扎鲁特旗山地草地土壤含水量动态与气候因子的关系

通过对内蒙古通辽市扎鲁特旗巴雅尔吐胡硕牧业气象站1983-2012年气象数据和山地草地土壤含水量数据分析,揭示土壤含水量的动态变化及其与气候因子之间的相关关系。结果表明,1983-2012年山地草地土壤各层（0-10、10-20、20-30、30-40、40-50和0-50 cm）含水量均呈现逐渐降低的变化趋势,草地逐渐旱化;土壤含水量下降过程可以分为3个阶段, 第1阶段为1983-1987年,该阶段土壤含水量在15%~30%之间波动,属于土壤含水量的较高阶段;第2阶段为1988-1999年,该阶段土壤含水量在5%~15%范围内波动,属于土壤含水量高（15%~30%）向低（2%~10%）过渡阶段;第3阶段是2000-2012年,该阶段土壤含水量在2%~10%范围内波动,属于土壤含水量较低阶段;土壤含水量与温度和日照时数呈负相关,与降水量、相对湿度、蒸散量呈正相关。     

Fecal shedding of Salmonella spp. in dogs

Rectal swabs from 100 dogs that were admitted to the veterinary clinic and from randomly selected 100 dogs from one kennel were examined for the presence of Salmonella spp. S. Enteritidis was isolated from a household dog and the strain was susceptible to all antibiotics that were tested. S. Typhimurium was isolated from a dog from the kennel and it was sensitive to all the antibiotics except streptomycin and neomycin. Even though, the occurence of Salmonella spp. in the feces of the dogs in this study was low, attention should always be given when handling canine feces or contaminated materials.     

Comparative lethal effects on mice of ruminal fluid from cattle fed hay or grain.

Strained ruminal fluid from cattle fed hay or grain was lethal to mice when injected intraperitoneally, but the fluid from grain-fed cattle was approximately 3.7 times more toxic than that from hay-fed cattle. The lethal factor(s) was not resistant to heat, was nondialyzable, was retained on Seitz and membrane filters, and was associated with the bacterial fraction of ruminal fluid. We concluded that death of the mice resulted from infection produced by facultative bacteria normally in ruminal fluid. Ruminal fluid from grain-fed cattle contained a greater number of facultative bacteria than did that from hay-fed cattle.     

Epidemiology of reticuloendotheliosis virus in broiler breeder flocks

Six broiler breeder flocks from two companies in Mississippi were tested at intervals for reticuloendotheliosis (RE) virus infection. Virus was isolated and antibody demonstrated in all six flocks. Infection was first detected at ages ranging from 13 to 47 weeks. Studies showed that neither congenital transmission from grandparent flocks nor treatment with contaminated vaccines was a likely source of infection; thus, exposure to RE virus was assumed to come from the environment. Virus was isolated from litter samples from two of the flocks, but no specific environmental infection source was identified. Infection rates of flocks differed between the two companies. Although adequate controls were lacking, no performance problems due to RE virus infection were apparent in breeder or broiler progeny flocks. However, the RE viruses isolated from these flocks were immunosuppressive and oncogenic when inoculated into day-old chicks. A moderate (3-16%) incidence of neoplasms was induced by contact exposure to these field isolates in the laboratory.     

Intake energy, energy retention and heat production in lambs from birth to 24 weeks of age

Intake energy (IE), metabolizable energy intake (MEI), energy retention (ER) and heat production (HP) were estimated in twelve male and six female suckling lambs from birth to 4 wk of age and in nine of these male lambs after weaning from 9 to 24 wk of age. Intake energy and MEI were estimated from the milk intake and combustible energy of the milk in the suckling lambs and from digestibility trials and energy content of feed and feces in the weaned lambs. Energy retention was estimated from body composition changes and HP was calculated from MEI - ER and from the rate of O2 consumption. The O2 consumption of the ewes was also measured during late pregnancy and during lactation. In the suckling lambs, daily MEI was 277 kcal/kg.75 and ER was 112 kcal/kg.75 and as calculated from O2 consumption was 168 kcal/kg.75. Daily HP as calculated by MEI - ER was 165 kcal/kg.75. Daily maintenance HP was equal to 121 kcal/kg.75 and the efficiency of utilization of energy for ER was 70.7%. In the weaned lambs, HP as measured from O2 consumption was 10% lower than that estimated using MEI and ER. Comparison of 9- to 16-wk-old with 17- to 24-wk-old lambs, showed daily increases in MEI from 212 to 228 kcal/kg.75, in ER from 54 to 95 kcal/kg.75 and in HP from 158 to 194 kcal/kg.75, whereas there was a daily decrease in maintenance HP from 101 to 90 kcal/kg.75. Efficiency of utilization of energy for production was similar in the two postweaning periods (48.8 and 46.5%, respectively). The O2 consumption of the ewes (/kg.75) was increased over that of nonpregnant, nonlactating controls by 30% in late pregnancy, by 62% in the first month of lactation and by 50% in the second month of lactation.     

