6 The Effect of Processing on the Nutritive Value of Feedstuffs for Beef Cattle 1995 Beef Cattle Feeding and Nutrition Second Edition

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6 
The Effect of Processing on the Nutritive 
Value of Feedstuffs for Beef Cattle 
Tilden Wayne Perry 
During a two decade period (1960-1980) a great deal of research was con- 
ducted to determine the effect of various methods of processing on the nutritive 
value of feedstuffs for beef cattle. The National Academy of Sciences recognized 
the potential impact of the feed processing research which had been conducted 
and appointed a committee to prepare a review of such research (1973). Although 
some additional research on the effect of feed processing has been conducted 
since that time, such research has not made very great contributions to the 
subject. Prior to 1960 the major methods of feed processing for cattle consisted 
of the grinding of grains and the ensiling of certain hay crops and the whole corn 
plant. However, cattle feeders currently practice a wide variety of feed grain 
processing and roughage processing techniques. 
I. PROCESSING OF FEED GRAINS 
Several methods of grain processing have been developed. All but two of 
them require heat energy to complete the processmonly grinding and moisturiz- 
ing require no supplemental heat. Feed grain processing techniques in common 
practice today include extrusion, gelatinization, grinding, micronizing, mois- 
turizing, popping, roasting, and steam flaking. Much of the discussion on grain 
processingmexcept for moisturizingmis derived from the National Academy of 
Sciences (1973) publication referred to above; the discussion on high-moisture 
grains is based on a review by Merrill (1971). 
A. Extrusion 
This is accomplished by forcing dry grain through an orifice, utilizing an 
augerlike rotor which crushes the grain prior to the time it reaches the orifice. 
The resulting ribbonlike strip from the orifice breaks into flakes of different 
Beef Cattle Feeding and Nutrition, 
Second Edition 73 
Copyright �9 1995 by Academic Press, Inc. 
All rights of reproduction in any form reserved. 
74 6. The Effect of Processing on the Nutritive Value of Feedstuffs 
TABLE 6.1 
The Comparative Value of Flaked Raw Corn, Extruded Corn, Milo, 
and Ensiled High-Moisture Corn for Beef Cattle a 
Daily gain Daily feed 
Feed/unit 
Treatment lb kg lb kg gain 
Flaked corn 2.85 1.30 22.7 10.3 8.0 
Extruded corn 2.69 1.22 23.0 10.4 8.6 
Extruded milo 2.74 1.25 23.6 10.7 8.6 
High-moisture corn 2.73 1.24 21.9 10.0 8.0 
aMatsushima et al. (1969) 
shapes and lengths. A great deal of the research on extrusion was conducted at 
Colorado State University. 
In one experiment (Matsushima et a l . , 1969) finishing steers were fed a diet 
containing processed grain, limited corn silage (19 lb/day, or 8.6 kg), 2.4 lb (1.1 
kg) alfalfa hay, 1 lb (0.45 kg) beet pulp, and 0.71 lb (322 g) protein supplement. 
Cattle fed extruded grain gained more slowly and required more feed per unit 
gain than cattle fed flaked corn; those fed high-moisture corn gained similarly to 
those fed flaked corn (Table 6.1). In subsequent research, McLaren and Mat- 
sushima (1970) reported that cattle fed extruded grain at 85% concentration made 
gains comparable with those of cattle fed flaked corn (2.79 versus 2.76 lb/ 
day;1.26 versus 1.25 kg/day). Efficiency of gain and carcass quality were com- 
parable for the two groups. 
Digestibility studies compared extruded grain with flaked grain (Matsushima, 
1970). Both thin-flaking and dry extrusion improved digestibility of dry matter, 
crude fiber and crude protein over that of whole corn (Table 6.2). The wet- 
extrusion process was not as effective in improving digestion as was dry extru- 
sion. Conceivably, the presence of moisture in the wet-extrusion process caused 
TABLE 6.2 
Flaking versus Extrusion of Corn: Effect on Cattle Digestibility o 
i 
Digestibility (%) 
Treatment Dry matter Crude protein Crude fiber 
Whole 65 
Thin-flaked 74 
Dry-extruded 71 
Wet-extruded 68 
i i 
aMatsushima (1970). 
