Restricting Growth of Cattle Without Depressing Lactation

Abstract

Eight pairs of identical-twin heifers of mixed breeding and 34 pairs of non-twin purebred Holstein and Jersey heifers were used in a comparison of effects of slow growth and normal growth on lactation. Normal growth heifers received some concentrates up to 18 months of age and hay (or pasture) ad libitum. The slow growth heifers were limited to 69.5% of the total digestible nutrients (TDN) of the controls up to 91 wk, during which time they gained 81.3% as much body weight as the controls. In the 12-wk prepartum period, concentrates were fed to the slow growth heifers but not the controls. The supplemental prepartum feeding accelerated growth rate of the slow growth heifers above the controls, so that they were approaching the controls in body weight at calving. First lactation milk yields of the slow growth heifers averaged slightly, but not significantly, higher than those of the controls. Fat-corrected-milk (FCM) yields of the twins, purebred Holsteins, and purebred Jerseys, respectively, averaged 3,403, 4,696, and 2,837 kg for the controls, and 3,501, 4,796, and 3,337 kg for the slow growth heifers. A slow growth rate will not affect first lactation yield if prepartum supplemental feeding to improve body condition is practiced. Overall TDN savings of 20 to 25% of standard may be attained. © 1967, American Dairy Science Association. All rights reserved.