天祝县草产业发展的制约因素及其对策

通过分析天祝县草产业发展现状，指出天祝县草产业发展存在的问题，提出要大力发展天祝县草产业必须加强天然草原综合改良，科学合理利用草原资源，建立人工草地和牧草种子繁育基地，开发草产品；建立多元化的投入机制，培植草产业开发的龙头企业；进一步完善草地管理制度，全面彻底地落实草原有偿承包责任制；建立信息网络体系，把信息网络纳入畜牧业基础设施建设范围内，建立健全草畜产品信息网络。     

大肠埃希菌多重耐药调节子研究进展

大肠埃希菌多重抗生素耐药主要是由多重耐药调节基因和外输泵共同作用产生的。大肠埃希菌多重耐药调节子是广泛存在于肠杆菌科细菌染色体上的抗生素多重耐药调节中心,是大肠埃希菌耐药的主要组成部分。为解决多重抗生素耐药问题,很多专家和学者对大肠埃希菌多重耐药调节子和外输泵的耐药机制进行了深入的研究,研究开发多重抗生素耐药基因消除剂和外输泵抑制剂,或增加外输泵抑制基因的表达,将成为从根本上解决多重抗生素耐药问题的最好方法。文章对大肠埃希菌AcrAB、AcrAB-Tolc,Mar和膜孔蛋白Ompf、Ompc等多重抗生素耐药调节子的组成、功能及其影响因素进行了综述。     

反刍动物采食量的概念与研究方法

本研究对反刍家畜采食量的研究发展与现状进行了回顾与总结,采食量及其相关术语的定义主要基于饲草料或家畜,其测定方法和精确含义有差异;反刍家畜采食是由生物和非生物因素相互作用共同影响的复杂动态过程,采食量影响因子主要分为家畜的(胃肠蠕动力、选择性采食等)、饲草料的(粗纤维含量、抗营养成分等)和饲养条件的(草层结构、草地饮水点分布等)因素3个方面;采食量的测定方法有基于牧草测定的直接法和基于家畜测定的间接法,后者较多地应用于放牧家畜;预测方法有基于数学函数和生物学原理的模型法,基于消化试验的经验法和结合家畜属性的改进经验法。舍饲条件下可准确地测定和预测家畜的采食量,但对放牧家畜还没有精确的方法。通过测定与饲草水平密切相关的家畜尿液、血液或粪便中的代谢物水平将成为预测放牧家畜采食量的准确方法。     

Herd and sow-related risk factors for mortality in sows in group-housed systems

Mortality of sows is a major problem for pig production worldwide. In this study, we used hierarchical multivariable logistic analyses to investigate different risk factors for mortality at the sow and herd level in herds with group-housed pregnant sows. Data included 3652 pregnant and 1266 lactating sows from 34 sow herds. A clinical examination for 16 clinical signs was carried out for each sow, and information about 16 herd related factors was obtained by interviews. Farm records were used to obtain information about whether or not sows died suddenly or were euthanized within 3 months after the clinical examination. Factors increasing the risk of sow mortality in the gestation unit were solid pen floors (OR = 1.87), presence of vulva bites (OR = 1.73) and unwillingness to stand when approached (OR = 1.62). Factors increasing the risk of sow mortality in the lactation unit were pale vulva color (OR = 12.69), body leanness (OR = 4.11), and presence of shoulder ulcers (OR = 2.89). The estimated between herd variation was small. Thus, the findings for the sow level variables may be generally applicable for sows in herds with group housed systems.     

不同生长年限对青海草地早熟禾生长特性和种子产量及其构成因子的影响

探讨了不同生长年限对青海草地早熟禾人工草地生长特性和种子产量及构成因子的影响,为青海草地早熟禾种子生产提供理论依据。结果发现,随着人工草地生长年限的延长,生殖枝高度、营养枝高度以及花序长度总体上都呈降低的趋势。不同的生长年限对青海草地早熟禾种子产量及其构成因子的影响表现在：2龄人工草地的种子产量最高,达到496.96k...     

