The Prothrombin Time in the Newborn: Effect of Contact Activation

The effect of foreign-surface contact on prothrombin conversion in adult plasma is compared to that of the newborn. The tests utilized in this comparison were the one-stage prothrombin time of Quick, the second stage of the thromboplastin generation test, and the prothrombin consumption test or the serum prothrombin time. In all of these there is much less acceleration produced by foreign-surface contact in the plasma of the newborn. Acceleration of the prothrombin conversion time is directly related to an increase in activity of factors VII and XL At no time could an increase in prothrombin activity be demonstrated. The decreased acceleration produced by foreign-surface contact in the plasma of the newborn is due primarily to a decreased level of factor VII as well as those factors necessary for its activation.

Calfhood immunization against an experimental Parainfluenza and Pasteurella challenge

An inactivated vaccine including Parainfluenza-3, PASTEURELLA MULTOCIDA and PASTEURELLA HEMOLYTICA stimulated good immunity in calves against an experimental shipping fever challenge. Calves were first vaccinated when 4 to 10 weeks old and revaccinated at weaning age. There were higher HI titers, lower temperatures, and less lung lesions recorded in the vaccinated group when compared to the control animals.