The aims of this study were to estimate the variance components and heritability estimates for some lactation
and reproduction traits of Egyptian buffaloes using a repeatability animal model and Random Regression
Model (RRM) and plot the genetic and phenotypic trends. A total number of 7345 test-day records (TD) of milk
yield (TDMY), fat yield (TDFY), protein yield (TDPY) and somatic cell score (TDSCS) were gathered monthly
from 686 buffaloes. Also, a total number of 7279 reproduction records were collected from 1951 buffaloes. All
herds belong to the Animal Production Research Institute (APRI), Ministry of Agriculture and Land
Reclamation (MALR), Egypt. The genetic trends for lactation traits favorably increased from -4.63 kg to be 1.61
kg for TDMY, -5.0 g to be 495 g for TDFY and -26 g to be 280 g for TDPY, associated with favorably
decreasing trend from 1.19 to be 1.37 for TDSCS as year of TD of milk advanced. On the contrary, the
phenotypic trends decreased from 7.49 to 5.69 kg for TDMY, 510 to 360 g for TDFY and 284 to 223 g for
TDPY, while that of TDSCS increased to be from 1.62 to 2.43. The genetic trends for reproduction traits slightly
decreased from 0.24 mo to be -0.14 mo for AFC, 5.5 d to be 2.9 d for DO and 6.9 d to be 3.6 d for CI, while the
phenotypic trends favorably decreased from 36.57 to 36.52 mo for AFC, 127 to 71 d for DO and 416 to 354 d
for CI.