引起笼养蛋鸡疲劳症的主要因素研究

本试验以营养因子、产蛋率、钙源、笼养生态等角度对笼养蛋鸡疲劳症进行综合研究,寻找引起笼养蛋鸡疲劳症的主要因素及减少笼养蛋鸡疲劳症的途径。     

布鲁菌外膜蛋白及毒力因子研究进展

布鲁菌细胞膜的基本结构包括脂多糖和外膜蛋白,与细菌的毒力及免疫原性相关。文章描述了布鲁菌外膜蛋白分子结构的最新进展。该菌的外膜蛋白由第一组、第二组和第三组外膜蛋白构成。第一组外膜蛋白对维持布鲁菌外膜蛋白的结构起重要作用;第二组包括36 ku~38 ku外膜蛋白,为膜孔蛋白,由Omp2a和Omp2b基因编码,其中38 ku蛋白基因可能是一个与毒力相关的基因;第三组外膜蛋白包括31 ku和25 ku两个相关的蛋白,具有重要的免疫功能。31 ku蛋白属膜孔蛋白,25 ku蛋白还与毒力有关。文章也介绍了布鲁菌毒力因子研究的最新进展。     

仔猪肠道损伤修复营养调控及其机制和应用

仔猪早期断奶是现代养猪业中的一项重要技术措施,但断奶应激又导致仔猪出现早期断奶综合征,尤其是肠道损伤.肠道正常的功能依赖肠道黏膜上皮屏障、免疫屏障、生物屏障的完整性来维持.断奶应激会导致仔猪肠道黏膜形态结构改变、肠上皮屏障通透性增加、消化吸收功能降低、黏液层厚度下降、肠道pH升高、免疫抑制、肠道微生物菌群失衡等,甚至造成肠道功能的继发性损伤和功能紊乱.因此,肠道损伤修复及其营养调控研究日益受到关注.直接或间接调控因子主要包括:1)多肽类生长因子.主要包括表皮生长因子(EGF)、胰高血糖素样肽-2 (GLP-2)、胰岛素样生长因子-Ⅰ(IGF-Ⅰ)和转化生长因子(TGF)等.本文介绍了本团队制备的猪胰高血糖素样肽-2(pGLP-2)长效化产物对降低仔猪肠道炎性反应,提高黏膜屏障功能的作用.2)微生态调控剂.包括益生菌制剂和抗菌肽.猪饲粮中常用益生菌有屎肠球菌、芽孢杆菌、植物乳杆菌、乳球菌、酵母菌等.已报道用于仔猪饲粮的抗菌肽主要有天蚕素、防御素、抗菌肽buforinⅡ、抗菌肽P5及复合肽等.3)营养代谢调控剂.报道较多的氨基酸及其衍生物有谷氨酰胺及其替代品α-酮戊二酸、L-精氨酸、N-乙酰半胱氨酸等.研究较多的其他调控剂还有短链脂肪酸、壳聚糖、植物多糖、锌和硒等.本文对上述各类损伤修复调控因子研究进展进行了综述.     

Veterinarian injuries associated with bovine TB testing livestock in Michigan, 2001

Testing all the cattle in an entire state with a uniform procedure for each animal affords an opportunity to relate human injury data to a known number of animals handled while carrying out a standardized procedure. Our objective was to describe the type and incidence density of injuries associated with TB-testing a large number of cattle herds, and to delineate the various factors associated with the risk of injury. A survey was mailed to all veterinarians (N = 259) who had completed at least five official bovine TB (bTB) herd tests in Michigan in 2001. We collected data regarding basic demographics and health status, work experience, veterinary specialty, and practice information. Each veterinarian was also requested to complete a separate injury questionnaire for each injury received while TB testing livestock in 2001. Accurate addresses were found for 247 eligible veterinarians, 175 (71%) of whom returned the survey. Thirty-six veterinarians reported a total of 53 injuries (10 major, 12 minor and 31 self-treated). Hands (29%) and legs (21%) were the anatomic locations most frequently injured, with sprains/strains (30%) and abrasion/contusion (30%) the most common types of injuries sustained. The overall incidence density of injuries was 1.9 per 10,000 animals tested. Female gender (RR = 3.3), being employed by the government (RR = 4.5), and smoking (RR = 6.0) were significantly associated with a higher rate of injury. Significant colliniearities were found between some risk factors associated with an increased rate of injury and participants thought 81% of their injuries could have been prevented. These results are explained by the administrative structure of the bTB testing program in Michigan, and the changing demographics of the veterinary workforce.