A total of 960 crossbred pigs, initially 34.3
±
0.50 kg, were used in a 101-day trial to determine
the effects of corn particle size and diet form on growth performance and carcass
characteristics of finishing pigs. Pens were randomly allotted by initial weight to 1 of 6
experimental treatments with 8 pens per treatment and 20 pigs per pen. The 6 experimental
treatments were arranged in a 2
×
3 factorial with main effects of final feed form (meal
vs. pellet) and corn particle size (650 m, 350 m, or an equal blend of the 650 m and
350 m ground corn). The 650 m corn was ground using a two-high roller mill, and the
350 m corn was ground using a full circle hammer-mill equipped with a 1.59 mm screen.
After all corn was ground, the diet containing the blend of particle sizes was manufactured
by adding equal portions of the 2 at the mixer. Overall (day 0–101), linear particle
size
×
diet form interactions were observed (P < 0.05) for average daily feed intake (ADFI)
and gain:feed ratio (G:F), because ADFI decreased and G:F increased as particle size was
reduced for pigs fed meal diets but was unchanged for pigs fed pelleted diets. Pigs fed pelleted
diets had increased (P < 0.05) average daily gain (ADG) compared with pigs fed meal
diets. As corn particle size decreased, ADG decreased (linear; P < 0.05). Pigs fed pelleted
diets had increased (P < 0.05) hot carcass weight compared with pigs fed meal diets, but no
other effects on carcass characteristics were observed. In summary, grinding corn finer than
650 m decreased ADFI and improved G:F for pigs fed meal diets, but did not affect performance
of pigs fed pelleted diets. Pigs fed pelleted diets had improved ADG compared with
those fed meal-based diets. Thus, grinding corn finer than 650 m improved feed efficiency
for pigs fed meal diets, but provided no benefit in pelleted diets.