Keith C Behnke’s research while affiliated with Kansas State University and other places

Carryover of medicated feed additives between batches of feed can potentially result in harmful drug residues in the edible tissues of food-animals. Flushing the equipment with an ingredient, such as ground grain, is one method used to remove any residual medicated feed from the system. It is generally recommended that the quantity of flush used be between 50 and 100 g/kg of the mixer’s capacity. However, there is little data that supports this recommendation. Therefore, an experiment was conducted to determine the minimum quantity of flush material required to prevent drug carryover; and to quantify the interrelationship between flush size and drug concentration. The feed medicated with nicarbazin (Nicarb 250 g/kg®; 00.125 g/kg) was manufactured and conveyed from the mixer, through a drag conveyor and bucket elevator, and placed into a finished product bin. The system was then flushed using ground corn in the amount of 25, 50, 100, 150, or 200 g/kg of the mixer’s capacity (454.5 kg). Subsequently, a non-medicated diet was conveyed through the system and samples were collected and analyzed for nicarbazin. No differences were detected among the flush treatments, and all treatments were effective in reducing nicarbazin carryover to less than 2.2 mg/kg to the non-medicated diet. Collectively, these studies demonstrate that existing flushing guidelines meet or exceed what is required to prevent carryover of medicated feed additives.

A total of 200 finishing pigs (PIC TR4 1050; initially 46.8 ± 1.24 kg) were used in a 69 day growth assay to determine the effects of sorghum particle size on growth performance and carcass characteristics. Pigs were sorted by sex, ancestry, and BW with 5 pigs per pen and 10 pens per treatment. Treatments were a corn-soybean meal-based control with the corn milled to a target particle size of 600 μm and sorghum milled to target particle sizes of 800, 600, and 400 μm. Actual mean particle sizes were 555 μm for corn and 724, 573, and 319 μm for sorghum. All diets were pelleted. Pigs were slaughtered (average final BW of 123 kg) at a commercial abattoir. Pigs fed the sorghum-based treatments were not different in growth performance, hot carcass weight, backfat thickness, loin depth, or fat free lean index compared to those fed the corn control; however, there was a tendency for pigs fed sorghum based treatments to have increased (P < 0.09) ADG, ADFI, and dressing percentage. As particle size of sorghum was reduced from 724 to 319 μm, ADG was not affected but G:F increased (linear, P < 0.01). Reducing particle size of sorghum had no effect (P > 0.23) on hot carcass weight, backfat thickness, loin depth, or fat free lean index, but dressing percentage tended to improve (P < 0.06). In conclusion, linear improvements in G:F were demonstrated with reduction of sorghum particle size from 724 to 319 μm. Moreover, our data suggest that the performance of pigs fed corn-based diets were within the range of the responses to those fed sorghum-based diets with varying sorghum particle sizes.

An experiment was conducted to evaluate the effects of including pelleted and re-ground distillers dried grains with solubles (DDGS) on pellet durability and pellet mill performance in pelleted corn-soy based swine diets. Pelleted and re-ground DDGS have the potential to greatly improve handling and shipping of DDGS because of improvements in material flow and bulk density. The pellet manufacturing experiments were completed at the Department of Grain Science and Industry's Feed Research Facility at Kansas State University. Pellet durability index (PDI), electrical energy consumption, production rate, and bulk density served as the response criteria. The levels of DDGS evaluated were 10%, 20%, and 30%. Diets containing pelleted and re-ground DDGS were compared to diets with unpelleted DDGS added at the same levels and to a control diet with no added DDGS. Concerning PDI, the diets containing pelleted and re-ground DDGS showed no significant differences from the control at any inclusion level, while the diets containing unpelleted DDGS at 20% and 30% had significantly lower pellet durability than the control. Concerning the production response criteria, the diets containing pelleted and re-ground DDGS were superior or equal to treatments containing unpelleted DDGS. The data demonstrates that pelleted and re-ground DDGS do not negatively impact pellet durability or pelleting performance, and in fact may offer slight benefits, and therefore can be considered as an option for improving some aspects of working with DDGS. © 2013 American Society of Agricultural and Biological Engineers ISSN 0883-8542.

