高剂量植酸酶对肉鸡生长性能和消化率的影响

文章旨在研究植酸酶对1~42日龄肉鸡生长发育的影响。采用完全随机试验设计,试验共分为5组,每组6个重复,每个重复24只鸡,各组分别为阳性对照组、负对照、负对照日粮+1000、2000和3000IU/kg植酸酶,试验结束后测定各组对骨功能、骨质量和血液矿物质的影响。随着日粮植酸酶添加水平的升高,显著改善了1~21d肉鸡日增重、采食量和料比(P<0.05),而1~42d肉鸡生长性能表现为显著二次曲线效应(P<0.05),其中负对照组肉鸡日增重和采食量最低(P<0.05),料比最高(P<0.05)。对照组较负对照组显著提高了42d肉鸡胫骨干物质含量(P<0.05)。随着植酸酶添加水平的升高,21d肉鸡血钙浓度表现为显著线性降低(P<0.05),而血磷浓度先升高后降低,负对照日粮+1000IU/kg植酸酶组最高(P<0.05)。42d肉鸡血磷浓度随日粮植酸酶水平的升高表现为二次曲线效应。对照组和负对照组较处理组显著提高了42d肉鸡血钙浓度(P<0.05)。与对照和负对照组相比,负对照添加植酸酶组显著降低了矿物质回肠表观消化系数(P<0.05),而负对照组+3000IU/kg植酸酶较对照组显著降低了能量回肠表观消化系数(P<0.05)。植酸酶在回归分析的基础上提高了肉鸡生长性能,添加高剂量植酸酶3000IU/kg显著提高21d肉鸡日增重。试验为期42d,日粮添加2000IU/kg植酸酶对肉鸡的增重和饲料转化率效果较好。     

锌和维生素C对热应激条件下肉鸡生长性能和免疫反应的影响

文章旨在研究日粮单独或联合使用锌和维生素C对高温条件下肉鸡生长性能和免疫反应的影响。试验选择320只1d肉仔鸡,根据体重随机分为4组,每组4个重复,每个重复20只鸡。对照组饲喂基础日粮(锌含量为40mg/kg),处理1组在基础日粮中添加60mg/kg锌,处理2组在基础日粮中添加200mg维生素C,处理3组在基础日粮中添加60mg/kg锌+300mg/kg维生素C,试验共开展35d。在试验第21~35天对鸡只进行热应激诱导,即25℃12h,25~34℃3h,34℃6h,34~25℃3h。结果显示:处理组较对照组均显著提高了肉鸡的采食量、体增重(P<0.05),显著降低了料比(P<0.05)。日粮同时添加锌和维生素C组肉鸡采食量和体增重最高(P<0.05)。与对照组相比,日粮添加60mg/kg锌、200mg/kg维生素C或锌和维生素C联合使用的肉鸡脾脏、胸腺和法氏囊重量显著提高(P<0.05)。60mg/kg锌+200mg/kg维生素C和200mg/kg维生素C组较对照组显著提高了新城疫、传染性法氏囊炎和传染性支气管炎的抗体滴度(P<0.05)。与对照组相比,60mg/kg锌+200mg/kg维生素C、200mg/kg维生素C组和60mg/kg锌组显著提高了血液白细胞总数、淋巴细胞和单核细胞占比(P<0.05)。结论:在本试验条件下,日粮单独或联合添加锌和维生素C均可显著改善热应激条件下肉鸡的生长性能和免疫状态。     

