738. Maturity, a New Indicator to Improve Longevity of Saanen Dairy Goats in France

The objective of this study was to obtain a maturity EBV to improve longevity in dairy goat. Several multi-parities models were developed in this study: a multi-trait model (MULTI) that used lactational production and a test day model (TDM) that used directly test day data. They were compared to the current repeatability model routinely used in France. There were no major differences for heritabilities and EBVs. It was found that the ability to produce milk in first parity was not the same as the ability to produce milk in third lactation. The second eigenvector of the (co)variance matrix permitted to discriminate the first and the third parity and to obtain a maturity EBV. This EBV was linked positively with longevity EBV and could be used to predict longevity. The multi trait model could be used to modify the way to calculate milk yield EBV used routinely in France by putting more emphasis on third parity EBVs, which is less negatively linked to longevity than first parity EBVs.