低蛋白质氨基酸平衡饲粮对黄羽肉种鸡产蛋性能、蛋品质、孵化性能和氮排放的影响

本试验旨在研究低蛋白质氨基酸平衡饲粮对黄羽肉种鸡生产性能、蛋品质、孵化性能和氮排放的影响。选用30周龄健康的快大型岭南黄羽肉种母鸡288只,根据体重和产蛋率相近原则,随机分为4个组,每组6个重复,每个重复12只鸡。各组饲粮粗蛋白质(CP)水平分别为16%(对照组)、15%、14%、13%,各组的赖氨酸、蛋氨酸、色氨酸、苏氨酸、缬氨酸、亮氨酸及异亮氨酸水平一致。试验期10周。结果表明:1)低蛋白质氨基酸平衡饲粮对黄羽肉种鸡末重、平均日增重、平均日产蛋量、料蛋比、平均蛋重、产蛋率、破蛋率和不合格蛋率均无显著影响(P>0.05)。2)低蛋白质氨基酸平衡饲粮对黄羽肉种鸡鸡蛋的蛋形指数、蛋白高度、哈氏单位、蛋黄重、蛋壳重和蛋壳厚度均无显著影响(P>0.05)。13%CP组的蛋黄颜色显著高于16%CP组(P<0.05)。3)低蛋白质氨基酸平衡饲粮对黄羽肉种鸡的雏鸡初生重、受精蛋孵化率、弱雏率和受精率均无显著影响(P>0.05)。4)13%、14%CP组的血浆尿素氮含量显著低于16%CP组(P<0.05),13%CP组的血浆尿酸含量显著低于16%CP组(P<0.05),13%CP组的粪便氮含量显著低于16%CP组(P<0.05)。由此可见,低蛋白质氨基酸平衡饲粮对黄羽肉种鸡的生产性能、蛋品质和孵化性能无负面影响,但能够降低血浆尿素氮、尿酸含量和粪便氮含量。本试验条件下,黄羽肉种鸡产蛋高峰期的饲粮CP水平可以降低至13%(补充7种必需氨基酸)。     

饲粮卵磷脂添加水平对肉鸡生长性能、屠宰性能、肝脏营养成分及肝脏和血清生化指标的影响

本试验旨在研究饲粮卵磷脂添加水平对肉鸡生长性能、屠宰性能、肝脏营养成分及肝脏和血清生化指标的影响。选取体重一致的1日龄爱拔益加(AA)肉仔鸡500只,随机分成5个组,每组10个重复,每个重复10只鸡。对照组饲喂基础饲粮,试验组在基础饲粮中分别添加500、1000、1500和2000 mg/kg卵磷脂。试验期42 d。结果表明:1)随着饲粮卵磷脂添加水平的增加,21和42日龄肉鸡平均体重呈二次曲线升高(P<0.05)。2)随着饲粮卵磷脂添加水平的增加,42日龄肉鸡半净膛率和全净膛率呈线性和二次曲线升高(P<0.05),42日龄肉鸡腿肌率呈线性升高(P<0.05)。3)随着饲粮卵磷脂添加水平的增加,21日龄肉鸡新鲜样本基础和干物质基础上肝脏有机物含量呈线性和二次曲线升高(P<0.05或P<0.01),42日龄肉鸡新鲜样本基础和干物质基础上肝脏有机物和粗脂肪含量均呈线性和二次曲线升高(P<0.05或P<0.01)。4)随着饲粮卵磷脂添加水平的增加,21日龄肉鸡肝脏总胆固醇含量呈线性升高(P<0.05),42日龄肉鸡肝脏甘油三酯含量呈线性和二次曲线升高(P<0.01)。5)与对照组相比,饲粮添加1000、1500和2000 mg/kg卵磷脂显著降低了21和42日龄肉鸡血清甘油三酯含量(P<0.05),饲粮添加2000 mg/kg卵磷脂显著降低21和42日龄肉鸡血清尿素氮含量(P<0.05)。随着饲粮卵磷脂添加水平的增加,21日龄肉鸡血清低密度脂蛋白、甘油三酯和总胆固醇含量呈线性降低(P<0.05),42日龄肉鸡血清甘油三酯含量呈线性和二次曲线降低(P<0.05)。由此可见,饲粮添加卵磷脂能够提高肉鸡生长性能和屠宰性能,调节肝脏和血清脂质代谢,降低血清尿素氮含量。以肉鸡平均体重为判断指标,推荐1~21日龄和22~42日龄肉鸡基础饲粮中卵磷脂添加水平分别为952和1246 mg/kg。     

