Evaluation of durum midds
in finishing diets for yearling steers
Carrington Research Extension Center
North Dakota State University
Middlings from durum wheat were evaluated in finishing diets for steers in two experiments. Midds were fed as pellets or meal at 50% and 20% of the corn component in finishing diets in experiment 1. Steers (n=44, avg. wt. 763 + 6.74 lb.) consumed the same amount of dry matter but gains were greater with pelleted midds than meal (P<.05) at the 50% level. No differences (P>.05)) were observed in gains at the 20% level although gains trended higher for pellets vs meal. In experiment 2, pelleted midds were included in finishing rations for heavy steers (n=72, avg. wt 975 + 14.38 lb.) at 0, 20, 40 and 60% replacement for dry rolled corn. Intake and gain decreased with increasing midds beyond 20% (P<.05). Feed conversion and carcass traits were similar for all treatments. Durum midds maximum feed value was calculated using the cost of gain for the control group (0%) as reference value. The price cattlemen can afford to pay for midds with the same feed cost per unit gain decreased as the amount in the finishing diet increased.
Wheat middlings or "midds" is the generic term referring to the residual products from the milling of hard red spring or hard red winter wheat and durum. Components include the bran, germ, screenings and residual endosperm (flour or semolina) from the milling process. Nearly 600 tons of midds are produced per day in North Dakota from hard wheat and durum. Wheat midds constitute 20 to 21% of the pre-milled wheat by weight. Currently, a very high percentage of the midds leave the state to be used in commercial feed manufacturing and feedlot rations in other states.
Value added processing of wheat and durum focuses on flour and semolina/pasta production for human consumption. Little attention is given to marketing wheat midds. Nutrient content of wheat midds may vary with the milling process. Table 1 provides nutritive data on durum wheat midds used in this study compared with reported values for wheat midds and common feed grains (NRC, 1984, 1996). Starch content averaged 35% for durum midds.
Midds are available year round at milling sites in North Dakota (Table 2). With a continual supply, less feed storage may be needed, although midds prices vary dramatically by season. Volume purchases or long term contracts may be negotiated at lower than spot market quotes. Midds are relatively consistent in nutrient content over time, do not require further processing for feeding, and will maintain quality in storage.
It may be possible to use wheat midds as a major feed ingredient in cattle feeding in the Northern Plains. Midds can be used in several rations for beef cattle. Specific rations and amount fed depends on several factors including protein needs, feeding system, and obviously competitiveness of price. Commercial feed companies use high proportions of midds in creep feed and range cake. More producers are using midds in replacement heifer and backgrounding steer diets. Little data is available on the use of midds in finishing rations, especially durum midds.
Wheat midds are marketed in either pelleted or meal forms. The meal form has a lower bulk density than pellets resulting in some logistical problems. Meal bridges easily in a bin, reduces the carrying capacity of truck and rail containers, and is best handled with front end loaders. Pelleted midds can be handled easily in conventional grain systems.
The difference in feeding pellets vs. meal has not been previously researched. Experiment 1 evaluated intake and animal performance using pelleted vs. meal form midds at two levels in finishing diets. We are confident that midds can be used in growing rations although more than nominal levels have not been explored. Experiment 2 was conducted to explore steer performance at several levels of durum midds in finishing rations. The amount of wheat or durum midds that can be "marketed" through finishing cattle is potentially much greater because heavier cattle eat more "grain" and finishing rations are usually fed for longer periods of time. The equivalent value of midds in finishing diets is calculated from the feed intake and steer performance data.
Materials and methods
Forty four head of preconditioned crossbred steer calves (avg. wt. 763 + 6.74 lb.) were randomly allotted to two treatments in four pens on December 22, 1995. Steers in all four pens were fed a finishing ration of approximately 80% concentrate. Durum midds were included as 50% of the concentrate during the first two 21 day weigh periods and as 20% of the concentrate during the last two 21 day weigh periods. Two pens were fed pelleted durum midds and two pens were fed midds in the meal form during the 84 day study. Remaining ration ingredients included dry rolled corn grain, corn silage, chopped alfalfa hay, feedlot mineral and an ionophore supplements (Bovatec). Table 3 gives diet formulations for the 50% and 20% midds diets. Durum midds were procured from the Dakota Growers Pasta Company, a farmer owned cooperative in Carrington, ND. Midds were pelleted at G and R Feeds in New Rockford, ND using a 3/16th inch die. Meal form midds were stored on a concrete floor in a covered hay shed and added to the feed mixer wagons by front end loader .
