Some Factors Influencing the Male Hormone Content of Cow Manure

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Abstract
Manure from cows of the Guernsey, Holstein and Jersey breeds during various physiological states was dried at 45[degree]C and assayed biologically for male (androgenic) hormone. Sexually mature non-pregnant heifers excrete male hormone at a level comparable to those of mature cows. During the first 2/3 of pregnancy, no tendency for a rise in androgen excretion was observed. There was evidence of a preparturient rise in androgens. With the advance of lactation, no change in androgen excretion was noted except when associated with the approach of the subsequent parturition. Dried cow manure from the Guernsey and Holstein breeds appeared comparable in biological activity; the Jersey cows appeared to excrete slightly more male hormone. It is suggested that the preparturient rise in androgen may be related to the marked rise in estrogen at the same time. It is possible that androgens as well as estrogens play roles in the stimulation of the secretion of the lactogenic hormone by the pituitary at the time of parturition.