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Busboom JR Nelson ML Jeremiah LE Duckett SK Cronrath JD Falen L Kuber PS 《Journal of animal science》2000,78(7):1837-1844
The objective of this study was to evaluate the effects of barley- or corn-based diets containing 0, 10, or 20% potato by-product (DM basis) on Warner-Bratzler shear force and palatability of beef. One hundred forty-four crossbred beef steers (333+/-.44 kg) were allotted within weight block (3) to a randomized complete block design with a 2 x 3 factorial arrangement of dietary treatments. Main effects were grain (barley or corn) and level of potato by-product (0, 10, or 20% of diet DM). There were a total of 18 pens with eight steers per pen and three pens per treatment. Steers were fed diets containing 83% concentrate (grain plus potato by-product), 10% supplement, and 7% alfalfa (DM basis) for an average of 130 d. Longissimus muscle cuts were used for Warner-Bratzler shear force determination (four steers per pen) and evaluation (two steers per pen) by a 10-member trained laboratory panel, a professional flavor/texture profile panel, and by consumer panels. Diet did not affect (P > .10) Warner-Bratzler shear force or trained laboratory panel tenderness, juiciness, and flavor intensity scores. Flavor/texture profile panel scores indicated feeding a corn-based diet as opposed to barley-based diet produced a more appropriate well-balanced and well-blended beef flavor and texture. However, the magnitudes of the differences were relatively small, and flavor and texture amplitude ratings for both barley- and corn-fed beef were well above average. Beef from steers fed 10 or 20% potato by-product had lower (P < .05) incidences of inappropriate aromatics and aftertastes, which may have a slightly beneficial effect on beef flavor, but flavor amplitude was not affected (P > .05) by level of potato. Moreover, consumer panel overall acceptability scores were not affected by diet. Thus, feedlot diets containing corn or barley with or without potato by-product should result in palatable beef products. 相似文献
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The interrelationships between our diets and the structure and operations of our gut microbial communities are poorly understood. A model community of 10 sequenced human gut bacteria was introduced into gnotobiotic mice, and changes in species abundance and microbial gene expression were measured in response to randomized perturbations of four defined ingredients in the host diet. From the responses, we developed a statistical model that predicted over 60% of the variation in species abundance evoked by diet perturbations, and we were able to identify which factors in the diet best explained changes seen for each community member. The approach is generally applicable, as shown by a follow-up study involving diets containing various mixtures of pureed human baby foods. 相似文献
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Garcia-Garcia JC de la Fuente J Kocan KM Blouin EF Halbur T Onet VC Saliki JT 《Veterinary immunology and immunopathology》2004,98(3-4):137-151
Major surface protein (MSP) 1a of the genus type species Anaplasma marginale (Rickettsiales: Anaplasmataceae) together with MSP1b forms the MSP1 complex. MSP1a has been shown to be involved in adhesion, infection and tick transmission of A. marginale, as well as to contribute to protective immunity in cattle. A differential antibody response to MSP1a and MSP1b was observed in cattle immunized with A. marginale derived from bovine erythrocytes (anti-MSP1a response) or cultured tick cells (anti-MSP1b response). In this study, we further characterized the MSP1a antibody response of cattle using several immunogens, including recombinant MSP1a (rMSP1a) protein, erythrocyte- or tick cell culture-derived A. marginale, or a combination of tick cell culture-derived A. marginale and rMSP1a. The MSP1a antibody response to all these immunogens was directed primarily against the N-terminal region of MSP1a that contains tandemly repeated peptides, whereas low antibody levels were detected against the C-terminal portion. Linear B-cell epitopes of MSP1a were mapped using synthetic peptides representing the entire sequence of the protein that were prepared by SPOT synthesis technology. Only two peptides in the N-terminal repeats were recognized by sera from immunized cattle. These peptides shared the sequence SSAGGQQQESS, which is likely to contain the linear B-cell epitope that was recognized by the pools of bovine sera. The average differential of antibody titers against MSP1a minus those against MSP1b correlated with lower percent reductions in PCV. A preferential antibody response to MSP1a was observed in cattle immunized with erythrocyte-derived, cell culture-derived plus rMSP1a or rMSP1a alone, and the percent reduction PCV was significantly lower in these cattle as compared with the other immunization groups. These results provide insight into the bovine antibody response against A. marginale and the role of MSP1a in protection of cattle against A. marginale infection. 相似文献
