A52-75-2007E.pdf - AgroMedia International Inc

Genetics1The value of genetic information in selecting dairy replacementsCorresponding AuthorRadke, B.R.University of AlbertaCollaboratorsLloyd, J.W.Michigan State UniversityBlack, J.R.Michigan State UniversityHarsh, S.Michigan State UniversityPreventive Veterinary Medicine (2005) Vol. 71 p. 71-81.The primary goal of dairy herd replacement management is to raiseenough heifers to replace culled cows. Ideally, when a culling decision ismade, the replacement will provide more profit than the cow she replaces.What information can be used to select replacements and how valuableis the information? It is often suggested that genetic estimates, based onthe heifer’s pedigree should be used. The objective of this paper was todetermine the actual dollar value of that information, based on the recordsof 115 Holstein herds in Michigan. Data for each of 1,982 potential replacementsincluded estimated breeding value for milk (EBV) at the beginningand end of the rearing period and her estimated lifetime profit. Using aneconomic model of herds selecting 70 or 80% of potential replacements,herd profit was calculated for 3 selection methods. ‘Ex poste’ selection assumesthat selection could be made with perfect knowledge of a heifer’sfuture performance and the profit she will contribute to the herd. Randomselection is based on using none of the available information to predict herfuture profitability. Genetic selection is based on each heifer’s EBV. The valueof random or genetic selection was calculated by comparing averageherd profit per replacement with the value that would have been achievedusing ex poste selection. Using EBV to select replacements increased herdprofit by $22 to $30 per replacement, compared with random selection.Genetics 55