Steers were individually weighed at the start of the trial, and every 21 days. Bunks were read daily and ration changes made to reflected increase or decrease in feed intake. Steers were fed once daily in fenceline feedbunks using a truck mounted Little Augie feed wagon for weighing, mixing, and delivery of the totally mixed ration. Feed intake was recorded daily. Data were analyzed by analysis of variance with pen as the experimental unit.
Heavy yearling steers (n=72, avg. wt. = 974 + 14.38 lb.) were randomly allotted to one of four treatments with three replicates per treatment and assigned to twelve identical pens during the summer of 1996. Treatments were increasing levels of pelleted durum midds in the finishing ration as a percentage replacement for dry rolled corn. Levels were 0 (control), 20, 40, and 60% midds with reciprocal decreasing levels of dry rolled corn grain. Table 5 presents diet composition for all diets. Canola meal (35% crude protein) was used as a protein source in the 0 and 20% diets. No additional protein was needed in the 40 and 60% treatments. Steers were fed a totally mixed ration once daily in fenceline feedbunks during the 65 day trial. Steers were weighed individually at the start of the trial and twice during the study with final weights taken just prior to shipment. Carcass merit was determined by qualified graders. Feed value of wheat midds was calculated by first determining the cost per pound of gain including feed, yardage and interest for the control group. The equivalent value of midds at each inclusion rate was determined by varying midds price to match feed cost of the controls using a computer spreadsheet. Calculations were made for each treatment using four different corn prices. Statistical comparisons were made by analysis of variance with pen as the experimental unit.
Results and Discussion
Steer performance data for pelleted vs meal are reported in Table 4. Pelleting midds produced increased gains (P<.05 ). Gains were nearly 14% higher (.43 lb.) with pelleted durum midds than in meal form at the 50% level. At the 20% level, gains were not statistically different (P>.10)) but numerically greater (3.5% or .12 lb.) with pelleted midds. Though not different (P>.10), feed efficiencies reflect the differences in gain at equal feed intake.
It is generally thought that pelleting will cause an increase in intake due to higher bulk density (less space occupied per unit of weight). The more rapidly pellets degrade in the warm moist rumen, the less difference in intake would be expected. Pelleting wheat midds in this study translates into a substantial economic advantage provided the cost of pelleting is less than the value of increased gain. The advantage in pelleting decreases with decreasing proportions of wheat midds in the ration. The advantage to pelleting may be the result of compressing midds to reduce the surface area immediately available for fermentation. Some changes may also occur to the starch molecules from pressure and heat, causing a gelatinizing effect which would also reduce the rate of fermentation. Slowing the fermentation rate may create a more stable pH environment in the rumen which may contribute to improved gains and feed efficiency.
Feedlot performance data for 0, 20, 40, and 60% durum midds in finishing diets is reported in Table 6. Feed intake and average daily gains followed similar patterns for the four treatments. Treatments 0 and 20% were similar but the 60% treatment resulted in reduced intake and lower gains (P<.06). The 40% level was intermediate. Dalke et al., (1993a) included wheat midds at 0, 5, 10, and 15% replacing corn. Intake and feed/gain increased with increasing midds in the ration but did not affect gain or final weight. Digestibility decreased with increasing wheat midds (Dalke, et al., 1993b). Brandt et al., (1986) observed a linear decrease in gain and feed conversion using 0, 10, 20, and 30% midds replacing corn in finishing diets.
Gain per unit feed was similar for all treatments as decreased intake resulted in decreased gain. Carcass traits were similar for all treatments (Table 7). Feed value of durum midds was calculated and reported in Table 8 for four different corn prices and the three treatment inclusion rates. Durum midds have more value at the lower inclusion rates (Table 8). Protein supplement replacement and the complementarity of two feed sources may contribute to this result. At higher midds levels, lower energy concentration and higher fiber levels may contribute to reduced gains. With midds prices compared to corn, producers can better assess the break-even point for procurement of wheat midds for finishing diets.
Laboratory analysis (Table 1) of durum midds, the nutrient profile in wheat midds (NRC, 1984, 1996) and the results of this study suggest durum midds may contain more nutrients and be more valuable as a feedstuff than the wheat midds used in the Kansas studies. If this hypothesis creates additional demand and higher prices for midds in North Dakota, any advantage in feeding midds in place of other feed grains may be lost.
The data indicates that pelleted midds should produce increased gains over meal in finishing diets, especially at higher levels in the diet. The extra cost of pelleting needs to be considered although it is common that mills offer only one form of midds. The amount of midds to include in finishing rations requires a bit more thought. Interpreting Table 8, it is critical to procure midds at less than the price given for each respective corn price and inclusion rate in order to have any advantage over corn.