An experiment was designed to determine the effect of hydrothermal treatment (HT) on the coefficient of apparent ileal digestibilities (CAID) of crude protein (CP), amino acids (AA), starch and phosphorous (P) in growing pigs (initial body weight (BW) of 29.5 ± 2.4 kg) fitted with a T-cannula in distal ileum. The mash, based on wheat, fishmeal and soybean meal, was subjected to four HT, giving diets: (1) unconditioned mash as control; (2) low-temperature steam conditioning before pelleting (SC-Low); (3) high-temperature steam conditioning before pelleting (SP-High); (4) expander conditioning before pelleting (EXP); and (5) extruder processing (EXT). The diets were fed to five growing pigs allotted to treatments in a 5 × 5 Latin square design. The HT (average of four HT diets) increased CAID of starch (P=0.001), but did not affect that of DM, CP or P. The CAID for total indispensible AA was improved by HT processing (P=0.041), as were the CAID for Arg (P=0.018), Ile (P=0.044), Lys (P=0.006) and Thr (P=0.013), when compared to the control. For Lys, CAID was greater (P=0.006) for pigs fed the HT diets compared to the control and for the average of EXP and EXT compared to the average of SC-Low and SC-High. For dispensable AA, CAID were not affected by the treatments. In conclusion, HT increased ileal digestibility of starch, total IAA, Arg, Ile, Lys and Thr compared to a control diet fed as mash in growing pigs, with expander conditioning and extruder processing of particular merit for Lys.

Soybean hulls were subjected to thermo-mechanical extrusion pretreatment at various in-barrel moisture contents and screw speeds. Extrusion degraded the lignocellulosic structure and enhanced enzymatic hydrolysis of soybean hulls, with up to 155% increase in glucose yield as compared to untreated substrate. Greater glucose yields were observed at higher in-barrel moistures (45% and 50%) and lower screw speed (280 and 350 rpm). Maximum 74% cellulose to glucose conversion resulted from using a two-enzyme cocktail consisting of cellulase and β-glucosidase. Conversion increased to 87% when a three-enzyme cocktail having a cell wall degrading enzyme complex was used for hydrolysis. Fermentation inhibitors, such as furfural, 5-(hydroxymethyl)-2-furaldehyde (HMF), and acetic acid, were found in the extrusion pretreated soybean hulls and hydrolysate. However, their concentrations were below the known thresholds for inhibition. Fermentation of hydrolysate by Saccharomyces cerevisiae led to high yields of ethanol, with concentration ranging from 13.04 to 15.44 g/L.

The aim of the present study was to investigate effects of feed conditioning prior to pelleting and extrusion processing on average daily gain (ADG), average daily feed intake (ADFI), gain to feed (G:F) and coefficient of total tract apparent digestibility (CTTAD) in nursery pigs and broiler chickens. The mash, based on wheat, fishmeal and soybean meal, was subjected to 4 heat treatments (hydro-thermal processing) giving Diet 1: unconditioned mash as control (mash); Diet 2: low-temperature steam conditioning before pelleting (STP47); Diet 3: high-temperature steam conditioning before pelleting (STP90); Diet 4: expander conditioning before pelleting (EXP); and Diet 5: extruder processing (EXT).Nursery pigs (average body weight of 5.6kg) were used in a 36-d experiment. The results showed that hydro-thermal processing improved G:F in nursery pigs (P=0.006) compared to the mash. The G:F was also improved for pigs fed the EXT diet compared to the EXP diet (P=0.030). The CTTAD of dry matter was greater in pigs fed the hydro-thermal processed diets compared to the mash (P=0.018), and in pigs fed the STP47 compared to the STP90 (P=0.001). The CTTAD of organic matter was improved for pigs fed STP47 and STP90 diets compared to the EXP and EXT diets (P=0.010), and for the STP47 compared to the STP90 diets (P=0.001). The CTTAD of protein (P=0.004) and energy (P=0.001) was greatest in pigs fed the STP47 compared to the STP90. Starch digestibility was improved in pigs fed the EXT compared to the EXP diet (P=0.041).Broiler chickens (1-d old, average body weight of 41g) were used in a 21-d experiment. The ADFI and ADG were greater (P

Meat birds fed high-quality pellets exhibit advantages in rate and efficiency of growth over birds fed poorer quality pellets. However, the associated feed manufacturing cost and reduced production rates to obtain high-quality pellets are viewed by the industry as offsetting the benefits in broiler performance provided by high-quality pellets. With the combination of increased costs for utilities in the feed mill and for feed ingredients, strategies are needed to conserve milling costs while optimizing the efficiency of broiler growth. In this study, we evaluated the effects of feed form on live performance and meat yield of broiler chickens during a 42-d production period. Four treatments were provided from 18 to 42 d of age: 1) high-quality pellets (88% pellet durability index), 2) low-quality pellets (66% pellet durability index), 3) a proportion of the formulated corn added post-pellet (89% pellet durability index), and 4) mash (corn was ground via a roller mill). Broilers fed the high-quality pellets had higher cumulative BW gain and consumed more feed than birds fed low-quality pellets. Mash-fed broilers had poorer growth performance and less meat recovery than birds in the other treatments. Adding corn post-pellet resulted in broilers having similar performance and meat yields compared with those fed high-quality pellets. In this study, we confirm that adding corn post-pellet does not negatively affect growth performance and meat yield. Feeding broilers high-quality pellets provides a benefit in growth rate over feeding low-quality pellets by increasing feed consumption.