41 17 
55 23 
52 21 
48 20 
I. Processing of Feed Grains 75 
sufficient cooling that the usual cooking-heating associated with dry extrusion 
did not take place. Feedlot tests on the four types of corn showed comparable 
daily gains (2.97-3.17 lb/day; 1.35-1.44 kg/day), but feed efficiencies (unit of 
feed per unit of gain) showed interesting differences: whole corn, 7.6; thin 
flaked, 7.0; dry extruded, 7.1; wet extruded, 6.8. 
B. Gelatinization 
Gelatinization is accomplished by subjecting ground grain to heating with 
steam to soften the grain, followed by forcing the resultant product with an auger 
through cone-shaped holes in an expander head. Such holes are smaller where 
the material enters and gradually enlarge until the feed is expelled, which causes 
a release as the grain moves through the die. This causes expansion of the grain. 
This technique is employed in the manufacture of expanded pet foods. Mudd and 
Perry (1969) conducted three metabolism trials and one feeding experiment with 
corn in which the starch was 100% gelatinized. In two of the three metabolism 
studies, the substitution of gelatinized corn for raw corn as a major constituent 
of the diet resulted in a significant and linear depression in the digestibility of 
nutrients; in the feeding trial, gelatinized corn decreased both feed intake and 
cattle gains. 
Nebraska researchers (Wilson and Woods, 1966) reported that substitution of 
15, 30, or 45% gelatinized corn for raw corn tended to improve both gains and 
efficiency of feed conversion of cattle. 
C. Grinding 
Grinding of corn is undoubtedly the oldest processing technique applied to 
feedstuffs for cattle, especially for feed grains. More recent research has demon- 
strated that grinding does not improve the nutrient value of corn for beef cattle. 
However, there may be situations wherein grinding is almost a necessity in order 
to obtain a relatively homogeneous mixture of the ingredients. 
It has been demonstrated that on extremely high corn diets, with little or no 
roughage present, it is a distinct advantage not to grind the corn kernels. At time 
of slaughter, cattle fed high corn diets in which the corn has not been ground 
have a lower incidence of rumen parakeratosis than do those whose corn was 
ground. One explanation is that the hard kernel and sharp tip cap of unground 
corn may serve in part for the "scratch" effect provided by roughages in less 
concentrated diets. 
D. Micronizing 
Micronizing consists of heating grain to 300~ (149~ by gas-fired infrared 
generators. The term micronizing was coined to describe this dry heat treatment 
76 6. The Effect of Processing on the Nutritive Value of Feedstuffs 
since microwaves are emitted from the infrared burners during the process. Texas 
research (Schake et al., 1970) utilized a field trial involving two lots of 100 steers 
each to evaluate micronized milo against steam-flaked milo. Feedlot gains fa- 
vored steers fed micronized milo, but efficiency of feed conversion favored 
steam-flaked milo. However, the report indicated that micronizing was a more 
economical process than steam flaking. 
E. Mo is tur i z ing 
Moisturized or high-moisture grain is the processing technique which perhaps 
gave impetus to the whole area of grain processing. The earliest reported data on 
the feeding value of ensiled high-moisture grains was in 1958 (Beeson and 
Perry), in which it was reported that ensiled high-moisture ground ear corn had 
12-15% greater feeding value per unit of dry matter, based on comparable rates 
of gain and decreased dry matter intake. Unfortunately, the corn ear picker has 
been replaced by the picker-sheller combine and thus ear corn rarely is available 
for ensiling. 
The storage of high-moisture grains is dependent upon either anaerobic fer- 
mentation, as in ensiling, or the prevention of mold formation by the use of suchmaterials as organic acids, e.g., propionic acid. The matter of choosing which 
technique to employ is a matter of which method fits best into a given system of 
feed storage and cattle feeding, plus which is more economical (Fig. 6.1). 
One of the real advantages of the high-moisture grain system of cattle feeding 
is that the harvest may be initiated 2 to 3 weeks before normally possible for 
harvesting grain which is to be artificially dried and stored in binsmthe excep- 
tion being barley. An equally substantial advantage to such a program is that 
expensive artificial drying is not necessary. Perhaps the greatest drawback to the 
high-moisture storage system is that such grain cannot be sold in commercial 
channels once it has been stored as high-moisture grain. Acid-treated high- 
moisture grain may be dried to an acceptable moisture content and subsequently 
introduced into commercial trade. 
