passages.id: split_1_test_3204_passage
passages.type: progene_text
passages.text: The serum sIL1R2 concentrations were 5.56 +/- 0.69 ng / ml ( colostrum ) , 3.14 +/- 0.72 ng / ml ( the early stage of lactation ) and 5.76 +/- 1.25 ng / ml ( the late stage of lactation ) .