[Study of disorders in calcium and phosphorus metabolism in the intensive fattening of young cattle].

Studied were mass disease outbreaks on eight farms in calves intensively fed concentrate mixtures that were rich in phosphorus compounds. Clinically, there were selling and deformations of the joints with pains. The tarsal and carpal joints were chiefly involved. Kyphosis of the backbone, spastic paresis of the posterior part of the body as well as tetaniform spasms in the initial stage of the disease were also observed. Morphologically, the diseased animals manifested erosions and thinning of the joint cartilage, tearing of the Achilles tendon, and increased amounts of the joint fluid. The histologic study revealed edema of the cartilage cells, disorders in the structure of the hyalin cartilage, formation of cavities, and broadening of the lumen of the Haversian canals. In most cases the blood serum presented hyperphosphatemia (up to 15.67 mg% inorganic P) and relative or absolute hypocalcemia (up to 4.47 mg% Ca). On the farm both hypocalcemia and hypophosphatemia were observed. Good prophylactic results were obtained through correct Ca:P ratios in the diet that contained calcium additives as well as by the injection of vitamin D solutions, etc. It is believed that these cases should be referred to a distinctive form of rickets of a characteristic clinical course' the inadequate Ca:P ratios in the rations playing the main etiologic role. Subsidiary causes are probably vitamin D deficiency, restricted movement of the animals, and mechanical traumata caused by the animal's own bodyweight.