Moisture level of high-moisture corn is important. Burroughs et al. (1971) 
summarized the data from 17 reports involving different moisture levels of corn 
stored in limited oxygen storage (as in ensiling). An average improved feeding 
value of 10% for high-moisture ear corn showed a low of +7% when the corn 
contained 23 to 32% moisture, and a high of + 13% for moisture levels of 33- 
44% (there was one high level of 23% improvement for 44% moisture corn in the 
higher moisture group). The higher moisture levels in the corn may cause some 
harvesting problems, and thus a realistic optimum for high-moisture ear corn is 
30 to 35% moisture. 
From high-moisture shelled corn, the average improved feeding value of 6% 
was partitioned into + 7% for moisture levels of 23-27% and + 5% for 28-35% 
I. Processing of Feed Grains 77 
Fig. 6.1 Ensiled high-moisture corn is a most excellent cattle feedstuff. (Photo courtesy of BEEF 
Magazine.) 
moisture levels. The recommended moisture level for high-moisture shelled corn 
ensiling is 25-30%. 
The feeding results from "reconstituted" corn (dry corn treated with water to 
bring the moisture level to 25-30%) have been quite erratic. Generally, in the 
case of corn, it is recommended that original moisture high-moisture corn will 
give more consistent benefits than reconstituted high moisture corn. 
Table 6.3 summarizes experiments in which high-moisture corn was com- 
pared with dry corn as cattle feed for beef cattle. From this summary, it is 
obvious that comparable gains were obtained from both types of corn, but cattle 
consumed an average of 6.9% less dry matter and thus required 6.7% less dry 
matter per unit of gain. 
Embry (1971) presented data to show that rolled high-moisture shelled corn 
has a greater advantage over rolled dry corn when fed with corn silage than when 
fed in an all-concentrate diet. With corn silage, rolled high-moisture shelled corn 
produced equal or greater gains and had greater feed efficiency, whereas in all- 
concentrate diets, all comparative data were nearly the same for both types of 
corn. When hay represented about 65% of daily dry matter, high-moisture shel- 
led corn resulted in 8% increased ghin and 7% improved feed efficiency; with 
haylage at 65% of daily dry matter intake, rolled high-moisture shelled corn 
resulted in 12% faster gains and 10% less feed per unit gain than for dry rolled 
COrn. 
It has been concluded generally by research data on the subject that cattle 
respond to high-moisture shelled corn treated with organic acids as well as they 
respond to ensiled high-moisture shelled corn. 
78 6. The Effect of Processing on the Nutritive Value of Feedstuffs 
Station 
TABLE 6.3 
Dry versus High-Moisture Harvested Corn Stored Whole a 
Dry-rolled corn Ground-ensiled corn 
Daily Corn Corn Water Daily Corn 
gain per day conv. b content (%) gain per day 
Corn 
conv . b 
Illinois 1972 
lb 3.21 13.4 4.17 29.0 2.91 11.9 4.09 
kg 1.4 6.1 1.3 5.4 
Iowa 1970 
lb 2.00 11.7 5.85 24.3 2.09 10.9 5.22 
kg 0.9 5.3 1.0 5.0 
Iowa 1971 
lb 2.56 15.5 6.05 24.0 2.79 15.5 5.55 
kg 1.2 7.0 1.3 7.0 
Iowa 1972 
lb 2.32 13.3 5.73 27.3 2.40 12.6 5.25 
kg 1.1 6.0 1.1 5.7 
Michigan 1970 
lb 3.54 18.5 5.23 32.0 3.33 15.3 4.59 
kg 1.6 8.4 1.5 7.0 
Minnesota 197 lc 
lb 2.81 16.9 6.02 26.0 2.90 16.9 5.85 
kg 1.3 7.7 1.3 7.7 
Minnesota 1971 r 
lb 2.69 11.7 4.36 30.0 2.56 10.9 4.30 
kg 1.2 5.3 1.2 5.0 
Average lb 2.73 14.4 5.34 27.5 2.71 13.4 4.98 
Change (%) 0 -6.9 -6.7 
aData from Annual Beef Cattle Research Reports. 
bConv. = units of corn dry matter/unit of gain. 
cTwo different trials. 
1. HIGH-MOISTURE SORGHUM GRAIN 
Since milo is the basic energy grain of the sprawling cattle feeding industry of 
the Southwest, it is appropriate that Texas, Oklahoma and Kansas have con- 
ducted the majority of the research concerned with the nutritive value of high- 
moisture sorghum grains for beef cattle. 
