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

AIMS: This paper reviews the principles for the establishment of biochemica l reference criteria for assessing the trace element status of farmed lives tock and summarises data for copper, selenium, vitamin B-12 and iodine for farmed red deer. COPPER: Enzootic ataxia and osteochondrosis occur when liver copper concent rations are below 60 mu mol/kg fresh tissue, and serum copper concentration s are below 3-4 mu mol/l. Growth responses to copper supplementation have b een equivocal when blood copper concentrations were 3-4 mu mol/l, but were significant when mean blood copper concentrations were 0.9-4.0 mu mol/l. No antler growth or bodyweight response to copper supplementation was observe d when blood ferroxidase levels averaged 10-23 IU/l (equivalent to serum co pper concentrations of 6-13 mu mol/l) and liver copper concentrations avera ged 98 mu mol/kg fresh tissue. These data suggest that 'deficient', 'margin al' and 'adequate' ranges for serum copper concentrations should be <5, 5-8 , and >8 mu mol/l, respectively, and those for liver copper concentrations should be <60, 60-100, and >100 mu mol/kg, respectively. SELENIUM: White muscle disease has been reported in young deer with blood a nd 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 ex pected in sheep. VITAMIN B-12: Vitamin B-12 concentrations in deer are frequently below 185 pmol/l without clinical or subclinical effects. No growth response was obse rved in young deer with vitamin B-12 concentrations as low as 75-83 pmol/l. A growth response to cobalt/vitamin B-12 supplementation occurs in lambs w ith serum vitamin B-12 concentrations <336 pmol/l. CONCLUSIONS: Data that can be used to establish reference ranges for assess ing 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.