Epidemiological investigation of health and performance of Holstein dairy heifers

A prospective cohort study was undertaken to determine calf-level factors that affected calf health status and performance (growth) from birth to 14 months of age. A convenience sample of approximately 3300 Holstein calves from two large Florida dairy farms were used for the study. Data collected on each calf at birth included farm of origin, weight, height at the pelvis, birth date, and serum total protein (a measure of colostral immunoglobulin absorption). Birth season was dichotomized into summer and winter using meteorological data collected by University of Florida Agricultural Research Stations. Data collected at approximately 6 and 14 months included age, weight, height at the pelvis, and height at the withers. Growth in weight and stature (height) was calculated for each growth period; growth period 1 (GP1) = birth to 6 months and growth period 2 (GP2) = 6 to 14 months. Health data including date of initial treatment and number of treatments were collected monthly for the diseases diarrhea, omphalitis or 'navel infection', septicemia, pneumonia and keratoconjunctivitis or 'pinkeye'. (Abstract shortened by UMI.).