The benefits from high-moisture sorghum grain over comparable dry sorghum 
are more dramatic than those for corn. Their feeding value in the dry form is 
lower than their chemical composition would predict. Basic research into this 
discrepancy indicates that the starch of dry sorghum grain is less available and 
the protein is not utilized as well as that of dry corn or dry barley. Therefore, 
almost anything that can be done to sorghum grain probably will improve its 
nutritive value for cattle. 
I. Processing of Feed Grains 79 
Cattle fed ground moist sorghum grain have required less grain dry matter per 
unit gain than those fed ground dry sorghum grain, ranging from 15 to 25% with 
an overall average of 20%. In practically all comparisons, high-moisture sor- 
ghum grains have resulted in lowered dry matter intake compared to other pro- 
cessing.methods such as steam-flaked, ground, or rolled dry grain. With similar 
weight gains, then, feed efficiency favors utilization of high-moisture sorghum 
grain. 
Further processing of high-moisture sorghum grain is important. For example, 
beef cattle fed ground high-moisture sorghum grain gained 11% faster and re- 
quired 37% less grain dry matter per unit of gain than cattle fed the same high- 
moisture grain in whole form. Rolling either high-moisture grain sorghum or dry 
sorghum grain is superior to fine grinding for increasing efficiency of feed con- 
version. 
Some investigators feel that the change that takes place in reconstituting grain 
sorghum is similar to that which occurs during germination in which the starch of 
the endosperm is liquified to an extent for use by the growing seedling. 
The ideal average moisture content for high-moisture sorghum grain is 30% 
with a range of 25 to 35%. Similarly, the ideal reconstituted level is 30% 
moisture. However, it is most difficult to add more than 10 points of moisture 
above the starting point. 
It is critical in the reconstituting of sorghum grain that the grain remain in the 
reconstituting-fermentation process for a minimum of approximately 21 days. 
Increased dry matter digestibility has been proposed as the primary factor 
causing increased feed efficiency from using high-moisture sorghum grain. It has 
been shown, for example, that reconstituted high-moisture sorghum grain in- 
creases the digestibility of dry matter, organic matter, and nonprotein organic 
matter with a magnitude of 12 to 29%. 
2. HIGH-MOISTURE BARLEY 
Barley kernels are physiologically mature when the moisture content drops 
below 40%. The ideal average moisture content for high-moisture barley is 30%, 
similar to that for high-moisture sorghum grain. All the physical advantages 
related to earlier harvesting for barley add to the increased feeding value of high- 
moisture barley. Research indicates that high-moisture barley has a place in cattle 
feeding~not because of increased gain, but because of improved efficiency of 
feed conversion. The chief advantageof high-moisture barley appears to be its 
high acceptability, with cattle "going on feed" more rapidly, resulting in better 
early gains. Cattle stay "on feed" easier on high-moisture barley than on dry- 
rolled barley. 
High-moisture barley should be rolled for beef cattle. In comparative studies, 
cattle fed whole high-moisture barley gained 0.3 lb (136 g) less per day, and 
required 63 units of feed more per unit of gain than cattle whose high-moisture 
barley was rolled prior to feeding. 
80 6. The Effect of Processing on the Nutritive Value of Feedstuffs 
F. Popping 
Popping is primarily restricted to sorghum grain and is accomplished by the 
use of gas-fired infrared generators, rated at about 50,000 BTU per hour, each, 
suspended above the table to heat the grain as it passes beneath. The percentage 
of milo that will actually pop ranges from 13 to 45% and appears to be influenced 
by the moisture content of the grain, the temperature within the machine, and the 
rate of flow through the machine. As moisture content of the grain increases, the 
percentage of popping increases. 
Riggs et al. (1970) made an in-depth study of the effect of popping on 
nutritional value. Four types of popping were compared: rolled (unpopped), 
normal run (13-45% popped), 100% popped, and partially popped, or that 
fraction left over from screening out the 100% popped fraction. The processed 
milos were self-fed in a mixture composed of 92% milo, 7% cottonseed meal, 
and minerals. 
The most striking feature of these data is the great reduction in dry matter 
consumption of all three groups fed popped milo (Table 6.4). Steers fed rolled 
dry milo consumed 19 to 37% more dry matter per day than those fed popped 
milo. The reduction in feed intake was accompanied by improved feed utilization 
but also decreased daily gain. 
