Determination of sulfamethazine and trimethoprim in liquid feed premixes by HPLC and diode array detection, with an analysis of the uncertainty of the analytical results.

Sulfamethazine (SMZ) and trimethoprim (TMP) are antibacterials used in veterinary practice. This paper describes a method for their determination in veterinary liquid feed premixes that is based on liquid chromatography with diode array detection. Gradient elution with methanol and ammonium acetate achieved excellent separation of the two analytes within 15 min without any interference from the matrix. Absorbance of the column effluent was monitored at 264 nm for SMZ and at 230 nm for TMP. Detailed analyses of the uncertainties of determinations afford estimated expanded uncertainties of, respectively, 0.2 and 0.1 w/v % for typical SMZ and TMP concentrations of 10.7 and 2.1 w/v %, respectively. At the lower end of the calibrated range of the method, the dominant source of uncertainty is the preparation of standards and the construction of the calibration line.     

油脂在提高公猪生产力和生育力上的潜在作用

精子及其相关精浆中所含的脂肪成分在组成和脂肪酸成分上是非常独特的。长链多不饱和脂肪酸 (即具有 2 0或 2 2个碳原子并含三个以上双键的脂肪酸 )在绝大多数主要组织所含脂肪中的含量非常有限 ,但在精子和精浆中的含量相当高 ,并具有明显的种属特异性。油脂的这种特性现在日益被认为是使受精最终成功所特别需要的。本综述根据最近一的些研究结果撰写而成 ,从精液质量和功能的一系列决定因子的角度论述了使现代种公猪精子中脂肪 /脂肪酸参数最佳化的可能性 ,可见人们对一系列参数所作的一系列重要研究 ,产生了使公猪和母猪的繁殖能力都得到提高的高度有益结果。文章还从主要的营养学特性和化学特性方面对研究结果进行了讨论 ,并与其它家畜进行了比较 ,还讨论了其对猪繁育部门可能的商业应用价值。     

Effect of milk sampling techniques on milk composition, bacterial contamination, viability and functions of resident cells in milk.

Three different milk sampling techniques were evaluated during milk sampling: a direct aseptic collection from the udder through a sterile cannula was used as the reference technique, compared with either a manual or a mechanical sampling method. In this study 30 high-yielding Holstein-Friesian dairy cows at different stages of lactation and free of udder infection were used. For each milk sample, the influence of milk sampling techniques was determined for the following parameters: somatic cell count, milk composition, bacterial contamination, viability, in vitro phagocytosis and overall killing of Staphylococcus aureus Newbould 305, and cellular chemiluminescence. Because milk sampling occurred throughout lactation, the differences between early, mid- and late lactation were estimated. It was concluded that bacterial contamination was not significantly different in manual milking samples and the reference technique; bacterial contamination was, however, significantly (P < 0.001) higher in machine milking samples than in the reference technique. Among the different sampling techniques, no significant effects on SCC, milk composition, viability and functions of the cells isolated from milk were observed. It was found that viability, intracellular killing and cellular chemiluminescence of milk PMN were significantly lower (P < 0.05) in early lactation compared to mid-lactation. Phagocytosis was significantly (P < 0.05) higher in early lactation compared to mid- and late lactation, and no significant differences were observed between mid- and late lactation. From this study, it can be concluded that despite a higher bacterial contamination obtained with the mechanical sampling method, the 3 milk sampling techniques described in this study can be used for the evaluation of milk cell functions.     

RADIOGRAPHIC FINDINGS OF CANINE DYSAUTONOMIA IN TWENTY-FOUR DOGS

Canine dysautonomia is an idiopathic condition resulting in loss of autonomic nervous system function. Recently, the prevalence of dogs diagnosed with dysautonomia in the mid-western United States has increased. In this study the medical records and radiographic findings in 24 dogs with dysautonomia were reviewed. A diagnosis of dysautonomia was made in 17 (71%) of the dogs in this study by postmortem examination, the remaining 7 (29%) dogs were diagnosed pharmacologically. The radiographic findings supportive of dysautonomia include aspiration pneumonia, megaesophagus, or a distended stomach, small bowel, or urinary bladder. In some instances, the disease radiographically mimicked other disorders of the gastrointestinal tract, including mechanical obstruction.     

Use of laser photocoagulation for treatment of cutaneous angiomatosis in one dog and two cats.

