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The Comparative Value of Yellow Corn, Yellow Milo, and Hegari in a Diet for Growing Chicks
The Comparative Value of Yellow Corn, Yellow Milo, and Hegari in a Diet for Growing Chicks BURT W. HEYWANG AND RUDOLPH B. MORGAN* Bureau of Animal Industry, U. S. Department of Agriculture (Received for Publication February 1, 1932)
ELLOW corn is not successfully grown in the arid regions of the Southwest, but the grain sorghums are grown extensively and are of considerable economic importance. The grain sorghums, yellow milof and hegari, are usually cheaper, at least in the Salt River Valley region of Arizona, than the imported yellow corn, and are used extensively in poultry rations in some localities. In the diets recommended for poultry of different ages by the U. S. Poultry Experiment Station, Glendale, Arizona, yellow milo partly replaces yellow corn. Hoist and Newlon (1927), Payne (1926), and Sherwood (1926) suggest that milo may be substituted, wholly or in part, for yellow corn in diets for laying hens. However, there are no experimental data available which show the comparative nutritive value of yellow corn, yellow milo, and hegari when they are used in diets for chicks. Smith (1930a) used albino rats as experimental subjects, and concluded that: "Comparative chemical analysis of hegari, yellow milo, and yellow corn shows the sorghums to be somewhat higher in protein and lower in fat than corn. This difference in chemical composition, however, does not satisfactorily explain the observed difference * The assistance of Dr. Harry W. Titus in preparing this paper for publication is hereby gratefully acknowledged. j "Yellow" milo is sometimes called "red" milo.
in nutritive value." Smith (1930b) also made a quantitative study of the vitamin A content of yellow corn, hegari, and yellow milo, and found yellow corn to be twenty times, and yellow milo two times, as rich in vitamin A as hegari. Smith and Lynott (1931) found that five percent" of alfalfa leaf meal as a source of vitamin A promoted good growth when added to sorghum grain rations fed to albino rats. Penquite (1931) states that: "Grain sorghums are good poultry feeds," and that: "Tests . . . indicate that kafir and darso can be substituted for yellow corn if green feed or some green feed substitute . . . is fed every day during the year." The "Uniform Method"! of comparing feedstuffs which is being developed by the Animal Husbandry Division of the United States Department of Agriculture and several of the southern and southwestern agricultural experiment stations, was used in obtaining the data given in this paper. The basal diet used in this work is believed to be complete in all essential nutrients, but is not t By actual experimental tests, or in some other manner, poultry departments at the following institutions have shown an interest in the "Uniform Method": New Mexico A. & M. College, Louisiana State University, Mississippi A. & M. College, Oklahoma A. & M. College, Texas Agricultural Experiment Station, U. S. Animal Husbandry Experiment Farm, Beltsville, Md., and the U. S. Poultry Experiment Station, Glendale, Arizona.
[307]
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308
POULTRY
SCIENCE
suitable for feeding trials in which it is de- recommended maximum period of twelve sired to study the relative value of any one; weeks, and feed was given ad libitum in the nutrient of a feedstuff. The presence off second experiment. biologically tested cod liver oil and alfalfai Forty vigorous Single Comb White Legleaf meal in the basal diet eliminates the; horn chicks were started on each diet. They possibility that differences in the vitamin Ai were weighed before feeding on the second content of the feedstuffs studied may ma- and seventh day after hatching and at weekterially affect their nutritive value. As the: ly periods thereafter, until the experiments other nutrients are also quite generously' had been conducted for thirteen weeks. Each supplied in the basal ration by ingredients; group was confined to a pen, 10 by 20 feet other than the feedstuffs to be studied, it: in a house having a concrete floor. Electric is also probable that slight differences in thej brooders were used. To each of the five diets TABLE la. The diets used Diet 1* percent
Diet 2 percent
Diet 3 percent
Yellow corn meal Yellow milo meal Hegari meal Corn gluten meal Ground wheat Dried buttermilk Meat scraps (50% protein) Alfalfa leaf meal Ground limestone Yeast ("Animal-Poultry Yeast Foam") Salt
40,0
20.0 20.0
20.0
—
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— — ToTo 22.0 10.0 10.0 2.5 3.0 2.0 0.5
10.0 22.0 10.0 10.0 2.5 3.0 2.0 0.5
—
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—.
40.0 —
i22.0 o— 10.0 10.0 • 2.5 3.0 2.0 0.5
* Diet 1 is a slight modification of the basal diet originally recommended for use when the "Uniform Method" is followed.
protein, fat, or mineral content of the feedstuffs would not affect the results obtained. In short, the basal diet used in the "Uniform Method" is comparable to a good commercial mixed feed, and substitutions which are satisfactory in the basal diet should be equally satisfactory in a properly formulated mixed feed.
V/z percent of biologically tested cod liver oil was added. The yellow corn meal was prepared from Nebraska No. 2 yellow corn, and the corn gluten meal was also prepared from corn grown in Nebraska. The yellow milo and hegari were grown in the Salt River Valley section of Arizona.
