灌注必需和非必需氨基酸对泌乳奶牛乳腺代谢和产奶量变化的影响

本试验旨在研究乳腺对不同类型的氨基酸需求和乳腺对不同的氨基酸供给模式其代谢模式的变化。试验采用带14d残差效应的重复4×4平衡拉丁方试验设计,8头荷斯坦奶牛(泌乳日龄61d±4d)被随机分配到4个处理组中。试验日粮满足100%净能需要和72%代谢蛋白需要。4个处理组分别为皱胃灌注水处理组(1组)、皱胃灌注必需氨基酸组(359g/d)(2组)、皱胃灌注非必需氨基酸组(356g/d)(3组)、皱胃灌注必需氨基酸(359g/d)和非必需氨基酸(356g/d)组(总计715g/d)(4组)。灌注液氨基酸组成除了蛋氨酸被提高到与赖氨酸保持3∶1比例、酪氨酸由于其溶解性低全部由苯丙氨酸替代和部分谷氨酸由谷氨酰胺替代外,灌注氨基酸谱图与酪蛋白氨基酸谱图相同;与其他处理组相比,必需氨基酸处理组提高了乳产量和乳蛋白产量,非必需氨基酸处理组趋向于提高乳腺对葡萄糖的摄取率。必需氨基酸处理组,乳腺摄取的氨基酸(His、Met、Phe、Trp和Tyr)与乳蛋白排出的氨基酸(His、Met、Phe、Trp和Tyr)比例不一致且这种比值有增加的趋势。灌注必需氨基酸时,Ile、Leu、Lys和Val表现出相同的试验结果。结果表明,当供给的氨基酸谱图和剂量不同时,乳腺能选择性的吸收氨基酸和产能营养素;当供给蛋白质缺乏非必需氨基酸时,未发现乳产量和乳蛋白合成的提高。     

颈静脉灌注不同模式的氨基酸混合物对泌乳奶牛乳蛋白合成的影响

本试验旨在比较颈静脉灌注酪蛋白模式和理想模式的氨基酸混合物对泌乳中期荷斯坦奶牛乳产量、乳成分以及乳腺对氨基酸摄取利用的影响。选择8头泌乳中期[泌乳天数:(82±11)d]荷斯坦奶牛作为试验动物,试验采用随机区组设计,将试验牛随机分为2组,分别颈静脉灌注160g/d酪蛋白模式(Casein组)和理想模式的氨基酸混合物(R组)。2个试验组分别以各自灌注前作为空白对照组(C1组为Casein组的空白对照组,C2组为R组的空白对照组)。预试期14d,灌注期5d。试验采用全混合日粮(TMR)饲喂,以玉米、豆粕、棉籽粕、玉米青贮、苜蓿干草和羊草为主要原料,参照NRC(2001)奶牛饲养标准配制。结果表明:灌注酪蛋白模式的氨基酸混合物后,乳蛋白产量和含量较灌注前呈上升趋势(乳蛋白产量上升7.14%,P=0.078;乳蛋白含量上升3.27%,P=0.072);并且,奶牛动脉血浆中异亮氨酸(Ile)、亮氨酸(Leu)、赖氨酸(Lys)和组氨酸(His)的浓度较灌注前有不同程度的上升(Ile的浓度提高31.5%,P=0.097;Leu的浓度提高65.9%,P=0.041;Lys的浓度提高36.9%,P=0.088;His的浓度提高40.1%,P=0.010),而苏氨酸(Thr)、缬氨酸(Val)、蛋氨酸(Met)、苯丙氨酸(Phe)和精氨酸(Arg)的浓度在数值上虽较灌注前高但无显著差异(P0.05)。灌注酪蛋白模式的氨基酸混合物后,奶牛乳腺对天冬氨酸(Asp)和半胱氨酸(Cys)的摄取率显著升高(Asp的摄取率提高95.2%,P=0.031;Cys的摄取率提高49.6%,P=0.031),而奶牛乳腺对甘氨酸(Gly)的摄取率显著降低(降低158.3%,P=0.041)。灌注理想模式的氨基酸混合物后,乳蛋白含量比灌注前有上升趋势(提高5.78%,P=0.064),而乳脂产量显著低于灌注前(降低8.57%,P=0.015);并且,奶牛动脉血浆中Arg的浓度有上升趋势(提高18.0%,P=0.093),而酪氨酸(Tyr)的浓度呈下降趋势(降低47.8%,P=0.074)。灌注理想模式的氨基酸混合物后,奶牛乳腺对谷氨酸(Glu)、Cys和Ile的摄取率显著上升(Glu的摄取率提高118.7%,P=0.015;Cys的摄取率提高77.4%,P=0.032;Ile的摄取率提高46.0%,P=0.012),而奶牛乳腺对Ser的摄取率呈下降趋势(降低56.2%,P=0.052)。灌注氨基酸混合物后,Casein组乳脂产量增量显著高于R组(P=0.012),且Casein组的乳产量增量(P=0.095)和乳糖产量增量(P=0.091)较R组有升高的趋势,而2组间其他指标增量无显著差异(P0.05)。由此得出,在本试验条件下,颈静脉灌注酪蛋白模式和理想模式的氨基酸混合物均可提高泌乳奶牛的乳蛋白含量,而灌注酪蛋白模式氨基酸混合物同时可以促进乳蛋白产量的升高,因此,颈静脉灌注酪蛋白模式氨基酸混合物的效果优于灌注理想模式氨基酸混合物。     