维生素A添加水平对22～42日龄黄羽肉鸡生长性能、血清和肝脏维生素A含量及抗氧化能力的影响

本试验旨在研究饲粮中添加不同水平维生素A对22～42日龄黄羽肉鸡生长性能、血清和肝脏维生素A含量及抗氧化能力的影响。选用22日龄快长型岭南黄羽肉公鸡1 440只,根据体重均衡原则随机分为6个处理,每个处理6个重复,每个重复40只。各处理维生素A添加水平分别为0(对照组)、750、1 500、3 000、6 000、12 000 IU/kg。试鸡自由采食与饮水,饲养21 d。结果表明:1)饲粮添加维生素A显著提高试鸡42日龄体重和平均日增重(P<0.05),并显著降低料重比(P<0.05),添加维生素A 1 500、3 000 IU/kg显著提高试鸡平均日采食量(P<0.05)。2)随维生素A添加水平升高,试鸡血清、肝脏维生素A含量显著提高(P<0.05)。添加维生素A 12 000 IU/kg组血清和肝脏维生素A含量显著高于其他各组(P<0.05),添加维生素A 3 000、6 000 IU/kg组血清维生素A含量显著高于除添加维生素A 12 000 IU/kg组外的其他各组(P<0.05),添加维生素A 6 000 IU/kg组肝脏维生素A含量显著高于除添加维生素A 12000 IU/kg组外的其他各组(P<0.05)。3)饲粮中添加维生素A 1 500、3 000、6 000 IU/kg可显著提高试鸡血清谷胱甘肽过氧化物酶(GSH-Px)活力(P<0.05),添加维生素A可显著提高肝脏GSH-Px活力(P<0.05);添加维生素A 1 500、3 000、6 000、12 000 IU/kg可显著降低血清丙二醛(MDA)含量(P<0.05),添加维生素A 3 000 IU/kg可显著降低肝脏MDA含量(P<0.05)。结果提示,饲粮添加维生素A 3 000～6 000 IU/kg能维持血清维生素A含量稳定,提高机体抗氧化能力,从而促进22～42日龄黄羽肉鸡生长。     

植物粉剂对肉鸡生长性能、肠道菌群数量和肌肉脂肪酸的影响

文章旨在评估植物粉剂(大蒜粉和石莲花粉)对1~42d肉鸡生长性能、肠道菌群和肌肉脂肪酸组成的影响。试验选择平均初始体重为(48.33±0.47)g的1日龄商品肉仔鸡640只,随机分为4组,每组5个重复,每个重复32只。对照组饲喂基础日粮,药物组肉鸡饲喂基础日粮,但通过饮水补充2mg/L维吉尼亚霉素水溶剂,大蒜粉组肉鸡饲喂基础日粮+10mg/kg大蒜粉,石莲花粉组肉鸡饲喂基础日粮+10mg/kg石莲花粉。试验共进行42d。结果:药物组及植物粉剂组肉鸡在21和42d时的体重均显著高于对照组(P<0.05),同时对照组肉鸡在22~42d和1~42d时的日增重和采食量显著低于处理组(P<0.05),与药物组相比,大蒜粉组肉鸡1~21d和1~42d的料重比显著提高3.33%和1.72%(P<0.05)。对照组小肠大肠杆菌数量较药物组、大蒜粉组和石莲花粉组显著提高37.19%、34.60%和35.76%(P<0.05),处理组肉鸡小肠乳酸菌数量较对照组显著提高13.15%、14.16%和15.32%(P<0.05)。石莲花粉组胸肌C18:3脂肪酸含量较对照组、药物组和大蒜粉组分别显著提高了63.46%、88.89%和57.41%(P<0.05),同时药物组n-6与n-3脂肪酸比例较石莲花粉组显著提高32.44%(P<0.05)。结论:在本试验条件下,1~42d肉鸡日粮中添加大蒜粉和石莲花粉可以改善生长性能,同时降低小肠大肠杆菌数量、增加小肠乳酸菌数量。     

中草药提取物对肉鸡生长性能、器官发育、免疫功能及肠道菌群的影响

文章旨在研究日粮添加中草药提取物替代抗生素对1～42 d肉鸡生长性能、器官发育、免疫功能及肠道菌群的影响。试验选择1日龄商品肉鸡1008只,随机分为6组,每组6个重复,每个重复28只鸡。试验设计的6个组分别为对照组、抗生素组和中草药提取物组,其中对照组饲喂基础日粮,抗生素组在基础日粮中添加15 mg/kg维吉霉素,中草药提取物组分别在基础日粮中添加0.1%金花菊、大蒜素、百里香和3种中草药混合物,试验开展42 d。结果显示:日粮添加中草药提取物显著影响42 d肉鸡日采食量和料重比(P 0.05);与抗生素组相比,处理1组肉鸡采食量和体重显著降低(P 0.05),料重比显著提高(P 0.05)。抗生素组较对照组、处理1组、处理2组和处理3组显著降低了小肠的相对重量(P 0.05),而处理4组较对照组和处理3组显著降低了小肠的相对重量(P 0.05)。处理2组较其他组显著提高了法氏囊相对重量(P 0.05),处理1组抗免疫红细胞和过敏反应程度显著高于其他各组(P 0.05)。处理2组显著降低了血清甘油三酯、胆固醇和低密度脂蛋白含量(P 0.05),同时显著提高高密度脂蛋白含量(P 0.05)。处理3组较对照组显著降低回肠内容物大肠杆菌的含量(P 0.05),处理4组较其他各组显著提高回肠内容物乳酸杆菌的含量(P 0.05)。结论 :日粮添加大蒜素可以达到与抗生素一致的效果,提高1～42 d肉鸡料重比,大蒜素和金花菊可以改善免疫性能,降低血清甘油三酯含量和肠道大肠杆菌含量。     

