unique strain of pseudocowpox virus, a parapoxvirus. To estimate the prevalence of this virus, and in an attempt to define the reservoir, Parapoxvirus surveillance was undertaken between November 2009 and January 2010. 125 samples from four ruminant species (cows, goat, sheep and white‐tailed deer) were collected in Virginia, and nine samples from white‐tailed deer were collected in Connecticut. We found no evidence that the parapoxvirus species that infected the deer hunters is circulating among domesticated ruminants or white‐tailed deer. However, parapoxvirus DNA of a different parapoxvirus species, bovine papular stomatitis virus (BPSV), was detected in 31 samples obtained from asymptomatic cattle in Virginia. Parapoxvirus DNA–positive cattle originated from the same counties indicating probable transmission among animals. Molecular analysis identified BPSV as the parapoxvirus affecting animals. Asymptomatic parapoxvirus infections in livestock, particularly young animals, may be common, and further investigation will inform our knowledge of virus transmission.     

Influence of varying dietary electrolyte balance on broiler performance under tropical summer conditions

A 6‐week feeding trial was conducted to determine the effects of varying dietary electrolyte balance (DEB) on growth performance and physiological responses in broiler chicks reared during hot summer months (26.1–37.5 °C). The average minimum and maximum room temperatures recorded from 14 to 42 days of age were 26.1 and 37.5 °C, respectively, with relative humidity ranging from 51% to 55%. Five DEB treatments supplying 0, 50, 150, 250 and 350 (Na⁺+K⁺–Cl^?) mEq/kg of diet were prepared by adding NaHCO₃ and/or NH₄Cl to basal diet that contained 185 mEq/kg from 1 to 28 days and 172 mEq/kg from 29 to 42 days. These DEB diets were randomly offered to six experimental units of 20 chicks each. Improved 42‐day body weight gain (BWG), feed:gain (F:G) and reduced mortality was noted with DEB 50, 150 and 250 mEq/kg compared to DEB 0 and 350 mEq/kg. A quadratic effect of increasing DEB level was observed on BWG and F:G, whereas the effect was linear for feed intake, water intake and litter moisture. The DEB 50, 150 and 250 maintained better blood pH, pCO₂ and HCO₃ concentrations during acute heat stress periods than that of 0 and 350. The blood heterophil and lymphocyte percent as well as heterophil:lymphocyte were remained unaffected. The lowest DEB (0 mEq/kg) diet reduced the feed intake and promoted metabolic acidosis. At 350 mEq/kg DEB, water intake and metabolic alkalosis were promoted probably due to high levels of dietary NaHCO₃. The study concluded that overall better performance was recorded with DEB 50, 150 and 250 mEq/kg. These results indicated that single optimal DEB value could not be recommended to combat heat stress in broilers.