Breastmilk obtained within the first 48–72 hours after delivery by manual expression contains a higher fat content than breastmilk obtained by an electric pump. 
The higher fat content of manually expressed breastmilk during the first 72 hours following delivery may be due to the presence of hindmilk in the manually expressed milk.This may occur because the technique of massaging the breast during manual expression may result in the ejection of hindmilk, which has higher fat content than foremilk. Enhanced caloric intake during the early days following birth may be advantageous to a newborn in preventing excessive weight loss and/or in reducing the development of high bilirubin levels.
Mangel L, Ovental A, Batscha N, Arnon M, Yarkoni I, Dollberg S. Higher fat content in breastmilk expressed manually: A randomized trial. Breastfeeding Medicine 2015;10:352-354.