Digestibility studies explain some of the reasons for the improvement in 
efficiency of feed conversion for the popped milo. It should be noted from Table 
6.4 that digestion of the nitrogen-free extract (NFE) was approximately 26% 
greater (61% for rolled versus an average of 77% for popped). Since NFE 
represents nearly 73% of milo, a 26% increase in digestibility would enhance its 
utilization tremendously. 
The decline in dry matter consumption of popped milo has a very logical 
explanation (Table 6.5). From the data in that table, it may be observed that the 
TABLE 6.4 
Comparative Feeding Value of Rolled and Popped Milo ~ 
Nutrient digestibility (%) 
Daily gain Daily feed 
Milo Feed Dry Crude 
treatment lb kg lb kg efficiency matter protein NFEb 
Rolled 3.10 1.4 21.2 9.6 6.9 57 39 61 
Normal, popped 2.73 1.2 14.9 6.8 5.5 75 39 75 
100% popped 2.55 1.1 15.1 6.9 5.9 79 38 80 
Partially popped 2.75 1.3 17.5 7.3 6.4 76 41 77 
aRiggs et al. (1970). 
bNFE, nitrogen-free extract. 
I. Process ing of Feed Gra ins 81 
TABLE 6.5 
Effect of Popped Milo on Average Molar Percentage of Volatile Fatty 
Acid Production in the Rumen o 
Rolled Normal 100% Partially 
Fatty acids milo popped popped popped 
Acetic 54.9 b 41.9 c 44.6 c 45.5 b, c 
Propionic 30.2b 47.6 c 44.3 r 42.0 r 
Butyric 8.8 7.8 8.3 8.9 
Isovaleric 4.3 b 1.0 r 0.5 r 0.8 r 
Valeric 1.2b 1.6 b 2.4c 1.6 b 
Note. Values on same line with differing superscripts differ for acetic, propionic, and 
isovaleric by p < 0.01, and for valeric by p < 0.05. 
aRiggs et al. (1970). 
feeding of popped milo resulted in greatly increased levels of propionic acid in 
the rumen. Research data (discussed in a separate chapter) demonstrate that the 
feeding of the ionophore monensin results in (1) increased production of pro- 
pionic acid in the rumen, (2) a 10% depression in feed intake, and (3) an 
approximately 10% increase in efficiency of feed conversion. 
G. Pelleting 
Pelleting of beef cattle diets attracted considerable interest several years ago. 
However, very little pelleting of beef cattle diets is practiced anywhere today. 
Research from the Dixon Springs, Illinois, experiment station showed that pellet- 
ing of lower quality hay resulted in greater acceptability and digestibility. How- 
ever, research has not shown any benefit from pelleting either high-quality hay or 
high-concentrate diets. Furthermore, the cost of pelleting would require quite 
large nutritional or economic benefits from such practice in order to justify using 
that technique of feed processing. 
H. Roasting 
Corn roasting offers great nutritional benefits as a processing technique for the 
grain portion of cattle diets. However, because of the cost of heat energy, all 
processing techniques which require heat (steam flaking, popping, micronizing, 
roasting, gelatinizing) generally are more expensive to utilize than those using 
high-moisture grains. 
The grain roasting technique, discovered by T. W. Perry in the late 1960s, has 
been shown to result in an average of 8% more rapid gain, plus a nearly 10% feed 
saving in beef cattle diets (Table 6.6). 
TABLE 6.6 
Comparative Performance of Cattle Fed Raw and Roasted Corn, 1970-1975, Six Trials ~ 
| 
1970 1971 1972 1973 1974 1975 
300~ 300~ 300~ 300~ 300~ 300~ 
Raw (148~ Raw (148~ Raw (148~ Raw (148~ Raw (148~ Raw (148~ 
Number of cattle 91 91 75 75 61 61 25 25 25 25 27 28 
Initial weight 
lb 509 513 550 551 507 507 516 518 550 552 524 524 
kg 231 233 250 250 230 230 234 235 250 251 238 234 
Length of study 112 112 127 127 106 106 191 191 170 170 189 189 
(days) 
Daily gain 
lb 2.33 2.66 2.33 2.47 2.23 2.37 2.34 2.42 2.60 2.73 2.19 2.40 
kg 1.06 1.21 1.06 1.03 1.03 1.08 1.06 1.10 1.18 1.24 1.00 1.09 
Percentage change + 14 + 6 + 6 + 8 + 5 + 10 
Daily corn 
lb 11.9 12.4 15.1 13.5 13.8 12.9 15.3 15.4 10.4 9.2 15.2 13.8 
kg 5.4 5.6 6.9 6.1 6.3 5.9 7.0 7.0 4.7 4.2 6.9 6.3 
Dry feed/unit gain 6.8 5.2 7.5 6.4 6.7 6.1 7.6 7.0 7.9 7.4 8.4 7.3 
Percentage change -7 .4 - 14.7 -9 .0 -8 .0 -6 .0 - 13.0 
aT. W. Perry's summary of Purdue University research data. Average increase in gain due to roasted corn, 8.29%; average decrease in feed required per unit of gain, 9.7%. 