EXPERIMENTAL PROCEDURE
T H E FIRST EXPERIMENT
The experimental data presented in this article were obtained at the U. S. Poultry Experiment Station, Glendale, Arizona. Two separate experiments were conducted, and the basal diet and the substitutions in the basal diet were identical in both. The "Uniform Method" was followed in all details, except that the experiments were conducted for periods of thirteen weeks instead of the
In the first experiment, as recommended in the outline of the "Uniform Method", feed consumption was restricted to "an amount less than ad libitum consumption, and the same amount of feed was given to the chicks receiving the different diets. The feed was weighed out daily, and the amount approximated eighty percent of the average ad libitum consumption as determined in
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POULTRY
SCIENCE
Diet 4 (31 survivors) Age
Grams 32.9 43.3 57.4 86.4 109.8 150.0 192.2 238.8 277.8 338.8 395.8 462.1 516.9 585.2
Average feed consumption Per period
Total
Grams
Grams
—
25.0 48.0 70.0 94.0 115.0 122.0 152.0 173.0 204.0 224.0 243.0 259.0 272.0
—
25.0 73.0 143.0 237.0 352.0 474.0 626.0 799.0 1003.0 1227.0 1470.0 1729.0 2001.0
Efficiency of diet Per period
—
0.414 0.294 0.415 0.248 0.350 0.346 0.307 0.225 0.299 0.254 0.273 0.212 0.251
Cumulative
—
0.414 0.335 0.374 0.324 0.332 0.336 0.329 0.307 0.305 0.296 0.292 0.280 0.276
Diet 5 (31 survivors) (2 days) 1 2 3 4 5 6 7 8 9 10 11 12 13
33.2 42.5 55.2 80.0 106.5 148.4 183.1 234.3 271.0 326.6 385.3 448.8 500.8 574.1
25.0 48.0 70.0 94.0 115.0 122.0 152.0 173.0 204.0 224.0 243.0 259.0 272.0
previous experiments. Obviously, as the average amount of feed per chick was the same for all diets, the total daily amount of any diet fed depended upon the number of survivors in the group which received the diet. The first experiment was started September 3, 1930, and continued until the chicks were 91 days old. In Table 1 are given the average live weights of the chicks, the average feed consumption on the five diets, and the efficiencies of the diets. It should be noted that the average weekly feed consumption and the cumulative feed consumption were identical for the five diets, excepting diet 2. Through an error, an excess of 3.3 grams of diet 2 was fed during the sixth week.
25.0 73.0 143.0 237.0 352.0 474.0 626.0 799.0 1003.0 1227.0 1470.0 1729.0 2001.0
—
—
0.374 0.264 0.355 0.281 0.365 0.284 0.337 0.212 0.272 0.262 0.262 0.201 0.269
0.374 0.302 0.328 0.309 0.327 0.316 0.321 0.298 0.293 0.287 0.283 0.271 0.270
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Weeks (2 days) 1 2 3 4 5 6 7 8 9 10 11 12 13
Average live weight
In computing the efficiencies of the diets for the different periods, it was possible to use either the average weights of all the chicks surviving at the end of a period, or the average weights of the final survivors. When no deaths had occurred during a period, the results were identical, and it was found by actual calculation that in these experiments the differences were insignificant whichever method was used. The average weights of the final survivors were used in computing all efficiencies given in this paper. The cumulative efficiencies of diets 1 and 2 were nearly identical, and greater than those of the other three diets at the end of eight weeks, while the efficiency of diet 5 was the least of the five. At the end of thirteen weeks, the cumulative efficiency of diet
SEPTEMBER,
1932.
VOL.
XI,
No.
T H E SECOND EXPERIMENT
Since feed consumption was restricted in the first experiment, it was desirable to conduct another experiment to ascertain whether or not the efficiencies of the diets would be similar when feed consumption is not restricted. Accordingly, the diets were fed ad libitum in the second experiment. In all other respects the procedure followed in both experiments was identical. The diets used were identical with those used in the first experiment. The second experiment was started January 14, 1931. In Table 2 are given the average live weights of the chicks, the average feed consumption on the five diets, and the efficiencies of the diets in the second experiment. At the end of eight weeks the average feed consumption was greatest on diet 1 and least on diet 5, being nearly 300 grams greater on the former than on the latter. At the end of thirteen weeks the average feed consumption was also greatest on diet 1 and least on diet 5, being more than 500 grams greater on diet 1 than diet 5. The cumulative efficiencies of the same diets in the two experiments were in good
311
agreement at the end of eight and thirteen weeks. This indicates that any unequal distribution of the sexes did not materially affect the calculated efficiencies of the diets, for the distribution of the sexes on the same diet was different in the two experiments. For example: on diet 1 in the first experiment there was only 0.67 male for each female, and the cumulative efficiency of the diet at the end of thirteen weeks was 0.270. On diet 1 in the second experiment there were 1.19 males for each female, and the cumulative efficiency of the diet at the end of thirteen weeks was 0.260. In the second experiment, at the end of thirteen weeks, the average weight of the males divided by the average weight of the females on the same diets gave the following ratios: 1.25 on diet 1, 1.23 on diet 2, 1.29 on diet 3, 1.24 on diet 4, and 1.24 on diet 5. In the case of all the diets the ratios were larger than they were in the first experiment. Apparently, when feed was given on a restricted basis in the first experiment the feed consumption of males and females was more nearly equal than when feed was given ad libitum in the second experiment. The total mortality on the different diets was in a different relative order than in the first experiment, indicating that the mortality in both experiments was due to factors other than the diets. In the second experiment the mortality was relatively high on diet 1 and relatively low on diet 5, while in the first experiment it was relatively low on diet 1 and relatively high on diet 5. Only one chick died after the seventh week during the second experiment. During the entire experiment a total of 5 deaths occurred on diet 1, 4 on diet 2, 1 on diet 3, 6 on diet 4, and 2 on diet 5. AVERAGE EFFICIENCIES OF THE DIETS
While the feed allowances were different in the two experiments, the results obtained
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2 was the greatest, diets 3 and 4 were nearly identical and next in efficiency, and diets 1 and 5 were identical and the least efficient. However, there was very little difference between the cumulative efficiencies of any of the diets at the end of thirteen weeks. At the end of the experiment the average weights of the males on a given diet divided by the average weights of the females on the same diets showed the following ratios: 1.11 on diet 1,1.09 on diet 2,1.15 on diet 3, 1.20 on diet 4, and 1.09 on diet 5. The total number of deaths among the chicks receiving the different diets was: 0 on diet 1, 5 on diet 2, 6 on diet 3, 9 on diet 4, 9 on diet 5. All mortality occurred during the first eight weeks.
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SEPTEMBER,
1932.
VOL.
XI,
No.