淀粉和氨基酸对泌乳奶牛乳腺内乳蛋白合成调控的影响

本试验旨在研究乳腺内局部分子适应以调控乳蛋白的合成。研究假设氨基酸和产能底物通过系统和局部机制组合独立调控乳腺内氨基酸的代谢和乳蛋白的合成。试验选用6头具瘤胃瘘管的初产泌乳中期荷斯坦奶牛,随即分配到4个处理组中。试验采用重复的不完全4×4拉丁方试验设计。试验期间,试验动物的基础日粮组成(17.6%粗蛋白质和6.61MJ/kg泌乳净能)相同。泌乳奶牛限饲采食量至70%并通过蠕动泵连续36h分别灌注水、酪蛋白(0.86kg/d)、淀粉(2kg/d)和淀粉与酪蛋白的混合物(2kg/d淀粉+0.86kg/d酪蛋白)。整个试验期间测定乳产量和乳成分组成;灌注的最后8h每20min采集动脉和静脉血浆样品,用于测定乳腺对氨基酸的吸收率;每期灌注末采集乳腺组织样品,用于评定调控乳蛋白合成的细胞内信号分子磷酸化位点。结果显示,灌注酪蛋白组增加了动脉血浆中氨基酸的浓度,提高了乳腺从血浆中摄取氨基酸的效率,但对氨基酸的清除率和乳蛋白的产量没有影响。灌注淀粉组增加了乳产量和乳蛋白产量,提高了乳腺血浆流量,但降低了动脉血浆中氨基酸的浓度,同时,提高了乳腺对氨基酸的清除率和乳腺对氨基酸的净吸收量。灌注淀粉组同时提高了血浆中葡萄糖、胰岛素和胰岛素样生长因子-1的浓度,核糖体蛋白S6的磷酸化和内皮型一氧化氮合成酶含量也随之提高并伴随着乳蛋白产量和血浆流量的变化。灌注酪蛋白和淀粉的混合物处理组提高了哺乳动物雷帕霉素靶标的磷酸化。结果表明,不同的营养素刺激,乳蛋白合成调控的细胞信号分子机制反应不同。试验过程中,由于灌注酪蛋白对乳蛋白合成的影响不明显,未发现试验假设的酪蛋白和淀粉对动物代谢和细胞信号传导的独立效应。     

氨基酸模式对体外培养瘤胃主要蛋白质降解菌的影响

本研究以4头装有永久性瘤胃瘘管的徐淮山羊为试验动物,利用体外培养法研究了不同氨基酸模式对瘤胃内主要蛋白质降解菌的影响.研究结果表明不同氨基酸模式对不同菌种的作用有所差异:试验组C的氨基酸组成(Lys 16.2%、Met 5.4%、Thr 12.5%、His 5.0%、Arg 10.2%、Try 4.2%、Leu 14.7%、Ile 10.6%、Phe 10.7%、Val 10.5%)对嗜淀粉瘤胃杆菌和栖瘤胃普雷沃氏茵的促进生长效应最高;而试验组B的氨基酸组成(Lys 16.0%、Met 5.4%、Thr11.9%、His 4.5%、Arg 10.2%、Try 3.5%、Leu 15.5%、Ile 11.1%、Phe 10.5%、Val 11.5%)对溶纤维丁酸弧菌的促进生长效应最高.     

