A total of 288 pigs (PIC 327 × 1050; initially 96.4 lb) were used in an 83-d study to
determine the effects of hard red winter wheat particle size on finishing pig growth
performance, diet digestibility, and caloric efficiency. Pens of pigs were balanced by
initial BW and randomly allotted to 1 of 3 treatments with 8 pigs per pen and 12 pens
per treatment. The same wheat-soybean meal–based diets were used for all treatments.
Diets were fed in three phases in meal form. The 3 dietary treatments were hard red
winter wheat ground with a hammer mill to 730, 580, or 330 μ.
From d 0 to 40, decreasing wheat particle size decreased (linear; P < 0.05) ADFI but
improved (quadratic; P < 0.05) F/G and caloric efficiency (CE), with no change in
ADG. From d 40 to 83, decreasing wheat particle size increased (quadratic; P < 0.05)
ADG and improved (linear; P < 0.05) F/G and CE, with no change in ADFI. Overall
from d 0 to 83, decreasing wheat particle size improved (linear; P < 0.05) F/G and CE
on both an ME and NE basis, with no difference in ADG or ADFI. Finally, reducing
wheat particle size improved (linear; P < 0.05) DM and GE digestibility.
In summary, fine-grinding hard red winter wheat was detrimental to feed intake in early
finishing, but improved ADG in late finishing and improved F/G in both periods and
overall. Dry matter and GE digestibility as well as CE were all improved for the overall
period with fine-grinding wheat. Grinding wheat from 730 to 330 improved the caloric
content on an NE basis by 100 kcal/lb.
