Changes in immunoglobulin A and immunoglobulin G concentrations in the saliva of Japanese Black beef cows during calving: A pilot study

Abstract

Immunoglobulin A (IgA) in saliva, mostly consisting of secretory IgA, plays an important role in the mucosal immune mechanism. This study evaluated changes in salivary IgA and Immunoglobulin G (IgG) concentrations in Japanese Black cows (n = 16) during calving. Individual saliva samples were collected À2, 0, and 2 weeks postpartum. Immunoglobulin concentrations differed significantly among weeks (P < 0.05), but the effect of parity and week  parity was insignificant. Salivary IgA concentrations decreased drastically (P < 0.05) after calving compared with those at À2 weeks postpartum and remained low until 2 weeks postpartum. The salivary IgG concentrations decreased gradually during peripartum and differed at À2 and 2 weeks postpartum (P < 0.05). Considering the immunoglobulin concentrations at À2 weeks postpartum as the reference standard for 100%, the rates of decrease in IgA concentrations (36.7 AE 6.9%) were significantly lower (P < 0.05) than those of IgG (70.3 AE 10.1%) at calving day. To our knowledge, this is the first report indicating that salivary IgA concentrations decreased drastically after calving in Japanese Black cows. Further studies monitoring the secretory functions of IgA in the salivary gland are essential for understanding maternal immunity in cattle.