L-精氨酸对肉种鸡产蛋后期生产性能以及肉种鸡、鸡蛋和后代鸡的抗氧化能力的影响

本试验主要研究L-精氨酸对肉种鸡生产性能以及肉种鸡、蛋黄和一日龄后代鸡的抗氧化能力的影响。试验期为9周,210只60周龄的AA健康肉种母鸡随机分为5个处理组,每个处理组6个重复,每个重复7只鸡。试验基础饲粮为玉米豆粕型饲粮,5个处理组在基础日粮中分别添加0.96%,1.16%,1.36%,1.56%和1.76%可消化氨基酸。检测肉种鸡生产性能以及肉种鸡、蛋黄和一日龄后代鸡的抗氧化能力。结果显示,饲粮中可消化精氨酸的水平对肉种鸡产蛋率有显著的影响(线性和二次方效应,P0.0001)。饲粮中添加1.36%精氨酸,肉种鸡的产蛋率最高。饲粮中可消化精氨酸的水平对肉种鸡血清、蛋黄和一日龄后代鸡肝脏和胸肌重的T-AOC水平和MDA浓度有显著影响(线性和二次方效应,P0.05)。饲粮中添加1.36%精氨酸,肉种鸡所有组织的T-AOC水平最高并且MDA的浓度最低。各个处理组间肉种鸡血清中GSH-PX活性无显著差异。饲粮中可消化精氨酸的水平对蛋黄(线性效应,P0.01;二次方效应,P0.05)和一日龄后代鸡的肝脏和胸肌的GSH-PX活性(线性和二次方效应,P≤0.01)有显著影响。饲粮中添加1.36%精氨酸,肉种鸡所有组织的GSH-PX活性最高。根据这些结果得出,饲粮中添加1.36%精氨酸(1,972 mg/d)是产蛋后期最适宜的精氨酸添加水平。     

白酒糟酵母培养物对肉仔鸡生长性能、血清抗氧化指标和肠道形态结构的影响

本试验旨在研究白酒糟酵母培养物(DGYC)对肉仔鸡生长性能、血清抗氧化指标和肠道形态结构的影响,以确定肉仔鸡饲粮中DGYC的适宜添加水平。选取525只1日龄健康的爱拔益加肉仔鸡公雏,随机分为5个组,每组7个重复,每个重复15只鸡。对照组饲喂基础饲粮,试验组在基础饲粮基础上分别添加0.25%、0.50%、1.00%和2.00%的DGYC。试验期42 d。结果表明:1)与对照组相比,饲粮添加1.00%DGYC提高了肉仔鸡生长后期(22～42日龄)平均日增重(0.05≤P<0.10),显著降低了料重比(P<0.05),且均随DGYC添加水平提高呈二次曲线变化(P<0.05)。2)与对照组相比,饲粮添加0.25%DGYC显著降低了肉仔鸡21日龄腹脂率(P<0.05),显著提高了42日龄腿肌率(P<0.05);饲粮添加0.50%和1.00%DGYC有降低肉仔鸡42日龄胸肌滴水损失的趋势(0.05≤P<0.10)。3)饲粮添加DGYC线性提高了肉仔鸡21和42日龄血清谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性和总抗氧化能力(T-AOC)(P<0.05);饲粮添加DGYC二次性提高了肉仔鸡21日龄血清GSH-Px活性以及42日龄血清SOD活性和T-AOC (P<0.05)。与对照组相比,饲粮添加1.00%DGYC显著提高了肉仔鸡21日龄血清GSH-Px活性(P<0.05);饲粮添加0.50%、1.00%和2.00%DGYC显著提高了肉仔鸡21日龄血清SOD活性(P<0.05),显著提高了肉仔鸡21和42日龄血清T-AOC(P<0.05);饲粮添加0.50%和1.00%DGYC显著提高了肉仔鸡42日龄血清SOD活性(P<0.05)。4) 1.00%DGYC添加组肉仔鸡21日龄空肠绒毛高度和42日龄绒毛高度/隐窝深度(V/C)显著高于对照组(P<0.05),且均随DGYC添加水平提高呈二次性升高(P <0.05)。5)肉仔鸡生长性能、血清抗氧化指标和空肠形态结构随DGYC添加水平升高存在二次曲线效应。二次曲线拟合结果表明,DGYC添加水平为0.9%～1.1%时,空肠形态结构最佳;添加水平为1.1%～1.2%时,生长性能和血清抗氧化能力最佳。由此可见,饲粮添加DGYC能提高肉仔鸡血清抗氧化能力,改善空肠黏膜形态结构,从而改善生长性能。以肉仔鸡生长性能、血清抗氧化指标和肠黏膜形态结构为判断指标,推荐肉仔鸡基础饲粮中DGYC添加水平为0.9%～1.2%。     