One dog and 2 cats were evaluated because of multiple progressively enlarging cutaneous vascular plaques. Biopsies were performed and revealed small well-circumscribed dermal nodules of dilated fully enclosed blood-filled spaces lined by single layers of endothelial cells aligned on thin fibrous walls, with minimal mitotic activity. A diagnosis of cutaneous angiomatosis was made in all 3 animals. Cutaneous angiomatosis is a progressive proliferative lesion of vascular tissue involving the dermis and subcutaneous tissues of dogs and cats. Lasers of selected wavelengths have been used to induce photothermal coagulation of hemoglobin-containing cutaneous lesions in humans; argon-pumped dye and neodymium:yttrium-aluminum-garnet lasers were used to treat the cutaneous lesions in the animals of this report. Laser treatment may provide an alternative to wide surgical resection or limb amputation for management of this condition in veterinary patients.     

Immunohistochemical Detection of Mycoplasma agalactiae in Formalin‐Fixed,Paraffin‐Embedded Tissues from Naturally and Experimentally Infected Goats

Samples from the mammary tissue of 14 lactating goats (12 naturally infected and two experimentally infected) were examined for the presence of Mycoplasma agalactiae. A monoclonal antibody (5G12) was applied to formalin‐fixed, paraffin‐wax‐embedded sections and labelled by the avidin–biotin peroxidase complex (ABC) method. Histological examination of tissue sections revealed strong immunoreactivity in all animals included in the study. Mycoplasma agalactiae antigen was mainly detected in the cellular debris at the periphery of purulent exudates present within lactiferous sinuses, and lactiferous and interlobular ducts. In addition, M. agalactiae organisms appeared in the cytoplasm of the epithelium of ducts, and in infiltrating macrophages and neutrophils within the ducts, alveoli, interstitial tissue and regional lymph node sinuses. It is concluded that this monoclonal antibody‐based immunohistochemical technique is an efficient and specific method for the post‐mortem detection of M. agalactiae in cases of clinical mastitis as well as being a useful tool for the study of the route of infection and cellular types involved during mastitis caused by this organism.     

关于饲料的胆碱含量

关于饲料中胆碱含量化学分析值的资料很多。饲料中的胆碱含量因饲料种类、出产国别、出产年份等的不同而不同。问题还不止于此，据发现，测定饲料中胆碱含量时所用的技术也不能给出充分可靠的结果，因而需要一种新技术。     

Presentation of postweaning Escherichia coli diarrhea in southern Ontario, prevalence of hemolytic E. coli serogroups involved, and their antimicrobial resistance patterns

Post-weaning Escherichia coli diarrhea (PWECD) in Ontario was investigated using a case-control study involving 50 Ontario nurseries. The clinical signs and the impact on productive parameters were determined by means of a producer survey. The hemolytic E. coli serogroups involved in PWECD (O149:K91:K88) were examined in this study. Based on a polymerase chain reaction test, the hemolytic E. coli from 82% of the case herds were positive for 3 enterotoxins (STa, STb, and LT), those from 12% of the case herds were positive for STb and LT only, and those from one herd (6%) were positive for 3 enterotoxins, as well as for verotoxin and F18 pili. The E. coli involved in disease were resistant to multiple antibiotics. Case farms commonly used a wide variety of antibiotics either in the feed or water, or as injectable drugs. The most common antibiotic used to treat PWECD on the study farms was apramycin, but evidence of resistance to this antibiotic was noted. The PWECD problem was commonly seen within a week of weaning but onset of diarrhea was reported as late as the grower-finisher stage. Growth rate was poorer in case herds and mortality was higher than in control herds, demonstrating that PWECD is an economically important disease in Ontario.     

Application and crop safety parameters for soil fumigants

Metam sodium alone and in combination with 1,3-dichloropropene plus 17% chloropicrin (1,3-D+C-17) were evaluated under polyethylene mulch film as alternatives for methyl bromide in tobacco and tomato transplant production for both efficacy against pests and crop safety. Eight different weed species, 10 genera or species of fungi and several agronomic criteria were evaluated at three different sites. In general both the metam sodium alone and in combination with 1,3-D+C-17 were highly efficacious when compared to methyl bromide. Short polyethylene film retention times and short aeration times resulted in poor stands and poor crop vigor while relatively long polyethylene film retention times and long aeration periods at the same rates typically resulted in high stand counts and vigor. Combination treatments were more phytotoxic to germinating seed of tobacco and tomato. Vigor and stand counts of the seedlings were higher as aeration time increased, suggesting phytotoxic residues dissipate with time. Method of application of metam sodium, either injected with chisels or sprayed onto the soil surface and incorporated with a tractor-powered tiller alone or co- applied with 1,3-D+C-17 chisel injected, did not affect the efficacy of the treatments. Caution regarding phytotoxicity must be exercised when seeding into soil fumigated with metam sodium alone or combined with 1,3-D+C-17. Additional work will be required to establish safety periods required prior to transplanting crops into fumigated soil.