Effect of Rapid Growth with Fattening of Dairy Heifers on Their Lactational Ability

Abstract

Identical twin heifers were separated at 4 to 12 mo. and reared either normally, with little grain feed, or by nearly full feeding of grain along with hay. The latter fattened heifers were 32% heavier than their mates at 2 yr. After calving they were fed alike. Milk production of 7 fattened twins averaged only 84.8% as much as normals. The lower average production of fattened twins persisted also in the 2d lactation. Udders of some of the rapidly grown twins were incompletely developed, with open areas lacking lobule-alveolar tissue.