Subclinical hypocalcemia is a common metabolic disorder of dairy cows that occurs during early lactation.Many studies have focused on the involvement of calcitropic hormones in hypocalcemia;however,little is known about calcitonin, PTH and 1,25 (OH)2D3 concentrations in dairy cows with subclinical hypoealcemia.Other mineral elements may also play prominent roles in regulating Ca homeostasis and may be involved in the pathogenesis of subclinical hypocalcemia in dairy cows;these hypotheses have not been verified so far.The aim of the study was to measure the serum concentrations of macrominerals elements, major calcitropic hormones and signal molecules related to energy metabolism levels of healthy periparturient cows and to compare the state of energy metabolism and the concentrations of macromineral elements and major calcium-regulating hormones in the serum of cows with subclinical hypocalcemia and healthy cows.Blood samples were taken from 219 multiparous Holstein cows near parturition.Fifty-one cows were identified as having subclinical hypocalcemia given their parity, body condition score (BCS) and total blood Ca levels (total blood Ca 1.4-2.0 mmol/L);51 cows with normal Ca levels (total blood Ca 2.0-2.5 mmol/L within 24 h postpartum) and no obvious signs of other diseases were selected as healthy cows (the control group).The blood samples were collected from the coccygeal vein in the morning before feeding.Nine blood biochemical parameters were evaluated by means of individual analysis method.The results showed that the serum concentrations of Ca and K were lowest at parturition.Calcium concentrations remained low during the first 2 wk postpartum then rose gradually;K levels increased gradually to reach their baseline levels within 2 wk postpartum.Mg serum concentrations were lowest at 1 wk postpartum and subsequently returned to their baseline levels.Serum Na levels peaked at parturition (day 0) then decreased gradually to their baseline levels.Serum P concentrations peaked during the first week prepartum and returned to baseline levels at parturition.Serum C1 concentrations peaked during the first week postpartum then decreased gradually and remained low during lactation;Serum PTH concentrations peaked at calving and returned to baseline levels during the first 4 wk postpartum.Serum 1,25 (OH)aD3 concentrations were highest during the first week postpartum and remained high for the first 4 wk postpartum.Calcitonin concentrations did not significantly fluctuate during the peripartum period;The levels of macromineral elements and major calcium-regulating hormones (with the exception of calcitonin) change dramatically in dairy cows during the periparturient period, particularly at or near calving.In contrast to the healthy cows, subclinically hypocalcemic dairy cows had significantly lower serum levels of calcium, potassium, sodium, magnesium, chlorine, 1,25 (OH) 2 D3 and glucose (P < 0.05) and significantly higher levels of serum phosphorus, non-esterified fatty acids (NEFAs) and β-hydroxybutyrate (BHBA) (P < 0.05).There were no significant differences in calcitonin and PTH concentrations in the two groups of cows.The present data indicate that the subclinically hypocalcemic cows experienced a blunted PTH response and a more severe negative energy balance, which can aggravate the subclinical hypocalcemia and may increase the animals risk of acquiring other metabolic diseases.