313
5
Diet 4 (34 survivors) Age
Grams 35.7 43.9 65.8 92.2 125.1 171.9 220.6 304.4 382.3 485.2 568.4 676.9 786.9 897.9
Average feed consumption Per period
Total
Grams
Grams
23.4 60.2 82.9 109.7 135.6 174.3 247.3 303.2 297.7 360.3 434.1 420.0 473.8
23.4 83.6 166.5 276.2 411.8 586.1 833.4 1136.6 1434.3 1794.6 2228.7 2648.7 3122.5
Efficiency of diet Per period
0.350 0.364 0.319 0.300 0.345 0.279 0.339 0.257 0.346 0.231 0.250 0.262 0.235
Cumulative
0.350 0.360 0.340 0.324 0.331 0.316 0.323 0.305 0.314 0.297 0.288 0.284 0.276
Diet 5 (38 survivors) 2 (days) 1 2 3 4 5 6 7 8 9 10 11 12 13
35.3 43.2 63.1 87.4 119.0 163.6 222.5 289.3 363.2 435.8 541.8 630.2 723.5 829.9
— 26.7 58.0 82.1 101.8 133.9 177.4 213.4 281.6 301.1 351.1 377.1 396.1 426.1
— 26.7 84.7 166.8 268.6 402.5 579.9 793.3 1074.9 1376.0 1727.0 2104.1 2500.2 2926.3
0.299 0.343 0.296 0.311 0.333 0.332 0.313 0.262 0.241 0.302 0.234 ' 0.235 0.250
. 0.299 0.329 0.313 0.312 0.319 0.323 0.320 0.305 0.291 0.293 0.283 0.275 0.272
were similar enough to permit a combination strain of Rhode Island Reds which they used of the two sets of data. It was believed that in their experiments. such a combination would emphasize the It is particularly interesting to note that similarity between the results obtained from the cumulative efficiencies of the five diets feeding the five different diets, and conse- are nearly identical at the end of thirteen quently the mutual replacabilities of yellow weeks, indicating that either 20 or 40 parts milo, hegari, and yellow corn. of yellow maize or hegari may be substituted The data given in Table 3 show that the for equal parts of yellow corn in a diet for cumulative efficiency of diet 1 was the great- chicks. At least, the substitutions may be est of the five diets at the end of the eighth made if the diet is not deficient in any of the week, but at the end of thirteen weeks, the essential nutrients and is fed until the avercumulative efficiency of diet 1 was the least age weight of the chicks is about one and of five diets. The reversal of the relative one-half pounds. position of diet 1 was in accordance with the The cumulative efficiency of diet 5 was observations of Titus and Jull (1928) and much lower than that of the other four diets Titus, McNally, and Hulberg (1930), who during the first four weeks. Inasmuch as the found that the acceleration of early growth average feed consumption was nearly idenwas later followed by slower growth in the tical on diets 2,3,4, and 5 during this period,
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Weeks (2 days) 1 2 3 4 5 6 7 8 9 10 11 12 13
Average live weight
314
POULTRY
the lesser cumulative efficiency of diet 5 indicates that it was of less value for growth during the first four weeks. In Figure 1 the cumulative efficiencies at the end of the first, third, fifth, seventh, ninth, eleventh, and thirteenth weeks have been plotted against age. The "curves" indicate that the cumulative efficiencies decreased at a practically constant time-rate. Titus and co-workers (1930) used time intervals of two weeks in computing efficiencies, and also observed that the cumulative
SCIENCE
"Uniform Method" do not always show these fluctuations in the weekly efficiencies. T H E "PHYSIOLOGICAL" EFFICIENCIES OF THE DIETS
As previously stated, weekly and cumulative efficiencies of the diets are merely expressions representing the ratio of gain in live weight to feed consumption. These efficiencies are calculated by simple arithmetical processes, and inasmuch as no allowance is made for the feed needed for main-
Diet 1
Diet 3
Diet 2
Diet 4
Diet 5
Age
Weekly
Cumulative
Weekly
Cumulative
Weekly
Cumulative
Weekly
Cumulative
Weekly
Cumulative
Weeks 1 2 3 4 5 6 7 8 9 10 11 12 13
Grams 0.442 0.335 0.382 0.348 0.285 0.322 0.360 0.273 0.223 0.287 0.239 0.171 0.201
Grams 0.442 0.367 0.375 0.364 0.336 0.332 0.339 0.324 0.304 0.300 0.290 0.273 0.263
Grams 0.449 0.323 0.372 0.300 0.342 0.325 0.342 0.257 0.276 0.276 0.221 0.156 0.239
Grams 0.449 0.360 0.366 0.340 0.340 0.336 0.338 0.318 0.310 0.303 0.290 0.270 0.265
Grams 0.396 0.320 0.362 0.300 0.348 0.301 0.333 0.228 0.279 0.247 0.212 0.140 0.315
Grams 0.396 0.343 0.353 0.332 0.337 0.327 0.329 0.305 0.300 0.290 0.276 0.257 0.265
Grams 0.383 0.333 0.363 0.276 0.347 0.307 0.327 0.245 0.327 0.240 0.258 0.243 0.240
Grams 0.383 0.349 0.356 0.324 0.331 0.325 0.325 0.306 0.310 0.296 0.289 0.282 0.276
Grams 0.335 0.307 0.323 0.296 0.348 0.313 0.323 0.243 0.254 0.286 0.245 0.222 0.258
Grams 0.335 0.316 0.320 0.311 0.323 0.320 0.321 0.302 0.292 0.331 0.283 0.273 0.271
efficiencies decreased at a practically constant time-rate after the fourth week. However, the data in Table 3 show that the cumulative efficiencies fluctuated from week to week, and if they had been plotted against age at one-week intervals the curves would be quite irregular although they would still show the same trend. The average weekly efficiencies of the diets are given in Table 3 principally to show that although growth, as measured by change in live weight, may increase each week, the efficiency of feed may fluctuate markedly from one weekly period to another. It should be stated, however, that the results of the other workers who have used the
tenance they do not necessarily represent the "true" efficiencies of the diets for growth. It is commonly accepted that the amount of feed required for maintenance increases as the animal becomes heavier, and Spillman, as quoted by Jull and Titus (1928), has discussed the applicability of the law of diminishing increment in describing the relationship between the live weight and the feed consumption of growing animals. Jull and Titus (loc. cit.) as a result of their work concluded that: ". . . the relationship between feed consumption and growth of the domestic fowl is expressible by the law of diminishing increment, at least for
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TABLE 3. The average efficiencies of the diets during both experiments
SEPTEMBER,
1932.