快大型黄羽肉种鸡饲粮中维生素A最适添加量的研究

本试验旨在通过探究饲粮维生素A添加量对黄羽肉种鸡产蛋性能、生殖器官发育、激素水平、种蛋品质、孵化性能及后代鸡生长性能的影响,确立黄羽肉种鸡饲粮中维生素A最适添加量。试验采用单因素随机分组设计,选用512只25周龄快大型岭南黄羽肉种鸡,根据体重和产蛋率一致原则分为4个组,每组8个重复,每个重复16只,各组分别饲喂添加0(对照组)、10 800、21 600、32 400 IU/kg维生素A的试验饲粮,试验期12周。种鸡饲养试验结束后选取种蛋孵化,子代肉鸡按照种鸡的组别进行分组分栏饲喂(基础饲粮中含15 000 IU/kg维生素A),试验期21 d。结果表明:1)与对照组相比,饲粮添加10 800～32 400 IU/kg维生素A显著提高了种鸡的产蛋率(P0.05),并显著降低了料蛋比(P0.05);饲粮维生素A添加量未对试验鸡生殖器官发育产生显著影响(P0.05);饲粮添加10 800 IU/kg维生素A显著提高了血浆雌激素(E2)含量(P0.05),添加21 600、32 400 IU/kg维生素A显著提高了血浆孕酮(PRG)含量(P0.05),添加10 800、32 400 IU/kg维生素A提高了血浆促卵泡激素(FSH)含量(P0.05);添加10 800、21 600 IU/kg维生素A显著增加了蛋形指数(P0.05),添加10 800～32 400 IU/kg维生素A显著提高了蛋黄色泽(P0.05);随着饲粮维生素A添加量升高,种鸡肝脏与种蛋蛋黄中视黄醇含量均显著上升(P0.05)。2)与对照组相比,种鸡饲粮添加10 800 IU/kg维生素A雏鸡平均出壳重显著提高(P0.05);种鸡饲粮添加10 800～32 400 IU/kg维生素A显著提高了子代鸡生长末重、平均日增重与平均日采食量(P0.05)。在本试验条件下,饲粮维生素A添加量影响快大型黄羽肉种鸡产蛋性能、种蛋品质、孵化性能、血浆激素含量、后代鸡生长性能及种鸡肝脏与种蛋蛋黄中的视黄醇含量。通过回归模型估测得到,以产蛋性能、种蛋品质、子代肉鸡生长性能为评价指标,快大型黄羽肉种鸡饲粮最适维生素A添加量分别为18 121～20 251 IU/kg、16 600～20 046 IU/kg、25 113～31 069 IU/kg。     

