Overwintering of Bovine Gastrointestinal Nematodes in Southwestern Ontario

Several steers, reared in isolation until approximately six months of age, were placed on a small isolated enclosed pasture from late spring to late fall of 1970, 1971 and 1972. The pasture was left vacant and unused during the winters and early springs. The pasture had been used in previous years by cattle, and in the late spring of 1970 was grazed by cattle know to be passing gastrointestinal nematode eggs in their feces. The steers were slaughtered periodically, and the prevalence of nematode species in the abomasum, small intestine, and large intestine, was determined from random samples of up to 100 adult male worms from each segment. The following nematodes were found in the steers in 1971 and 1972 and survived winters on pasture: Ostertagia ostertagi, O. lyrata, Cooperia oncophora, C. mcmasteri, Nematodirus helvetianus and Trichuris discolor. Two nematodes Cooperia punctata and Bunostomum phlebotomum known to be present on pasture in 1970, since they were recovered from the steers in that year, were not found in the steers in 1971 and 1972.     

On the Development of Gastrointestinal Parasitism in Bovine Yearlings

A comparative study on the development of Osteragia Ostertagi, Cooperia oncophora and Nematodirus helvetianus in 15-month-old yearlings and three-month-old calves demonstrated that yearlings have considerably greater resistance to gastrointestinal parasitism than calves. This was manifested by the establishment of smaller worm burdens, marked stunting of worms and a markedly lower worm egg output in the yearlings. The characteristic marked rise in egg counts observed in calves a few weeks after exposure to a heavy gastro-intestinal parasite infection did not occur in the yearlings. It was concluded that fecal examinations have a limited usefulness as a reliable aid to diagnosis of gastrointestinal parasitism in older cattle.     

On the Natural Seeding of Marshland Pastures with Bovine Gastrointestinal Parasites

By placing parasite-free calves in paddocks grazed by infected animals for 18 day periods at various times during the previous season it was shown that eggs of Ostertagia ostertagi, Cooperia oncophora and Nematodirus helvetianus deposited on pastures from early July to October of one year were able to survive in the Maritime area of Canada over winter either as eggs and/or larvae and contribute to residual infections on these pastures the following spring. The greatest deposition and/or survival of those eggs that were shed on pasture occurred in August and September for Cooperia and in September and October for Ostertagia. Greatest deposition of Nematodirus occurred in July and August and relatively few Nematodirus eggs shed in late September or early October were infective early in the next season.

The number of generations of worms per year was low, ranging from one to two or perhaps three per year depending on the species. There was a delay in the maturation of many worm eggs.

Residual overwintering infections play a significant role in the establishment of initial infections each summer in susceptible stock. These animals recontaminate the pastures leading to the subsequent development of large numbers of infective larvae by late summer and autumn.

     

退化高寒草甸暖季休牧恢复过程中植被和土壤特性

为探讨暖季休牧恢复过程中退化高寒草甸植被和土壤恢复特性,本研究对泽库县退化高山嵩草草甸暖季休牧样地不同恢复阶段植被和土壤特性进行调查,结果显示植被高度、地上生物量、土壤含水量、土壤有机碳含量等生态功能属性随自然恢复时间的延长不断得到改善(P<0.05),在恢复末期(9—10年)恢复最好;植被盖度、地下生物量、多样性、土...     

桑尺蠖越冬幼虫的耐寒性研究

研究了桑尺蠖越冬幼虫的耐寒能力 ,测定了虫体内抗寒物质的组成成分 ,并对其耐寒机理作了初步探讨。结果表明 :越冬幼虫从越冬初期至越冬滞育期 ,4龄幼虫的平均过冷却点从初期的-1 7 2℃下降至滞育期的 -2 4 4℃ ;5龄幼虫的平均过冷却点从 -1 3 4℃下降至 -2 4 8℃。越冬幼虫体内水分、糖元、脂肪含量下降 ,其中以糖元含量下降明显 ;越冬幼虫以“小分子糖—氨基酸—糖蛋白”物质系统形成抗寒基质 ,增强耐寒性。     

放牧牦牛冷季补饲效果观察

本试验以1岁、2岁公牛和成年母牦牛为研究对象,了解冷季补饲对放母牦牛生产性能的影响。试验选取1岁、2岁公牛和成年母牦牛各20头,不同年龄的牦牛均随机平分为试验组和对照组。试验时间为2010年10月13日～2011年4月30日,共计183d。结果试验组1岁牛总增重-2.31kg,增重率为-2.53%。夏季平均体重116.53kg,增重25.17kg,增重率为21.60%。对照组1岁牛总增重-14.17kg,增重率为-18.34%。夏季体重90.36kg,增重13.11kg,增重率为14.51%。试验组2岁牛总增重-8.11kg,增重率为-6.00%。夏季体重178.55kg,增重43.44kg,增重率为24.33%。对照组2岁牛总增重-14.17kg,增重率为-18.34%。夏季体重147.61kg,增重24.27kg,增重率为16.44%。试验组成年母牛总增重-43.37kg,增重率为-24.16%。夏季体重208.44kg,增重25.17kg,增重率为21.60%。对照组成年母牦牛总增重-50.81kg,增重率为-22.42%。夏季体重188.11kg,增重32.79kg,增重率为17.43%。结果表明冷季补饲有助于放牧牦牛生长发育。     