油脂氧化日粮添加维生素E和抗氧化剂对肉鸡生长性能、肉品质和抗氧化性能的影响

试验旨在研究油脂氧化日粮中添加维生素E(VE)和抗氧化剂对1~42 d肉鸡生长性能、肉品质和抗氧化性能的影响。选择500羽1 d岭南黄鸡,随机分为5组,每组5个重复(20羽/重复),对照组饲喂以玉米—豆粕为主的基础日粮,油脂氧化组饲喂加入3%氧化豆油的日粮,VE组、抗氧化剂组和VE+抗氧化剂组饲喂分别在油脂氧化日粮中添加200 IU/kg VE、100 mg/kg抗氧化剂和100 IU/kg+50 mg/kg抗氧化剂的日粮,试验期42 d。结果显示:与对照组相比,油脂氧化组和各处理组显著提高21 d肉鸡体重、平均日增重和平均日采食量(P0.05),油脂氧化组和VE组肉鸡42 d末重显著高于其他各组(P0.05)。与其他各组相比,VE组肉鸡生长后期(22~42 d)平均日增重和平均日采食量显著低于其他各组(P0.05)。VE+抗氧化剂组对21 d岭南黄鸡血浆α-1酸性糖蛋白(AGP)水平显著高于对照组(P0.05),VE组42 d肉鸡血浆硫代巴比妥酸反应物(TBARS)水平表现为最高(P0.05)。对照组肝脏超氧化物歧化酶(Superoxide Dismutase,SOD)基因m RNA表达水平显著高于油脂氧化组(P0.05)。VE组和抗氧化剂组胸肌滴水损失显著低于油脂氧化组(P0.05)。与其他各组相比,油脂氧化日粮添加VE显著提高胸肌VE含量(P0.05)。在本试验条件下,单独添加抗氧化剂和VE降低胸肌滴水损失,但高水平的VE会降低1~42 d岭南黄鸡生长后期的生长性能。     

左旋肉碱对低温条件下肉鸡生长性能、器官重量及腹水敏感性的影响

本研究旨在探讨低温饲养条件下左旋肉碱对不同日龄肉鸡生长性能、器官重量、血液生化指标和腹水易感性的影响。试验选择1日龄肉仔鸡620只,根据体重随机分为2组,每组5个重复,每个重复62只。对照组饲喂基础日粮,处理组在基础日粮中添加80mg/kg的L-肉碱,试验共开展42d。结果 :肉鸡在1～21d的日增重及1～21d和21～42d的平均日采食量不受日粮肉碱添加水平的影响(P 0.05),但肉碱组显著降低了21～42d的平均日采食量(P 0.05),同时肉鸡补充左旋肉碱显著降低了21～42d肉鸡腹水导致的死亡率(P 0.05)。日粮添加肉碱显著降低了42d肉鸡肝脏、35d肺和21d心脏的相对重量(P 0.05),肉碱组较对照组显著降低了42d肉鸡血液红细胞数量、血红蛋白含量和血细胞比容(P 0.05)。日粮添加肉碱显著提高了42d肉鸡肝脏谷胱甘肽过氧化物酶和超氧化物歧化酶活性(P 0.05)。与对照组相比,肉碱组显著降低了血清葡萄糖和尿酸含量(P 0.05),显著提高了血清球蛋白和总蛋白含量(P 0.05)。结论 :日粮中添加左旋肉碱可降低器官指数、红细胞数和血细胞比容,从而降低腹水易感性,同时也可增加肝脏抗氧化能力,保护肝细胞免受脂质过氧化损伤,改善葡萄糖氧化代谢。     