A total of 240 weanling pigs (avg initial wt of 11.7 lb) was used to determine the effects of particle size of corn and two sorghum genotypes on growth performance. In addition to the pig feeding experiment, 420 broiler chicks (avg initial wt of .15 lb) were fed the same grain treatments to determine if they were a reliable model for the effects of diet particle size on nursery pig performance. Milling characteristics of the cereal grains were measured. Treatments were corn, hard endosperm sorghum, and soft endosperm sorghum, ground to particle sizes of 900, 700, 500, and 300 µm (geometric mean), with a 3 x 4 factorial arrangement of treatments. In general, reducing particle size increased electrical energy required for milling and decreased production rate. However, there were differences among the grain sources for energy required for milling and production rates, e.g., grinding the sorghums to 500 µm took less energy than grinding corn to 900 µm. In starter pigs, the most efficient gains were achieved at 300 µm for d 0 to 7, 300 to 500 µm for d 0 to 14, and at 500 µm for d 0 to 35. It should be noted that the pig diets were in pelleted form, so problems with bridging and reduced flowability were not a concern with the finely ground grain sources. Overall, pigs fed diets containing corn grew faster, consumed more feed, and were more efficient than those fed sorghum. When compared at their optimum particle sizes, hard and soft sorghum supported ADGs that were 80 and 84%that of corn, and efficiencies of gain that were 96% that of corn. For broiler chicks, reducing particle size of corn below 900 µm did not improve gain to d 21, but grinding sorghum to 500 to 700 µm did improve gain. Efficiency of gain also was improved more with fine grinding of sorghum than corn. Optimum particle sizes for F/G were 300 and 500 µm for hard and soft sorghum, respectively. It is important to note that relative to corn, at 900 p.m feeding values for chicks fed hard and soft sorghums were 92%, but at the optimum particle size for each grain, relative feeding values for hard and soft sorghum were 99% that of corn. These data suggest that sorghums can equal corn in feeding value for broiler chicks when milled to their optimum particle size, and that as pigs and chicks get older, optimum particle size increases. However, starter pigs fed corn had 15 to 20% greater ADG and 4% greater efficiency of gain than pigs fed the sorghums. Swine Day, Manhattan, KS, November 21. 1991

The American Society of Agricultural and Biological Engineers (ASABE) publishes a standard for identifying particle size by sieving (ASABE S319.4). However, this standard includes a number of options that allow the test to be conducted differently, and different laboratories may analyze a single sample with different results. Options include the type of sieve shaker used, the use of sieve agitators, the use of a dispersion agent, and the sieving time. A small study was conducted to examine the effect of varying these methods on the calculated geometric mean diameter by weight (dgw) and geometric standard deviation by weight (sgw). Results indicated that large differences existed depending on the methods used, with dgw varying by as much as 100 microns, and sgw varying by as much as 0.42 simply by altering one option. When compounding the differences in methods, the variations can be even larger. These discrepancies demonstrate that, for particle size analysis by sieving to be used as an effective tool, the same methodology must be used to compare samples. Additionally, the data demonstrate that unless the methods in the current standard are better defined, dgw and sgw should be used only as relative values for comparison.

Poor pelleting production rates can raise the milling cost and increase the frequency of feed outages for broiler integrated operations. The number of broilers marketed to heavy BW has been increasing, and meeting feed delivery schedules can be problematic with "big bird" complexes. Adding rolled corn post pellet is a management strategy to increase feed production rate while concurrently decreasing energy use of the grinding and pelleting processes. This study evaluated the addition of screened rolled corn to pelleted feed on live performance and meat yield of broiler chickens during a 56-d grow-out. Four dietary treatments were provided: A) a control, no added corn post pellet from 18 to 56 d of age; B) addition of 25% of the formulated corn post pellet from 18 to 56 d of age; C) addition of 10, 20, and 30% of the formulated corn post pellet from 18 to 35, 36 to 46, and 47 to 56 d of age, respectively; and D) addition of 20, 30, and 40% of the formulated corn post pellet from 18 to 35, 36 to 46, and 47 to 56 d of age, respectively. Final BW, cumulative feed conversion, 38-d BW uniformity, and 57-d breast meat weight and yield were similar among the dietary treatments. These results indicate screened rolled corn can be added post pellet without adversely affecting broiler performance and meat yield.