I. Processing of Feed Grains 83 
Roasting of corn is accomplished by exposing the whole grain to open flame 
heat. A common model for roasting grain consists of a cylinder housed within a 
jacket. The inside cylinder has spiral fins on its inside surface which lift the grain 
through jets of flame pointing downward from the top of the jacket. Many 
revolutions of the inside drum take the grain through the flames many times until 
it is heated to 275~ (135~ Roasted corn has a pleasant "nutty" flavor and 
aroma, and a puffed, caramelized appearance. Very few of the kernels are actu- 
ally popped. While raw corn weighs 45 lb/cubic foot, roasted corn weighs only 
39 lb/cubic foot, indicating expansion during the roasting process. The moisture 
content of roasted corn is about 5-9% less than that of raw corn. 
Cattle relish roasted corn and tend to "go on feed" more readily than they do 
on nonroasted (or raw) corn. However, although cattle do not eat any more dry 
matter on a roasted corn diet, they gain more rapidly, thus causing such cattle to 
convert dietary dry matter to gain more efficiently. 
Another effect observed from feeding roasted corn to finishing cattle is that 
the carcasses from cattle fed roasted corn grade approximately one-half grade 
higher than those from cattle fed regular corn. 
I. Steam Flaking and Steam Rolling 
These two processes are somewhat similar except the former technique is 
more specific and a longer time is given to the cooking or steaming process. In 
addition, the flaking process results in elevated moisture content of the grain. In 
flaking of corn a cooking or steaming time of 12 min at a temperature of 200~ 
(93~ will elevate the moisture from 15 to 18%; holding milo at this temperature 
for 14min will increase the moisture content from 14 to 20%. Following the 
cooking process, the grain is passed through rollers set to produce flakes ~ inch 
(~ mm) in thickness. As soon as the grain is rolled, it should be dried to 
approximately 15% moisture. Colorado research (Matsushima and Montgomery, 
1967) demonstrated the importance of producing thin flakes in the milling pro- 
cess (Table 6.7, Fig. 6.2). 
Cattle fed raw ground corn did gain as rapidly (Table 6.7) as those fed either 
of the two thicknesses of flaked corn; those fed the thinner-flaked corn gained 
most rapidly and required the least dry matter per unit of gain. 
Flaking of corn increased efficiency of feed conversion over pelleted corn by 
5%, and by 10-15% over grinding or cracking in Florida research (Hentges et 
al., 1966) (Table 6.8). 
In Oklahoma research, steam flaking of milo (Totusek et al., 1967) resulted in 
a nearly 7% increase in feed intake (11.3 vs 10.6 lb/day, or 5.1 vs 4.8 kg) and 
increased rate of gain (2.63 vs 2.43 lb/day, or 1.2 vs 1.1 kg), but no improve- 
ment in efficiency of feed conversion. Hale et al. (1966)reported that steam 
processing and flaking of milo resulted in increased rate of gain (3.10 vs 2.83 
84 6. The Effect of Processing on the Nutritive Value of Feedstuffs 
TABLE 6.7 
Comparative Feeding Value of Corn Steam-Flaked 
to Different Thicknesses a 
Thickness of flakes 
1/32 inch 1/12 inch 
(1/8 cm) (1.2 cm) 
Finely ground, 
1/4-inch screen 
(60 mm) 
Number of cattle 14 
Initial weight 
lb 485 
kg 220 
Daily gain (163 days) 
lb 
kg 
Corn consumed/day 
lb 12.4 
kg 5.6 
Units feed/unit gain 6.1 
14 14 
aMatsushima and Montgomery (1967). 
