Preliminary observations on the occurrence of the equine XO syndrome.     

A N Bruère  M G Blue  P M Jaine  K S Walker  L M Henderson  H M Chapman 《New Zealand veterinary journal》1978,26(6):145-146

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Announcement     

Allan Walker 《Weed Research》2002,42(6):415-415

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Effect of recent cropping history and herbicide use on the degradation rates of isoproturon in soils     

A Walker  & C R Austin† 《Weed Research》2004,44(1):5-11

Five soil samples were taken from each of five fields with different crop management histories. Three of the fields were in an arable rotation, the fourth field was temporary grassland, and the final field was under permanent grass. Of the three arable fields, two had been cropped with winter wheat in three of the preceding 6 years, and the third had last been cropped with winter wheat once only, 6 years previously. With one exception, the winter wheat had been sprayed with the herbicide isoproturon. The rate of isoproturon degradation in laboratory incubations was strongly related to the previous management practices. In the five soils from the field that had been treated most regularly with isoproturon in recent years, <2.5% of the initial dose remained after 14 days, indicating considerable enhancement of degradation. In the soils from the field with two applications of the herbicide in the past 6 years, residues after 27 days varied from 5% to 37% of the amount applied. In soils from the other three sites, residue levels were less variable, and were inversely related to microbial biomass. In studies with selected soils from the field that had received three applications of isoproturon in the previous 6 years, kinetics of degradation were not first‐order but were indicative of microbial adaptation, and the average time to 50% loss of the herbicide (DT₅₀) was 7.5 days. In selected soils from the field that had received just one application of isoproturon, degradation followed first‐order kinetics, indicative of cometabolism. Pre‐incubation of isoproturon in soil from the five fields led to significant enhancement of degradation only in the samples from the two fields that had a recent history of isoproturon application.  相似文献   

Comparison of bupivacaine and dexmedetomidine femoral and sciatic nerve blocks with bupivacaine and buprenorphine epidural injection for stifle arthroplasty in dogs          下载免费PDF全文

Annatasha KG Bartel  Luis Campoy  Manuel Martin‐Flores  Robin D Gleed  Kyle J Walker  Courtney E Scanapico  Alison B Reichard 《Veterinary anaesthesia and analgesia》2016,43(4):435-443

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Sarcocystid organisms found in bile from a dog with acute hepatitis: a case report and review of intestinal and hepatobiliary Sarcocystidae infections in dogs and cats          下载免费PDF全文

Katherine L. Irvine  Julie M. Walker  Kristen R. Friedrichs 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2016,45(1):57-65

Sarcocystidae is a family of coccidian protozoa from the phylum Apicomplexa that includes Toxoplasma, Neospora, Sarcocystis, Hammondia, and Besnoitia spp. All species undergo a 2‐host sexual and asexual cycle. In the definitive host, replication is enteroepithelial, and infection is typically asymptomatic or less commonly causes mild diarrhea. Clinical disease is most frequently observed in the intermediate host, often as an aberrant infection, and is mostly associated with neurologic, muscular, or hepatic inflammation. Here, we review the literature regarding intestinal Sarcocystidae infections in dogs and cats, with emphasis on the life cycle stages and the available diagnostic assays and their limitations. We also report the diagnostic findings for an 11‐year‐old dog with acute neutrophilic hepatitis, biliary protozoa, and negative biliary culture. Although Toxoplasma and Neospora IgG titers were both high, PCR for these 2 organisms was negative for bile. The organisms were identified by 18S rDNA PCR as most consistent with Hammondia, either H heydorni or H triffittae. This is the first report of presumed Hammondia organisms being found in canine bile.  相似文献   

Lungeing on hard and soft surfaces: Movement symmetry of trotting horses considered sound by their owners          下载免费PDF全文

T. Pfau  C. Jennings  H. Mitchell  E. Olsen  A. Walker  A. Egenvall  S. Tröster  R. Weller  M. Rhodin 《Equine veterinary journal》2016,48(1):83-89

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Suppression of behavioural and physiological oestrus in the mare by vaccination against GnRH     

Elhay M  Newbold A  Britton A  Turley P  Dowsett K  Walker J 《Australian veterinary journal》2007,85(1-2):39-45

OBJECTIVE: To examine the immunogenicity of an equine immunocontraceptive vaccine and its efficacy in controlling hormone-related behaviour. DESIGN: A total of 24 mares at two sites in Australia were vaccinated with an immunocontraceptive vaccine comprising gonadotrophin releasing hormone (GnRH) conjugated to a carrier protein in immunostimulating complex as an adjuvant. Twelve animals at each site received a placebo of adjuvant alone and served as controls for seasonal oestrus, hormonal and behaviour patterns. Animals were observed for injection site reactions, ovarian and follicular activity, and serum levels of antibody, 17beta-oestradiol and progesterone in the weeks following vaccination. Mares were also examined for oestrous behaviour by teasing with a stallion. RESULTS: All mares responded to vaccination. Two weeks following the second vaccination there was a peak in antibody response to GnRH that declined gradually over the following weeks. Commensurate with the elevated anti-GnRH antibody there was a marked effect on ovarian activity with a reduction in 17beta-oestradiol and progesterone levels in the 24 vaccinated mares. There was also a reduction of oestrus-related behaviour as determined by a teaser stallion. This effect lasted a minimum of 3 months and correlated with the initial level of antibody response. CONCLUSION: Following a conventional two-dose immunisation regime this commercially available equine immunocontraceptive vaccine was effective at inhibiting oestrous behaviour for at least 3 months. This vaccine has a high level of safety since there were no significant local reactions nor were there any adverse systemic responses to vaccination.  相似文献   

