| Summary: | The study evaluates the effects of two dietary Ca : P ratios (1·5 : 1 v. 2·5 : 1) and metabolizable energy (ME) contents (17·3 MJ/kg dry matter ( DM) v. 19·2 MJ/kg DM) on the development of osteochondrosis, foot bending and performance in juvenile male blue foxes (Alopex lagopus). Four experimental groups (no. = 10 per group) were formed : (1) low energy, low Ca : P ( LELC); (2) normal energy, low Ca : P ( NELC); (3) low energy, normal Ca : P ( LENC); and (4) normal energy, normal Ca : P ( NENC). The experiment started at weaning in mid July and finished in early October. From mid August onwards, animals on the normal energy diets ( NELC, NENC) grew signi?cantly faster ( P < 0·001) than animals on the low energy diets ( LELC, LENC). The final body weights of the normal energy groups were 1·5 kg higher than those of the low energy groups ( P < 0·001). The dietary Ca : P ratio did not affect live-weight gain. Foot bending increased significantly from summer to autumn ( P < 0·001). Changes in foot bending between initial and ?nal evaluations showed that bending was significantly greater( P < 0·05) in animals on normal energy ( NELC, NENC) than on low energy diets ( LELC, LENC). Significant differences were not found in the mean degree of damage in foot and cartilage between the groups. Ulna breaking strength was significantly higher ( P < 0·05) in normal energy ( NELC, NENC) than in low energy ( LELC, LENC) animals. Ulna calcium and phosphorus concentrations of the normal Ca : P ( LENC, NENC) groups were significantly higher ( P < 0·001, P < 0·05) than those of the lower Ca : P ( LELC, NELC) groups. The bone (ulna) calcium and phosphorus concentrations tended to be higher in the normal energy ( NELC, NENC) than in the low energy ( LELC, LENC) groups (calcium P = 0·07; phosphorus P = 0·06). The bone Ca : P ratio was higher ( P < 0·001) in the normal ( LENC, NENC) than in the low Ca : P diet ( LELC, NELC) animals. The carcass weights of normal energy animals ( NELC, NENC) were signi?cantly ...
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