饲粮添加铜对1～21日龄肉仔鸡生长性能和血清生化指标的影响

本试验旨在研究饲粮中添加不同水平铜对1～21日龄肉仔鸡生长性能和血清生化指标的影响。选用192只初始体重(42.68±0.18)g的1日龄健康商品代爱拔益加(AA)肉公雏,随机分为3组,每组8个重复,每个重复8只鸡。采用单因子完全随机试验设计,对照组饲喂玉米-豆粕型基础饲粮(铜含量为5.17 mg/kg),其余2组分别在基础饲粮中添加6、12 mg/kg铜(源自无机硫酸铜),试验期21 d。结果表明:饲粮添加铜对1～21日龄肉仔鸡平均日增重、耗料增重比和死亡率均无显著影响;与对照组相比,饲粮中添加6 mg/kg或12 mg/kg铜显著降低了肉仔鸡平均日采食量;饲粮添加铜对21日龄肉仔鸡血清总胆固醇、甘油三酯、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇含量均无显著影响;饲粮添加铜对21日龄肉仔鸡血清总蛋白、白蛋白、球蛋白、尿酸和尿素氮、葡萄糖含量及碱性磷酸酶、谷丙转氨酶、谷草转氨酶活性均无显著影响。综上,饲粮添加无机硫酸铜形式的铜可降低1～21日龄肉仔鸡采食量,但对肉仔鸡其他生长性能指标及血清生化指标均无不良影响。     

饲粮能量和蛋白质水平对21～60日龄湖羊生长、消化性能及血清指标的影响

旨在研究饲粮能量和蛋白质水平对21～60日龄湖羊羔羊生长、消化性能和血清指标的影响。本研究采用两因素两水平试验设计,选取64只17日龄体重相近、健康的湖羊羔羊,随机分为高能高蛋白(HE-HP)、高能低蛋白(HE-LP)、低能高蛋白(LE-HP)、低能低蛋白(LE-LP)4组,每组4个重复,每重复4只羊。试验预试期3d,21日龄起所有羔羊断母乳,饲喂代乳粉、补饲开食料。正试期40d。每天记录羔羊采食量,每隔20d晨饲前称重、颈静脉采血测定血清指标;31～40和51～60日龄期间采用全收粪法进行消化试验。结果表明:1)饲粮能量与蛋白水平对羔羊生长性能无显著交互作用(P>0.05),但羔羊日增重与饲料转化效率均随饲粮能量或蛋白质水平的降低而显著降低(P<0.05)。2)饲粮能量和蛋白质水平对羔羊31～40日龄干物质和总能消化率存在显著交互作用(P<0.05),表现为饲喂高能量饲粮时羔羊对饲粮干物质和和总能消化率随蛋白质水平的降低而显著降低(P<0.05)。3)40日龄羔羊血清葡萄糖含量随能量水平降低而显著降低(P<0.05);60日龄时,降低蛋白质水平显著降低了羔羊血清尿素氮含量(P<0.05)、提高了血清生长激素含量(P<0.05),降低饲粮能量水平显著提高了血清尿素氮和三酰甘油含量(P<0.05)。综上所述,能量和蛋白质水平对21～60日龄羔羊生长性能有显著影响,适当的能量和蛋白水平能够改善羔羊生长和消化性能。     

饲粮中添加植物精油对黄羽肉种鸡产蛋性能、蛋品质、孵化性能、生殖器官发育以及血浆和肝脏生化指标的影响

本试验旨在研究饲粮中添加植物精油对黄羽肉种鸡产蛋性能、蛋品质、孵化性能、生殖器官发育以及血浆和肝脏生化指标的影响。选择288只产蛋率和体重接近的45周龄岭南黄羽肉种母鸡,随机分为4个组,每组6个重复,每个重复12只鸡。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加10、20、30 mg/kg植物精油。试验期10周。结果显示:1)饲粮中添加植物精油对黄羽肉种鸡的平均日产蛋重、料蛋比、平均蛋重、产蛋率、合格蛋率均无显著影响(P>0.05)。2)对照组的蛋白高度显著低于其他各组(P<0.05),对照组的哈氏单位显著低于10和20 mg/kg植物精油组(P<0.05),对照组的蛋壳厚度显著低于20 mg/kg植物精油组(P<0.05)。3)对照组的受精蛋孵化率显著低于10 mg/kg植物精油组(P<0.05)。4)对照组的卵巢系数显著低于10和20 mg/kg植物精油组(P<0.05),对照组的输卵管重量和输卵管系数显著低于10 mg/kg植物精油组(P<0.05)。5)对照组的血浆低密度脂蛋白胆固醇含量显著高于20 mg/kg植物精油组(P<0.05),对照组的肝脏甘油三酯含量显著高于10 mg/kg植物精油组(P<0.05)。由此可知,饲粮中添加植物精油不影响黄羽肉种鸡的产蛋性能,但能够改善蛋品质,提高受精蛋孵化率和生殖器官(输卵管和卵巢)系数,降低血浆低密度脂蛋白胆固醇含量和肝脏甘油三酯含量。本试验条件下,产蛋期黄羽肉种鸡饲粮植物精油适宜添加水平为10~20 mg/kg。     