玉屏风和甘草提取物对白羽肉鸡生长性能和免疫功能的影响

试验旨在研究饲料中添加玉屏风和甘草提取物对白羽肉鸡生长性能和免疫功能的影响。试验选取1日龄科宝白羽肉鸡600只,按照体重一致的原则随机分为3组,每组10个重复,每个重复20只,试验期42 d。对照组饲喂基础饲粮,处理组1饲喂添加玉屏风提取物500 mg/kg的基础饲粮,处理组2饲喂添加玉屏风提取物500 mg/kg+甘草提取物200 mg/kg的基础饲粮。结果表明：(1)与对照组比较,处理组1可以显著提高22-42 d和全期的平均日增重（P<0.05）;处理组2可以显著提高第21天和第42天的末重（P<0.05）,可以显著提高0-21、22-42 d和全期的平均日增重和平均日采食量（P<0.05）。(2)与对照组相比,处理组1可以显著提高肉鸡第42天禽流感病毒H5-11(H5-11)、禽流感病毒H7(H7)和新城疫病毒（NDV）抗体水平（P<0.05）;处理组2可以显著提高肉鸡第21天H7和NDV抗体水平（P<0.05）,和第42天H7、NDV、H5-11和H9抗体水平（P<0.05）。(3)与对照组相比,处理组2可以显著提高第42天肉鸡肝脏指数和脾...     

木聚糖酶和葡聚糖酶对肉鸡生长性能、屠宰性能、胴体成分及血液指标的影响

文章旨在研究玉米-小麦-豆粕型日粮添加木聚糖酶和葡聚糖酶对1～42 d肉鸡生长性能、屠宰性能、胴体成分及血液指标的影响。试验选择健康、体重一致的1日龄Cobb肉仔鸡800只,随机分为2组,每组5个重复,每个重复80只。对照组饲喂玉米-小麦-豆粕型日粮,试验组饲喂基础日粮添加2000 U/g木聚糖酶+800 U/g葡聚糖酶,试验分为3个阶段,1～14 d,15～28 d和29～42 d。与对照组相比,酶制剂组显著提高了28～42 d肉鸡能量和蛋白质利用率(P <0.05),显著降低了平均日采食量、日增重和料重比(P <0.05)。对于试验全期,酶制剂组显著提高了1～42 d肉鸡能量和粗蛋白质利用率(P <0.05),同时显著降低了平均日采食量、日增重和料重比(P <0.05)。酶制剂组较对照组显著提高了肉鸡的屠宰率和腿肌率(P <0.05)。对照组与酶制剂组对肉鸡胴体干物质、脂肪和灰分含量的影响均无显著差异(P> 0.05)。日粮添加复合酶较对照组显著提高了28和42 d肉鸡血液T3的含量(P <0.05),显著降低了42 d肉鸡血液T4的含量(P <0.05),同时酶制剂组较对照组显著提高了42 d肉鸡血液葡萄糖的浓度(P <0.05)。与对照组相比,酶制剂组显著降低了28和42 d肉鸡血液尿酸含量(P <0.05),显著提高了14和42 d肉鸡血液甘油三酯含量(P <0.05)。综上所述,1～42 d肉鸡日粮添加2000 U/g木聚糖酶和800 U/g葡聚糖酶可以显著改善料肉比,提高屠宰性能,可改变血液中甲状腺激素和部分代谢物的浓度,但对胴体成分影响不大。     