奶牛乳蛋白产量的营养调节效应与乳腺真核起始因子-2(eIF2)和核糖体s6(S6)激酶-1(S6K1)的磷酸化有关

日粮蛋白质和能量同时影响泌乳动物乳蛋白的产量,必需氨基酸单独不能完全解释营养素对乳蛋白产量的影响。生长动物组织中,营养素对蛋白质合成受哺乳动物雷帕霉素靶点(mTOR)和整合应激网络(ISR)的调控。本试验旨在探讨乳腺内营养素信号是否也通过mTOR和ISR网络调控乳蛋白的合成。泌乳奶牛饥饿22 h后,静脉内分别灌注必需氨基酸(EAA)和葡萄糖混合物,葡萄糖、l-Met+l-Lys、l-His或l-Leu 9 h。结果表明,EAA和葡萄糖混合物或葡萄糖能分别提高乳蛋白产量的33%和27%。Met+Lys或His产生的效应分别是EAA和葡萄糖混合物效应的35%和41%。乳腺组织中,EAA和葡萄糖混合物降低了ISR靶点eIF2的磷酸化,但增强了mTOR靶点S6K1和S6的磷酸化,同时刺激了乳蛋白的合成。葡萄糖提高了乳腺内S6K1的磷酸化(P0.05),降低了eIF2磷酸化62%,暗示着ISR网络在刺激乳蛋白产量中的作用。与此相反,EAA提高或趋向于(P0.1)提高乳腺内mTOR的活性(P0.05),但His,如葡萄糖一样降低了eIF2磷酸化62%。尽管EAA和葡萄糖混合物激活了乳蛋白合成信号的活性83%到127%,但EAA产生的效应还不到EAA和葡萄糖混合物效应的50%。因此,本试验结果表明,ISR和mTOR网络在调控乳蛋白产量中只起着部分的作用。     

十二指肠灌注蛋氨酸对肉牛小肠氨基酸消化率的研究

根据基础日粮+待测氨基酸法,由十二指肠瘘管连续灌注DL Met,通过小肠氨基酸消化率确定基础日粮条件下十二指肠蛋氨酸最佳灌注量。试验采用4×4拉丁方设计,试牛饲喂相同的基础日粮,DL 蛋氨酸的浓度为0(Ⅰ组)、9(Ⅱ组)、13(Ⅲ组)和17(Ⅳ组)g/d,预试期12d,正试期7d,采用Cr2O3标记物法测定食糜流通量。结果表明:十二指肠灌注13g蛋氨酸(Ⅲ组)显著增加十二指肠Met、Cys、Pro、Lys以及TAA和EAA流通量(P<0 05),降低回肠Asp、Thr、Glu、Gly、Val、Ile、Phe、Lys和His的流通量,但差异不显著(P>0 05),显著提高Asp、Thr、Ser、Glu、Phe、His、Arg在小肠的表观消化率(P<0 05),证明本试验条件下十二指肠蛋氨酸最佳灌注量为13g/d。     

真胃灌注缺失精氨酸、苏氨酸或组氨酸的混合氨基酸对泌乳山羊乳腺氨基酸代谢的影响

本试验旨在研究真胃灌注缺失精氨酸(Arg)、苏氨酸(Thr)或组氨酸(His)的混合氨基酸对泌乳山羊乳腺氨基酸代谢的影响。选择4只泌乳中期萨能奶山羊,安装真胃插管(用于灌注氨基酸)、颈动脉和乳静脉血管插管(用于采集血样),在外阴动脉安装血液流量计探头(记录乳腺血流量)。试验羊限饲基础饲粮,满足维持能量和蛋白质需要。真胃灌注葡萄糖和按瘤胃微生物蛋白氨基酸构成配制的混合氨基酸。采用4×4拉丁方试验设计,对照组灌注全混合氨基酸,试验组分别灌注缺失Arg、Thr、His的混合氨基酸;试验共进行4期,每期7 d,前4天为灌注期,后3天为采样期。结果表明:1)单一氨基酸缺失灌注对产奶量和乳蛋白产量均无显著影响(P0.05)。2)Arg和Thr缺失显著提高了乳腺血流量(P≤0.05),降低了该氨基酸的动脉浓度、静脉浓度,乳腺清除率分别上升25.9%和199.2%;单一氨基酸缺失灌注对该氨基酸乳腺吸收量和乳腺吸收产出比无显著影响(P0.05)。3)Arg、Thr和His缺失,泌乳转化效率分别提高25.4%(4.02 vs.5.04,P≤0.05)、34.5%(9.09 vs.12.23,P≤0.05)和14.6%(10.51 vs.12.04,0.05P≤0.10)。结果提示,泌乳山羊通过提高乳腺血流量和乳腺清除率增加了饲粮对乳腺缺失氨基酸的供给,从而提高了缺失氨基酸的泌乳转化效率。     

