The effect of gestation and lactation on bone calcium, phosphorus and magnesium in dairy cows.

摘要: A study was conducted to monitor changes in cortical bone mineral the dairy cow response demands of lactation and pregnancy using rib biopsies serial sampling. Sixteen Friesian cows from University herd were used collect 9 samples during period 5 dry period. The data analysed a split-plot design analysis variance. There no significant (P > 0.05) differences phosphorus concentrations period, but calcium significantly Ca or Mg gestation Cortical P thickness < greater at end compared first 30 days In general, values decreased as milk production increased up 20 kg/day increased. animals producing over kg/day, however, lower those less than kg.