All silage forage programs for dairy cattle. III. Health, survival, and reproduction

Holstein-Friesian heifer calves were fed roughage consisting of corn silage only, corn silage and haycrop silage (60:40, dry matter), or corn silage and dry hay (60:40 dry matter) from birth through completion of three lactations. Forages were fed ad libitum throughout and supplemented as required. Objectives were to determine effects of forage on survival, health, and reproduction. Of the 15 calves allotted per treatment 6, 10, and 7 completed three lactations fed corn silage, corn silage plus haycrop silage, or corn silage plus hay. At any time fewer animals survived on corn silage treatment resulting in 22 completed lactations compared to 36 and 29 lactations for those receiving haycrop silage or hay. Primary reasons for removal from experiment were enzootic pneumonia, 7; reproductive failure, 8; and mastitis, 6; and not forage treatment. Fewer animals on corn silage treatment were primarily from calfhood pneumonia. Reproduction measured by age at first calving (24.6 mo), calving interval (398 days), and services per conception (2.1) was similar across treatments. Incidence of health problems was in normal ranges and similar across treatments. Forage treatment had no effect on incidence of ketosis, left displaced abomasum, or simple indigestion.