Enhancing feed efficiency with grain particle size

Previous research has shown the average particle size of milled grains in Australia is extremely variable, suggesting poor milling practice. It has also been shown that starch digestion declines dramatically with increasing particle size, reducing the amount of energy available to the animal.

This project evaluated the particle size distributions of milled grains currently used in feeds by both large and small producers.

Value for producers:

• Correct particle size when milling feed can help improve digestion and feed efficiency in pigs.

Recommendations:

• Recommended average particle size - Corn: <0.6mm, Wheat: 0.6mm, Sorghum <0.5mm, and Barley <0.7mm
• Using a hand-held sieve offers the potential for on-site adjustment of milling parameters, helping to reduce the levels of particles greater than one millimetre in size.
• Larger particles may be more tolerated in diets containing diverse grains than in single grain formulations.
• There are no significant performance differences for weaner pigs on sorghum or pea-rich diets with mean particle sizes between 0.4 and 0.8 millimetres. Improved animal performance is likely to be achieved with grains ground even finer.
• Feeds with larger particles have a slower rate of passage, suggesting the negative effect of large particle sizes on feed efficiency may be related to passage rate as well as digestibility effects.