VOL.
XI,
No.
the time interval studied." Titus (1928) demonstrated that the growth of White Pekin ducklings could be expressed by the equation developed by Spillman. Hendricks (1931) has offered a physiological interpretation of the law of the diminishing increment when applied to data obtained in animal feeding experiments, and has developed a method by which the relative "physiological" efficiency of diets may be computed. The amount of feed used for maintenance is expressed in terms of a loss of body tissues, and it is assumed that this loss in live weight per unit of feed con-
315
5
sent the average maximum weight attainable by the animal if it continues on the same diet at the same relative rate of increase in feed consumption. The values of C C, m, and — for the five diets are given in m Table 4. The "physiological" or "true" efficiencies of the diets, C in Table 4, differ in their relative order from the cumulative efficiencies given in Table 3. The cumulative efficiencies of the diets at the end of thirteen weeks were nearly identical, but there are considerable differences between some of
Diet 1 2 3 4 5
m
C m
.00029077+.00003363 .00028054+ .00003655 .00023227+ .00004788 .00017930+.00002852 .00015098 ±.00002330
1337 + 160.9 1364+184.1 1540 + 325.6 1962 + 317.4 2193 + 634.4
C .3859+ .01294 .3827+.01347 .3576+.01681 .3517+.01038 .3311+.00810
sumed is proportional to the live weight of the animal. In Hendricks' equation AW AW = C — mW, the ratio repreAF AF sents the gain in live weight per unit of feed eaten over a short interval of time; W represents the average live weight of the animal during that interval of time; and C represents the "true" or "physiological" efficiency of the feed. AW The values of and W were obAF tained from the combined data of the two experiments, and the values of C, m, and C — were calculated by the method proposed m by Hendricks (loc. cit.). C is constant for a given diet, and m is constant for a given diet fed at a given level; and since W apC C proaches — asymptotically, — must reprem m
the "physiological" efficiencies. However, there is much to be learned about the actual significance of both C and m in Hendricks' equation. His proposed method for determining the "physiological" efficiencies of feedstuffs has been used here because this method, which is now being developed, may prove to be quite valuable in interpreting the results of feeding trials, and because, in this case, it brings out differences between the several diets which undoubtedly exist but which can not be easily demonstrated by a comparison of the cumulative efficiencies. From the scientific viewpoint, the "physiological" efficiency of a feedstuff, or diet, is of interest and value, but from the economic viewpoint, the cumulative efficiency is of equal or even greater importance. This is particularly true because the "physiological" efficiency of a given diet is constant throughout the period of active
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TABLE 4. The values of C, m, and —for the five diets, calculated from the combined data of the two experiments
316
POULTRY
growth of the chicken, whereas the cumulative efficiency is not and, in general, decreases more or less regularly as the chick becomes larger.
SCIENCE
lowered by the substitution of 20 or 40 percent of either of these two grains for equal weights of yellow corn. The significance of this difference is, as yet, not clear.
CONCLUSIONS
REFERENCES
Either yellow milo or hegari may replace yellow corn, to the extent of from SO to 100 percent, in a chick diet which is not defi-
Hendricks, Walter A., 1931. Fitting the curve of the diminishing increment to feed consumptionlive weight growth curves. Sci., 74:290-291. Hendricks, Walter A., Morley A. Jull, and Harry
°
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3
5
7 s4(?E IN
9
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WEEKS'
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\
/3
FIG. 1. The relation between average cumulative efficiency of the diets and age.
cient in any way, particularly if the diet is fed until the chicks average about one and one-half pounds live weight. The growth-feed consumption ratio, or efficiency, is not changed appreciably when either yellow milo or hegari is substituted for yellow corn in a chick ration which is not deficient in any way. However, the "physiological" efficiency is progressively
W. Titus, 1931. A possible physiological interpretation of the law of the diminishing increment. Sci., 73:427-429. Hoist, Walther F., and Wilson E. Newlon, 1927. Poultry feeding: principles and practice. Cal. Agr. Exp. Sta. Bui. 417 :36-37. Jull, Morley A., and Harry W. Titus, 1928. Growth of chickens in relation to feed consumption. J. Agr. Res., 36:541-550. Payne, Loyal F., 1926. Poultry management on the farm. Kan. Agr. Exp. Sta. Cir. 122 :l-28.
SEPTEMBER,
1932.
VOL.
XI,
Penquite, Robert, 1931. Science tests poultry practices. Reprint from Okla. Agr. Exp. Sta. 1930 Rpt.:3-10. Sherwood, Ross M., 1926. Feeding chickens. Tex. Agr. Exp. Sta. Cir. 42 :l-7. Smith, Margaret Cammack, 1930a. The comparative nutritive value of yellow corn and the grain sorghums hegari and yellow milo. J. Agr. Res., 40:1129-1145. 1930b. A quantitative comparison of the vitamin A content of yellow corn and the grain sorphums hegari and yellow milo. J. Agr. Res., 40:1147-1153. Smith, Margaret Cammack, and Mable L. Lynott, 1931. The value of alfalfa as a source of vitamin
No.
5
317
A in sorghum-grain rations. J. Agr. Res., 42: 421-432. Titus, Harry W., 1928. Growth and the relation between live-weight and feed consumption in the case of White Pekin ducklings. Poul. Sci., 7:254-262. Titus, Harry W., and Morley A. JuU, 1928. The growth of Rhode Island Reds and the effect of feeding skim milk on the constants of their growth curves. J. Agr. Res., 36:515-540. Titus, Harry W., Edmund McNally, and Frank C. Hulberg, 1930. A comparison of shrimp "bran" and two kinds of fish meal when fed at a level of ten percent in diets for growing chicks. Poul. Sci., 9:219-234.
