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| Filter results6 paper(s) found. |
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1. Seasonal Patterns of Vegetative Indices Over Cropping SystemsRemote sensing of reflectance in the visible and near-infrared portions of the spectrum has been used for agronomic applications for a number of years. The combination of different wavelengths into vegetative indices have proven useful for a variety of applications that range from biomass, leaf area, leaf chlorophyll, yield, crop residue, and crop damage. To help refine our understanding of vegetative indices studies were conducted on corn (Zea mays L.), soybean (Glycine max (L.) Merr.), wheat... J.L. Hatfield, J.H. Prueger |
2. Spatial Patterns of Nitrogen Response Within Corn Production FieldsCorn (Zea mays L.) yield response to nitrogen (N) application is critical to being able to develop management practices that reduce N application or improve N use efficiency. Nitrogen rate studies have been conducted within small plots; however, there have been few field scale evaluations. This study was designed to evaluate N response across 14 corn fields in central Iowa using different rates of N applied in strips across fields. These fields ranged in size from 15 to 130 ha with N... J.L. Hatfield |
3. Exploring Relationships Between Dairy Herd Improvement Metrics in Minas Gerais – Brazil Dairy HerdsThe objective of the present study was to apply principal component analysis (PCA) on Brazilian Dairy Herd Improvement (DHI) data to discover the subset of most meaningful variables to describe complete lactations. The Holstein Livestock Breeders Association of Minas Gerais provided data collected between 2005 and 2016 from 122 dairy farms located in the State of Minas Gerais – Brazil. Twelve numerical variables were selected from the original dataset and four additional variables were created.... G.M. Dallago, D. Figueiredo, R. Santos, P. Andrade, D. Santos |
4. Time Series Analysis of Somatic Cell Count from Dairy Herds in Minas Gerais - BrazilThe objective of this study was to analyze the temporal variation of somatic cell count (SCC) in milk of dairy cows from the state of Minas Gerais, Brazil. The Holstein Livestock Breeders Association of Minas Gerais provided data collected from 128 dairy farms located in the state of Minas Gerais between the years of 2000 and 2016. The database contains the SCC average of a total of 91,851 305-day lactations of Holstein animals. The annual SCC average was calculated as well as the percentage of... G.M. Dallago, D. Figueiredo, R. Santos, D. Santos, L. Guimarães, C. Santos, T. Castro, A. Santos, L. Otoni, J. Andrade |
5. The Influence of Calf’s Sex on Total Milk Yield and Its Constituents of Dairy CowsThe objective of the present work was to evaluate the influence of the sex of the calf on total milk yield and its constituents of Holstein-Friesian dairy cows. The Holstein Livestock Breeders Association of Minas Gerais provided data collected over the years from 2000 to 2016 from 127 dairy farms located in the state of Minas Gerais – Brazil. The data set analyzed contained 61747 observations of Holstein-Friesian animals that calved female (n = 28903) or male (n = 32844) calf. Fat, protein,... G.M. Dallago, D. Figueiredo, R. Santos, D. Santos, L. Barroso, G. Alves, J. Vieira, L. Guimarães, C. Santos , L. Maciel |
6. Relationships Between First Test Day Metrics of First Lactation Cows to Evaluate Transition PeriodThe objective of this study was to apply principal component analysis (PCA) and multiple correspondence analysis (MCA) on Dairy Herd Improvement (DHI) data of animals on their first lactation to discover the most meaningful set of variables that describe the outcome on the first test day. Data collected over 4 years were obtained from 13 dairy herds located in Québec – Canada. The data set was filtered to contain only information from first test day of animals on their first lactation,... G.M. Dallago, D. Figueiredo, R. Santos, P. Andrade, D.E. Santschi, R. Lacroix, D.M. Lefebvre |