Life Sciences Commons^™

Simulation Comparison Of Statistical Methods Used In Assessing Vaccine Efficacy In Veterinary Biologics, Kenny Wakeland, Brian Fergen

Conference on Applied Statistics in Agriculture

In veterinary biologics, clinical studies conducted to support the licensure of a vaccine generally include a demonstration of efficacy in the species of interest. Typically, these studies are designed to assess a vaccine’s ability to prevent or mitigate clinical disease. Study designs utilize two or more treatment groups, and often incorporate blocking structure restrictions to accommodate animal housing or litter-related effects. When assessing a vaccine’s ability to prevent clinical disease, the prevented fraction (PF), a function of the group proportions of affected animals, is often utilized. Typically the sample size per treatment group is limited, and each block is represented …

The Effect Of Poultry Litter Application On Agricultural Production: A Meta-Analysis Of Crop Yield, Nutrient Uptake And Soil Fertility, Yaru Lin, Edzard Van Santen, Dexter Watts

Conference on Applied Statistics in Agriculture

Meta-analysis is a statistical technique used to analyze large datasets containing results from numerous individual studies. It appears to be a promising approach in agricultural sciences. This study aimed to conduct a meta-analytic assessment to elucidate the influence of poultry litter (PL) application on crop yield, plant nutrient uptake, and soil fertility as compared to inorganic fertilizer (IF). A meta-analysis based on 116 studies (111 refereed articles and five unpublished data sets) with 2293 observations compared agronomic responses to PL and IF application. The natural log of the response ratio was used as effect size (ES) to express differences in …

Topological Methods For The Quantification And Analysis Of Complex Phenotypes, Patrick S. Medina, Rebecca W. Doerge

Conference on Applied Statistics in Agriculture

Quantitative Trait Locus (QTL) mapping of complex traits, such as leaf venation or root structures, require the phenotyping and genotyping of large populations. Sufficient genotyping is accomplished with cost effective high-throughput assays, however labor costs often makes sufficient phenotyping prohibitively limited. In order to develop efficient high-throughput phenotyping platforms for complex traits algorithms and methods for quantifying these traits are needed. It is often desirable to study the spatial organization of these phenotypes from the images generated by high-throughput platforms. With the goal of quantifying the traits, many approaches try to identify several core traits useful in describing the phenotypic …

Bayesian Estimation Of Stability Indices Of Sorghum Variety Trials, Siraj Osman Omer, Abdel Wahab Hassan Abdalla, Mohammed Hamza Mohammed, International Center For Agricultural Research In The Dry Areas (Icarda), Amman, Jordan

Conference on Applied Statistics in Agriculture

Multiple–environmental trials are routinely conducted by crop improvement programs for developing desired genotypes. Over a long run, these programs gather information on genotypic performance and variability. Bayesian approach can be used to utilize prior information to identify genotypes for high and stable yield. A set of 18 sorghum genotypes were evaluated in randomized complete block designs (RCBD) with four replications during three seasons, 2009-2012 at diverse locations, North-Gedarif and South-Gedarif, in Sudan. Data on grain yield was analyzed. The aim of this paper was to estimate stability indices such as regression coefficient, coefficient of variation (CV %) and coefficient of …

Strategies For Reducing Control Group Size In Experiments Using Live Animals, Matthew Kramer, Enrique Font

Conference on Applied Statistics in Agriculture

Reducing the number of animal subjects used in biomedical experiments is desirable for both ethical and practical reasons. Previous suggestions for reducing sample sizes in these experiments have focused on improving experimental designs and methods of statistical analysis; reducing the number of controls (thus, the number of overall animals used) is rarely mentioned. We discuss how the number of current control animals can be reduced, without loss of statistical power, by incorporating information from historical controls, i.e. animals used as controls in similar previous experiments. Using example data from the literature, we describe how to incorporate information from historical controls …

Alternative Estimation Techniques For Correlated Discrete Data, William J. Price Ph.D., Bahman Shafii Ph.D.

Conference on Applied Statistics in Agriculture

Binary or multinomial data often occur in agricultural and biological research. Advancements in measurement and video technologies now allow such data to be sequentially recorded through time or space. These data sets, however, can exhibit a serial correlation structure, which in turn, can bias and influence point estimates as well as inferences made regarding the data. Statistical methods using generalized mixed models and probability distributions such as the beta-binomial and correlated binomial have been proposed as potential solutions for estimating the parameters of interest in these cases. In this paper, we will explore the properties of these techniques through simulation …

Developing Prediction Equations For Fat Free Lean In The Presence Of An Unknown Amount Of Proportional Measurement Error, Zachary J. Hass, Bruce A. Craig, Allan Schinckel

