“…Wynn, Teramura, Sato, and Hanada () demonstrated that serum Ca concentrations after calving were positively associated with the rumen contraction frequency and DMI after calving. Although there was no significant difference in the serum Ca concentration at 3 days after calving between the first lactation heifers and the multiparous cows, the serum Ca concentration generally tends to be low in high parity cows (Teramura et al., ; Wynn et al., ). First lactation heifers can maintain serum Ca at steady concentrations without any treatments after calving because low parity cows absorb Ca efficiently, owing to active mechanisms of Ca homeostasis, including Ca absorption from the intestine and bone resorption (Bronner, ; Goff, Reinhardt, & Horst, ; Kamiya, Kamiya, Tanaka, & Shioya, ).…”