483 490 
220 223 
2.82 2.70 2.65 
1.28 1.23 1.20 
12.7 12.8 
5.8 5.8 
6.7 6.9 
lb/day, or 1.4 vs 1.3 kg), and improved efficiency of feed conversion (7.6 vs 8.0 
units of feed per unit of gain). The same investigators reported that steam pro- 
cessing and flaking of barley also resulted in increased gain of cattle (3.10 vs 
2.88 lb/day, or 1.4 vs 1.3 kg), but no improvement in efficiency of feed conver- 
sion (7.2 vs 7.2 units of feed per unit of gain). 
Fig. 6.2 Examples of undesirable (thick flake) and desirable (thin flake) steamed and flaked com. 
(Photo courtesy of BEEF Magazine.) 
II. Processing of Roughage 85 
TABLE 6.8 
Effect of Grinding, Cracking, Flaking, or Pelleting Corn for Beef Cattle a 
Corn treatment 
Ground Cracked Flaked Pelleted 
Number of cattle 20 20 20 20 
Initial weight (lb) 588 585 577 588 
Daily gain, 126 days (lb) 3.30 3.40 3.60 3.50 
Daily concentrates (lb) 18.1 19.5 18.3 18.5 
Feed per pound gain (lb) 6.5 6.7 5.8 6.3 
aHentges et al. (1966). 
II. PROCESSING OF ROUGHAGE 
Considerable research has been conducted in the area of the value of process- 
ing roughage for beef cattle. In general, processing of higher-quality roughage 
does not result in greater feed intake, improved gain, or improved efficiency of 
feed conversion; in contrast, some types of roughage processing of poorer quality 
roughages will improve nutritive value. Such improvement in nutrient value of 
roughage often is attributed to improved con'sumption on lower quality rough- 
ages. However, because of the low economic value of many roughages, usually 
it is questionable whether one can afford to spend more than token amounts of 
time and labor on such practices. 
A. Grinding 
Grinding of roughages is restricted almost entirely to corn cobs. When proper- 
ly balanced, ground corn cobs have an energy equivalent to that of medium- 
quality hay. In contrast, unground cobs have practically no feeding value. Be- 
cause of the abrasive nature of corn cobs, they are extremely hard on a hammer 
mill. 
Grinding of hay has little nutritive value for beef cattle except as a prerequisite 
to pelleting or complete mixing of diets. However, the grinding produces so 
much dust that this causes a feeding problem. Grinding of hay is not practical for 
dairy cattle because it results in lowered butterfat content of the milk produced. 
B. Pelleting 
Pelleting of roughages has received a great deal of interest. The Illinois 
Station at Dixon Springs indicated greatly increased nutritive value of hay as the 
86 6. The Effect of Processing on the Nutritive Value of Feedstuffs 
result of pelleting. Subsequent research indicated that the benefit from pelleting 
could be realized only with lower-quality haymthere was no benefit from pellet- 
ing high-quality hay. 
Pelleting of corn cobs will improve nutritive value; similarly, dehydrating and 
pelleting whole-plant corn silage will improve its nutritive value. However, the 
cost of processing such products for pelleting is almost prohibitive. 
C. Wafering 
Wafering of hay holds considerable promise. In this process the stems are 
broken somewhat and the resultant product is about 3 inches (7.6 cm) in diameter 
and 1 to 3 inches (2.5 to 7.6 cm) in thickness. This process has been employed in 
preparinghay for shipment to other countries, as well as for long distances within 
the United States; the reduction in volume by such process permits shipment of 
much greater weights of hay, which in turn may more than pay for the cost of the 
wafering process. 
D. Predigestion, Ammonification 
Predigestion using alkali such as NaOH or KOH will increase nutrient avail- 
ability of low-quality roughages by as much as 33%. Likewise, the ammonifica- 
tion of roughages increases the availability of nutrients and increases the nitrogen 
(crude protein) content of treated roughages. However, such treatments require 
much added expense in terms of special equipment, labor, and personal atten- 
tion. 
E. Dehydration 
This process is restricted almost entirely to high-quality roughages such as 
alfalfa. The energy cost is too great to permit its use under other conditions. 
F. Ensiling and Hay Making 
The use of these proc~essing techniques for roughages is discussed in another 
section of this text. 
REFERENCES 
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