低蛋白质饲粮添加载锌蒙脱石对肉鸡生长性能、免疫器官发育和肠道组织形态的影响

本试验旨在研究低蛋白质饲粮添加载锌蒙脱石(Zn-MMT)对肉鸡生长性能、免疫器官发育和肠道组织形态的影响。随机选择1日龄健康科宝公雏288只,按体重一致原则随机分成6个组,每组6个重复,每个重复8只鸡。对照组饲喂玉米-豆粕型低蛋白质基础饲粮,正对照组[硫酸锌(ZnSO 4)组]饲喂低蛋白质基础饲粮+40 mg/kg ZnSO 4,4个试验组分别在低蛋白质基础饲粮中添加20、40、60和80 mg/kg Zn-MMT(均以锌含量计算)。试验鸡自由采食和饮水,试验期为42 d。结果表明:1)与对照组和ZnSO 4组相比,低蛋白质饲粮添加60和80 mg/kg Zn-MMT显著降低肉鸡1~21日龄平均日增重(ADG,P<0.05),添加80 mg/kg Zn-MMT显著提高肉鸡1~21日龄料重比(F/G,P<0.05);添加Zn-MMT对肉鸡22~42日龄和1~42日龄ADG、平均日采食量和F/G以及1~21日龄ADG无显著影响(P>0.05)。2)与对照组相比,低蛋白质饲粮添加Zn-MMT对肉鸡21和42日龄免疫器官指数无显著影响(P>0.05);但与ZnSO 4组相比,低蛋白质饲粮添加Zn-MMT显著提高肉鸡21日龄胸腺指数和法氏囊指数(P<0.05),且添加80 mg/kg Zn-MMT显著提高肉鸡42日龄胸腺指数(P<0.05)。3)与对照组相比,低蛋白质饲粮添加20和60 mg/kg Zn-MMT显著提高肉鸡42日龄腿比率(P<0.05);与ZnSO 4组相比,低蛋白质饲粮添加Zn-MMT对肉鸡屠宰性能无显著影响(P>0.05)。4)与对照组相比,低蛋白质饲粮添加40和60 mg/kg Zn-MMT显著降低肉鸡十二指肠隐窝深度(CD,P<0.05),且添加60 mg/kg Zn-MMT显著降低肉鸡空肠CD(P<0.05);添加20 mg/kg Zn-MMT显著降低肉鸡回肠CD(P<0.05),并显著提高肉鸡回肠绒毛高度(VH)/CD(V/C)值(P<0.05);同时,添加80 mg/kg Zn-MMT显著降低肉鸡空肠V/C值(P<0.05)。与ZnSO 4组相比,低蛋白质饲粮添加20 mg/kg Zn-MMT显著提高肉鸡回肠V/C值(P<0.05),并显著降低回肠CD(P<0.05);添加40 mg/kg Zn-MMT显著提高肉鸡空肠VH(P<0.05),并显著降低肉鸡十二指肠CD(P<0.05);添加20和60 mg/kg Zn-MMT显著降低肉鸡空肠CD(P<0.05);添加20、40和60 mg/kg Zn-MMT显著提高肉鸡空肠V/C值(P<0.05)。综上所述,在低蛋白质饲粮中添加Zn-MMT对肉鸡后期生长性能无显著影响,但与添加ZnSO 4相比,可显著提高肉鸡免疫器官指数,提高小肠VH和V/C值,降低小肠CD,促进肉鸡肠道发育。     

腐殖酸钠对肉仔鸡生长性能、免疫功能和抗氧化能力的影响

本试验旨在研究饲粮中添加腐殖酸钠对肉仔鸡生长性能、免疫功能和抗氧化能力的影响。选择1日龄健康爱拔益加(AA)肉仔鸡600只,随机分为5组,分别为抗生素对照组(T1)、无抗对照组(T2)和0.1%(T3)、0.3%(T4)、0.5%腐殖酸钠添加组(T5),每组12个重复(公母各6个重复),每个重复10只鸡。试验分2个阶段进行,1～21日龄为试验前期,22～42日龄为试验后期。结果表明:1) 1～21日龄时,抗生素对照组和0.3%腐殖酸钠添加组公鸡的平均日增重显著高于0.1%和0.5%腐殖酸钠添加组(P<0.05)。2)饲粮添加腐殖酸钠对42日龄肉鸡的屠宰率、半净膛率、全净膛率、胸肌率、腿肌率和腹脂率均无显著影响(P>0.05)。3) 42日龄时,抗生素对照组公鸡的脾脏指数和母鸡的胸腺指数显著高于无抗对照组和0.1%腐殖酸钠添加组(P<0.05)。4) 21日龄时,0.3%和0.5%腐殖酸钠添加组肉仔鸡的血清免疫球蛋白A(IgA)和免疫球蛋白G(IgG)含量显著高于抗生素对照组和无抗对照组(P<0.05); 0.5%腐殖酸钠添加组的血清免疫球蛋白M(IgM)含量显著高于其他组(P<0.05)。42日龄时,0.5%腐殖酸钠添加组肉仔鸡的血清IgA和IgM含量显著高于其他组(P<0.05)。5) 21日龄时,0.3%和0.5%腐殖酸钠添加组肉仔鸡的血清丙二醛(MDA)含量显著低于抗生素对照组、无抗对照组和0.1%腐殖酸钠添加组(P<0.05);而血清总抗氧化能力(T-AOC)显著高于抗生素对照组、无抗对照组和0.1%腐殖酸钠添加组(P<0.05)。42日龄时,抗生素对照组肉仔鸡的血清MDA含量显著高于其他组(P<0.05); 0.3%和0.5%腐殖酸钠添加组的血清T-AOC显著高于抗生素对照组(P <0.05)。综合生产性能、免疫功能和抗氧化能力,建议肉仔鸡饲粮中腐殖酸钠的适宜添加剂量为0.3%～0.5%。     

