Reduction in P concentration from 3.4 to 2.3 g P/kg DM reduced DMI, milk yield,milk
protein yield and plasma Pi concentration, and increased serum concentration of CTX, but
did not affect serum concentration of OC inearly lactation. Reduced dietary P concentration from 3.4 to 2.8g P/kg DM did not affect DMI or milk production in early lactation.Dry
matter in take and milk yield were not affected by dietary P concentration in late lactation.
Plasma Ca increased in LP, whereas there was no effect on serum concentration of P THor
on plasma concentration of vitamin D3 pre-partum, inearly or late lactation.Despitean
estimated mobilization of P in early lactation,on the basis of results of CTX and OC,itis
not possible to reduce P concentration from 3.4 to 2.3g P/kg DM in dairy cows in this
period without compromising DMI and milk production.There sults in dicatea potential
for reducing P concentration in early and late lactation from the current recommendations
of 3.4to2.8gP/kg DM without effects on performance,but this level of dietary P might
not allow for repletion of bone P mobilized in early lactation