Effects of dietary vitamin D3 on concentrations of vitamin D and its metabolites in blood plasma and milk of dairy cows

J Dairy Sci. 1985 Aug;68(8):1959-67. doi: 10.3168/jds.S0022-0302(85)81057-2.

Abstract

To determine the effect of supplemental dietary vitamin D3 on concentration of vitamin D and its metabolites in milk, 20 Holstein cows were assigned to four groups and fed either 0, 10,000, 50,000, or 250,000 IU of vitamin D3/d beginning approximately 2 wk prepartum and continuing through wk 12 of lactation. Samples of blood plasma and milk were assayed for concentrations of vitamin D, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D. Only the daily dosage of 250,000 IU caused significant increases of concentrations of vitamin D or 25-hydroxyvitamin D in plasma. Concentrations of vitamin D and 25-hydroxyvitamin D in milk were approximately equal and averaged .2 ng/ml. Little 1,25-dihydroxyvitamin D and no 24,25-dihydroxyvitamin D could be detected in milk from any of the four treatment groups. Cows fed 250,000 IU of vitamin D3/d produced milk containing 54 IU of vitamin D activity per liter, whereas unsupplemented cows produced milk containing 17 IU/L. Oral supplementation with up to 250,000 IU of vitamin D3/d does not increase effectively vitamin D activity of milk.

MeSH terms

  • 24,25-Dihydroxyvitamin D 3
  • Animals
  • Calcifediol / blood
  • Calcitriol / blood
  • Cattle / metabolism*
  • Cholecalciferol / administration & dosage*
  • Cholecalciferol / blood
  • Dihydroxycholecalciferols / blood
  • Female
  • Food, Fortified
  • Milk / metabolism*
  • Pregnancy
  • Vitamin D / metabolism*

Substances

  • Dihydroxycholecalciferols
  • Vitamin D
  • Cholecalciferol
  • 24,25-Dihydroxyvitamin D 3
  • Calcitriol
  • Calcifediol
  • 25,26-dihydroxycholecalciferol