Data on various grades (3/8, 7/16, 5/8, 3/4, 15/16 and 55 to 75%, named Frieswal) of Holstein
Friesian x Sahiwal cows maintained at the Military Dairy Farm, Secunderabad, over a period of 19
years (1988-2006) were utilized to study the effect of various levels of Holstein Friesian inheritance
and period and season of birth on body weights from birth to 24 months age. Genetic grades affected
the body weight at 1, 21 and 24 months of age whereas the period of birth significantly affected body
weights at all ages studied. Season of birth affected body weight at 3, 6, 12 and 21 months age.
Heritabilities of body weights ranged from 0.08 to 0.63 while the genetic correlations ranged
from -0.14 to 0.97.