The skeletal development of three groups of great dane dogs, fed a diet composed according to the published nutritional requirements for dogs (controls) or with increased
calcium or
calcium and
phosphorus content, was examined radiographically, histologically and biochemically. The diets were fed from the time the dogs first began eating food in addition to their dam's milk, until they were 17 weeks old. Thereafter, the
calcium and
phosphorus intakes of the dogs in the high
calcium groups were normalised for a further 10 weeks. The dogs fed the high
calcium diet without a proportionally high
phosphorus intake became hypercalcaemic and hypophosphataemic, and had severe disturbances in skeletal development, growth, and mineralisation which were typical for
rickets. After their
calcium intake was normalised the lesions of
rickets resolved but osteochondrotic lesions became apparent. The dogs fed the high
calcium and
phosphorus diet became slightly hypophosphataemic, their growth was retarded, and they had disturbances in skeletal development resembling
osteochondrosis, which had only partly resolved after 10 weeks on the normal
calcium and
phosphorus diet.