The change of dry matter intake, milk yield and bone turnover in primiparous cows compared to multiparous cows during early lactation

摘要

Data from six primiparous and nine multiparous Holstein cows were used to clarify the difference of Ca and P mobilization between primipdrous and multiparous cows during early lactation. The dry matter intake (DMI) of primiparous cows was lower (P< 0.01) than those of multiparous cows. Milk yield was lower in primiparous cows at 7, 14, 21 (P< 0.01), and 28 days (P< 0,05) after parturition. There was no significant difference in milk Ca and P concentrations between primiparous and multiparous cows. There were no significant differences in plasma Ca and P concentrations between primiparous and multiparous cows. The plasma P level at 7 days postpartum in primiparous cows was lower (P< 0.05) than 28 days postpartum. The concentration of plasma osteocalcin (OC) measured as bone formation marker of primiparous cows was significantly higher than multiparous cows (P< 0.01) at 21 and 28 days postpartum. The urinary deoxypyridi-noline (DPD) as bone resorption marker of primiparous cows tended to be higher (P< 0,10) than multiparous cows at 21 days after parturition and decreased to the same level as that of multiparae toward the peak lactation. These results show that Ca and P mobilization of primiparous cows are more active than multiparous cows.