Some Physical Characteristics of the Tissue and Contents of the Rumen, Abomasum and Intestines in Male Holstein Calves of Various Ages

A total of 59 calves were slaughtered at ages varying from 8 days to 16 weeks. Mean weights of rumen contents and tissues are presented. A pronounced increase in these weights occurred between the ages of 32 days and 6 weeks. A change in the characteristics of the rumen contents occurred by the age of 6 weeks and it appeared that rumination, as measured by the criteria of this experiment, had begun at this age. Mean-weights of tissue and contents are presented for other parts of the digestive tract for the young calves, along with pH, dry matter and other observations on the nature of the contents.