New-born calves excrete feces during the first week of life which show distinct variations in the gross appearance. A study was made, therefore, of the amount of fat present in the feces, from birth to the time when the calves were approximately a week old. It is during this time that the calf readjusts its metabolic activities from that of an intra-uterine existence to one in which it subsists by absorption from its gastro-intestinal tract. It was found in general that the fat content of feces increases from birth to approximately the third day, after which it decreases and assumes an approximately normal level. At the time of the high fat content, there is present in the feces a greater proportion of fatty acids in the form of soap, indicating a lack of absorption on the part of the young animal.
The method used for the determination of fat
HOWE PE. THE FAT CONTENT OF FECES OF YOUNG CALVES. Am J Dis Child. 1921;21(1):57-64. doi:10.1001/archpedi.1921.01910310062005