Salmonella virchow infection in an infant transmitted by household dogs

A 4-month-old male infant manifested diarrhea and Salmonella Virchow was isolated from his stool. The pathogen was repeatedly isolated from the infant over one month despite three regimens of treatment with antibiotics, to which the isolate was sensitive. Three household dogs were kept in his home and S. Virchow was isolated from two of them. The infant was admitted to hospital and was treated with antibiotic, then the pathogen was finally eliminated. Antibiotic sensitivity pattern and PFGE pattern produced by restriction enzyme Xba I of the isolate from the infant was completely similar to those of the isolates from the dogs. The above findings indicated that the present S. Virchow infection in the infant was transmitted by the household dogs.     

The characteristics and regulation of glutamate dehydrogenase in strains of Bacteroides ruminicola ssp. ruminicola isolated from the rumen of fallow deer]

Very little information about NH4+ assimilation paths in rumen anaerobic bacteria is available, and the information about wild animals is completely missing. Glutamate dehydrogenase (GDH) isolated from the rumen strain B. ruminicola in fallow deer was purified and its properties were specified after crystalline ammonium sulphate precipitation and gel filtration on Sephadex G-200. The properties of partly purified GDH were specified. One of the first specifications concerning GDH from various sources was to determine its coenzyme specificity. The results of these determinations enabled to draw a general conclusion that GDH from non-animal sources was specific to only one coenzyme while GDH from animal sources could utilize the two coenzymes (Frieden, 1964). In our study the specificity of GDH isolated from the rumen strain B. ruminicola in fallow deer to the coenzyme NADH (Tab. I) was determined; this specificity was different from the coenzyme specificity of GDH isolated from the rumen strain B. ruminicola in calves where GDH was found to be specific to the coenzyme NADPH. The effect of increasing concentrations of NADH, 2-oxoglutarate and NH4+ on the enzyme reaction velocity was also investigated and Km was determined for NADH, 2-oxoglutarate and NH4+ (Tab. II). The kinetic properties of GDH isolated from different sources are considerably variable. Michaelis constants for GDH range from 0.003 to 0.125 mmol/dm3 for NADPH (NADH), from 0.95 to 7.4 mmol/dm3 for 2-oxoglutarate, and from 0.25 to 16 mmol/dm3 for NH4+ (Misono et al., 1985). The average value of Km for NH4+ in a mixed rumen population was 33 mmol/dm3 (Erfle et al., 1977).(ABSTRACT TRUNCATED AT 250 WORDS)     

苜蓿干草捆贮藏过程中的营养物质含量动态变化研究

为探讨苜蓿干草捆贮藏过程中营养物质含量的动态变化规律,对含水量为15%、打捆密度为150kg/m3的苜蓿草捆在不同贮藏时间(1、10、30、90、180、360d)营养物质含量和相对饲喂价值(RFV)的动态变化情况进行研究。结果表明,在整个贮藏过程中,苜蓿干草的粗蛋白(CP)含量总体呈下降趋势,与贮藏1d时相比,不同贮藏时间段苜蓿干草的CP含量均显著下降(P<0.05);从CP含量角度评价,苜蓿干草等级由1级下降到2级。苜蓿干草的中性洗涤纤维(NDF)含量随贮藏时间的延长而增加,贮藏360d时的NDF含量显著高于贮藏时间在90d之内的NDF含量(P<0.05);从NDF含量角度评价,苜蓿干草等级由2级下降到3级。酸性洗涤纤维(ADF)含量也随贮藏时间的延长而增加,贮藏10d之后ADF含量开始显著增加(P<0.05);从ADF含量角度评价,苜蓿干草等级由1级下降到4级。贮藏时间在30d以上的苜蓿干草DMI值显著低于贮藏时间在30d之内的DMI值(P<0.05);从DMI值角度评价,苜蓿干草等级由1级下降到3级。贮藏时间在90d以上的苜蓿干草DDM值显著低于贮藏时间在90d之内的DDM值(P<0.05);从DDM值角度评价,苜蓿干草等级由1级下降到4级。随着贮藏时间的延长,苜蓿干草的RFV值显著降低(P<0.05),且在贮藏180~360d的时间段内,RFV值下降幅度较大;从RFV值角度评价,苜蓿干草等级由2级下降到3级。综合比较,苜蓿干草在贮藏180d之后营养价值大幅度下降,因此,在贮藏180d之内出售或者饲喂家畜比较适合。     

Isolation of Mycobacterium paratuberculosis after oral inoculation in uninfected cattle.