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ELLOW corn is not successfully grown in the arid regions of the Southwest, but the grain sorghums are grown extensively and are of considerable economic importance. The grain sorghums, yellow milof and hegari, are usually cheaper, at least in the Salt River Valley region of Arizona, than the imported yellow corn, and are used extensively in poultry rations in some localities. In the diets recommended for poultry of different ages by the U. S. Poultry Experiment Station, Glendale, Arizona, yellow milo partly replaces yellow corn. Hoist and Newlon (1927), Payne (1926), and Sherwood (1926) suggest that milo may be substituted, wholly or in part, for yellow corn in diets for laying hens. However, there are no experimental data available which show the comparative nutritive value of yellow corn, yellow milo, and hegari when they are used in diets for chicks. Smith (1930a) used albino rats as experimental subjects, and concluded that: "Comparative chemical analysis of hegari, yellow milo, and yellow corn shows the sorghums to be somewhat higher in protein and lower in fat than corn. This difference in chemical composition, however, does not satisfactorily explain the observed difference * The assistance of Dr. Harry W. Titus in preparing this paper for publication is hereby gratefully acknowledged. j "Yellow" milo is sometimes called "red" milo.
in nutritive value." Smith (1930b) also made a quantitative study of the vitamin A content of yellow corn, hegari, and yellow milo, and found yellow corn to be twenty times, and yellow milo two times, as rich in vitamin A as hegari. Smith and Lynott (1931) found that five percent" of alfalfa leaf meal as a source of vitamin A promoted good growth when added to sorghum grain rations fed to albino rats. Penquite (1931) states that: "Grain sorghums are good poultry feeds," and that: "Tests . . . indicate that kafir and darso can be substituted for yellow corn if green feed or some green feed substitute . . . is fed every day during the year." The "Uniform Method"! of comparing feedstuffs which is being developed by the Animal Husbandry Division of the United States Department of Agriculture and several of the southern and southwestern agricultural experiment stations, was used in obtaining the data given in this paper. The basal diet used in this work is believed to be complete in all essential nutrients, but is not t By actual experimental tests, or in some other manner, poultry departments at the following institutions have shown an interest in the "Uniform Method": New Mexico A. & M. College, Louisiana State University, Mississippi A. & M. College, Oklahoma A. & M. College, Texas Agricultural Experiment Station, U. S. Animal Husbandry Experiment Farm, Beltsville, Md., and the U. S. Poultry Experiment Station, Glendale, Arizona.
[307]
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Y
308
POULTRY
SCIENCE
suitable for feeding trials in which it is de- recommended maximum period of twelve sired to study the relative value of any one; weeks, and feed was given ad libitum in the nutrient of a feedstuff. The presence off second experiment. biologically tested cod liver oil and alfalfai Forty vigorous Single Comb White Legleaf meal in the basal diet eliminates the; horn chicks were started on each diet. They possibility that differences in the vitamin Ai were weighed before feeding on the second content of the feedstuffs studied may ma- and seventh day after hatching and at weekterially affect their nutritive value. As the: ly periods thereafter, until the experiments other nutrients are also quite generously' had been conducted for thirteen weeks. Each supplied in the basal ration by ingredients; group was confined to a pen, 10 by 20 feet other than the feedstuffs to be studied, it: in a house having a concrete floor. Electric is also probable that slight differences in thej brooders were used. To each of the five diets TABLE la. The diets used Diet 1* percent
Diet 2 percent
Diet 3 percent
Yellow corn meal Yellow milo meal Hegari meal Corn gluten meal Ground wheat Dried buttermilk Meat scraps (50% protein) Alfalfa leaf meal Ground limestone Yeast ("Animal-Poultry Yeast Foam") Salt
40,0
20.0 20.0
20.0
—
20.0 10.0 22.0 10.0 10.0 2.5 3.0 2.0 0.5
— — ToTo 22.0 10.0 10.0 2.5 3.0 2.0 0.5
10.0 22.0 10.0 10.0 2.5 3.0 2.0 0.5
—
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Diet 5 percent
—.
40.0 —
i22.0 o— 10.0 10.0 • 2.5 3.0 2.0 0.5
* Diet 1 is a slight modification of the basal diet originally recommended for use when the "Uniform Method" is followed.
protein, fat, or mineral content of the feedstuffs would not affect the results obtained. In short, the basal diet used in the "Uniform Method" is comparable to a good commercial mixed feed, and substitutions which are satisfactory in the basal diet should be equally satisfactory in a properly formulated mixed feed.
V/z percent of biologically tested cod liver oil was added. The yellow corn meal was prepared from Nebraska No. 2 yellow corn, and the corn gluten meal was also prepared from corn grown in Nebraska. The yellow milo and hegari were grown in the Salt River Valley section of Arizona.
