Aphosphorosis in North Yemen cattle.

A syndrome of unthriftiness, stiffness, anorexia, recumbency and pica in cattle of the Yemen Arab Republic was investigated for the first time. The condition is virtually confined to cows in the Central and Northern Highlands where they are housed continuously and hand fed fresh lucerne and dried sorghum stalks frequently supplemented with domestic scraps. Affected cows had a low mean blood inorganic phosphorus (0.6 mmol/litre) but normal serum calcium and magnesium. Blood phosphorus and serum calcium levels were negatively correlated and fluctuated seasonally, possibly associated with rainfall. The basic diet of lucerne and sorghum stalks was adequate for maintenance but deficient in phosphorus, energy and protein for milk production. The high calcium content of the lucerne portion resulted in wide calcium: phosphorus ratios of 8.8 to 16.5:1. The similarity of the syndrome to osteomalacia caused by phosphorus deficiency in other parts of the world is discussed.