Stress and Blood Components in Swine

T HIS study was conducted in two phases. Phase one involved eight swine that were catheterized to facilitate blood collections at 8 am, 4 pm and midnight to determine circulating levels of plasma hydrocortisone, growth hormone, glucose, lactate, sodium, potassium, chloride and blood pH. Growth hormone levels decreased significantly from the 8 am to the 4 pm collection. Hydrocortisone levels were highest in the morning, lowest in the afternoon and increased slightly at the midnight collection. Plasma lactate, sodium and potassium values were highest at the 8 am collection, but the differences were not significant when compared with the 4 pm and midnight values. Phase two compared arterial and venous blood from 10 pigs for the same parameters studied in phase one. No significant differences in mean values were obtained when the two blood sources were compared, except for blood pH. The venous blood had significantly lower values than did arterial blood. Postmortem longissimus muscle color and lactate values were in normal ranges for the pigs used in both studies.