EXPERIMENTAL PROCEDURE
T H E FIRST EXPERIMENT
The experimental data presented in this article were obtained at the U. S. Poultry Experiment Station, Glendale, Arizona. Two separate experiments were conducted, and the basal diet and the substitutions in the basal diet were identical in both. The "Uniform Method" was followed in all details, except that the experiments were conducted for periods of thirteen weeks instead of the
In the first experiment, as recommended in the outline of the "Uniform Method", feed consumption was restricted to "an amount less than ad libitum consumption, and the same amount of feed was given to the chicks receiving the different diets. The feed was weighed out daily, and the amount approximated eighty percent of the average ad libitum consumption as determined in
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310
POULTRY
SCIENCE
Diet 4 (31 survivors) Age
Grams 32.9 43.3 57.4 86.4 109.8 150.0 192.2 238.8 277.8 338.8 395.8 462.1 516.9 585.2
Average feed consumption Per period
Total
Grams
Grams
—
25.0 48.0 70.0 94.0 115.0 122.0 152.0 173.0 204.0 224.0 243.0 259.0 272.0
—
25.0 73.0 143.0 237.0 352.0 474.0 626.0 799.0 1003.0 1227.0 1470.0 1729.0 2001.0
Efficiency of diet Per period
—
0.414 0.294 0.415 0.248 0.350 0.346 0.307 0.225 0.299 0.254 0.273 0.212 0.251
Cumulative
—
0.414 0.335 0.374 0.324 0.332 0.336 0.329 0.307 0.305 0.296 0.292 0.280 0.276
Diet 5 (31 survivors) (2 days) 1 2 3 4 5 6 7 8 9 10 11 12 13
33.2 42.5 55.2 80.0 106.5 148.4 183.1 234.3 271.0 326.6 385.3 448.8 500.8 574.1
25.0 48.0 70.0 94.0 115.0 122.0 152.0 173.0 204.0 224.0 243.0 259.0 272.0
previous experiments. Obviously, as the average amount of feed per chick was the same for all diets, the total daily amount of any diet fed depended upon the number of survivors in the group which received the diet. The first experiment was started September 3, 1930, and continued until the chicks were 91 days old. In Table 1 are given the average live weights of the chicks, the average feed consumption on the five diets, and the efficiencies of the diets. It should be noted that the average weekly feed consumption and the cumulative feed consumption were identical for the five diets, excepting diet 2. Through an error, an excess of 3.3 grams of diet 2 was fed during the sixth week.
25.0 73.0 143.0 237.0 352.0 474.0 626.0 799.0 1003.0 1227.0 1470.0 1729.0 2001.0
—
—
0.374 0.264 0.355 0.281 0.365 0.284 0.337 0.212 0.272 0.262 0.262 0.201 0.269
0.374 0.302 0.328 0.309 0.327 0.316 0.321 0.298 0.293 0.287 0.283 0.271 0.270
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Weeks (2 days) 1 2 3 4 5 6 7 8 9 10 11 12 13
Average live weight
In computing the efficiencies of the diets for the different periods, it was possible to use either the average weights of all the chicks surviving at the end of a period, or the average weights of the final survivors. When no deaths had occurred during a period, the results were identical, and it was found by actual calculation that in these experiments the differences were insignificant whichever method was used. The average weights of the final survivors were used in computing all efficiencies given in this paper. The cumulative efficiencies of diets 1 and 2 were nearly identical, and greater than those of the other three diets at the end of eight weeks, while the efficiency of diet 5 was the least of the five. At the end of thirteen weeks, the cumulative efficiency of diet
SEPTEMBER,
1932.
VOL.
XI,
No.
T H E SECOND EXPERIMENT
Since feed consumption was restricted in the first experiment, it was desirable to conduct another experiment to ascertain whether or not the efficiencies of the diets would be similar when feed consumption is not restricted. Accordingly, the diets were fed ad libitum in the second experiment. In all other respects the procedure followed in both experiments was identical. The diets used were identical with those used in the first experiment. The second experiment was started January 14, 1931. In Table 2 are given the average live weights of the chicks, the average feed consumption on the five diets, and the efficiencies of the diets in the second experiment. At the end of eight weeks the average feed consumption was greatest on diet 1 and least on diet 5, being nearly 300 grams greater on the former than on the latter. At the end of thirteen weeks the average feed consumption was also greatest on diet 1 and least on diet 5, being more than 500 grams greater on diet 1 than diet 5. The cumulative efficiencies of the same diets in the two experiments were in good
311
agreement at the end of eight and thirteen weeks. This indicates that any unequal distribution of the sexes did not materially affect the calculated efficiencies of the diets, for the distribution of the sexes on the same diet was different in the two experiments. For example: on diet 1 in the first experiment there was only 0.67 male for each female, and the cumulative efficiency of the diet at the end of thirteen weeks was 0.270. On diet 1 in the second experiment there were 1.19 males for each female, and the cumulative efficiency of the diet at the end of thirteen weeks was 0.260. In the second experiment, at the end of thirteen weeks, the average weight of the males divided by the average weight of the females on the same diets gave the following ratios: 1.25 on diet 1, 1.23 on diet 2, 1.29 on diet 3, 1.24 on diet 4, and 1.24 on diet 5. In the case of all the diets the ratios were larger than they were in the first experiment. Apparently, when feed was given on a restricted basis in the first experiment the feed consumption of males and females was more nearly equal than when feed was given ad libitum in the second experiment. The total mortality on the different diets was in a different relative order than in the first experiment, indicating that the mortality in both experiments was due to factors other than the diets. In the second experiment the mortality was relatively high on diet 1 and relatively low on diet 5, while in the first experiment it was relatively low on diet 1 and relatively high on diet 5. Only one chick died after the seventh week during the second experiment. During the entire experiment a total of 5 deaths occurred on diet 1, 4 on diet 2, 1 on diet 3, 6 on diet 4, and 2 on diet 5. AVERAGE EFFICIENCIES OF THE DIETS
While the feed allowances were different in the two experiments, the results obtained
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2 was the greatest, diets 3 and 4 were nearly identical and next in efficiency, and diets 1 and 5 were identical and the least efficient. However, there was very little difference between the cumulative efficiencies of any of the diets at the end of thirteen weeks. At the end of the experiment the average weights of the males on a given diet divided by the average weights of the females on the same diets showed the following ratios: 1.11 on diet 1,1.09 on diet 2,1.15 on diet 3, 1.20 on diet 4, and 1.09 on diet 5. The total number of deaths among the chicks receiving the different diets was: 0 on diet 1, 5 on diet 2, 6 on diet 3, 9 on diet 4, 9 on diet 5. All mortality occurred during the first eight weeks.
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SEPTEMBER,
1932.
VOL.
XI,
No.
