Assessment of Reference Values for Copper and Zinc in Blood Serum of First and Second Lactating Dairy Cows

Table 2

Mean copper and zinc contents of the different feed components (mg/kg DM).

	Cu	Zn
Grass silage ($n$ = 10)	8.2 ± 1.4	34.0 ± 5.9
Maize silage ($n$ = 10)	4.8 ± 0.5	23.7 ± 2.6
Concentrate A ($n$ = 9)	18.2 ± 0.5	105.5 ± 2.9
Concentrate B ($n$ = 9)	47.3 ± 1.4	243.3 ± 7.1
Total ration A ($n$ = 9)	11.1 ± 1.6	61.9 ± 17.0
Total ration B ($n$ = 9)	22.6 ± 4.9	113.0 ± 30.0