草原放牧绵羊消化道寄生虫感染调查

为了解草原放牧条件下绵羊消化道寄生虫的感染情况,采用麦克马斯特氏法(Mc Master's method)对100只草原放牧绵羊(乌珠穆沁羊20只,昭乌达肉羊80只)粪便进行了虫卵检测计数及感染种类鉴定。结果显示,线虫总感染率为58%,线虫平均感染强度为544.83,每克粪便样品中的虫卵数(EPG)最高达5 800;乌珠穆沁羊线虫感染率为75%,昭乌达肉羊线虫感染率为53.75%,成年公羊、成年母羊和羔羊的线虫感染率分别为72.73%、56.79%和50%。球虫总感染率为15%,球虫平均感染强度为586.67卵囊数(OPG)最高达3 000;乌珠穆沁羊球虫感染率为35%,昭乌达肉羊球虫感染率为10%,成年公羊、成年母羊和羔羊的球虫感染率分别为18.18%、14.81%和12.5%。研究结果表明,在草原放牧条件下,乌珠穆沁羊线虫和球虫的感染率、平均感染强度和高感染率均高于昭乌达肉羊,线虫和球虫的平均感染强度和感染率均表现为公羊>母羊>羔羊,总体线虫的感染率高于球虫感染率。     

倍克虫复合制剂对放牧绵羊线虫的驱虫效果

应用不同剂量倍克虫复合制剂(伊维菌素,丙硫苯咪唑),对放牧绵羊胃肠道线虫,肺线虫等进行驱除试验,结果表明：中剂量组(伊维菌素0．2mg／kg,丙硫苯咪唑10mg／kg)绵羊的消化道线虫虫卵转阴率达100％,减少率达100％,原圆科线虫幼虫转阴率达70％,减少率为77．35％。     

两种药物驱除放牧绵羊线虫的效果对比试验

选用伊维菌素注射剂按0.1,0.2,0.3mg/kg剂量和盐酸左旋咪唑片剂7.5,15,22.5mg/kg剂量对放牧绵羊进行驱虫试验,分别于给药后7d、14d检查效果。结果：伊维菌素组第7d消化道线虫的虫卵减少率分别为99.10%,99.18%和99.21%。14d分别为97.18%,98.91%,99.21%;肺线虫幼虫7d无明显变化,14d减少率分别为96.59%,96.51%,97.37%。左旋咪唑组第7d消化道线虫的虫卵减少率分别为67.79%,93.17%和95.52%,14d分别为54.68%,83.62%,84.30%;对肺线虫第7d幼虫减少率分别为62.76%,58.13%和45.74%,14d分别为0、72.76%,83.72%。试验表明伊维菌素注射液驱虫效果明显优于左旋咪唑片剂。     

Gastrointestinal Nematode Populations in Stabled Ewes of Rimouski Region

Nematode populations is stabled ewes of the Rimouski region were studied by means of fecal worm egg counts, fecal culture of larvae, and worm counts at necropsy. It was found that during the winter strongyle egg counts were low, Trichostrongylus eggs being most numerous, The stronglye egg counts increased following lambing and reached peak in June. Ostertagia spp was the principal contributor to this “spring-rise”, with substantial contribution from Trichostrongylus and Haemonchus contortus. The bulk of adult worm populations in winter, however, was made up of Trichostrongylus, whereas the great majority of the populations of Ostertagia spp, H. contortus and Nematodirus spp were inhibited in development at the fourth larval stage. All the worms recovered at necropsy in spring were adults, coinciding with the “spring-rise”.     

放牧藏羊冷季营养调控试验报告

藏系绵羊在产羔后分为4组,进行为期90天的补饲试验,结果:试验1组只均日补饲优质青干草0.5 kg,母羊和羔羊的增重分别为1.57kg和5.29kg;试验2组只均日补饲精料0.25kg,母羊和羔羊的增重分别为2.36 kg和7.9kg;试验3组只均日补饲精料0.5kg,母羊和羔羊的增重分别为4.25 kg和10.02kg;试验4组只均日补饲营养添砖0.15kg,母羊和羔羊的增重分别为1.7kg和6.51kg。4个试验组均达到了母羊保膘和羔羊成活的目的。其中,第3组母羊和羔羊的增重最高,饲料成本也最高;第1组母羊和羔羊的增重最少,但补饲成本最低。     

Albendazole Resistance in Gastrointestinal Nematode Parasites of Cattle in Bangladesh

