Current knowledge on the nutritional requirements of swine and the components of the different dietary ingredients have reduced significantly the problems associated with faulty nutrition. Deficiencies in the diet however do still occur from time to time and can be considered from four aspects: energy, protein, vitamins and minerals. Whereas most problems arise due to deficiencies, diseases can also occur due to excesses. The clinical signs of both are shown in Fig.2-14 and Fig.2-15. A consistent feature of vitamin deficiencies is poor growth but this can also be associated with many other factors.

Mineral deficiencies are not uncommon today, particularly where the demands of lactation in the modern rapidly growing genotypes are difficult to satisfy.