Using Selection Indices to Improve Lactation Curve Parameters in Egypt

- The buffalo's number in Egypt is estimated to by 3.9 million. - They are one of the main dairy animals in Egypt; their contribution to the country’s milk production is nearly 45.5 % (FAOSTAT, 2013). - Aims: - Investigating genetic improvement possibilities for TD milk yield traits and their lactation curve parameters. - Determining genetic and phenotypic trends for TD milk, fat and protein yields applying a Random Regression Model. - Generating a S.I. for milk production and persistency using eigenvalue and eigenvector indices derived from Random Regression Model. - Results: - Genetic selection for curve parameters (initial, persistency and maximum milk yield) would improve total milk yield traits especially persistency. - Both of the first and the second eigenvalues explained 96% of the variation in improving milk yield and persistency. - Selection based on the second individual eigenvector index is expected to better improve the persistency. - If the breeding goal is to improve persistency and milk yield, then using the 2nd eigenvector index (I*2) with a relative economic value of 1:25 is recommended.