The factor with the greatest impact on calf mortality up to 21 days of age is colostrum management. Calves which did not receive colostrum had a increased risk of dying 74 times greater than that for calves receiving colostrum by the recommended method. The method associated with the least calf mortality was to feed at least 2 quarts of first milking colostrum via bucket or bottle within the first 6 hours after birth. A comparison of the methods of colostrum feeding and other factors is shown below:

Feeding colostrum via an esophageal feeder may be itself not be associated with increased risk of mortality, however, this method is usually used when calves are weak and unable to nurse. Whatever disposed the calf to weakness (i.e. some sort of health problem), may be the cause of the increased mortality. Or perhaps there might be problems with tubing technique or cleaning of the feeders themselves.

In addition to these factors, feeding pasteurized colostrum and milk has also been shown to reduce early calfhood sickness from scours and respiratory diseases compared to feeding unpasteurized colostrum and milk. This is thought to be from reduced bacterial load in the colostrum and milk.