Characterization of multidrug resistant Salmonella recovered from diseased animals     

Zhao S  McDermott PF  White DG  Qaiyumi S  Friedman SL  Abbott JW  Glenn A  Ayers SL  Post KW  Fales WH  Wilson RB  Reggiardo C  Walker RD 《Veterinary microbiology》2007,123(1-3):122-132

Three hundred and eighty Salmonella isolates recovered from animal diagnostic samples obtained from four state veterinary diagnostic laboratories (AZ, NC, MO, and TN) between 2002 and 2003 were tested for antimicrobial susceptibilities and further characterized for bla(CMY) beta-lactamase genes, class 1 integrons and genetic relatedness using PFGE. Forty-seven serovars were identified, the most common being S. Typhimurium (26%), S. Heidelberg (9%), S, Dublin (8%), S. Newport (8%), S. Derby (7%), and S. Choleraesuis (7%). Three hundred and thirteen (82%) isolates were resistant to at least one antimicrobial, and 265 (70%) to three or more antimicrobials. Resistance was most often observed to tetracycline (78%), followed by streptomycin (73%), sulfamethoxazole (68%), and ampicillin (54%), and to a lesser extent chloramphenicol (37%), kanamycin (37%), amoxicillin-clavulanic acid (20%), and ceftiofur (17%). With regards to animal of origin, swine Salmonella isolates displayed the highest rate of resistance, being resistant to at least one antimicrobial (92%), followed by those recovered from turkey (91%), cattle (77%), chicken (68%), and equine (20%). Serovars commonly showing multidrug resistance (MDR) to > or =9 antimicrobials were S. Uganda (100%), S. Agona (79%), and S. Newport (62%), compared to S. Heidelberg (11%) and S. Typhimurium (7%). Class-1 integrons were detected in 43% of all isolates, and were found to contain aadA, aadB, dhfr, cmlA and sat1 gene cassettes alone or in various combinations. All ceftiofur resistant isolates (n=66) carried the bla(CMY) beta-lactamase gene. A total of 230 PFGE patterns were generated among the 380 isolates tested using XbaI, indicating extensive genetic diversity across recovered Salmonella serovars, however, several MDR clones were repeatedly recovered from different diseased animals.  相似文献   

Supplementation of laying-hen feed with palm tocos and algae astaxanthin for egg yolk nutrient enrichment     

Walker LA  Wang T  Xin H  Dolde D 《Journal of agricultural and food chemistry》2012,60(8):1989-1999

Adding supplements to hen feed can increase egg nutritional value. Astaxanthin, tocotrienols, and tocopherols are potent antioxidants that provide health benefits to humans. We hypothesized that the addition of these nutrients to hen feed would result in an increased nutrient content in egg yolk with minimum changes in functional properties. Laying hens (Hy-Line W-36 breed) were fed four diets with different supplementation levels of palm toco concentrate and algae biomass containing astaxanthin for 8 weeks. Egg yolks were analyzed for physical, chemical, and functional properties. The feed with the highest nutrient concentration was also studied for stability of these antioxidants using the Arrhenius approach. No significant differences were observed in functional properties except for emulsification capacity and sensory characteristics among eggs from different diet treatments. Changes in egg yolk color reached the maximum values at day 8. Incorporation of tocopherols and tocotrienols increased until day 8, astaxanthin incorporation increased until day 10, and all decreased thereafter. Feed nutrients resulted in a dose-response relationship of these compounds in the egg yolk. The transfer efficiency ranged from 0 to 9.9% for tocotrienols and tocopherols and from 7.6 to 14.9% for astaxanthin at their peak values. Results of the Arrhenius accelerated stability study showed significant differences in the shelf life of various nutrients, and these results can be used to properly formulate and store the feed materials.  相似文献   

The Shifting Destinations of Metropolitan Migrants in the U.S., 2005–2011          下载免费PDF全文

Kyle E. Walker 《Growth and change》2017,48(4):532-551

Recent estimates that central cities are growing faster than their suburbs in the U.S. have captured the attention of both academics and the popular media. Many commentators have used these numbers to claim that internal migration trends in the U.S. have reached a turning point, in which migrants increasingly prefer urban residences to suburban locales. However, these assertions often rely on problematic definitions of city and suburb, and pay too little attention to demographic variations among migrants. This paper examines whether recent internal migrants in the U.S. are choosing closer‐in destinations, drawing from microdata samples from the American Community Survey since 2005. During this period, there is an overall trend of migrants to the largest metropolitan areas in the U.S. choosing to migrate closer to the metropolitan core. However, this trend varies significantly among major demographic groups; whereas younger, single, educated, and white‐collar migrants show evidence of a return to the core, migrants who are blue‐collar, less‐educated, older, and with families remain more suburban. In turn, this analysis suggests that overall trends of “back to the city” migration are producing considerable divergence in the metropolitan destinations of different demographic groups.  相似文献