GENETIC CHANGES FOR DAILY MILK YIELD AND MILK CONTENTS IN EGYPTIAN BUFFALO BULLS

Predicting the characteristics of buffalo milk lactation curves is more important for sustaining the genetic diversity in Egyptian native populations. The Wood's function was fitting for individual test-day records over the entire range of calving, from 1999 to 2021, in three experimental buffalo herds at the Animal Production Research Institute of the Agricultural Research Center. Wood’s daily milk yield (WM), daily peak milk yield (PM), days to peak milk yield (DP), persistency (PS), fat percentage (FP), and protein percentage (PP) were estimated using the best linear unbiased prediction (BLUP) approach for predicting daily genetic values of the studied bulls. Genetic changes for the studied traits were obtained as the regressing the average estimated daily breeding values (EDBVs)of bulls on birth year of their daughters over three generation interval for assessing the genetic progress. The average EDBVs for the investigated traits were found to be lower and insignificant. EDBVs varied from -0.30 to 0.31 for WM, -0.23 to 0.19 for PM, -0.14 to 0.25 for PS, -2.5 to 6.63 for DP, -0.56 to 0.09 for FP, and -0.44 to 0.21 for PP over the three separated lactations. Chiefly, bulls' genetic responses are either positive or negative and insignificant over the study period. These findings suggested implementing sustained straight-breeding schemes for the experimental native Egyptian buffalo populations