A POSSIBLE LINKAGE BETWEEN GONADAL-HORMONES, SERUM AND UTERINE LEVELS OF IGG OF DAIRY-COWS

We have investigated the possible linkage between serum and uterine fluid immunoglobulin G (IgG) levels and the hormonal status of the cow. In cycling cows there was a significant (P < 0.01) drop in average (of 4 consecutive days) serum IgG levels, from 36.4 +/- 6.7 mg ml(-1) during the luteal phase of the estrous cycle to 28.3 +/- 5.3 mg ml(-1) during and around estrus. In prepartum cows, there was a significant drop (P < 0.01) from an average of 37.6 +/- 3.7 mg ml(-1) from 5 consecutive days, i.e. 11-7 before parturition, to 28.0 +/- 5.5 mg ml(-1) on the day of parturition. Total IgG in the uterine fluid ranged from 30 to 115 mg in one horn and from 24 mg ml(-1) to 70 mg ml(-1) in the other horn during the luteal phase, but was essentially undetectable at estrus. The drop in serum and uterine IgG occurred concomitantly with the drop in peripheral serum progesterone, from 2-3 ng ml(-1) at the luteal phase, and 11-7 days before calving to less than 0.5 ng ml(-1) around estrus and calving. Data suggest a possible linkage between steroid hormone and IgG levels.