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Emily Rutto Cody Daft Jonathan Kelly Bee Khim Chim Jeremiah Mullock Guilherme Torres 《Journal of plant nutrition》2014,37(2):198-208
Uneven crop stands result in a reduction in corn yield production. This study was conducted to determine the effect of delayed emergence on corn yields and the effect of nitrogen (N) applications to compensate for yield reductions. The design used was a randomized complete block, with 4 sequences of delayed planting (0,4,7,and 10 days after planting) and 3 rates of nitrogen fertilizer (0, 40, 80 kg N ha?1). At maturity, individual plants were tagged in sets of three and hand harvested. Corn ears were shelled, and yield per plant calculated. Grain yield of the delayed plant compared to that of the neighbors was reduced by 27, 8, 20 and 12 kg ha?1day?1 for 2007 LCB1, 2007 LCB2, 2010 LCB1 and 2010 LCB2, respectively. Over locations and years, the mean grain yield decrease of the delayed plant versus neighboring plants for each day delay was 122 kg ha?1. 相似文献
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Transmission of Bovine viral diarrhea virus 1b to susceptible and vaccinated calves by exposure to persistently infected calves 
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下载免费PDF全文 Robert W. Fulton Robert E. Briggs Julia F. Ridpath Jeremiah T. Saliki Anthony W. Confer Mark E. Payton Glenn C. Duff D.L. Step D.A. Walker 《Canadian journal of veterinary research》2005,69(3):161-169
Bovine viral diarrhea virus (BVDV) persistently infected (PI) calves represent significant sources of infection to susceptible cattle. The objectives of this study were to determine if PI calves transmitted infection to vaccinated and unvaccinated calves, to determine if BVDV vaccine strains could be differentiated from the PI field strains by subtyping molecular techniques, and if there were different rates of recovery from peripheral blood leukocytes (PBL) versus serums for acutely infected calves. Calves PI with BVDV1b were placed in pens with nonvaccinated and vaccinated calves for 35 d. Peripheral blood leukocytes, serums, and nasal swabs were collected for viral isolation and serology. In addition, transmission of Bovine herpes virus 1 (BHV-1), Parainfluenza-3 virus (PI-3V), and Bovine respiratory syncytial virus (BRSV) was monitored during the 35 d observation period. Bovine viral diarrhea virus subtype 1b was transmitted to both vaccinated and nonvaccinated calves, including BVDV1b seronegative and seropositive calves, after exposure to PI calves. There was evidence of transmission by viral isolation from PBL, nasal swabs, or both, and seroconversions to BVDV1b. For the unvaccinated calves, 83.2% seroconverted to BVDV1b. The high level of transmission by PI calves is illustrated by seroconversion rates of nonvaccinated calves in individual pens: 70% to 100% seroconversion to the BVDV1b. Bovine viral diarrhea virus was isolated from 45 out of 202 calves in this study. These included BVDV1b in ranch and order buyer (OB) calves, plus BVDV strains identified as vaccinal strains that were in modified live virus (MLV) vaccines given to half the OB calves 3 d prior to the study. The BVDV1b isolates in exposed calves were detected between collection days 7 and 21 after exposure to PI calves. Bovine viral diarrhea virus was recovered more frequently from PBL than serum in acutely infected calves. Bovine viral diarrhea virus was also isolated from the lungs of 2 of 7 calves that were dying with pulmonary lesions. Two of the calves dying with pneumonic lesions in the study had been BVDV1b viremic prior to death. Bovine viral diarrhea virus 1b was isolated from both calves that received the killed or MLV vaccines. There were cytopathic (CP) strains isolated from MLV vaccinated calves during the same time frame as the BVDV1b isolations. These viruses were typed by polymerase chain reaction (PCR) and genetic sequencing, and most CP were confirmed as vaccinal origin. A BVDV2 NCP strain was found in only 1 OB calf, on multiple collections, and the calf seroconverted to BVDV2. This virus was not identical to the BVDV2 CP 296 vaccine strain. The use of subtyping is required to differentiate vaccinal strains from the field strains. This study detected 2 different vaccine strains, the BVDV1b in PI calves and infected contact calves, and a heterologous BVDV2 subtype brought in as an acutely infected calf. The MLV vaccination, with BVDV1a and BVDV2 components, administered 3 d prior to exposure to PI calves did not protect 100% against BVDV1b viremias or nasal shedding. There were other agents associated with the bovine respiratory disease signs and lesions in this study including Mannheimia haemolytica, Mycoplasma spp., PI-3V, BRSV, and BHV-1. 相似文献
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Blouin EF de la Fuente J Garcia-Garcia JC Sauer JR Saliki JT Kocan KM 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2002,3(2):57-68
