Assessment of Diversity of Antimicrobial Resistance Phenotypes and Genotypes of \u3ci\u3eMannheimia haemolytica\u3c/i\u3e Isolates from Bovine Nasopharyngeal Swabs

The threat of bovine respiratory disease (BRD) for cattle operations is exacerbated by increasing prevalence of antimicrobial resistance (AMR) in Mannheimia haemolytica, a leading cause of BRD. Characterization of AMR in M. haemolytica by culture and susceptibility testing is complicated by uncertainty regarding the number of colonies that must be selected to accurately characterize AMR phenotypes (antibiograms) and genotypes in a culture. The study objective was to assess phenotypic and genotypic diversity of M. haemolytica isolates on nasopharyngeal swabs (NPS) from 28 cattle at risk for BRD or with BRD. NPS were swabbed onto five consecutive blood agar plates; after incubation up to 20 M. haemolytica colonies were selected per plate (up to 100 colonies per NPS). Phenotype was determined by measuring minimum inhibitory concentrations (MIC) for 11 antimicrobials and classifying isolates as resistant or not. Genotype was indirectly determined by matrix-assisted laser desorption/ionization time of flight mass spectroscopy (MALDI-TOF MS). NPS from 11 of 28 cattle yielded at least one M. haemolytica isolate; median (range) of isolates per NPS was 48 (1–94). NPS from seven cattle yielded one phenotype, 3 NPS yielded two, and 1 NPS yielded three; however, within a sample all phenotypic differences were due to only oneMIC dilution. On each NPS all M. haemolytica isolated were the same genotype; genotype 1 was isolated from three NPS and genotype two was isolated from eight. Diversity of M. haemolytica on bovine NPS was limited, suggesting that selection of few colonies might adequately identify relevant phenotypes and genotypes

Application of Item Analysis to Assess Multiple-Choice Examinations in the Mississippi Master Cattle Producer Program

Item analysis can serve as a useful tool in improvingmultiple-choice questions used in Extension programming. It can identify gaps between instruction and assessment. An item analysis of Mississippi Master Cattle Producer program multiple-choice examination responses was performed to determine the difficulty of individual examinations, assess the effectiveness of distractors for individual items, and identify specific topics appropriate for placing further educational emphasis. Specific problems with items and distractors with examinations were identified and slated for revision. The item analysis results were then combined with program participant feedback to provide further insight into the instructional needs of Extension clientele

Assessment of Beef Cattle Extension Publication Use via Internet Download Monitoring

Publication download monitoring allows Extension professionals the ability to determine client interests. Downloads from a beef cattle Extension website were monitored from January 1, 2010 to September 1, 2011. Trends in Internet download monitoring of the MSUcares site were assessed. Basic beef cattle production publications were most downloaded. Beef cattle reproduction was identified as a key topic area of interest to website users. Popularity of Spanish language publications indicated an increased need for Spanish language translations Extension publications. This information provides a basis for developing future publications, trainings, and Web-based resources that are most in demand by clientele

Determining Interest in YouTube Topics for Extension-Authored Video Development

With an audience of over 1 billion users per month, YouTube is an attractive medium for delivering Extension programming. Amidst growing competition for viewership, determining content that is in demand by Extension clientele on YouTube is a daunting challenge that Extension educators face. The YouTube Search function of Google Trends and monitoring of existing YouTube views for related content can help guide topic selection in developing Extension-authored video content. Example applications of these tools are detailed to show how to select relevant YouTube topics with viral appeal and extend the reach of Extension programming

Comparing Carcass End-Point and Profit Maximization Decision Rules Using Dynamic Nonlinear Growth Functions

We develop a practical methodology for producers to estimate the optimal harvest time of live animals. We incorporate nonlinear dynamic growth functions into the producer’s objective function. Currently, the cattle industry objective is to produce a constant carcass end-point quality. We find significant increases in profitability using our methodology

Table_5_Impact of preweaning vaccination on host gene expression and antibody titers in healthy beef calves.xlsx

The impact of preweaning vaccination for bovine respiratory viruses on cattle health and subsequent bovine respiratory disease morbidity has been widely studied yet questions remain regarding the impact of these vaccines on host response and gene expression. Six randomly selected calves were vaccinated twice preweaning (T1 and T3) with a modified live vaccine for respiratory pathogens and 6 randomly selected calves were left unvaccinated. Whole blood samples were taken at first vaccination (T1), seven days later (T2), at revaccination and castration (T3), and at weaning (T4), and utilized for RNA isolation and sequencing. Serum from T3 and T4 was analyzed for antibodies to BRSV, BVDV1a, and BHV1. Sequenced RNA for all 48 samples was bioinformatically processed with a HISAT2/StringTie pipeline, utilizing reference guided assembly with the ARS-UCD1.2 bovine genome. Differentially expressed genes were identified through analyzing the impact of time across all calves, influence of vaccination across treatment groups at each timepoint, and the interaction of time and vaccination. Calves, regardless of vaccine administration, demonstrated an increase in gene expression over time related to specialized proresolving mediator production, lipid metabolism, and stimulation of immunoregulatory T-cells. Vaccination was associated with gene expression related to natural killer cell activity and helper T-cell differentiation, enriching for an upregulation in Th17-related gene expression, and downregulated genes involved in complement system activity and coagulation mechanisms. Type-1 interferon production was unaffected by the influence of vaccination nor time. To our knowledge, this is the first study to evaluate mechanisms of vaccination and development in healthy calves through RNA sequencing analysis.</p