Abstract:
Since 1982, farmers in the North West province and other parts of South Africa have noticed an
increase in the incidence of lameness in cattle. Macro- and microscopical lesions of joints
resembled osteochondrosis. Pre-trial data indicated that cattle with osteochondrotic lesions
recovered almost completely when fed a supplement containing bio-available micro- and
macrominerals of high quality. In the present trial, 43 clinically affected cattle of varying ages
(1–5 years) and sexes were randomly divided into three groups. Each group was fed the same
commercial supplement base with differing micro- and macromineral concentrations to
determine the effect of mineral concentrations on the recovery from osteochondrosis. Both
supplements 1 and 2 contained 25% of the recommended National Research Council (NRC)
mineral values. Additional phosphate was added to supplement 2. Supplement 3, containing
80% of the NRC mineral values, was used as the control. Results from all three groups indicated
no recovery from osteochondrosis. Urine pH of a small sample of the test cattle showed
aciduria (pH < 6). Supplement analysis revealed addition of ammonium sulphate that
contributed sulphate and nitrogen to the supplement. Supplementary dietary cation anion
difference (DCAD) values were negative at -411 mEq/kg, -466 mEq/kg and -467 mEq/kg
for supplements 1, 2 and 3, respectively, whereas the pre-trial supplement was calculated at
+19.87 mEq/kg. It was hypothesised that feeding a low (negative) DCAD diet will predispose
growing cattle to the development of osteochondrosis or exacerbate subclinical or clinical
osteochondrosis in cattle.
