犊牛腹泻原因及预防

犊牛腹泻是临床上常见病之一,本病一年四季均可发生,尤其以初春及夏末秋初多发,于出生后3周龄以内的新生犊牛多发生,特征是拉稀便,软便或水样便,呕吐,脱水和体重减轻。它是造成犊牛生长发育不良和死亡的主要疾病之一,以出生一个月内发病率和死亡率最高,被称为新生犊牛的杀手。致命的腹泻多侵害生后2周内的犊牛：约占犊牛发病率的80％。给养牛业造成较大的经济损失。腹泻分为营养性（如牛奶饲喂过量、牛奶突然改变成份、低质代乳品、奶温过低等引起）和传染性（诸如细菌、病毒、寄生虫等引起）腹泻两种。大肠杆菌是引起新生犊牛腹泻的主要病源菌。     

猪大肠杆菌病主要特点和防治措施

猪大肠杆菌病是由致病性大肠杆菌引起的一种急性传染病。根据我们在发病区临床观测,主要表现肠炎、肠毒血症等多种症状。本病在固原市各区均有发生,在养猪厂及养猪大户造成新生仔猪死亡或生长发育不良,成为固原市发展养猪业的制约因素之一。     

史氏鲟鱼硫酸软骨素的提取及抗肿瘤活性的研究

以史氏鲟鱼软骨为原料,按碱提酶解醇沉的工艺流程,进行硫酸软骨素的碱提工艺优化研究。分别通过碱浓度、碱液温度、碱液量的单因素试验及该3个因素的正交试验,研究其对产品得率及其氨基己糖含量的影响,综合分析得出最佳的碱提工艺为2倍量6%的NaOH,于40℃的水浴中搅拌提取4h;该工艺条件制备鲟鱼硫酸软骨素的得率可高达40.45%,产品质量符合硫酸软骨素口服片(WS1-C3-0030-2000)标准的要求。鲟鱼硫酸软骨素精品和粗品对3种细胞乳腺癌细胞株(MCF-7细胞)、胃癌细胞株(MGc803细胞)、肝癌细胞株(SMMC7721)作用72h时,其IC₅₀分别为7.28mg/mL、7.68mg/mL、4.25mg/mL和8.86mg/mL、9.27mg/mL、7.37mg/mL,与鲨鱼硫酸软骨素精品和粗品有着相似的抗肿瘤活性。     

Nonphytate Phosphorus Requirement and Efficacy of a Genetically Engineered Yeast Phytase for Yellow Broilers at 22- to 42-d-Old Age

An experiment was conducted to investigate the requirement of nonphytate phosphorus (OP) and efficacy of a genetically engineered yeast phytase (PHY A) for Lingnan yellow broilers from 22- to 42-d-old age. A total of 1320 1 -d-old male chicks were randomly divided into 11 dietary treatment groups, which consisted of 4 replicate floor pens with 30 birds per pen.The control group (treatment 1) was fed with basal diet of nPP 0.08% without dicalcium phosphate or phytase supplementation. Dietary levels of nPP were 0.16, 0.24, 0.32, 0.40, 0.48, and 0.56%, respectively, for treatments 2 to 7,through addition of dicalcium phosphate (chemistry grade) to the basal diet. Diets of treatments 8 to 11 were supplemented with PHY A at 200, 400 and 600 U kg-t, a commercial phytase product (PHY B) at 400 U kg-1 level, respectively. The birds in 0.32-0.56% nPP groups gained more than those of the other groups (P<0.05). The nPP supplementation significantly improved feed intake (P<0.05). The feed gain ratio was significantly decreased by 0.40% nPP diet compared to the control birds (P<0.05). The level of 0.48% nPP was required for optimum tibia development. The additions of PHY A at 400 and 600 U kg-1 level and PHY B all significantly improved ADG (P<0.05), ADFI (P<0.05), and dry defatted tibia weight (P<0.05).Similarly, the percentage of tibia ash was increased by 600 U kg-1 PHY A supplementation (P<0.05). The requirement of nPP for maximal ADG and highest percentage tibia ash both was 0.40%. The phosphorus equivalency value of PHY A was estimated as 685 U kg-1 for male yellow broilers of 22- to 42-d-old age.     

玉米种植中常出现的问题

一、玉米空杆原因 没有空杆是提高玉米产量的主要原因之一。造成玉米空杆的原因是： 1、雄穗对雌穗的抑制：玉米的雄穗是由顶芽发育而成,生长势强,雄穗分化比雌穗分化早7—10天,而雌穗是由腋芽发能而成,发能较晚,生长势较弱,当外界不符合条件下,雄穗会对雌穗的抑制作用非常明显。如缺乏营养时,雄穗就利用顶端生长优势,将大量养分吸收到顶端,致使雌穗因营养不良足导致发育不良而形成空杆。     

海洋软骨鱼软骨抗肿瘤物质的研究进展

筛选高效低毒的抗肿瘤药物是海洋新药研发最为重要的课题之一。软骨鱼软骨中富含多肽、低分子量蛋白、糖蛋白和多糖等活性物质,可以作为新生血管生成抑制因子、肿瘤细胞抑制因子、免疫调节因子和抗入侵因子等用于肿瘤的治疗和预防。本文对软骨鱼软骨中活性物质及其功效进行综述,将为软骨的研究利用提供参考。     

油菜科学施硼技术

油菜缺硼时,根系停止生长,无根毛和侧根,根表面变褐、龟裂,根颈肿大,心叶卷曲,叶肉增厚,生长点枯萎死亡,下部叶片的叶缘和脉间呈现紫红色斑块,渐变为黄褐色而枯萎。茎髓部变褐坏死,木质部发育不良,脆弱易碎,植株矮化和分枝丛生。花蕾易脱落,雌蕊柱头突出,主花序萎缩,侧花序丛生。胚珠萎缩不能形成正常的种子和角果,开花结实不正常,导致"花而不实"。     

中西医结合治疗三例犬椎间盘突出症的疗效观察

<正>椎间盘突出症是椎间盘的髓核或者纤维环突出到椎管内,脊髓受到物理性压迫引起的神经障碍性疾病。该病多见于体型小、年龄大的软骨营养障碍类犬,其中腊肠犬发病率最高(45%～60%)。患犬以疼痛、后躯麻痹、运动失调或瘫痪等运动障碍为主要特     

观察牛尾知牛病

发育良好的健康牛,其尾巴粗细长短适中、摆动灵活有力、幅度大;发育不良或患病的牛尾巴细小或弯曲、摆动不灵活、乏力、幅度小,触摸尾体没有弹性,尾椎弯曲性能差;热症病牛常表现尾卷耳耷、活动少,重     

玉米缺素症及防治措施

<正>玉米缺素时,植株矮小根系发育不良,生长缓慢,叶色淡绿且有黄绿色条纹,严重时叶缘和叶尖呈现紫色,随后干枯呈灼烧状,叶片中间部分仍可保持绿色,叶片却逐渐变皱,植株表现茎秆短,细小而柔弱,易倒伏,易感病、果穗发育不良,顶端特别细,秃