Energy can come from starch, fat, protein or fibre, but the efficiency varies depending on which source is used to obtain the energy. Energy is used by the pig for either maintenance or growth.

Growth can be achieved through protein or lipid deposition and, while their efficiencies are similar, lean accretion is much more efficient than fat accretion due to the water requirement.

Still, lean pigs are not necessarily the most cost effective if they are gaining weight slowly, as they will require extra barn time and maintenance energy. There are variations between herds in ability to maintain growth rate with lower energy density foods.

Generally, herds that can increase feed intake to maintain energy intake will maintain growth, and will be desirable continuing into the future.

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