Conference on Applied Statistics in Agriculture

Published prediction equations for fat-free lean mass are widely used by producers for carcass evaluation. These regression equations are commonly derived under the assumption that the predictors are measured without error. In practice, however, it is known that some predictors, such as backfat and loin muscle depth, are measured imperfectly with variance that is proportional to the mean. Failure to account for these measurement errors will cause bias in the estimated equation. In this paper, we describe an empirical Bayes approach, using technical replicates, to accurately estimate the regression relationship in the presence of proportional measurement error. We demonstrate, via …

Paired Competition Analysis Using Mixed Models, Patrick Gallagher, Bruce A. Craig, Tim Luttermoser, Grzegorz Buczkowski

Conference on Applied Statistics in Agriculture

Urban and rural colonies of odorous house ants (Tapinoma sessile) have very different social structures. Urban colonies are very large with hundreds of cohabiting queens, while rural colonies are small with only one queen. To investigate whether worker ant aggressiveness varies across these two colony types, an experiment was performed using an aggression assay, in which 50 ants from each of two colonies were placed in a petri dish and allowed to fight. The response was the total number of dead ants within 24 hours. Because the ants were all the same species and not marked by colony, …

Irrigated And Rainfed Crops Zea Mays L. (Maize) And Glycine Max (Soybean) Acting As A Source Or Sink For Atmospheric Warming At Mead, Nebraska, Jane A. Okalebo Dr., Kenneth G. Hubbard, Andy Suyker

Conference on Applied Statistics in Agriculture

Land Use and Land Cover Change (LULCC) influence the climate at a global and local scale. Using long term microclimate data (2002-2009, 2011-2012) from the Carbon Sequestration Project (CSP), Mead, NE, this study examines how crop selection and water management can mitigate heat in the atmosphere. Mitigation of global warming is dependent on the management of crop lands, and the amount and timing of rainfall during the growing season. Rainfed crops were found to heat the passing air. The irrigated maize crop was able to mitigate 20 to 62% of the sensible heat (H) compared to the rainfed maize counterpart, …

Should Blocks Be Fixed Or Random?, Philip Dixon

Conference on Applied Statistics in Agriculture

Many studies include some form of blocking in the study design. Block effects are rarely of intrinsic interest; instead they are included in a model so that that model reflects the study design. I consider the question of how these block effects should be modeled: as fixed effects or as random effects. I discuss the consequences of the choice, including the recovery of inter-block information when available, give a simple example to illustrate the connection between recovery of inter-block information and pooling two estimators of a treatment effect, and give an example where fitting a model with random block effects …

Comparing Linear Mixed Models For Preliminary Yield Trials That Follow Augmented Experimental Designs, Sudha Neupane Adhikari, Jixiang Wu, Melanie Caffe

Conference on Applied Statistics in Agriculture

COMPARING LINEAR MIXED MODELS FOR PRELIMINARY YIELD TRIALS THAT FOLLOW AUGMENTED EXPERIMENTAL DESIGNS

Sudha Neupane Adhikari, Jixiang Wu, and Melanie Caffe-Treml

Agronomy, Horticulture, and Plant Science Department,

South Dakota State University, Brookings, SD 57007

Abstract

Ineffective control of spatial variation when analyzing field trials data may lead to biased conclusions, which in turn could impact selection efficiency in plant breeding programs. In this study, a group of 78 oats breeding lines were evaluated in preliminary yield trials at four locations in South Dakota in 2015. Four linear mixed models (with and without row and column effects) were compared regarding reduction …

A Bayesian Gwas Method Utilizing Haplotype Clusters For A Composite Breed Population, Danielle F. Wilson-Wells, Stephen D. Kachman

Conference on Applied Statistics in Agriculture

Commercial beef cattle are often composites of multiple breeds. Current methods used to produce genomic predictors are based on the underlying assumption of animals being sampled from a homogeneous population. As a result, the predictors can perform poorly when used to predict the relative genetic merit of animals whose breed composition are different. In part, this is due to the changes in linkage disequilibrium between the markers and the quantitative trait loci as we move from one breed to the next. An alternative model based on breed specific haplotype clusters was developed to allow for differences in linkage disequilibrium across …

Editor's Preface And Table Of Contents, Perla Reyes

Conference on Applied Statistics in Agriculture

2016 Conference on Applied Statistics in Agriculture Proceedings

The Finney County, Kansas Community Assessment Process: Fact Book, Debra J. Bolton Phd, Shannon L. Dick M.S.

NPP eBooks

This multi-lingual/multi-cultural study was called, Community Assets Processt, by the groups that “commissioned” it: Finnup Foundation, Finney County K-State Research & Extension, Western Kansas Community Foundation, Finney County United Way, Finney County Health Department, United Methodist Community Health Center (UMMAM), Center for Children and Families, Garden City Recreation Commission, and the Garden City Cultural Relations Board, because we intend for this to be an ongoing discussion.

