Osteochondrosis, skeletal abnormalities and enzootic ataxia associated with copper deficiency in a farmed red deer (Cervus elaphus) herd

Abstract

A red deer herd of 150 mixed-age hinds, 48 stags and 102 weaners was identified as severely copper deficient during an observational study of 15 deer farms in the lower North Island of New Zealand during 1992 and 1993. Severe lameness was observed in nine weaners in 1992 (8.8% prevalence) and 15 in 1993 (12% prevalence). Typical abnormalities included swollen hocks and carpal joints and outward rotation of hind legs with hocks touching. At postmortem examination, there were epiphyseal fractures of the femoral head, severe degenerative arthropathy of the coxo-femoral joints and erosions of cartilage in many other limb joints. Osteochondrosis was confirmed histologically. Concurrently, three adult hinds and one adult stag developed into-ordination typical of enzootic ataxia which was confirmed histologically. Blood and liver copper concentrations in untreated affected weaner deer ranged from undetectable to 16.0 micromol/l (mean 7.6 micromol/l) and 25 to 53 micromol/kg (mean 39 micromol/kg), respectively. Mean blood copper concentrations in unaffected weaners in March 1992 and 1993 were 5.3 micromol/l and 4.4 micromol/l, respectively. The mean blood copper concentration in seven hinds in September 1992, prior to onset of clinical signs of enzootic ataxia, was 1.5 micromol/l (range 1.0-2.4 micromol/l). At other times of the year, mean blood copper concentrations ranged up to 12.5 micromol/l in adults and 8.9 micromol/l in weaners before treatment began in 1993. Pasture analyses showed copper contents of 6-11 ppm in 11 samples collected during 1992 and 1993. Sulphur ranged from 0.18 to 0.37%, molybdenum from 0.51 to 3.56 ppm and iron from 130 to 2886 ppm. These measurements supported a diagnosis of secondary copper deficiency. Supplementation with oral oxidised copper wire particles was undertaken from December 1992, resulting in an improvement in blood copper concentrations in some classes of deer. No further clinical abnormalities have been observed.