IgA Immunoglobulin Levels in Porcine Sera and Mammary Secretions

Abstract

IgA immunoglobulin levels were measured in the sera of 29 pigs from birth to maturity and in their dams. Adult levels were reached by 18-21 weeks of age. The serum IgA concentration at 6 weeks of age was double that of the concentration at 3 weeks and it appears that the IgA synthesis in young colostrum-fed pigs already has reached a significant level by 6 weeks of age. IgA immunoglobulin levels were estimated in porcine mammary secretions during the first 35 days of lactation and in secretions of individual mammary glands of vaccinated and non-vaccinated sows during the first 7 days of lactation. It appears that a 3-week-old pig receives 1.6 g of IgA per day via the milk of the dam and that IgA quantitatively is a major immunoglobulin in sows’ milk. There are significant differences in the IgA concentrations in secretions from individual glands of a SOW and in the IgA concentrations from different SOWS. Intramammary vaccination with an E. coli vaccine had no apparent influence on the quantity of IgA in secretions from the vaccinated gland when compared to the concentrations in non-vaccinated glands from the same sow or to the concentration in secretions from non-vaccinated sows. The significance of mammary secretion IgA in relation to enteric diseases in suckling pigs is discussed.