A review of tissue reference values used to assess the trace element status of farmed red deer (Cervus elaphus)

Abstract AIMS: This paper reviews the principles for the establishment of biochemical reference criteria for assessing the trace element status of farmed livestock and summarises data for copper, selenium, vitamin B12 and iodine for farmed red deer. COPPER: Enzootic ataxia and osteochondrosis occur when liver copper concentrations are below 60 µmol/kg fresh tissue, and serum copper concentrations are below 3–4 µmol/l. Growth responses to copper supplementation have been equivocal when blood copper concentrations were 3–4 µmol/l, but were significant when mean blood copper concentrations were 0.9–4.0 µmol/l. No antler growth or bodyweight response to copper supplementation was observed when blood ferroxidase levels averaged 10–23 IU/l (equivalent to serum copper concentrations of 6–13 ώmol/l) and liver copper concentrations averaged 98 µmol/kg fresh tissue. These data suggest that ‘deficient’, ‘marginal’ and ‘adequate’ ranges for serum copper concentrations should be <5, 5–8, and >8 µmol/l, respectively, and those for liver copper concentrations should be <60, 60–100, and >100 µmol/kg, respectively. SELENIUM: White muscle disease has been reported in young deer with blood and liver selenium concentrations of 84–140 nmol/l and 240–500 nmol/kg fresh tissue, respectively. No growth-rate response to selenium supplementation occurred in rising 1-year-old deer when blood selenium concentrations were less than 130 nmol/l, the range in which a growth-rate response would be expected in sheep. VITAMIN B12: Vitamin B12 concentrations in deer are frequently below 185 pmol/l without clinical or subclinical effects. No growth response was observed in young deer with vitamin B12 concentrations as low as 75–83 pmol/l. A growth response to cobalt/vitamin B12 supplementation occurs in lambs with serum vitamin B12 concentrations <336 pmol/l. CONCLUSIONS: Data that can be used to establish reference ranges for assessing trace element status in deer are limited. More robust reference values for farmed red deer need to be established through further studies relating biochemical data to health and performance.