A study was made of the reaction of the white blood corpuscles in bovines at parturition.
Graphs made from the differential total counts of the white blood corpuscles from shortly before calving and at intervals through the period of parturition and for 24–48 hr. after calving show a definite absolute lymphopoenia with a rise in the neturophils.
The type of graph produced resembles that found in bovines when cortisone is injected.
The peak of the white blood cell reaction usually takes place about 5–9 hr. after the delivery of the calf. This is also the period of the peak reaction in the cellular relations after injection of cortisone.
The observations recorded seem to afford positive evidence that C 11 hydroxy steroids (cortisone) are poured out in the last stage of parturition in the normal bovine. The desensitization of the skin in animals which were sensitized to Trichomonas foetus an which was found at this time is considered to be connected with the action of the hormone.