Effects of vitamin D and A, calcium, phosphorus, and protein on frequency and severity of osteochondrosis in pigs.

The generalized nature of osteochondrosis indicates that systemic factors, i.e. of nutritional or genetic origin, are of importance in etiology of osteochondrosis. Several experimental investigations are reported. On the basis of the morphologic findings it was considered possible that dietary factors such as hypovitaminosis D, hyper- or hypovitaminosis A, and low calcium or high protein intake could be of importance in etiology. The reason for this was that there were similarities between cartilage changes in osteochondrosis and those observed in various dietary imbalances in other domestic animals and in experiments with pigs. The effect of hyper- and hypovitaminosis A and hypovitaminosis D was studied in 23 pigs from 2 litters. In another experiment 32 pigs from 4 litters were fed rations with varying levels of calcium, phosphorus, and protein in the feed. Clinical examinations were made of these animals. Bone seeking fluorochromes were given prior to slaughter, and complete necropsy was performed, including macroscopic, radiologic, histologic and microradiographic techniques. Neither hypervitaminosis A, nor hypovitaminosis A and D had any noticeable effect on frequency and severity of osteochondrosis. A similar negative finding was made in the experiment with different intake of calcium and protein.