Other factors may affect the decision to use midds in feedlot rations such as availability and cost of conventional feed grains, storage space, transportation, and ration mixing capability. It is clear from these experiments, that durum midds can make up a substantial portion of the diet for finishing steers.
Brandt, R. T., R. W. Lee, and J. Carrica. 1986. Replacing corn with pelleted wheat midds in finishing diets. Cattle Feeders Day Report of Progress 497. Garden City Branch Ag. Exp. Station, Kansas State University.
Dalke, B. S., K. K. Boson, R. N. Sonon, and D. L. Holthaus. 1993a. The feeding value of wheat middlings in high concentrate diets of finishing steers. J. Anim. Sci. 71 (Suppl. 1):291 (Abs.).
Dalke, B. S., K. K. Boson, R. N. Sonon, D. L. Holthaus, and M. A. Young. 1993b. The effects of wheat middling, ruminal metabolism, and passage rates of finishing steers. J. Anim. Sci. 71 (Suppl. 1):291 (Abs.).
Ishler, V., J. Heinrichs, and G. Varga. 1996. From feed to milk: Understanding rumen function. Pennsylvania State University Extension Circular 422
National Research Council. 1984. Nutrient requirements of beef cattle. Sixth Revised Edition. National Academy Press, Washington D. C.
National Research Council. 1996. Nutrient requirements of beef cattle. Seventh Revised
Edition. National Academy Press, Washington D. C.
Table 1. Nutrient content of midds and other feeds
|Acid Detergent Fiber||11.04||11.70-||16.00||7.00||-|
|Total Digestible Nutrients||80.20****||69.00||77.00||84.00||90.00|
* Summary of 8 samples of midds from durum wheat sent to 4 different laboratories
includes both pelleted and meal forms
**Values from National Research Council, Nutrient Requirements for Beef Cattle, 7th Ed. 1996. National Academy Press.
***Values from National Research Council, Nutrient Requirements for Beef Cattle, 6th Ed. 1984. National Academy Press.
****Estimate based on equations developed by R. S. Adams, Penn State Univ, Revised 1994 (Ishler et al., 1996)
Table 2. Sources of Middlings in North Dakota
|North Dakota Mill and Elevator||Grand Forks||(701)795-7000|
|Dakota Growers Pasta Company||Carrington||(701)652-2855|
|Noodles by Leonardo||Cando||(701)968-4464|
|or Mayville||1 800-437-4004|
Table 3. Finishing diets for steers fed durum midds at 50% or 20% of corn grain.
|Ingredient||50% Midds||20% Midds|
------------------Percent as fed--------------
|Rolled corn grain||36.1||56.8|
|Chopped alfalfa hay||7.2||7.2|
Table 4. Performance of steers fed 50% or 20% durum midds in meal or pelleted form in finishing diets.
|50% Wheat midds|
Dry Matter intake, lb.
|20% Wheat midds|
|Dry Matter intake, lb.||23.98||23.99||.23|
a, b values with different superscripts are significantly different (P<.05)
Table 5. Finishing diets consumed by yearling steers fed increasing levels of durum midds.
----------------pounds per head per day------------------
|Dry rolled corn||22.29||17.05||13.71||8.61|
|Durum midds pellets||-||4.25||9.10||12.91|
Table 6. Feedlot performance of yearling steers fed increasing levels of durum midds in finishing diets.
|Number of head||18||17||18||18|
|Initial wt, lb.||976||973||974||974||14.38|
|Final wt, lb.||1214||1215||1203||1185||19.18|
|Avg. daily gain, lb.||3.67a||3.70a||3.52ab||3.24b||.21|
|Dry matter intake, lb.||25.49a||25.60a||24.61ab||23.61b||.52|
a, b Values with different superscripts are significantly different (P<.06)
Table 7. Carcass traits for yearling steers fed increasing levels of durum midds in finishing diets.
|Rib eye area, sq. in||12.41||12.79||12.79||12.44||.33|
|Fat thickness, in||.43||.47||.41||.43||.04|
* Yield grade indicates fatness of carcass, 1= very lean and 5= very fat
** Score indicates quality grade with 400 + = low choice and 500 + = average choice.
Table 8. Comparative feed value of durum midds at increasing levels in finishing steer diets for equivalent cost of gain
|Cost of gain||Midds value|
* Includes feed cost, yardage, and interest on cattle and feed
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