Calves born after a difficult birth are at a high risk of failing to receive adequate colostrum by natural suckling because of greatly decreased colostrum intake. Calves that are born to a prolonged stage II of parturition (delivery through the pelvic canal) very often suffer from severe respiratory acidosis. Acidotic calves are less efficient at absorbing colostral immunoglobulins even if artificially fed colostrum, therefore effort should be made to provide weak newborn calves with the best source of colostrum available via bottle suckling or tube feeding.
The amount of immunoglobulin ingested is also a major determinant of final serum immunoglobulin concentration. A practical "rule-of-thumb" is to feed 5 to 6% of the calf's body weight within the first 6 hours and repeat the feeding when the calf is about 12 hours old. For an 80 pound calf, this will equate to approximately 2 quarts of colostrum per feeding. Consequently, if the calf is quite large (about 100 pounds), then the amount of colostrum will need to be increased accordingly to 2 ½ quarts per feeding.