68个去皮和带皮豆粕的氨基酸组成及其回归估测

采集美国、巴西、中国加工的11个去皮豆粕和中国13个省市的51个大、中、小型企业加工的57个带皮豆粕,对其必需氨基酸组成进行比较研究。结果显示:去皮豆粕优于带皮豆粕。去皮豆粕的赖氨酸(88%干物质基础)为3.08%,比带皮豆粕高0.09%P(<0.01);其它氨基酸如Ile、Lys、Met、Phe、Cys和总必需氨基酸(P<0.01),Leu、Thr和V alP(<0.05)的含量均高于带皮豆粕。本次研究建立了以豆粕中粗蛋白质含量为自变量估测豆粕中必需氨基酸含量的有效方程;Lys、Thr、Trp、Met+Cys和Arg的回归估测值与实测值的差异较小,差异度分别为0.95%、0.30%和-2.19%;通过豆粕粗蛋白质含量回归估测Lys、Thr和Arg含量是可行的。     

阿拉善双峰驼不同部位肌肉氨基酸的研究

对不同性别的阿拉善双峰骆驼股二头肌、臂三头肌和背最长肌中氨基酸组成进行分析,研究性别和部位对肌肉氨基酸含量的影响并评价其营养价值。结果表明:阿拉善双峰驼肉中共检测出18种氨基酸,总氨基酸(TAA)含量为19.32%,其中必需氨基酸(EAA)含量为8.13%,必需氨基酸占总氨基酸的比例为42%。阿拉善双峰驼肌肉中氨基酸含量不受性别影响(P0.05),但受部位影响较大。股二头肌和臂三头肌中的苏氨酸(Thr)、亮氨酸(Leu)、苯丙氨酸(Phe)、赖氨酸(Lys)、精氨酸(Arg)、天门冬氨酸(Asp)、丝氨酸(Ser)及谷氨酸(Glu)均显著高于背最长肌中的含量(P0.05)。阿拉善双峰驼肉中氨基酸组成非常接近联合国粮农组织/世界卫生组织(FAO/WHO)提出的模式,营养价值高。     

皖西白鹅对三种常用能量饲料原料的氨基酸标准回肠消化率研究

为研究皖西白鹅对玉米、稻谷及麸皮的氨基酸标准回肠消化率(SIAAD),选取体重相近的288只56日龄皖西白鹅,随机分为4个组,每组6个饲喂栏,每个饲喂栏12只(公母各半),于84日龄分别饲喂待测饲粮和无氮饲粮6 d,采集回肠食糜并测定食糜中的氨基酸含量。结果显示:玉米、稻谷和麸皮平均SIAAD分别为89.31%、71.72%、74.67%,且玉米SIAAD显著高于稻谷和麸皮(P0.05);玉米SIAAD分别为:赖氨酸(Lys)84.64%、蛋氨酸(Met)76.57%、苏氨酸(Thr)88.31%、缬氨酸(Val)87.12%、亮氨酸(Leu)94.61%、异亮氨酸(Ile)84.84%、苯丙氨酸(Phe)94.17%、组氨酸(His)91.05%和精氨酸(Arg)96.94%;稻谷SIAAD分别为:Lys 53.84%、Met 73.81%、Thr 58.63%、Val 68.43%、Leu 57.30%、Ile 58.91%、Phe 67.99%、His 77.24%和Arg 82.68%;麸皮SIAAD分别为:Lys 67.04%、Met 64.13%、Thr 65.78%、Val 75.35%、Leu72.88%、Ile 76.27%、Phe 79.90%、His 77.35%和Arg 84.20%。研究结果为合理配制皖西白鹅低氮饲粮提供了参考。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

A brief history of the prevention of infectious diseases by immunisations

Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.