EFFECT OF PREWEANING FEEDING OF PASTEURIZED AND NONPASTEURIZED MILK ON POSTWEANING WEIGHT-GAIN OF HEIFER CALVES ON A CALIFORNIAN DAIRY

The effect of preweaning feeding of pasteurized colostrum and pasteuri zed waste milk on postweaning performance of dairy heifers on a dairy in the Central Valley of California was investigated as an extension o f a clinical trial examining the effect of preweaning growth and morbi dity on performance at weaning, Of the 150 heifer calves originally en rolled in the field trial, 115 calves (59 treatment, 56 controls) were followed to about 6 months of age, during which time their weights we re measured. After weights were adjusted for several potential risk fa ctors and effect modifiers, calves fed pasteurized colostrum and paste urized waste milk were 3.7 kg heavier at 180 days of age than those fe d nonpasteurized colostrum and nonpasteurized milk.