W.E. Petersen

Mammary Development in the Thyroprived Bovine by Stilbestrol and Thyroprotein Administration

Summary In the thyroprived cow with pronounced myxedema no mammary development was obtained by diethylstilbestrol or thyroprotein administration. Negative results were also obtained with the simultaneous administration of these two substances as long as myxedema persisted. Substantial mammary development and lactation resulted from diethylstilbestrol administration following recovery from myxedematous symptoms by thyroprotein therapy. It is suggested that the failure of mammary development in the myxedematous animal is due to some phase of the myxedema and that the response obtained following thyroid therapy is not due to a synergistic action of thyroxine and diethylstilbestrol.

Effect of Infused Penicillin in the Bovine Mammary Gland.

Summary Aqueous solutions of penicillin (sodium salt) containing 5,000 Oxford Units per ml had slight irritating effects on the normal bovine mammary gland as measured by physical examination of the gland, body temperature and changes in the character and quantity of milk. The largest dose infused was 40 ml (200,000 O.U.). Increase in body temperature, tremors and greater changes in the character of the milk were observed after penicillin was introduced in large volumes of water. Largest volume infused was 950 ml (190,000 O. U.). These effects may have been due to the pyrogenic properties in the water used. In glands infused with small volumes of water containing 5,000 O. U. per ml., the rate of decline of penicillin per ml of milk is greatest during the first 10 hours after which the decline is at a slower rate. The milk contained 0.5 or more units of penicillin per ml 24 hours after the infusion of 30,000 or more units. The disappearance rate from pathologic glands was of the same order as for the normal gland except in coli-form infections. When penicillin was introduced in large volumes of water the infused water was rapidly absorbed leaving most of the penicillin in the gland.

Effect of Infused Streptomycin in the Mammary Gland.

Summary (1) Streptomycin infused into the normal bovine mammary gland in amounts ranging from 100,000 to 500,000 units per quarter could be detected in milk samples as long as 48 hours following infusion. As determined by the assay procedure used, the concentration did not fall below 20 units / ml in any of the samples after a 24-hour interval. (2) The concentration per ml in the sample was found to vary with (1) the size of the dose (2) time interval between infusion and sampling and (3) milk production of individual quarters. (3) At no time was there sufficient streptomycin present in the blood to be detected by the assay procedure used. However, in both the cow and goat significant amounts were found in urine samples as long as 27 hours following infusion. (4) Under the conditions of these experiments streptomycin was found to be relatively non-toxic when infused into the normal bovine mammary gland.