Tropical Animal Health and Production -     

华北驼绒藜雨季移栽成活率研究

本文是不同季节移栽华北驼绒藜(Ceratoides arborescens)系列研究之一。干旱区春季生态建植有补水之苦,雨季移栽表明,不需坐水或补水,成活率可高达60%,浸根可提高成活率至90%;说明雨季移栽是可行的。移栽植株数日内叶片含水量和叶绿素含量急剧下降、脯氨酸含量骤然升高,含量恢复过程则较缓慢,说明移栽使植株突然损伤,但终能恢复至正常生理状态。     

线虫寄生对柞蚕幼虫生长发育和营养物质代谢的影响

研究寄生线虫对柞蚕幼虫生长发育和营养物质代谢的影响,可以从生理生化角度揭示柞蚕寄生线虫的致病机制,明确线虫在柞蚕体内完成寄生生活史的生理生化调控机制。检测柞蚕5龄幼虫被线虫寄生后其生长发育速度、血淋巴营养物质含量和中肠蛋白酶活性,结果表明,柞蚕幼虫被线虫寄生6～11 d,其摄食量和体质量变化不明显,血淋巴总糖、海藻糖含量短暂性升高,随后便急剧下降,血淋巴蛋白质含量和酯酶活性升高,甘油酯含量降低,中肠蛋白酶活性极显著低于对照组;被寄生12～15 d,柞蚕摄食量升高、体质量增加,中肠蛋白酶活性升高,而血淋巴中总糖含量、海藻糖含量、海藻糖酶活性、甘油酯含量极显著低于对照组,说明此时是线虫迅速生长的时期,蚕体营养物质被线虫大量消耗;被寄生15 d后摄食量急剧下降,血淋巴中能源物质含量极显著降低,中肠蛋白酶活性极显著低于对照组。线虫寄生柞蚕幼虫后与寄主形成营养竞争关系,造成蚕体营养物质严重缺乏、消化能力减弱、生长发育迟缓。研究结果可为揭示线虫对柞蚕的致病机制以及利用索科线虫进行农林害虫的生物防治提供参考。     

捕食线虫性真菌--少孢节丛孢菌体外杀寄生性线虫幼虫的研究

对捕食线虫性真菌——少孢节丛孢菌(Arthrobotrys oligospora)菌株体外粪便捕杀马寄生性线虫幼虫进行了研究。结果表明：菌株可以在体外粪便中发育并发挥其捕食作用。在实验室条件下，其对寄生性线虫第一、二期幼虫的作用与对第三期幼虫的作用相比较．捕获致死速度快。菌株对马粪便中线虫幼虫的杀虫率高达98．7％；与对照组相比有显著差异。而且加入粪便的分生孢子数量在达到一定阈值后，再加入分生孢子，则杀虫率不再增加。此结论对捕食线虫性真菌今后临床的应用具有实际指导意义。     

羊胃肠道线虫非药物控制措施研究进展

胃肠道线虫感染长期以来一直影响着羊的生产性能、健康和福利。当前我国养羊生产中通常使用化学合成驱虫药来进行驱虫。但是随着抗驱虫药胃肠道线虫种类和范围的不断增加和扩大,迫切需要开发出新的替代方法来控制感染。因此本文从营养、生物防治、粪便和牧场管理、遗传手段和使用疫苗等几个方面综述了控制羊胃肠道线虫感染的非药物措施及其作用机理。     

典型草原植物养分对生长季不同放牧强度的动态响应

为阐明典型草原生长季放牧过程中植物养分的动态变化,本研究在2017年生长季的不同放牧阶段(放牧早期、放牧中期和休牧后)对不同放牧强度影响下内蒙古典型草原主要物种克氏针茅(Stipa krylovii)、羊草(Leymus chinensis)和糙隐子草(Cleistogenes squarrosa)的碳(Carbon,...     

Diet Composition of Cattle Grazing Sandhills Range During Spring

The grazing season on upland Sandhills range traditionally begins in mid-May when the dominant warm-season grasses have initiated growth. Initiating grazing earlier would improve efficiency of use of cool-season plants and reduce the time period during which hay is fed. A 2-year study was conducted to determine nutrient and botanical composition of cattle diets when grazing upland Sandhills range during spring. Diets were collected from esophageally-fistulated cows on 10 April, 1 May, and 22 May each year. Concurrently, current-year, and residual herbage was clipped to determine pasture composition and calculate preference indices for the primary plant species and groups. Averaged across dates, needleandthread (Stipa comata Trin. & Rupr.), bluegrasses (Poa spp.), and sedges (Carex spp.) accounted for 19% of the total herbage and 68% of the current-year herbage yield. These species constituted an average of 74% of cow diets. Diet composition of sedges was less on 10 April than on 22 May (P < 0.05), whereas similar amounts of needleandthread and bluegrasses were present on all dates. Preference indices indicated strong selection for species with abundant current-year growth and avoidance of residual herbage. Crude protein content of diets was less on 10 April (10.7%) than on 1 May or 22 May (13.9%, P < 0.05), likely because of a greater amount of residual herbage present in 10 April diets. Overall quality of diets would meet requirements of average spring-calving cows; however, grazing management strategies would need to account for the limited availability of current-year growth during spring, particularly April, to ensure that cattle are meeting their nutrient needs.