Feces from cows naturally infected with Mycobacterium paratuberculosis was given to 6 uninfected heifers by orogastric intubation, to determine whether ingested organisms could be passively excreted and detected by bacteriologic culture of feces (ie, false-positive result). Heifers were paired, and each pair received a different dose of feces on days 1 and 2. Fecal samples were collected from the heifers 3 times daily. Mycobacterium paratuberculosis was detected in fecal samples of all heifers within 18 hours of being given the first dose of feces. The number of colony-forming units peaked on days 3 or 4, and organisms were no longer detected by day 7. The number of colony-forming units in fecal samples from the heifers was approximately proportional to the dose given. On days 15 and 16, the experiment was repeated with feces from a second infected cow. Results were similar to those in the first experiment. All heifers remained seronegative (agar-gel immunodiffusion test and ELISA) and had negative results to the intradermal johnin test throughout the experiment. Lymph node and intestinal tissues were obtained from all 6 heifers at slaughter on day 28. Mycobacterium paratuberculosis was not isolated from mesenteric lymph nodes from the ileocecal valve region, but was isolated from ileal mucosal samples from each heifer.     

Autogenous Cancellous Bone Grafts From the Sternum in Horses Comparison With Other Donor Sites and Results of Use in Orthopedic Surgery

Cancellous bone was collected from the fourth or fifth sternebra of six horses aged 12 to 36 months, and compared quantitatively and qualitatively with cancellous bone collected from the tuber coxa, proximal tibia, and rib at the time of necropsy, 28 to 49 days after surgery. Cancellous bone collected from the sternum was equivalent in amount and in microscopic appearance to that collected from the other three sites.
Cancellous bone also was collected from the sternum for use during clinical orthopedic surgery in 18 horses. Wound dehiscence occurring in two horses healed uneventfully by second intention. In each horse, an adequate amount of cancellous bone was obtained from one sternebra, with the exception of one horse where cancellous bone from two sternebra was used. Major complications with the donor sites were not encountered.     

Association between route of inoculation with infectious bovine rhinotracheitis virus and site of recrudescence after dexamethasone treatment

Four calves latently infected with infectious bovine rhinotracheitis virus (IBRV) were used to compare the ease of isolation of virus from neuronal ganglia and from mucosal surfaces. Two calves were slaughtered, and neuronal ganglia (cranial cervical, trigeminal, and 3rd and 4th sacral) were cocultivated on bovine fetal kidney cells. Virus was not isolated. Two calves given dexamethasone for 4 days were slaughtered on the 5th day. Virus was not isolated from cocultivated or macerated neuronal ganglia, but virus was isolated from nasal secretions taken from both calves on the day of slaughter. Eleven calves were inoculated with IBRV via different routes and were treated with dexamethasone 3 to 4 months after inoculation. virus was isolated from the nasal cavities, but not the vaginas of 6 heifers inoculated intranasally, and was isolated from the vaginas, but not the nasal cavities of 2 heifers inoculated intravaginally. Of 3 calves inoculated IV, virus was isolated from the nasal cavities of 3, from the oropharynxes of 2, and from the prepuce of 1.     

Verocytotoxin-producing Escherichia coli O157 on a farm open to the public: outbreak investigation and longitudinal bacteriological study

Verocytotoxin-producing Escherichia coli (VTEC) O157 phage type 2 (PT2) was isolated from three calves and two goats on a farm open to the public. Phenotypic and DNA-based typing showed that the strains were identical or very closely related to those obtained from an outbreak of VTEC O157 infection in two separate family groups who visited the farm. No VTEC O157 PT2 was isolated again from the farm during a 12-month longitudinal bacteriological study undertaken after the infected animals had been removed. However, phenotypically and genotypically indistinguishable VTEC O157 PT2/28 strains were detected in two of 474 faecal samples collected at monthly visits from 15 species of animals of various ages. The two isolates were obtained from calves from different sources sampled 146 days apart, suggesting that the infection had persisted on the farm although it was not detected in the other species. The same strain was subsequently isolated from another calf housed in the same pen as one of the infected calves. The longest period during which the organism was excreted was seven days. No VTEC O157 was isolated either from 204 replacement animals (including 138 orphan lambs and 10 calves) brought in from various sources, and sampled while they were kept in isolation for two weeks before being introduced to the farm, or from environmental samples. During the study a visitor became ill with VTEC O157 PT2. However, the isolate was distinct from those recovered from the farm and there was no evidence to suggest that the visit was the source of the infection.     

绿洲灌溉区与旱作区多龄苜蓿地土壤有机碳、氮及物理特性分析

以甘肃灌区和旱作区苜蓿(Medicago sativa)地土壤为研究对象,对不同地域的苜蓿地土壤全氮(TSN)、有机碳(SOC)、容重、含水量进行测定,结果表明:灌区SOC含量均高于旱作区,在90~100cm土层其含量与旱作区差值最大,达3.41g/kg。在0~100cm灌区SOC含量为6.81~12.49g/kg,均值为9.25g/kg,比旱作区高22%。旱作区TSN含量随土壤深度的增加而减小,含量在(1.03±0.01)~(0.44±0.04)g/kg。在0~30cm灌区TSN含量相对较稳定,差异不显著(P0.05),在30~60cm剖面全氮含量急剧下降,70~100cm含量变化较为稳定,TSN含量维持在(0.66±0.01)g/kg。旱作苜蓿地土壤含水量在0~60cm变化不显著(P0.05),0~100cm土壤含水量均值为(14.437±1.124)%,灌区苜蓿地土壤含水量均值为(16.025±2.029)%。随着土壤深度的增加,旱作区和灌区苜蓿地土壤容重均呈现依次增大的分布规律,旱作区最大值为(1.421±0.034)g/cm,比最小值高出17.5%,灌区最大值(1.332±0.017)g/cm,比最小值高出11.3%.     

Seminal shedding of bluetongue virus in experimentally infected mature bulls

Sixteen bulls ranging in age from 2 to 11 years were experimentally inoculated with bluetongue virus to investigate the frequency and duration of seminal shedding of the virus. All bulls developed typical viremia, lasting 21 to 58 days, and they seroconverted 2 to 3 weeks after inoculation. Virus isolation was attempted from a total of 232 ejaculates, 163 (70%) of which were collected during the period of viremia. Bluetongue virus was not isolated from any of the ejaculates collected from 11 of the 16 bulls. Virus was isolated from 9 of 52 ejaculates collected from the other 5 bulls during the period of viremia. In no instance was virus isolated from semen without concurrent isolation from blood.     

干旱半干旱区退耕还林还草工程效益综合评价——以榆中县为例

综合评价退耕还林还草生态工程的效益,是该工程持续推进的重要内容。国内退耕还林还草工程综合效益的评价均以大尺度为主,而基于县域尺度的评价较少。本研究以干旱半干旱地区的榆中县为例,通过构建小尺度退耕还林还草工程综合效益评价指标体系,定量评估了该县韦营乡退耕还林还草的生态、经济、社会效益。结果表明,韦营乡退耕还林还草工程的综合效益分值为70.85,较好;生态效益分值为74.8,较好;经济效益分值为55.5,一般;社会效益分值为78.2,较好。     

Embryo transfer from cattle infected with bluetongue virus

Embryos recovered nonsurgically from donor cattle during the peak of bluetongue viremia were surgically transferred to seronegative recipients 7 to 8 or 10 to 11 days after the onset of donor estrus. Virus was isolated from the uterine flushing medium recovered from 11 of the 20 donors. Bluetongue virus was not isolated from the blood of any of 39 recipients, nor did any recipient seroconvert to the virus following transfer. The number of recipients that became pregnant after transfer of embryos from infected donors (21 of 39) was not significantly different from contemporary controls. Virus antigen was not detected by immunofluorescence in any of 63 embryos and oocytes recovered from viremic donors. These results indicate that under standard embryo transfer conditions, transmission of bluetongue virus from infected donors to uninfected recipients is unlikely to occur.     

Molecular characterization of Mycoplasma gallisepticum isolates from Jordan

Two groups of Mycoplasma gallisepticum (MG) isolates (n = 24) from Jordan were analyzed by molecular methods and compared with other Middle Eastern isolates, related international isolates, and reference strains. The first group (n = 19) was isolated from July 2004 to January 2005 (isolation period A), and the newer group (n = 5) from June 2007 to April 2008 (isolation period B). The groups of isolates are from chicken flocks from northern Jordan, but are not from the same farms. None of the flocks were vaccinated for MG. Random amplified polymorphic DNA analysis, targeted sequencing of the partial MG cytadhesin 2 (mgc2), and the MG 16S-23S rRNA intergenic spacer region (IGSR) divided the Jordanian isolates into two groups. All of the 19 isolates from time period A, in addition to two isolates from time period B, were indistinguishable from the F strain. Three of five isolates from time period B were characterized as wild types and were indistinguishable from each other. The wild-type field strain was readily distinguished from the F strain. It was 91% and 96.4% similar to the F strain based on Clustal-W alignments of sequences of mgc2 and IGSR, respectively. Sequence similarity of mgc2 gene of the Jordan wild-type strain to isolates from Israel and Egypt ranged from 96.5% to 100%, whereas for IGSR it was 99.4%-100%. We theorize that the F-strain live MG vaccine, commonly used in Jordan prior to 2007, was transmitted to nonvaccinated poultry in the region and was a predominant genotype during time period A.     

Dynamics of viral spread in bluetongue virus infected calves

The kinetics of viremia and sites of viral replication in bluetongue virus (BTV) infected calves were characterized by virus isolation, serology and immunofluorescence staining procedures. In addition, the role of the regional lymph node and lymphatics draining inoculated skin in the pathogenesis of BTV infection was determined by analyzing efferent lymph collected from indwelling cannulas. Viremia persisted for 35 to 42 days after inoculation (DAI) and virus co-circulated with neutralizing antibodies for 23 to 26 days. Virus was first isolated from peripheral blood mononuclear (PBM) cells at 3 DAI, after stimulation of PBM cells with interleukin 2 and mitogen. BTV was frequently isolated from erythrocytes, platelets and stimulated PBM cells but never from granulocytes and rarely from plasma during viremia. Virus was consistently isolated from erythrocytes late in the course of veremia. Interruption of efferent lymph flow by cannulation delayed the onset of viremia to 7 DAI. BTV was infrequently isolated from lymph cells, and few fluorescence positive cells were observed after lymph and PBM cells were labelled with a BTV-specific monoclonal antibody. Virus was isolated from spleen by 4 DAI and most tissues by 6 DAI, whereas virus was isolated from bone marrow only at 10 DAI. Virus was not isolated from any tissue after termination of viremia. It is concluded that primary viral replication occurred in the local lymph node and BTV then was transported in low titer to secondary sites of replication via infected lymph and PBM cells. We speculate that virus replication in spleen resulted in release of virus into the circulation and non-selective infection of blood cells which disseminated BTV to other tissues. Virus association with erythrocytes likely was responsible for prolonged viremia, although infected erythrocytes eventually were cleared from the circulation and persistent BTV infection of calves did not occur.     

Molecular and phenotypical characterization of Clostridium perfringens isolates from poultry flocks with different disease status

Due to the diminished use of growth-promoting antibiotics in the European Union, Clostridium perfringens induced necrotic enteritis and subclinical disease have become important threats to poultry health. A study was set up to genotypically and phenotypically characterise C. perfringens isolates from poultry flocks with different health status. Animals from healthy flocks were sampled by cloacal swabs, while intestinal and liver samples of animals suffering from necrotic enteritis were analysed. A total of 27 isolates was obtained from 23 broiler flocks without clinical problems and 36 isolates were obtained from 8 flocks with clinical problems. Using PFGE typing, high genetic diversity was detected between isolates from different flocks. Isolates derived from flocks where disease outbreaks occurred were clonal within each flock, but each flock harboured a different clone. All isolates were of toxin type A. Isolates from 5 out of 35 PFGE types carried the cpb2 gene, encoding the beta2 toxin, and isolates from 2 out of 35 PFGE types harboured the cpe gene, encoding the enterotoxin. In vitro alpha toxin production for all isolates was quantified by enzyme-linked immunosorbent assay. It was shown that in vitro alpha toxin production of C. perfringens isolates from diseased flocks was not higher than in vitro alpha toxin production from isolates derived from healthy flocks.     

中国9个家驴品种mtDNA D-loop部分序列分析与系统进化研究

本研究利用Dnasp4.10软件对中国9个家驴品种162个个体的mtDNA D-loop区385bp进行遗传多样性分析,共检测到32种单倍型35个核苷酸多态位点,其单倍型多样度为0.8137～0.9722,核苷酸多样度为0.0182～0.0270,表明我国家驴的遗传多态性丰富;利用MEGA3.1软件采用邻接法与3个努比亚野驴、3个索马里野驴和6个亚洲野驴的序列构建NJ系统发育树,并进行系统进化分析。结果表明:我国家驴的母系起源是非洲野驴中的努比亚野驴和索马里野驴,亚洲野驴不是中国家驴的母系祖先。