饲粮粗纤维水平和砂砾对四川白鹅血清脂肪代谢指标、屠宰性能及肉品质的影响北大核心CSCD

本试验旨在研究饲粮粗纤维(CF)水平和砂砾对22~70日龄四川白鹅血清脂肪代谢指标、屠宰性能及肉品质的影响。采用双因素试验设计,即添加或不添加砂砾,饲粮CF水平分别为4.0%、7.0%和10.0%。选取22日龄体重相近的四川白鹅公鹅648只,随机分为6个处理,每个处理6个重复,每个重复18只鹅。试验期48 d。结果表明:1)饲粮CF水平显著影响了49日龄四川白鹅血清葡萄糖、总胆固醇、高密度脂蛋白含量(P<0.05),显著影响了70日龄四川白鹅血清葡萄糖、甘油三酯、总胆固醇、高密度脂蛋白含量(P<0.05)。饲粮砂砾显著影响了49、70日龄四川白鹅血清葡萄糖和甘油三酯含量(P<0.05)。2)饲粮CF水平和砂砾对70日龄四川白鹅的屠宰性能和肉品质无显著影响(P>0.05)。由此可见,增加饲粮CF水平可降低血清脂类含量,而添加砂砾可提高部分血清脂肪代谢指标。     

叶酸添加水平对肉仔鸡肝脏中脂肪代谢相关基因表达和甲基化的影响

本试验旨在考察叶酸添加水平对肉仔鸡血清中脂蛋白脂肪酶(LPL)和脂肪酸合成酶(FAS)活性、过氧化物酶体增殖物激活受体γ(PPARγ)含量以及肝脏中脂肪代谢相关基因表达和甲基化的影响。选择1日龄爱拔益加(AA)肉仔鸡300只,随机分成3组,每组5个重复,每个重复20只。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加5和10 mg/kg叶酸的试验饲粮。试验期为42 d。结果显示:1)与对照组相比,饲粮中添加10 mg/kg叶酸显著降低了21日龄肉仔鸡血清中LPL活性(P<0.05);饲粮中添加5和10 mg/kg叶酸极显著降低了42日龄肉仔鸡血清中LPL活性(P<0.01),极显著提高了21和42日龄肉仔鸡血清中PPARγ含量(P<0.01),极显著降低了21和42日龄肉仔鸡血清中FAS活性(P<0.01)。2)实时荧光定量PCR结果发现,饲粮中添加5和10 mg/kg叶酸均未显著影响42日龄肉仔鸡肝脏中LPL和PPARγ基因的相对表达量(P>0.05),但均显著降低了FAS基因的相对表达量(P <0.05)。3)甲基化分析显示,饲粮中添加5和10 mg/kg叶酸均未显著影响42日龄肉仔鸡肝脏中LPL和PPARγ基因的甲基化比率(P>0.05),但饲粮中添加5 mg/kg叶酸极显著提高了42日龄肉仔鸡肝脏中FAS基因的甲基化比率(P<0.01)。由此得出,饲粮中添加5和10 mg/kg叶酸极显著降低了42日龄肉仔鸡血清中LPL和FAS的活性,极显著增加了PPARγ的含量,显著降低了肝脏中FAS基因的表达;此外,饲粮中添加5 mg/kg叶酸还极显著提高了42日龄肉仔鸡肝脏中FAS基因的甲基化水平。     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.