Effect of parity on mineral concentration in milk and plasma of Holstein cows during early lactation

Plasma and milk samples of 24 periparturient Holstein cows were collected from 1 week prepartum to 10 week postpartum to measure the effects of parity on mineral status in periparturient cows. Cows were fed mainly mixed ration with the concentrate supplement during the experimental period to meet nutrient requirement of dairy cattle for TDN, protein, and minerals. Plasma Ca of cows decreased as parity increased, but plasma Mg, K, Fe and Zn were lowest in the first lactation cows. Plasma inorganic P, Na, and alkaline phosphatase were not affected by the parity. Plasma Ca, Fe and Zn of cows decreased at parturition, but plasma Mg increased. Plasma Ca of the first, second and third and more lactation cows at parturition were 9.65, 8.96, and 8.92 mg/dl, respectively. Colostral Ca, P, Mg, Na, and Zn were highest in the first lactation cows, although colostrum yield was lower. Milk yield from 1 to 10 weeks postpartum was lowest in the first lactation cows, but mineral concentrations in milk were not affected by the parity.