Macromineral and trace element concentrations and their seasonal variation in milk from organic and conventional dairy herds

To study the effects of dairy production system on milk macromineral and trace element concentrations, samples were collected monthly in 2019 from 43 conventional 27 organic farms. Organic contained more Ca (1049.5 vs. 995.8 mg/kg), K (1383.6 1362.4 P (806.5 792.5 mg/kg) Mo (73.3 60.6 ?g/kg) but less Cu (52.4 ?g/kg), Fe (0.66 vs 2.03 Mn (28.8 45.0 Zn (4.51 5.00 Al (0.32 1.14 than milk. Significant seasonal variation was observed all determined minerals’ concentrations. Milk I concentration not consistently affected by system, whereas June July Dietary factors contributing to different mineral concentrations between systems included intakes maize silage, dry-straights oils (higher diets), pasture, clover wholecrop diets).