The estimated average requirement ( EAR ) for protein in early and late gestation was determined to be 1.22 ( R ( 2 ) = 0.60 ; 95 % CI : 0.79 , 1.66 g kg ( -1 ) d ( -1 ) ) and 1.52 g kg ( -1 ) d ( -1 ) ( R ( 2 ) = 0.63 ; 95 % CI : 1.28 , 1.77 g kg ( -1 ) d ( -1 ) ) , respectively .