栗树叶营养价值分析

利用凯氏定氮法、索氏抽提法、高温炭化灼烧法、酸碱法、EDTA反滴定法、钼黄比色法对河北省唐山市迁西、遵化、迁安3市(县)采集的栗树叶样品的粗蛋白、粗脂肪、粗灰分、粗纤维、钙、总磷和无氮浸出物含量进行了测定,并与黑麦草、玉米秸秆和羊草的营养指标进行了分析比较,以研究栗树叶的饲料化利用价值。结果表明,遵化、迁安、迁西3市(县)栗树叶营养成分含量差异不显著,栗树叶中粗蛋白含量为10.81%、粗脂肪含量为5.44%、粗纤维含量为21.69%、粗灰分含量为9.86%、钙含量为1.82%、总磷含量为0.33%、无氮浸出物含量为52.20%。栗树叶的粗蛋白、粗脂肪、钙和总磷含量均高于黑麦草、玉米秸秆和羊草含量,而粗纤维含量低于黑麦草、玉米秸秆和羊草含量,因此其具有较高的饲料化利用价值。     

Pharmacokinetics and bioavailability of carbetocin after intravenous and intramuscular administration in cows and gilts

The pharmacokinetics of carbetocin, which is used to control postpartum hemorrhage after giving birth, was studied in cows and gilts after a single intravenous (IV) or intramuscular (IM) injection. Blood samples from animals were assessed by oxytocin radioimmunoassay, and then the pharmacokinetic parameters were calculated using a noncompartmental model. For gilts, there was no significant difference between half-life (T_1/2λZ), mean residue time (MRT), and maximum concentration (C_max) between IM and IV administration. Conversely, the time to reach the C_max (T_max) and MRT were higher following administration of 350 μg/animal in cows via the IM administration compared with IV. The longest T_1/2λZ was 0.85 hr, indicating carbetocin was absorbed and eliminated rapidly in both animal species after administration. The T_max was similar between cows and gilts following IM administration. Moreover, the C_max after IM injection was about half that of IV administration in both animals. The bioavailability was more than 80% in cows, suggesting administration via the IM route is efficient. This is in agreement with the longer T_1/2λZ in cows after IM administration. However, the IV route is recommended for gilts due to a lower bioavailability (35%) and shorter T_1/2λZ after IM administration compared with IV.     

中国伞形科当归属及相关类群毛状体和果实结构的系统学价值

深入研究了当归属及其相关7属,古当归属,高山芹属,柳叶芹属,独活属,欧当归属,山芹属及前胡属毛状体和果实结构。结果显示毛状体及果实结构(如:毛状体细胞,翅,油管,维管束,中果皮,内果皮,结合面及结晶)可以用于区分当归属及其相关类群。滇南当归及隆萼当归应从当归属移入独活属,其余当归属物种分为结合面宽及结合面窄两组,前者与前胡属较为相似,但与独活属差别较大,后者与古当归属,高山芹属,柳叶芹属,欧当归属有相似之处。支持分子系统学揭示的当归属不是个自然类群,当归属与前胡属共同位于当归分支,而独活属位于独活分支。山芹属果实结构与其他属不同,翅的中果皮无细胞,且伴生油管位于维管束内侧,为分子系统学显示此属与高山芹属,柳叶芹属,及欧当归属亲缘关系较远提供了形态学依据。     

Genetic and phenotypic parameters and annual trends for growth and fertility traits of Charolais and Hereford beef cattle breeds in Kenya

This study estimated genetic and phenotypic parameters and annual trends for growth and fertility traits of Charolais and Hereford cattle in Kenya. Traits considered were birth weight (BW, kg), pre-weaning average daily gain (ADG, kg/day) and weaning weight (WW, kg); calving interval (CI, days) and age at first calving (AFC, days). Direct heritability estimates for growth traits were 0.36 and 0.21; 0.25 and 0.10; 0.23 and 0.13 for BW, ADG and WW in Charolais and Hereford, respectively. Maternal heritability estimates were 0.11 and 0.01; 0.18 and 0.00; 0.17 and 0.17 for BW, ADG and WW in Charolais and Hereford, respectively. Direct-maternal genetic correlations ranged between −0.46 and 1.00; −0.51 and −1.00; −0.47 and −0.39 for BW, ADG and WW in Charolais and Hereford, respectively. Genetic correlations ranged from −0.99 to unity and −1.00 to unity for growth and fertility traits respectively. Prospects for improvement of growth and fertility traits exist.     

