Genetic Parameters For Various Random Regression Models To Describe The Total Sperm Cells Per Ejaculate Over The Active Lifetime Of Boars

North Carolina State University Swine Genetics Research from 2003. The objective of this study was to model the variances and covariances of total sperm cells ( 109) over the active lifetime of AI boars. Data from boars (n = 834) selected for AI were provided by NPD USA. Total number of records and animals were 19,629 and 1,736, respectively. Parameters were estimated for total sperm cells by age of boar classification under a random regression model using the Simplex method and DxMRR procedures. The analysis model included breed, collector and year-season as fixed effects. Random effects included additive genetic effect, permanent environmental effect of boar, and measurement error.