Why 3% of Body Weight?

Feeding approximately 3% of body weight is a widely used guideline in swine nutrition because it aligns with how growing pigs naturally eat and grow. It is not a magic number — it is a research-backed starting point that works well for the average pig under normal conditions.

1. Feed intake naturally scales with body weight

Research consistently shows that growing pigs voluntarily consume feed at roughly 2.5–3.5% of their body weight. Intake increases as pigs grow, then eventually levels off as fat deposition increases.

The 3% midpoint is where most pigs:

• Eat aggressively but consistently

• Maintain gut health

• Convert feed efficiently

This is why 3% appears in university research, extension publications, and commercial feeding models.

2. Energy needs for ~2 lb/day average daily gain

To gain approximately 2 lb per day, a pig must meet both:

• Maintenance energy needs (basic body function)

• Growth energy needs (lean tissue plus some fat)

When pigs are fed:

• A properly balanced grower diet

• Adequate amino acids (especially lysine)

• At roughly 3% of body weight

Daily energy intake typically supports ~2.0 lb/day ADG in genetically average pigs raised under normal conditions.

Feeding below this level often limits growth, while feeding above it rarely increases gain proportionally.

3. The feed efficiency “sweet spot”

Maximum feed intake does not equal maximum efficiency.

Research shows that:

• Feed efficiency is best slightly below maximum intake

• Maximum gain occurs near ad-lib consumption

• 3% strikes a balance between rate of gain and efficiency

For show pigs, this balance matters. Consistent growth without excess fat deposition is easier to manage than chasing rapid early gain.