Genetic diversity and antimicrobial resistance of Campylobacter and Salmonella strains isolated from decoys and raptors

Infections caused by thermotolerant Campylobacter spp. and Salmonella spp. are the leading causes of human gastroenteritis worldwide. Wild birds can act as reservoirs of both pathogens. A survey was carried out to determine the prevalence, genetic diversity and antimicrobial resistance of thermotolerant Campylobacter and Salmonella in waterfowl used as decoys and wild raptors in Andalusia (Southern Spain). The overall prevalence detected for Campylobacter was 5.9% (18/306; CI_95%: 3.25–8.52) in decoys and 2.3% (9/387; CI_95%: 0.82–3.83) in wild raptors. Isolates were identified as C. jejuni, C. coli and C. lari in both bird groups. Salmonella was isolated in 3.3% (10/306; CI_95%: 2.3–4.3) and 4.6% (18/394; CI_95%: 3.5–5.6) of the decoys and raptors, respectively. Salmonella Enteritidis and Typhimurium were the most frequently identified serovars, although Salmonella serovars Anatum, Bredeney, London and Mikawasima were also isolated. Pulsed-field gel electrophoresis analysis of isolates showed higher genetic diversity within Campylobacter species compared to Salmonella serovars. Campylobacter isolates showed resistance to gentamicin, ciprofloxacin and tetracycline, while resistance to erythromycin and tetracycline was found in Salmonella isolates. The results indicate that both decoys and raptors can act as natural carriers of Campylobacter and Salmonella in Spain, which may have important implications for public and animal health.     

Intake, live animal scores/measurements and carcass composition and value of late-maturing beef and dairy breeds

The objectives of this study were to compare the progeny of 1) late-maturing beef with dairy breeds and 2) Charolais (CH), Limousin (LM), Simmental (SM) and Belgian Blue (BB) sires bred to beef suckler dams, for feed intake, blood hormones and metabolites, live animal measurements, carcass traits and carcass value in bull and steer production systems. The bull system included 50 late-maturing beef breeds and 22 Holsteins (HO) slaughtered at approximately 15 months of age, whereas the steer system consisted of 56 late-maturing beef breeds and 23 British Friesians (FR) slaughtered at approximately 24 months of age. Beef breeds were suckled until approximately 8 months of age, while dairy breeds were artificially reared until weaning at approximately 3 months of age. All animals were finished on an ad libitum concentrate diet. Mean live weight, live weight gain, carcass gain and feed efficiency were greater (P < 0.05) in beef than dairy breeds in both systems during the finishing period when offered concentrates. Although there was no difference in feed intake between beef and dairy breeds, intake expressed relative to live weight was lower (P < 0.001) in beef breeds in both systems. At 10 months of age and pre-slaughter, beef breeds had higher (P < 0.001) muscularity scores and greater scanned muscle depth (P < 0.001) than their dairy contemporaries. Carcass weight, kill-out proportion, carcass conformation score, meat proportion and value were greater (P < 0.001) and carcass fat and bone proportions were lower (P < 0.05) in beef than dairy breeds in both systems. Insulin concentrations were lower (P < 0.001) in beef than dairy breeds, whereas there was no difference in blood metabolites or IGF-1 concentrations. Feed intake expressed relative to live weight or feed efficiency did not differ between CH, LM, SM or BB sired progeny. Muscularity scores were greater (P < 0.05) in BB than SM, whereas skeletal scores were lower (P < 0.05) in LM than SM. Limousin had lower (P < 0.05) carcass gain per day of age than CH and SM, whereas SM had a lower (P < 0.05) carcass conformation score than BB and CH and a higher (P < 0.05) carcass fat score than CH. Simmental had a lower (P < 0.05) carcass meat proportion and a higher (P < 0.05) carcass fat proportion than CH, LM and BB, which were similar (P > 0.05). The improvement obtained for beef over dairy breeds in live weight gain was 12%, while the improvements in carcass gain and meat produced was 24% and 33%, respectively. This demonstrates that the importance of carcass data contributing to breed comparison studies cannot be over-emphasised.     

