Effects of increasing dietary wheat middlings on nursery pig Effects of increasing dietary wheat middlings on nursery pig performance from 15 to 50 lb performance from 15 to 50 lb

A total of 210 pigs (PIC 327 × 1050, initially 15.12 lb BW) were used in a 35-d trial to evaluate the effects of increasing dietary wheat middlings (midds) on growth performance of 15-to 50-lb nursery pigs. Pens of pigs were balanced by initial BW and randomly allotted to 1 of 5 dietary treatments with 6 replications per treatment. The 5 corn-soybean meal–based diets contained 0, 5, 10, 15, or 20% midds. Pigs were fed in a 2-phase feeding program from d 0 to 14 and d 14 to 35. Diets were not balanced for energy; thus, as midds increased, dietary energy concentrations decreased. From d 0 to 14, midds had no effect on growth performance; however, from d 14 to 35, pigs fed increasing midds had decreased ADG (linear, P < 0.02) and poorer F/G (linear, P < 0 .004). Furthermore, pigs fed increasing midds had lower (linear, P < 0.05) feed cost/pig, revenue/pig, and income over feed cost (IOFC), and a tendency for increased (quadratic, P < 0.07) feed cost/lb gain. Overall (d 0 to 35), increasing dietary midds worsened F/G (quadratic, P < 0.01), driven by poorer F/G for pigs fed 15 and 20% midds. We also observed a quadratic effect ( P < 0.004) for feed cost/lb gain, with inclusion rates of 0 and 20% having the highest value. Caloric efficiency responded in a quadratic manner ( P < 0.01) on both an ME and NE basis with improved caloric efficiencies at intermediate levels (mainly 5%) of dietary middlings compared with 0 and 20% inclusions. These data suggest that the inclusion of midds at levels up to 15% do not negatively affect performance in 15-to 50-lb nursery pigs. Although we observed a linear decrease in overall IOFC, both inclusion rates of 5 and 10% were numerically more profitable than the control.


SWINE DAY 2012
Effects of Increasing Dietary Wheat Middlings on Nursery Pig Performance from 15 to 50 lb Introduction Wheat middlings are a wheat milling by-product that consist of fine particles of wheat bran, wheat shorts, wheat germ, and wheat flour; midds contain no more than 9.5% crude fiber (CF).With the sudden increase in the price of corn and soybean meal, wheat midds have become a more common ingredient in swine diets.Wheat midds have higher CP and CF but lower dietary energy than corn (corn ME = 1,551 kcal/ lb; wheat middlings ME = 1,372 kcal/lb; NRC, 1998 2 ), which must be accounted for when used in swine diets.

SWINE DAY 2012
Although extensive research has been conducted with midds and their effects on growing and finishing pigs 3 , little data is available on its effects in corn-soybean meal-based early nursery diets.In a recent study with nursery pigs fed midds from 25 to 50 lb BW, midds had no effect on performance when included up to 15% of the diet.Thus, although the effects in mid-to-late nursery phases have been quantified, research needs to be completed with younger nursery pigs to determine if a similar response exists throughout all nursery phases.
The objective of this study was to determine the effects of increasing dietary wheat midds (0, 5, 10, 15, and 20%) on growth performance, caloric efficiency, and economics of nursery pigs from 15 to 50 lb.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in this experiment.The study was conducted at the K-State Swine Teaching and Research Center in Manhattan, KS.
A total of 210 pigs (PIC 327 × 1050, initially 15.12 lb BW and 26 d of age) were used in a 35-d growth trial to determine the effects of dietary midds on pig growth performance, caloric efficiency, and economics.Pigs were allotted to pens by initial BW, and pens were assigned to treatments in a completely randomized design with 7 pigs per pen and 6 replications per treatment.The 5 treatment diets included 0, 5, 10, 15, or 20% midds (Tables 1 and 2).Diets were not balanced for energy, so as the level of midds increased, dietary ME decreased.The ME value for midds used in diet formulation was 1,372 kcal/lb (NRC, 1998), and the NE value was 1,850 (INRA, 2004 4 ).All diets were formulated to a constant standardized ileal digestible lysine level to ensure changes in performance were due to dietary energy differences rather than differences in amino acid concentrations.Diets were fed in two phases, with Phase 1 from d 0 to 14 and Phase 2 from d 14 to 35.All diets were fed in meal form and were prepared at the K-State Animal Science Feed Mill.
Each pen contained a 4-hole, dry self-feeder and a nipple waterer to provide ad libitum access to feed and water.Pens had wire-mesh floors and allowed approximately 3 ft 2 / pig.Pig weight and feed disappearance were measured on d 0, 7, 14, 21, 28, and 35 of the trial to determine ADG, ADFI, and F/G.Wheat midds and complete diet samples were collected and submitted to Ward Laboratories, Inc. (Kearney, NE) for analysis of DM, CP, ADF, NDF, CF, Ca, P, crude fat, and ash (Tables 3 and 4).Bulk density and particle size of the midds and complete diets were also measured.Caloric efficiencies of pens was determined on an ME and NE (INRA, 20045 ) basis.Efficiencies were calculated by multiplying total intake by the energy level in the feed (kcal/lb) and dividing by total gain.Lastly, feed cost/pig, feed

