457
Effects of duration of mixing diets with high inclusion of cereal grain co-products on growth performance and carcass measurements in finishing pigs
A total of 200 finishing pigs (average initial BW of 68 kg) were used in a 62-d growth assay to determine the effects of mix time in corn-soybean meal-based diets with high inclusion of distillers dried grains with solubles ( 32% DDGS) and wheat middlings (32% midds). The pigs were sorted by gender and ancestry and assigned to pens (5 pigs/pen and 8 pens/treatment) in a completely randomized design. A Davis and Sons horizontal ribbon mixer (model DS30) was used to mix 1-t batches of the diets. All ingredients (corn, DDGS, midds, soybean meal, crystalline amino acids, limestone, salt, vitamin mix, mineral mix, and tylosin) were added with the mixer stopped. Mix times were 0, 15, 30, 60, and 420 s before discharge, transfer to a surge bin, and sacking into 22.6 kg bags for delivery to the swine farm. Diets were formulated to at least 120, 120, and 110% of requirements for essential amino acids, vitamins, and minerals for 75 to 100 and 100 to 135 kg pigs according to NRC (2012) Nutrient Requirements of Swine. Feed and water were consumed on an ad libitum basis until the pigs were harvested (average BW of 125 kg) and processed at a commercial abattoir. As for results, there was a trend (quadratic effect, P < 0.07) for ADG to decrease as mix time was increased from 0 to 30 s and increase as mix time was further increased to 420 s. There was a trend (linear effect, P < 0.06) for G:F to increase as mix time was increased. Mix time did not affect (P > 0.19) ADFI, hot carcass weight (HCW), dressing percentage (Dressing %), or fat thickness at the last rib (BF). In conclusion, increasing mix time from 0 to 420 s in diets with high inclusion of DDGS and midds had inconsistent effects in growth performance and no effect in carcass measurements.
Item |
0 s |
15 s |
30 s |
60 s |
420 s |
SE |
Linear |
Quadratic |
ADG, g |
931
|
936 |
894 |
904 |
936 |
27 |
0.33 |
0.07 |
ADFI, kg |
3.02 |
3.19 |
3.05 |
3.07 |
2.99 |
0.11 |
0.19 |
0.83 |
G:F, g/kg |
308 |
293 |
293 |
294 |
313 |
7 |
0.06 |
0.12 |
HCW, kg |
91.0 |
89.9 |
88.9 |
88.8 |
90.9 |
3.3 |
0.81 |
0.23 |
Dressing % |
72.2 |
72.2 |
72.5 |
71.9 |
72.1 |
0.6 |
0.56 |
0.58 |
BF, mm |
21 |
21 |
21 |
20 |
20 |
1 |
0.29 |
0.76 |
Keywords:
duration of mixing, DDGS, pigs