313
5
Diet 4 (34 survivors) Age
Grams 35.7 43.9 65.8 92.2 125.1 171.9 220.6 304.4 382.3 485.2 568.4 676.9 786.9 897.9
Average feed consumption Per period
Total
Grams
Grams
23.4 60.2 82.9 109.7 135.6 174.3 247.3 303.2 297.7 360.3 434.1 420.0 473.8
23.4 83.6 166.5 276.2 411.8 586.1 833.4 1136.6 1434.3 1794.6 2228.7 2648.7 3122.5
Efficiency of diet Per period
0.350 0.364 0.319 0.300 0.345 0.279 0.339 0.257 0.346 0.231 0.250 0.262 0.235
Cumulative
0.350 0.360 0.340 0.324 0.331 0.316 0.323 0.305 0.314 0.297 0.288 0.284 0.276
Diet 5 (38 survivors) 2 (days) 1 2 3 4 5 6 7 8 9 10 11 12 13
35.3 43.2 63.1 87.4 119.0 163.6 222.5 289.3 363.2 435.8 541.8 630.2 723.5 829.9
— 26.7 58.0 82.1 101.8 133.9 177.4 213.4 281.6 301.1 351.1 377.1 396.1 426.1
— 26.7 84.7 166.8 268.6 402.5 579.9 793.3 1074.9 1376.0 1727.0 2104.1 2500.2 2926.3
0.299 0.343 0.296 0.311 0.333 0.332 0.313 0.262 0.241 0.302 0.234 ' 0.235 0.250
. 0.299 0.329 0.313 0.312 0.319 0.323 0.320 0.305 0.291 0.293 0.283 0.275 0.272
were similar enough to permit a combination strain of Rhode Island Reds which they used of the two sets of data. It was believed that in their experiments. such a combination would emphasize the It is particularly interesting to note that similarity between the results obtained from the cumulative efficiencies of the five diets feeding the five different diets, and conse- are nearly identical at the end of thirteen quently the mutual replacabilities of yellow weeks, indicating that either 20 or 40 parts milo, hegari, and yellow corn. of yellow maize or hegari may be substituted The data given in Table 3 show that the for equal parts of yellow corn in a diet for cumulative efficiency of diet 1 was the great- chicks. At least, the substitutions may be est of the five diets at the end of the eighth made if the diet is not deficient in any of the week, but at the end of thirteen weeks, the essential nutrients and is fed until the avercumulative efficiency of diet 1 was the least age weight of the chicks is about one and of five diets. The reversal of the relative one-half pounds. position of diet 1 was in accordance with the The cumulative efficiency of diet 5 was observations of Titus and Jull (1928) and much lower than that of the other four diets Titus, McNally, and Hulberg (1930), who during the first four weeks. Inasmuch as the found that the acceleration of early growth average feed consumption was nearly idenwas later followed by slower growth in the tical on diets 2,3,4, and 5 during this period,
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Weeks (2 days) 1 2 3 4 5 6 7 8 9 10 11 12 13
Average live weight
314
POULTRY
the lesser cumulative efficiency of diet 5 indicates that it was of less value for growth during the first four weeks. In Figure 1 the cumulative efficiencies at the end of the first, third, fifth, seventh, ninth, eleventh, and thirteenth weeks have been plotted against age. The "curves" indicate that the cumulative efficiencies decreased at a practically constant time-rate. Titus and co-workers (1930) used time intervals of two weeks in computing efficiencies, and also observed that the cumulative
SCIENCE
"Uniform Method" do not always show these fluctuations in the weekly efficiencies. T H E "PHYSIOLOGICAL" EFFICIENCIES OF THE DIETS
As previously stated, weekly and cumulative efficiencies of the diets are merely expressions representing the ratio of gain in live weight to feed consumption. These efficiencies are calculated by simple arithmetical processes, and inasmuch as no allowance is made for the feed needed for main-
Diet 1
Diet 3
Diet 2
Diet 4
Diet 5
Age
Weekly
Cumulative
Weekly
Cumulative
Weekly
Cumulative
Weekly
Cumulative
Weekly
Cumulative
Weeks 1 2 3 4 5 6 7 8 9 10 11 12 13
Grams 0.442 0.335 0.382 0.348 0.285 0.322 0.360 0.273 0.223 0.287 0.239 0.171 0.201
Grams 0.442 0.367 0.375 0.364 0.336 0.332 0.339 0.324 0.304 0.300 0.290 0.273 0.263
Grams 0.449 0.323 0.372 0.300 0.342 0.325 0.342 0.257 0.276 0.276 0.221 0.156 0.239
Grams 0.449 0.360 0.366 0.340 0.340 0.336 0.338 0.318 0.310 0.303 0.290 0.270 0.265
Grams 0.396 0.320 0.362 0.300 0.348 0.301 0.333 0.228 0.279 0.247 0.212 0.140 0.315
Grams 0.396 0.343 0.353 0.332 0.337 0.327 0.329 0.305 0.300 0.290 0.276 0.257 0.265
Grams 0.383 0.333 0.363 0.276 0.347 0.307 0.327 0.245 0.327 0.240 0.258 0.243 0.240
Grams 0.383 0.349 0.356 0.324 0.331 0.325 0.325 0.306 0.310 0.296 0.289 0.282 0.276
Grams 0.335 0.307 0.323 0.296 0.348 0.313 0.323 0.243 0.254 0.286 0.245 0.222 0.258
Grams 0.335 0.316 0.320 0.311 0.323 0.320 0.321 0.302 0.292 0.331 0.283 0.273 0.271
efficiencies decreased at a practically constant time-rate after the fourth week. However, the data in Table 3 show that the cumulative efficiencies fluctuated from week to week, and if they had been plotted against age at one-week intervals the curves would be quite irregular although they would still show the same trend. The average weekly efficiencies of the diets are given in Table 3 principally to show that although growth, as measured by change in live weight, may increase each week, the efficiency of feed may fluctuate markedly from one weekly period to another. It should be stated, however, that the results of the other workers who have used the
tenance they do not necessarily represent the "true" efficiencies of the diets for growth. It is commonly accepted that the amount of feed required for maintenance increases as the animal becomes heavier, and Spillman, as quoted by Jull and Titus (1928), has discussed the applicability of the law of diminishing increment in describing the relationship between the live weight and the feed consumption of growing animals. Jull and Titus (loc. cit.) as a result of their work concluded that: ". . . the relationship between feed consumption and growth of the domestic fowl is expressible by the law of diminishing increment, at least for
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TABLE 3. The average efficiencies of the diets during both experiments
SEPTEMBER,
1932.
