正确使用疫苗要注意的问题

(一)免疫对象与使用的疫苗应相符如鸡新城疫(ND)Ⅰ系苗一般用于2月龄以上鸡或经ND弱毒苗初免后的鸡。不看免疫对象，随意使用疫苗，不仅造成疫苗的浪费，有时还可能产生一些意想不到的不良后果。     

鸡新城疫油乳剂灭活苗与弱毒苗免疫效果比较

控制非典型鸡新城疫，用油乳剂灭活苗免疫是切实可行的手段。油乳剂灭活苗免疫后，抗原在体内长时间缓慢释放，可产生坚强而持久的免疫力，即在血清学上可产生高水平且比较均匀的抗体，在临床上，免疫鸡新城疫强毒感染后不患病，产蛋也不下降。较之弱毒疫苗免疫可大大减少免疫次数，减少因非典型鸡新城疫造成的死亡，提高生产性能。为了验证鸡新城疫油乳剂灭活苗的兔疫效果．我们自1993年8月份至1994年12月份，分别在十二个大型养鸡场进行了鸡新城疫弱毒苗免疫和油乳剂死活苗免疫效果对比试验。鸡新城四弱毒苗免疫程序是：1蛋鸡7－14日龄鸡…     

给鸡接种油乳剂苗的技术要求

油乳剂疫苗是灭活苗，是预防鸡疫病的主要疫苗，多用于加强免疫和最终免疫，其除了注射接种的应激反应外，毒副作用很小。目前应用于鸡的油乳剂苗主要有新城疫油苗、禽流感油苗、减蛋综合症油苗、大肠杆菌油苗、支原体油苗、传染性鼻炎油苗、传染性支气管炎油苗等，以及这些苗的多联多价油苗。给鸡接种油乳剂苗的技术规范与否，直接影响免疫效果。这里介绍给鸡接种油乳剂苗的技术要求。     

支原体活苗F株在肉鸡生产中应用的效果观察

鸡支原体疫苗有2种：活苗和灭活苗。活苗的菌株包括TS／11、68／5、F株等，灭活苗的常用菌株为R株。一般认为R株活苗可以诱发机体的体液免疫、细胞介导免疫和局部黏膜免疫。F株免疫接种产蛋鸡群能提高产蛋率，后备鸡免疫能导致接种前感染的野毒株经卵传播率下降。接种肉鸡能明显降低呼吸道病发病率，减少淘汰率，免疫鸡用R株攻毒时能保护气囊不受损伤。为了观察支原体活苗F株在肉鸡生产中的应用效果，探索通过疫苗免疫来减少肉鸡发生慢性呼吸道病而引起的经济损失。     

鸡混合联苗免疫效果的研究

鸡混合联苗免疫效果的研究康吉克孜钟旗玛依拉蔡宏（新疆畜牧科学院兽医研究所，乌鲁木齐８３００００）林承业赵雪梅李在兰（新疆华新牧工商公司）由于禽传染病种类的增加，用于免疫接种的疫苗种类也日益增多，而且有的疫苗还要做多次免疫，这必然增加免疫环节，给免疫接...     

鸡新城疫-传染性支气管炎二联油乳剂苗的研制

以NDV La Sota株，IBV呼吸道型H120株和肾型SN9301株为制苗毒株，病毒经鸡胚繁殖后甲醛灭活，灭活毒液依毒价按比例混合加入油佐剂中，乳化制成ND—IB二联油乳剂疫苗。对该疫苗的安全性、稳定性和免疫效果等进行了测定。结果表明：疫苗安全稳定，物理性状良好；将该苗与相应弱毒苗配合用于雏鸡首免，可获得稳定的免疫保护；单用该苗给雏鸡首免，或用相应弱毒苗免疫雏鸡，免疫效果均较差。     

鸡减蛋综合征与传染性支气管炎二联油佐剂灭活苗的研究--二联苗的保存期试验

鸡减蛋综合征(EELS-76)是引起产蛋母鸡产蛋量下降的一种病毒性传染病，广泛流行于国内外，给养鸡业造成巨大经济损失。鸡传染性支气管炎(IB)是一种病毒性传染病，各种品种、日龄的鸡均易感，但主要侵害1～4周龄鸡，以上呼吸道出现炎症为特征；该病还可能侵害肾脏及造成产蛋鸡产蛋量下降。IB在国内外普遍存在，给养鸡业带来严重危害。从发病地区分离病毒后制成灭活苗对鸡群进行免疫是EDS-76和IB的主要防制方法，因此，笔者应用从宁夏分离的EDS-76病毒和肾型IBV研制了EDS-76与IB二联灭活苗。为了进一步检验疫苗的免疫效果并为今后疫苗的大批量生产及推广应用做准备，进行了二联苗的保存期试验。     

鸡马立克氏病Z4＋HVT二价苗的免疫效力试验

用鸡马立克氏病(MD)血清Ⅱ型和Ⅲ型病毒制备了几种二价苗和单价苗。在实验室以高度易感的SPF鸡和商品鸡进行疫苗的免疫效力试验。结果表明,马立克氏病病毒(MDV)血清Ⅱ型毒株和Ⅲ型毒株之间存在协同保护作用。由血清Ⅱ型和Ⅲ型病毒组成的二价苗免疫效果明显优于单价苗。在以SPF鸡进行的免疫效力试验中,Z_4+HVT、SB_1+HVT、HVT、Z_4和SB_1的保护指数分别为78.9、78.6、41.7、46.7、和45.0;在以商品鸡进行的免疫效力试验中,Z_4+HVT、SB_1+HVT、HVT、Z_4和SB_1的保护指数分别为93.9、88.1、64.3、69.4和60.8。我们还用琼扩试验检查了强毒攻击后不同时期鸡羽囊排毒情况,发现Z_4+HVT二价苗抑制排毒的作用要比SB_1+HVT二价苗强。     

鸡新城疫Ⅰ系苗饮水免疫试验

本疫苗系中等毒力毒株制成,其免疫程序多是在经过鸡新城疫弱毒力疫苗(如Ⅱ系、B_1株、F株、La Sota株疫苗)免疫过的基础上进行Ⅰ系苗的免疫,且都是逐只捕捉进行肌肉注射,对饲养规模较大的养鸡场费人费时。使鸡惊扰和挣扎,使其生产能力有所下降。为克服这些弊端,吉林生物制品厂田春雨、姜崇子进行了鸡Ⅰ系苗饮水免疫试验,又据部颁《兽医生物制品制造和检验》规程有关条文,并结合我们点滴经验介绍于下。     

几种预防畜禽寄生虫病的"虫苗"

用于预防畜禽传染病和寄生虫病的免疫制剂 ,简称为“苗” ,目前共有三大类 ,即疫苗、菌苗和虫苗。疫苗有广义、狭义两种概念 ,广义泛指疾病免疫制剂和非疾病免疫制剂 ,狭义指用病毒免疫物质制成的免疫制剂 ;菌苗是指用细菌免疫物质制成的免疫制剂 ;虫苗是指用寄生虫免疫物质制成的免疫制剂。虫苗的研制是近十几年的事 ,由于起步较晚 ,目前国内外的定型产品尚寥寥无几。但由于是养殖业急需的防病制剂 ,故有强大的市场竞争力。目前国内已研制出的虫苗有以下几种 :(1)鸡柔嫩艾美耳球虫弱毒虫苗　是预防鸡柔嫩艾美耳球虫病的虫苗 ,系上海农科院…     

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.     

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.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein