Impact of field fungal contamination of barley on ensiling properties,nutritional quality and the microbiome of barley silage     

Jayakrishnan Nair  T. Kelly Turkington  Robert Blackshaw  Charles M. Geddes  Newton Z. Lupwayi  Shanwei Xu  Jinli Yang  Hee‐Eun Yang  Yuxi Wang  Tim A. McAllister 《Grass and Forage Science》2019,74(2):231-243

Barley varieties of differing fungal disease resistance were grown in triplicate plots at Lacombe and Lethbridge, Alberta with the disease resistant variety (FR) sprayed with a foliar fungicide to maximize differences in field fungal disease. Both varieties were harvested at soft dough and ensiled in minisilos to assess differences in fungal contamination on ensiling properties, nutritional quality, aerobic stability and associated bacterial and fungal microbiomes. Data were analysed as repeated measures with the effect of treatment × time (duration of ensiling or aerobic exposure) included in the model. The percentage leaf area diseased by net form net blotch was higher (p < 0.05) in the untreated barley cv. Sundre (UN, 59.1% leaf area affected at Lacombe and 25.2% at Lethbridge) than in the FR barley cv. Chigwell (0.7% leaf area affected at Lacombe and 0.1% at Lethbridge). Fungal resistant barley had a lower (p < 0.01) acid and neutral detergent fibre content. Relative abundance of Xanthomonadales was higher (p = 0.02) for FR than UN, while Lactobacillales dominated the bacterial microbiome after 60 day of ensiling in both silages. Bacillales dominated both FR and UN after 21 day of aerobic exposure. Fungal resistant fresh barley forage had a tendency (p = 0.10) for a greater relative abundance of Pleosporales, while UN had higher (p < 0.01) Hypocreales. Mould counts were lower (p = 0.01) for FR than UN after 7 day of ensiling. Fungal resistant barley had minimal influence on the fungal community that contributed to the aerobic deterioration of barley silage.  相似文献   

Patterns in species richness and assemblage structure of native mussels in the Upper Mississippi River     

Steven J. Zigler  Teresa J. Newton  Mike Davis  James T. Rogala 《水产资源保护:海洋与淡水生态系统》2012,22(5):577-587

Survival,distribution and genetic variability of inoculum of the strawberry red core pathogen,Phytophthora fragariae var. fragariae,in soil     

A. C. Newton  J. M. Duncan  N. H. Augustin  D. C. Guy  D. E. L. Cooke 《Plant pathology》2010,59(3):472-479

An experimental field infested with Phytophthora fragariae var. fragariae (Pff) and used for strawberry red core fungicide and cultivar resistance trials until 1981 was surveyed for the presence of inoculum of the pathogen 11 and 12 years later. Alpine strawberries, highly susceptible to all races of Pff, were grown from true seed and planted as a bait crop on a 0·5 m‐spaced grid. Rapid and widespread red core infection was observed, which provided good evidence that oospores had survived in soil for this extended period. Site elevation and the distribution of red core infected plants showed a strong correlation, with a higher frequency of infected and dead plants in the lowest areas of the field. The race designation of 18 recovered isolates were determined and AFLP fingerprint patterns of some of these and their single‐spore derivatives were analysed. The isolates differed little in race type, and the majority were genetically identical at 433 AFLP loci. Races used to inoculate the site in the 1970s were recovered. The fingerprints of the single variant isolate matched that of an isolation made by Hickman in the 1950s, originally used to inoculate the site. Clearly Pff is a very stable and long‐lived pathogen able to retain its genetic integrity and lie dormant in soil for many years, ensuring its survival between epidemiologically favourable conditions which occur erratically.  相似文献   

肉鸡肿头综合征的病理形态学变化   总被引：3，自引：0，他引：3  

吴东来  刘文周 《中国预防兽医学报》1999,21(4):301-302

对黑龙江省某鸡场发生肿头综合征（ Ｓ Ｈ Ｓ） 的４ 例肉鸡进行了病理学观察。肉眼所见为病鸡的眼周围、肉髯、肉冠的肿胀,包括肉髯、肉冠在内的头部皮下的蜂织炎,头盖骨气室内的干酪样物贮留。病理组织学所见主要为头部皮下组织、头盖骨气室及鼻粘膜下的纤维素性、化脓性肉芽肿性炎,并见有间质性心肌炎及支气管粘膜上皮组织纤毛脱落等变化。从上述病例的头部病灶中分离到了大肠杆菌。  相似文献   

Effectiveness of small workshops for improving farmers knowledge about ovine footrot     

GK THOMPSON  JWA LARSEN  AL VIZARD 《Australian veterinary journal》1999,77(5):318-321

OBJECTIVE: To determine sheep farmers' attitudes to and beliefs about ovine footrot, and to improve their knowledge about the diagnosis, control and eradication of this disease. METHOD: Eighteen workshops, involving 291 farmers, were conducted across Victoria in the spring of 1996. The workshops were designed as small-group discussions with a maximum attendance of 20 farmers to encourage active participation. All participants completed questionnaires before each workshop and 12 to 40 weeks after the last workshop. RESULTS: Before the workshops the farmers had a poor understanding of the principles of diagnosis, control and eradication of footrot. For example, only 50% knew the footrot organism survived in soil for less than 7 days, over two-thirds did not know the reason for paring sheep's feet during an eradication program, and only 31% realised cattle were a potential source of footrot infection for sheep. After the workshops, understanding about footrot was significantly improved; 87% said Dichelobacter nodosus survived in soil less than 7 days, 71% knew the reason for paring sheep's feet and 64% realised that cattle were a potential source of footrot infection. As well as improved knowledge, change of attitude among farmers is fundamentally important if virulent footrot is to be successfully controlled and eradicated. The workshops successfully initiated this process; 40% of farmers thought the workshops changed their attitudes to footrot, while 37% said they gained an increased understanding of other people's opinions about the disease. CONCLUSION: Farmers' poor understanding of ovine footrot is a constraint to the programs aimed at controlling this disease. Small group workshops may be an effective way to influence farmers' attitudes and beliefs, and could facilitate the effectiveness of regulatory disease control programs.  相似文献   

Epidemic of blindness in kangaroos - evidence of a viral aetiology     

PT HOOPER  RA LUNT  AR GOULD  AD HYATT  GM RUSSELL  JA KATTENBELT  SD BLACKSELL  LA REDDACLIFF  PD KIRKLAND  RJ DAVIS  PJK DURHAM  AL BISHOP  J WADDINGTON 《Australian veterinary journal》1999,77(8):529-536

OBJECTIVE: To determine the cause of an epidemic of blindness in kangaroos. DESIGN AND PROCEDURES: Laboratory examinations were made of eyes and brains of a large number of kangaroos using serological, virological, histopathological, electron microscopical, immunohistochemical methods, and PCR with cDNA sequencing. In addition, potential insect viral vectors identified during the disease outbreak were examined for specific viral genomic sequences. SAMPLE POPULATION: For histopathological analysis, 55 apparently blind and 18 apparently normal wild kangaroos and wallabies were obtained from New South Wales, Victoria, South Australia, and Western Australia. A total of 437 wild kangaroos and wallabies (including 23 animals with apparent blindness) were examined serologically. RESULTS: Orbiviruses of the Wallal and Warrego serogroups were isolated from kangaroos affected with blindness in a major epidemic in south-eastern Australia in 1994 and 1995 and extending to Western Australia in 1995/96. Histopathological examinations showed severe degeneration and inflammation in the eyes, and mild inflammation in the brains. In affected retinas, Wallal virus antigen was detected by immunohistochemical analysis and orbiviruses were seen in electron microscopy. There was serological variation in the newly isolated Wallal virus from archival Wallal virus that had been isolated in northern Australia. There were also variations of up to 20% in genotype sequence from the reference archival virus. Polymerase chain reactions showed that Wallal virus was present during the epidemic in three species of midges, Culicoides austropalpalis, C dycei and C marksi. Wallal virus nucleic acid was also detected by PCR in a paraffin-embedded retina taken from a blind kangaroo in 1975. CONCLUSION: Wallal virus and perhaps also Warrego virus are the cause of the outbreak of blindness in kangaroos. Other viruses may also be involved, but the evidence in this paper indicates a variant of Wallal virus, an orbivirus transmitted by midges, has the strongest aetiological association, and immunohistochemical analysis implicates it as the most damaging factor in the affected eyes.  相似文献   

COMPUTED TOMOGRAPHIC CHARACTERISTICS OF MULTILOBULAR TUMOR OF BONE INVOLVING THE CRANIUM IN 7 DOGS AND ZYGOMATIC ARCH IN 2 DOGS     

John T.  Hathcock  DVM  MS  Joseph C.  Newton  DVM  PhD 《Veterinary radiology & ultrasound》2000,41(3):214-217

Computed tomography (CT) images of nine dogs with a multilobular tumor of bone of the head were reviewed. The CT characteristics of the neoplasms involving the calvarium (n = 7) were rounded, well defined with a fine granular, nonhomogeneous bone opacity usually in the occipital region. Cranial vault invasion (5 of 7) was commonly found with a significant portion of the mass within the vault. The neoplasms involving the zygomatic arch (n = 2) were also generally rounded and well defined but with a more coarse granular appearance. The common CT findings were best seen when the images were viewed in a bone window.  相似文献   

The effect of foraging and ontogeny on the prevalence and intensity of the invasive parasite Anguillicola crassus in the European eel Anguilla anguilla          下载免费PDF全文

J Barry  M Newton  J A Dodd  D Evans  J Newton  C E Adams 《Journal of fish diseases》2017,40(9):1213-1222

Infection patterns of the invasive Anguillicola crassus nematode were investigated in a population of the European eel Anguilla anguilla where parasite invasion is very recent, Loch Lomond, Scotland. Intensity levels of the parasite were associated with differences in fish ontogeny and trophic ecology. Although eels foraged on both fish and invertebrates, individuals which were smaller and fed on invertebrates (>70% contribution to diet) were found to contain a greater number of swim bladder parasites compared to larger eel with a predominance of fish (>60% contribution) in their diet. Within affected fish, a significant negative relationship was found between fish length and parasite intensity, with smaller individuals having higher parasite intensity than larger individuals. This study indicates that food intake and infection risk are linked in this recently infected host–parasite system. From a management perspective increasing our understanding of how infection intensity and repeated exposure is linked to resource use in an ecosystem is important for the future management of this endangered species in Europe.  相似文献   

Annual variation in recruitment of freshwater mussels and its relationship with river discharge          下载免费PDF全文

Patricia R. Ries  Teresa J. Newton  Roger J. Haro  Steven J. Zigler  Mike Davis 《水产资源保护:海洋与淡水生态系统》2016,26(4):703-714

Increased crop diversity reduces the functional space available for weeds     

R J Pakeman  R W Brooker  A J Karley  A C Newton  C Mitchell  R L Hewison  J Pollenus  D C Guy  C Schöb 《Weed Research》2020,60(2):121-131

There is a drive to improve the sustainability of agricultural systems including the biodiversity component. Cultivar mixtures offer yield benefits from the same land area, but the mechanisms behind this overyielding have not been completely worked out. One potential mechanism is improved competition with weeds. We use an experimental approach of varying barley (Hordeum vulgare L.) genotypic and phenotypic diversity to test the hypothesis that increases in diversity have an impact on weed growth strategies and community assembly, or if responses are driven by barley performance. There was no effect of increasing barley mixture diversity on weed traits, either in terms of species means or the community-weighted mean. However, Functional Richness of the weed community decreased with increasing barley mixture diversity mainly as a result of reduced specific leaf area Functional Richness. This pattern was driven by a reduction in species richness of the weed community rather than by reduced variation within species. Whilst barley phenotype had different impacts on weed traits, there were no specific mixtures of phenotypes or genotypes that had consistent effects on community assembly or weed species responses. The competitive exclusion of weed species could have agronomic and environmental benefits, through better targeting or less frequent use of herbicides. Growing crop mixtures is one of many strategies available to improve agricultural sustainability and resilience, and one that has clear benefits.  相似文献