VOL.
XI,
No.
the time interval studied." Titus (1928) demonstrated that the growth of White Pekin ducklings could be expressed by the equation developed by Spillman. Hendricks (1931) has offered a physiological interpretation of the law of the diminishing increment when applied to data obtained in animal feeding experiments, and has developed a method by which the relative "physiological" efficiency of diets may be computed. The amount of feed used for maintenance is expressed in terms of a loss of body tissues, and it is assumed that this loss in live weight per unit of feed con-
315
5
sent the average maximum weight attainable by the animal if it continues on the same diet at the same relative rate of increase in feed consumption. The values of C C, m, and — for the five diets are given in m Table 4. The "physiological" or "true" efficiencies of the diets, C in Table 4, differ in their relative order from the cumulative efficiencies given in Table 3. The cumulative efficiencies of the diets at the end of thirteen weeks were nearly identical, but there are considerable differences between some of
Diet 1 2 3 4 5
m
C m
.00029077+.00003363 .00028054+ .00003655 .00023227+ .00004788 .00017930+.00002852 .00015098 ±.00002330
1337 + 160.9 1364+184.1 1540 + 325.6 1962 + 317.4 2193 + 634.4
C .3859+ .01294 .3827+.01347 .3576+.01681 .3517+.01038 .3311+.00810
sumed is proportional to the live weight of the animal. In Hendricks' equation AW AW = C — mW, the ratio repreAF AF sents the gain in live weight per unit of feed eaten over a short interval of time; W represents the average live weight of the animal during that interval of time; and C represents the "true" or "physiological" efficiency of the feed. AW The values of and W were obAF tained from the combined data of the two experiments, and the values of C, m, and C — were calculated by the method proposed m by Hendricks (loc. cit.). C is constant for a given diet, and m is constant for a given diet fed at a given level; and since W apC C proaches — asymptotically, — must reprem m
the "physiological" efficiencies. However, there is much to be learned about the actual significance of both C and m in Hendricks' equation. His proposed method for determining the "physiological" efficiencies of feedstuffs has been used here because this method, which is now being developed, may prove to be quite valuable in interpreting the results of feeding trials, and because, in this case, it brings out differences between the several diets which undoubtedly exist but which can not be easily demonstrated by a comparison of the cumulative efficiencies. From the scientific viewpoint, the "physiological" efficiency of a feedstuff, or diet, is of interest and value, but from the economic viewpoint, the cumulative efficiency is of equal or even greater importance. This is particularly true because the "physiological" efficiency of a given diet is constant throughout the period of active
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TABLE 4. The values of C, m, and —for the five diets, calculated from the combined data of the two experiments
316
POULTRY
growth of the chicken, whereas the cumulative efficiency is not and, in general, decreases more or less regularly as the chick becomes larger.
SCIENCE
lowered by the substitution of 20 or 40 percent of either of these two grains for equal weights of yellow corn. The significance of this difference is, as yet, not clear.
CONCLUSIONS
REFERENCES
Either yellow milo or hegari may replace yellow corn, to the extent of from SO to 100 percent, in a chick diet which is not defi-
Hendricks, Walter A., 1931. Fitting the curve of the diminishing increment to feed consumptionlive weight growth curves. Sci., 74:290-291. Hendricks, Walter A., Morley A. Jull, and Harry
°
/
3
5
7 s4(?E IN
9
//
WEEKS'
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\
/3
FIG. 1. The relation between average cumulative efficiency of the diets and age.
cient in any way, particularly if the diet is fed until the chicks average about one and one-half pounds live weight. The growth-feed consumption ratio, or efficiency, is not changed appreciably when either yellow milo or hegari is substituted for yellow corn in a chick ration which is not deficient in any way. However, the "physiological" efficiency is progressively
W. Titus, 1931. A possible physiological interpretation of the law of the diminishing increment. Sci., 73:427-429. Hoist, Walther F., and Wilson E. Newlon, 1927. Poultry feeding: principles and practice. Cal. Agr. Exp. Sta. Bui. 417 :36-37. Jull, Morley A., and Harry W. Titus, 1928. Growth of chickens in relation to feed consumption. J. Agr. Res., 36:541-550. Payne, Loyal F., 1926. Poultry management on the farm. Kan. Agr. Exp. Sta. Cir. 122 :l-28.
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1932.
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XI,
Penquite, Robert, 1931. Science tests poultry practices. Reprint from Okla. Agr. Exp. Sta. 1930 Rpt.:3-10. Sherwood, Ross M., 1926. Feeding chickens. Tex. Agr. Exp. Sta. Cir. 42 :l-7. Smith, Margaret Cammack, 1930a. The comparative nutritive value of yellow corn and the grain sorghums hegari and yellow milo. J. Agr. Res., 40:1129-1145. 1930b. A quantitative comparison of the vitamin A content of yellow corn and the grain sorphums hegari and yellow milo. J. Agr. Res., 40:1147-1153. Smith, Margaret Cammack, and Mable L. Lynott, 1931. The value of alfalfa as a source of vitamin
No.
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A in sorghum-grain rations. J. Agr. Res., 42: 421-432. Titus, Harry W., 1928. Growth and the relation between live-weight and feed consumption in the case of White Pekin ducklings. Poul. Sci., 7:254-262. Titus, Harry W., and Morley A. JuU, 1928. The growth of Rhode Island Reds and the effect of feeding skim milk on the constants of their growth curves. J. Agr. Res., 36:515-540. Titus, Harry W., Edmund McNally, and Frank C. Hulberg, 1930. A comparison of shrimp "bran" and two kinds of fish meal when fed at a level of ten percent in diets for growing chicks. Poul. Sci., 9:219-234.
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