SWINE DAY 2012
cost/lb gain, revenue/pig, and IOFC were also calculated.Diet costs were determined with the following ingredient costs: corn = $0.14/lb;soybean meal = 0.24/lb; midds = 0.12/lb; DDGS = 0.14/lb.Feed cost/pig was determined by total feed intake × cost/ lb feed.Feed cost/lb gain was calculated using F/G × feed cost/lb.Revenue/pig was determined by total gain × $0.65/lb live gain, and IOFC was calculated using revenue/ pig − feed cost/pig.Data were analyzed as a completely randomized design using the PROC MIXED procedure of SAS (SAS Institute, Inc., Cary, NC) with pen as the experimental unit.Contrasts were used to compare linear and quadratic effects of increasing wheat midds.Statistics were considered significant at P < 0.05 and tendencies at P > 0.05 but < 0.10.

Results and Discussion
The chemical analysis of the midds (Table 3) revealed that CP, CF, Ca, and P were all slightly higher than the formulated values, whereas the fat content was slightly lower than formulated values.The analysis of the dietary treatments showed that fiber analysis of ADF, NDF, and CF increased as expected as dietary wheat midds increased in the diet (Table 4).Diet bulk density also decreased as midds inclusion levels increased as expected, but they decreased slightly for Phase 2 compared with Phase 1 diets in this experiment.
Overall, (d 0 to 35), as dietary midds increased, F/G became poorer (quadratic, P < 0.01).This effect was mainly attributed to a notable increase for pigs fed 20% midds.For caloric efficiency, the response was quadratic (P < 0.01) on an ME and NE basis as the level of midds increased in the diet.The quadratic response is supported by the worst caloric efficiencies observed for both ME and NE at 0 and 20% inclusion rates.A quadratic effect (P < 0.004) also occurred for feed cost/lb gain, with inclusion rates of 0 and 20% having the highest value.Notably, the highest numerical IOFC occurred at 5 and 10% midds inclusion rates.
These data support other recent data in that midds inclusion levels up to 15% do not affect nursery pig performance, even when not formulated to a constant energy level.More research is needed to further explain the lack of negative effect when feeding up to 15% midds in nursery diets.These data support the potential use of midds in diets for 15-to 50-lb nursery pigs to improve net returns.
2 Phase 1 diets were fed from d 0 to 14, and Phase 2 diets were fed from d 14 to 35.2

Table 2 .
Phase 1 and 2 calculated nutrient profile (as-fed basis) 1 1 Phase 1 diets were fed from d 0 to 14, and Phase 2 diets were fed from d 14 to 35.

Table 4 .
Chemical analysis of diets containing wheat middlings (as-fed basis) 1 1 A composite sample consisting of 6 subsamples was used for analysis.

Table 5 .
The effects of increasing wheat middlings on nursery pig growth performance 1

Table 6 .
Economics of increasing wheat middlings in nursery pig diets 1