Babesiosis in dogs and cats--expanding parasitological and clinical spectra

Canine babesiosis caused by different Babesia species is a protozoal tick-borne disease with worldwide distribution and global significance. Historically, Babesia infection in dogs was identified based on the morphologic appearance of the parasite in the erythrocyte. All large forms of Babesia were designated Babesia canis, whereas all small forms of Babesia were considered to be Babesia gibsoni. However, the development of molecular methods has demonstrated that other Babesia species such as Babesia conradae, Babesia microti like piroplasm, Theileria spp. and a yet unnamed large form Babesia spp. infect dogs and cause distinct diseases. Babesia rossi, B. canis and Babesia vogeli previously considered as subspecies are identical morphologically but differ in the severity of clinical manifestations which they induce, their tick vectors, genetic characteristics, and geographic distributions, and are therefore currently considered separate species. The geographic distribution of the causative agent and thus the occurrence of babesiosis are largely dependent on the habitat of relevant tick vector species, with the exception of B. gibsoni where evidence for dog to dog transmission indicates that infection can be transmitted among fighting dog breeds independently of the limitations of vector tick infestation. Knowledge of the prevalence and clinicopathological aspects of Babesia species infecting dogs around the world is of epidemiologic and medical interest. Babesiosis in domestic cats is less common and has mostly been reported from South Africa where infection is mainly due to Babesia felis, a small Babesia that causes anemia and icterus. In addition, Babesia cati was reported from India and sporadic cases of B. canis infection in domestic cats have been reported in Europe, B. canis presentii in Israel and B. vogeli in Thailand. Babesiosis caused by large Babesia spp. is commonly treated with imidocarb dipropionate with good clinical response while small Babesia spp. are more resistant to anti-babesial therapy. Clinical and parasitological cure are often not achieved in the treatment of small Babesia species infections and clinical relapses are frequent. The spectrum of Babesia pathogens that infect dogs and cats is gradually being elucidated with the aid of molecular techniques and meticulous clinical investigation. Accurate detection and species recognition are important for the selection of the correct therapy and prediction of the course of disease.     

Seedling Defoliation and Drought Stress: Variation in Intensity and Frequency Affect Performance and Survival

Our ability to restore rangelands is limited, and it is unknown if seedling herbivory on its own, or in interaction with other stressors, is a major contributor to restoration failure. To address this, we conducted two experiments: a No Defoliation (ND) experiment (n = 48), in which seedlings from three perennial grasses (crested wheatgrass [Agropyron cristatum {(L.} Gaertn.], bluebunch wheatgrass [Psuedoroegnaria spicata {Pursh} Á. Love], Sandberg bluegrass [Poa secunda J Presl]) were subjected to wet and dry water regimes for 4 mo, and a concurrent Defoliation (D) experiment (n = 95), in which seedlings were factorially assigned to two defoliation treatments—frequency (LOW, HIGH) and intensity (30% vegetation removal, 70% vegetation removal). Indicators of seedling performance were aboveground and belowground biomass (AGB and BGB), root:shoot ratio, tillering, and mortality. The effect size statistic, Hedge’s g, allowed for comparisons between performance measures. Water stress induced reductions in most performance measures: BGB (g = ND: –1.3; D: –1.6), root:shoot ratio (g = ND: n.s.; D: –0.2), and tillering (g = ND: –1.7; D: –1.2), though not significantly for all species. For ABG, water stress interacted with defoliation, reducing performance less at an intensity of 70% (g = –2.0) as opposed to 30% (g = –3.0), but not always significantly in the former. Water stress also caused less reduction in AGB when no defoliation occurred (ND: –0.8; g = D: –2.5). Intensity and frequency of defoliation interacted; seedlings were generally resistant to reductions in performance except at high frequency, 70% defoliation. Agropyron cristatum and P. spicata displayed similar sensitivity to treatments, mostly in terms of changes in AGB and BGB, while P. secunda also experienced increased mortality and reduced tillering. If these differences in sensitivity result in differential survival, herbivory could impact species postrestoration population demographics.