An objective, for those promoting the study, was to connect foundation, state, and federal funding with activities or services that addressed the true needs of people living in Finney County. The group was looking …

Sorghum Yield Response To Water Supply And Irrigation Management, I. Kisekka, F. Lamm, A. Schlegel

Kansas Agricultural Experiment Station Research Reports

Grain sorghum yield, under full and limited irrigation, was evaluated at three locations in western Kansas (Colby, Tribune, and Garden City). The top-end yield under full ir­rigation was 190 bu/a. However, there were no significant differences among irrigation treatments at all the three locations due to the above normal rainfall received during the 2015 growing season. These preliminary results indicate that there is potential to improve grain sorghum yields under limited irrigation. Additionally, best management practices to maximize kernels per head could have the greatest effect on grain yields.

Annual Summary Of Weather Data For Parsons, M. Knapp

Kansas Agricultural Experiment Station Research Reports

Weather Data for Parsons, Kansas, 2015.

Precipitation Data, M. Knapp

Kansas Agricultural Experiment Station Research Reports

Precipitation data for agricultural experiment stations in Kansas, 2014-2015.

Forage Sorghum And Corn Silage Response To Full And Deficit Irrigation, I. Kisekka, J. D. Holman, J. W. Waggoner, J. Aguilar, R. Currie

Kansas Agricultural Experiment Station Research Reports

There is limited information on forage sorghum and corn silage yield response to full and deficit irrigation in Kansas. The objective of this study was to generate information on forage sorghum (brown mid-rib hybrids (BMR and non-BMR)) and corn silage yield response to different levels of irrigation as influenced by irrigation capacity in southwest Kansas. Preliminary results indicate the effect of irrigation capacity on forage yield was significant (P = 0.0009) in 2014 but not 2015, probably due to high growing season rainfall received in 2015. Corn silage produced significantly (p<0.05) higher biomass at all irrigation capacities compared to forage sorghum hybrids in 2015. BMR forage sorghum produced significantly lower biomass compared to non-BMR hybrid in both 2014 and 2015 (P<0.05). The highest amounts of forage produced for corn silage, BMR, and non-BMR forage sorghum were 24.6, 17.4, and 21.1 tons/a adjusted to 65%, moisture respectively. Water productivity ranged from 1.0 to 1.4 dry matter tons/a/in. More research is needed under normal and dry years to quantify forage sorghum and corn silage yield and forage quality response to full and deficit irrigation.

Mobile Drip Irrigation Evaluation In Corn, I. Kisekka, T. Oker, G. Nguyen, J. Aguilar, D. Rogers

Kansas Agricultural Experiment Station Research Reports

Mobile Drip Irrigation (MDI) involves attaching driplines to center pivot drops. MDI has potential to eliminate water losses due to spray droplet evaporation, water evapo­ration from the canopy, and wind drift. MDI also may reduce soil water evaporation due to limited surface wetting. A study was conducted with the following objectives: 1) compare soil water evaporation under MDI and in-canopy spray nozzles; 2) evalu­ate soil water redistribution under MDI at 60 inch dripline lateral spacing; 3) compare corn grain yield, water productivity, and irrigation water use efficiency; and 4) compare end-of-season profile soil water under MDI and in-canopy spray at …

Response Of Drought Tolerant And Conventional Corn To Limited Irrigation, I. Kisekka, F. Lamm

Kansas Agricultural Experiment Station Research Reports

The purpose of this study was to evaluate the response of two commercial hybrids (DKC 62-27 DGVT2PRO [drought tolerant trait (DT)] and DKC 62-98 VT2PRO [conventional]) to limited irrigation. Preliminary results from the 2014 and 2015 growing seasons at Southwest Research-Extension Center near Garden City, Kansas, indicate the effect of irrigation capacity on corn yield was significant (P<0.001)for both hybrids. The effect of the drought tolerance trait on yield was not significant (P>0.05)in both years. The effect of the interaction between irrigation capacity and corn hybrid on yield was also not significant (P>0.05) …

Alternative Cropping Systems With Limited Irrigation, A. Schlegel

Kansas Agricultural Experiment Station Research Reports

A limited irrigation study involving six cropping systems was initiated at the Southwest Research-Extension Center near Tribune, KS, in 2012. The cropping systems were two annual systems (continuous corn [C-C] and continuous grain sorghum [GS-GS]) and four 2-year systems (corn-sorghum [C-GS]), corn-sunflower [C-SF], corn-winter wheat [C-W], and corn-wheat/double sunflower [C-W/SF]). In 2015, corn yields were lower following corn than other crops while wheat and grain sorghum yields were similar for all rotations. This tended to agree with the 3-year average yields except for average sorghum yields being higher following corn than sorghum. Sunflowers were destroyed by rodents and no yields …