Atlas of pathology
Where: musculoskeletal system
The present form of lordosis and kyphosis was affecting up to 5% of the feeding herd with irrelevance of the sex, although males were more affected than females. This could be related to the fast growth rate of them over the females. The finding of bony exostoses in the ribs and the thickened costochondral junctions at post-mortem examination leaded to a metabolic disorder related to the diet by causing decreased mineralisation of the bone. The early onset of the problem combined with lameness from 5 weeks of age made the suspicion that the problem could have started during the foetal stage. Therefore, dry sow diets were the main focus of investigation. High levels of vitamin A and poor Ca:P ratio were detected in the dry sow diets. The correction of the diets improved the situation.
Kyphosis in pigs may develop secondary to a number of different primary lesions located in the vertebrae, such as osteomyelitis, fractures, neoplasm and metabolic diseases. Furthermore, painful conditions of the legs and back, musculo-mechanical stress on the lumbar spine, early onset of puberty in male pigs and intrauterine viral infections have been proposed as causes of kyphosis in pigs. Suggestions of genetic involvement have been suggested.
Kyphosis and lordosis could be a factor of carcass downgrading as a consequence of the difficulty of processing the muscles around the backbone by the butcher.