Absolute and relative concentrations of immunoglobulins G, M, and A, and albumin in the lacteal secretion of sows of different lactation numbers.

The concentrations of immunoglobulin (Ig)G, IgM, IgA, and albumin in the lacteal secretion of 80 sows were measured not more than 14 times during lactation to determine whether the age of the sow, the anatomic location of the mammae, or the farrowing barn housing of the sow influenced Ig concentrations. The combined data indicated that there were lactation stage-dependent changes in the total Ig concentration, as well as changes in the relative importance of the 3 classes of Ig studied. Mean values of any one time point showed enormous variation in absolute values, with coefficients of variation ranging up to 70% The largest variations were observed between colostral samples obtained on the first day. The IgM showed the least variation on day 1. Such variations hindered attempts to statistically identify their source. Normalization of Ig concentrations in relation to albumin concentrations decreased some of the apparent variation. Normalized data accentuated the changeover from colostrum to milk which occurred after the first 3 days. There was also a 3-fold increase in IgA concentrations which occurred during the last 4 weeks of lactation. Data showed that older sows tended to have higher concentrations of all Ig. Lactation number-dependent increases in IgM and IgG were restricted to colostrum in lactation numbers higher than 4. Immunoglobulin A increased in a similar pattern and, in addition, increased in mature milk in sows with more than 2 lactations. The enormous variations observed seemed to be individual animal variations. This allowed only trends, rather than statistically significant differences, to be recognized.(ABSTRACT TRUNCATED AT 250 WORDS)