In genetic association studies, due to the varying underlying genetic models, no single statistical test can be the most powerful test under all situations. Current studies show that if the underlying genetic models are known, trend-based tests, which outperform the classical Pearson χ² test, can be constructed. However, when the underlying genetic models are unknown, the χ² test is usually mor...

Data collected from Jersey herd in the central highland environment of Ethiopia was used to estimate genetic parameter and trend analysis for reproductive/fertility traits. Totally, 11,933 reproductive records recorded during last 30 years were analysis. Traits studied NSC (number service per conception), DO (days open), CI (calving interval), AFC (age at first calving) AFS service). Genetic ph...

A total of 72124 fertility records was used to estimate the genetic and phenotypic trend of fertility traits in Iranian Holstein cow from 1981 to 2007. Fertility traits in this study were: days from calving to first service (DFS), number of insemination per conception (INS), days open (DO), interval between first and last insemination (IFL), calving interval (CI) and success to first inseminati...

Data from the slaughter of 24,001 chickens that were part of a selection program for the production of commercial broilers were used to estimate genetic trend for absolute carcass (CW), breast meat (BRW), and leg (LW) weights, and relative carcass (CY), breast meat (BRY), and leg (LY) weights. The components of (co)variance and breeding values of individuals were obtained by the restricted maxi...