Variation of zinc and copper concentrations in the plasma of Nubian goats according to physiological state

The association between the combination of age and physiological status of dairy Nubian goats, pregnancy or lactation and blood concentration of zinc (Zn) and copper (Cu) was investigated. The animals were divided into (a) young (4–6 months old), (b) adult (9–12 months old), (c) pregnant (within 50 days of their first pregnancy and (e) lactating animals grouped according to parity (up to 50 days after first, second or third kidding). Each group or sub-group consisted of five animals. The data analysis revealed that plasma Zn concentration decreased (3.91–1.12 mg/l) significantly with increase in age. There was a significant increase in Zn levels in high yielders compared to low ones (2.00–6.59 mg/l). Cu plasma levels increased (5.01–3.17 mg/l) significantly in adult compared to young animals but decreased (5.01–4.13 mg/l) significantly after first kidding compared to second and third kidding as well as in pregnant animals. It can be shown that the different physiological states would impose certain demands on animal needs for these trace elements and hence adequate amounts in the diet should be accounted for to achieve the best animal performance.