Estimation of lactation curve in Jersey and Holstein-Friesian crosses with local cattle of Assam

Abstract

The data on weekly milk yield of 135 lactational records ofJersey and Assam Local (JxL) cross and Holstein-Friesian and Assam Local cross (HFxXL) cows with the level of exotic inheritance ranging from 50.0% to 87.5% maintained over 5 years fi'om 1998 to 2002 at the University were utilized to fit the gamma type and fifth degree polynomial function average records of four lactations. Polynomial function of degree five has been adjusted as more stable (I =5.51, 1=5.93) compared to gamma type function 0,=11.32, 1:::::7.83). Polynomial function having the power of explaining 91 to 96% of variation as that of 70 to 90