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A Working Party of the European Association for Animal Production surveyed the breed comparison and crossbreeding trials which were being carried out in Europe. The survey summarizes the experimental work in the different countries and gives details on 86 separate projects concerned with breed and strain evaluation in pure and crossbreeding situations. The paper gives a general summary of the survey and recommendations on the methodology for future experiments. More detailed abstracts of the individual trials included in the survey are obtainable on request.  相似文献   
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The objective of this study was to determine whether digesta kinetics, energy intake (EI, kcal ME intake x kg(-.75) x d(-1)), grazing behavior, or body temperature differed by breed, lactational state, or season of the year among cattle presumed to vary in adaptability to the subtropics. Two-year-old lactating and nonlactating Brahman x Angus (BA; n = 5, n = 5), Tuli x Angus (TA; n = 5, n = 4), and Angus (A; n = 4, n = 4) cows were used. During both early (ES) and late summer (LS), lactating cattle vs nonlactating cattle had greater gastrointestinal tract load (CM2) and EI (P < .01), although passage rate did not differ (P > .48). During LS, lactating cattle had decreased early morning rectal temperatures (P < .05) and spent more time grazing during the day compared with nonlactating cattle (P < .001). Among breeds, A had the largest CM2 (P < .01 compared with BA and P = .068 compared with TA) and accumulated the greatest heat during the day (P < .05). Due to greater daytime shading (P < .01) and less daytime grazing (P < .05), A had lower (P < .05) early morning and comparable (P > .26) late afternoon rectal temperatures compared with BA and TA. With data pooled over both grazing trials, BA cattle had the smallest CM2 (P < .01), and in ES they spent the least amount of time in the shade (P < .001). The TA spent more time in the shade than did BA (P < .001) during ES and less during LS (P < .001) and had similar (P > .28) early morning rectal temperatures compared with BA during ES and LS. During LS, TA spent more time in the sun and less time in the shade than did either A or BA (P < .001). During ES, EI did not differ among breeds (P > .50). During LS, EI for lactating A was greater than for BA and TA (P < .05), and EI for nonlactating BA was less than for A and TA (P < .05). Bite rate per minute for lactating cattle during ES was reduced (P < .03) by increased body condition score. Tuli x Angus cattle appear to be comparable to BA with respect to heat adaptation. It appears that EI demands are greater in a hot environment.  相似文献   
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OBJECTIVE: To compare synovial fluid characteristics of cattle with infectious and noninfectious arthritis. STUDY DESIGN: Retrospective cohort study. ANIMAL OR SAMPLE POPULATION: 130 cattle. METHODS: Synovial fluid was analyzed for total nucleated cell count (NCC), absolute number and percentages of polymorphonuclear (PMN) and mononuclear cells, total protein (TP) concentration, and specific gravity. Cattle were categorized as having infectious or noninfectious arthritis based on physical and lameness examinations, joint radiographs, and microbial culture results. Kruskal-Wallis 1-way analysis of variance was used to compare synovial fluid analysis data from different categories. Selection of cut-off values for the calculation of likelihood ratios, sensitivity, specificity, and positive and negative predictive values was based on examination of the distribution of the data using histograms. RESULTS: Cattle with infectious arthritis had significantly higher numbers of total NNC, PMN cells, TP concentration, and specific gravity (P = .0001) and a significantly higher percentage of PMN cells compared with cattle with noninfectious arthritis (P = .0001). The percentage of mononuclear cells was significantly higher in cattle with noninfectious arthritis (P = .0001). CONCLUSIONS: Synovial fluid analysis is useful for differentiation of infectious and noninfectious causes of joint disease in cattle. CLINICAL RELEVANCE: Cattle with a synovial fluid total NCC > 25,000 cells/microL, a PMN cell count > 20,000 cells/microL or more than 80% PMN cells, and TP > 4.5 g/dL should be considered to have infectious arthritis.  相似文献   
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OBJECTIVE: To compare molecular associations between the vesicular stomatitis virus (VSV)-New Jersey isolates of the 1995 outbreak with those from previous outbreaks between 1982 and 1985 in the western United States. SAMPLE POPULATION: 23 virus isolates considered representative of the 1995 outbreak of vesicular stomatitis. PROCEDURE: Viral gene coding for surface-envelope protein G was evaluated by use of nucleotide sequencing and phylogenetic analysis. RESULTS: Changes in up to 0.77% of the nucleotide bases and 1.35% of the amino acids were detected among the 1995 viral isolates, whereas changes in up to 3.2 and 2.9% of the nucleotides and amino acids, respectively, were found, compared with the 1982 to 1985 viruses. Insertions or deletions were not found in the entire gene, which spanned 1,554 nucleotide bases. CONCLUSIONS AND CLINICAL RELEVANCE: Phylogenetic analysis indicated that the 1995 VSV-New Jersey belongs to a lineage distinct from that of the 1982 to 1985 viruses that caused previous outbreaks in the western United States. Furthermore, it also is distinct from strains from Central America and from the Georgian Hazelhurst strain.  相似文献   
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