Epizootiologic Studies Of Shipping Fever: II. Exposure Of Calves To Pasteurellae and Para-lnfluenza 3 Virus

In four trials, the exposure of six calves to various stressors and an aerosol of pasteurellae did not evoke significant responses. In ten trials, 20 calves were exposed by aerosol or intratracheal injection to myxovirus para-influenza 3 (PI3) alone or combined with pasteurellae. A respiratory syndrome similar to that observed in mild cases of shipping fever was regularly reproduced in calves which had low serum hemagglutination titers to PI3. One calf developed a severe bronchopneumonia, was killed and the virus was reisolated from its lungs. Exposure to P13 plus pasteurellae usually resulted in an increased nasal discharge. The stressors employed in a few trials did not significantly alter the response.     

A Review of the Lesions in Shipping Fever of Cattle

A review of literature concerning the information published on the macroscopic and microscopic lung lesions in “shipping fever” of cattle is presented as reported in naturally occurring cases as well as the experimental disease.     

对一例疑似肉牛运输热的诊断

[目的]山东省泰安市某肉牛养殖场从山东省菏泽市引进肉犊牛2天后,部分犊牛出现高热、流涎、呼吸困难等症状,并且死亡2头。为诊断该病例,并查明发病的原因,深入该牛场进行了细致的信息收集和样品采集,以进行综合诊断。[方法]对该病例的发病背景和临床症状进行了细致的调查,并对病死犊牛进行了病理剖检,而后采集了病料样品以进行组织病理学检查、分子生物学检测及细菌分离鉴定等实验室诊断,最终汇总各项检查结果进行综合诊断并实施针对性的防治措施。[结果]调查发现该牛场所购犊牛来自不同养殖场,几经倒手,运输前已处于应激状态;犊牛发病急、发病率高、病情重,符合重症运输热的一般症状;剖检病变主要是间质性及浆液性复合型肺炎,心、肝、脾、肾等实质器官发生急性变质性病变;病原学检测未检测到副流感病毒3型,但存在巴氏杆菌感染,据病变推测可能还存在其它病毒、细菌感染。按照运输热的治疗手段对病重牛进行了试验性治疗措施,即在提供良好饲养环境的同时,注射庆大霉素,全群氟苯尼考饮水,取得了良好的防治效果。[结论]该例犊牛急性、热性、致死性疾病为重症运输热,在加强饲养管理的同时给予适当的药物治疗能够很好地控制病情并治愈该病。     

微生态制剂在奶牛生产中的应用

微生态制剂是一类根据微生态学原理制成的对动植物有益的活菌制剂,以其重要作用即无毒、无污染、无残留的特点,在奶牛养殖业中被广泛的应用。本文针对微生态制剂在奶牛生产中的作用及应用时应注意的问题进行了阐述。     

致肉牛运输热溶血曼氏杆菌的分离鉴定及部分生物学特性研究

为探明一起肉牛运输热的病原及生物学特性,本研究无菌采集病死牛心血、肺脏、肝脏和脾脏,对其进行细菌分离、生化试验和PCR鉴定,并对分离株进行毒力基因检测、致病性研究。结果显示,7株分离菌均为革兰氏阴性短杆菌,具有微弱的β-溶血,瑞氏染色可见两极浓染及明显的荚膜。生化试验结果显示,分离菌能发酵葡萄糖、麦芽糖、阿拉伯糖、甘露醇、甘露糖、木糖等碳水化合物,不发酵脲酶、MR-VP和吲哚,产生少量酸而不产气,结果符合溶血曼氏杆菌生化特性。PCR鉴定均为荚膜血清A2型,分离菌均含有四型菌毛相关基因ptfA、参与复制相关基因dnaN、白细胞介素相关基因LktC3种毒力基因。分离菌对小鼠的LD50值在107.83～108.50 CFU/mL之间,不同菌株间小鼠LD50值存在一定差异,但差异不明显。结果表明,引起该批肉牛运输热的病原为携带毒力基因的荚膜血清A2型溶血曼氏杆菌,本研究结果为进一步研究溶血曼氏杆菌的致病机制提供参考。     

对分离于中国河南省的一株牛的巴贝西原虫的鉴定

将分离于中国河南省的一株牛的巴贝西原虫用长角血蜱(Haemaphysalis longicomis)幼虫对牛进行了实验感染.依据感染牛呈现的临床症状、媒介蜱、红细胞内裂殖子出现的时间及形态学特征,以及荧光抗体试验结果,确认该原虫为卵形巴贝西虫(Babesia ovata).     

Serological Studies of Parasite Cattle: I. Complement-Fixing Activity of Serial Serum Samples

Complement-fixation (CF) tests with sonicated aqueous extracts of adult forms of five species of gastrointestinal nematodes as antigens have been made on serial biweekly bleedings from two groups of parasitized calves grazing on infected pastures during the 1963 or 1964 seasons. Three of these nematode species, Cooperia oncophora, Ostertagia ostertagi and Nematodirus helvetianus, were found in large numbers in most of these animals. The calves were negative serologically before being placed on pasture but within 2 to 4 weeks some had developed considerable CF activity with Cooperia and other nematode antigens. Ten calves died, however, before significant CF titres had been attained. Eight control calves in the 1963 or 1964 groups which were grazed on “clean” pastures, remained serologically negative during the summer and autumn months. Four of the six surviving exposed animals in the 1964 group showed a fall in CF activity during the winter months when they were stabled, whereas the six surviving controls developed low CF titres suggesting that they were becoming mildly parasitized. In the spring of 1965 CF titres began to rise in some of the previously exposed and control yearlings even before they were placed on infected pasture in June.     

Epizootiologic features of canine hydrocephalus.

In a retrospective study of hydrocephalus (of congenital origin) diagnosed in 564 dogs, 11 breeds (including 8 "toy" breeds) were identified as being a significantly high risk. An inverse relationship between risk and body size was detected. The smaller the dam at maturity, either in height at the shoulder or body weight, the greater the risk of hydrocephalus in the offspring.     

Animal Identification: I. Liquid Nitrogen Branding of Cattle

A number of branding tools of various metals and various sizes in combination with several wetting agents were cooled with liquid nitrogen and applied for different lengths of time to calves and mature cattle. White hair appeared in the shape of the brand on the animals in place of dark hair when the application was properly carried out. Best results can be obtained by using metal irons at least 25 millimeters thick and 14 millimeters wide with xylol as a wetting agent for ten seconds in young or thin skinned animals and up to twenty seconds in mature or thick skinned animals.