A cell culture system for the tick-borne rickettsia Anaplasma marginale offers new opportunities for research on this economically important pathogen of cattle. A. marginale multiplies in membrane-bound inclusions in host cells. Whereas erythrocytes appear to be the only site of infection in cattle, A. marginale undergoes a complex developmental cycle in ticks and transmission occurs via the salivary glands during feeding. We recently developed a cell culture system for A. marginale using a cell line derived from embryos of Ixodes scapularis. Here we review the use of this cell culture system for studying the interaction of A. marginale with tick cells. Several assays were developed using the A. marginale/tick cell system. An adhesion assay was developed for the identification of proteins required by A. marginale for adhesion to tick cells. The effect of antibodies against selected major surface proteins in inhibiting A. marginale infection was tested in an assay that allowed further confirmation of the role of surface proteins in the infection of tick cells. A drug screening assay for A. marginale was developed and provides a method of initial drug selection without the use of cattle. The culture system was used to test for enhancing effects of tick saliva and saliva components on A. marginale infection. The tick cell culture system has proved to be a good model for studying A. marginale-tick interactions. Information gained from these studies may be applicable to other closely related tick-borne pathogens that have been propagated in the same tick cell line. 相似文献
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Nollens HH Wellehan JF Saliki JT Caseltine SL Jensen ED Van Bonn W Venn-Watson S 《Veterinary microbiology》2008,128(3-4):231-242
A novel member of the parainfluenza virus family was identified in a bottlenose dolphin with respiratory disease. The case animal was a 19-year old male Atlantic bottlenose dolphin (Tursiops truncatus) that presented with signs of respiratory illness, including raspy, foul-odored breaths and cream-colored exudate from the blowhole. Focally extensive pyogranulomatous bronchointerstitial pneumonia with moderate numbers of intralesional yeast organisms was identified on histopathological examination. Other significant microscopic findings included multifocal erosive and ulcerative tracheitis and laryngitis consisting of active laryngeal lymphatic tissue and dilated glands with eosinophilic fluid. The cause of death was attributed to respiratory disease of unknown etiology. In addition to the postmortem isolation of Candida glabrata and mixed bacteria from lung tissue, a virus was isolated from two antemortem affected lung aspirates collected over a 2-month period and two postmortem samples (mediastinal lymph node and left lung tissue homogenate). The morphology of the virions on negative staining and transmission electron microscopy was consistent with that of paramyxoviruses. Two genomic fragments, comprising 532 and 419 nucleotides from the open reading frames that code for the viral polymerase and fusion protein, respectively, were amplified by polymerase chain reaction using degenerate primers. Phylogenetic analyses of the two viral RNA segments showed that the isolate comprised a novel virus strain, tentatively named T. truncatus parainfluenza virus type 1 (TtPIV-1). The virus is monophyletic with, but genetically distinct from, the various bovine parainfluenza virus type 3 strains. 相似文献
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ABSTRACT An experiment was carried out to determine the effect of using low-protein diets on production of Tilapia rendalli in semi-intensive pond cage culture. This was carried out at Bunda College of Agriculture's fish farm, University of Malawi, where two 200-m2 earthen ponds of 1-m depth were used for two months from February 2003 to early April 2003. Each pond had 6 cages of 1 m3 in size stocked with 15 fish, each 4.8 ± 1.2 g average weight and 6.7 ± 0.6 cm average length. Chicken manure was used as the organic manure applied at 500 kg/ha/wk and also acted as a control. All treatments were replicated three times. It was observed that fish growth was higher in the soybean meal-based diet, with final weight of 34.4 g, followed by sunflower cake, with final weight of 23.3 g. The lowest was 14.4 g in the chicken manure only, and cottonseed-based diet had final weight of 19.5 g. These results also agree with the specific growth rate (SGR) that ranged from 2.1%/day in the cages only fertilized with chicken manure to 3.6%/day in the soybean-based dietary treatment. The lowest feed conversion ratio of 1.2 was also observed in the soybean-based dietary treatment. This suggests that the use of lower protein diets that contain soybean would produce better results and may increase yield when combined with fertilization, as evidenced by high fish survival rates of more than 93% in all treatments. 相似文献