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Feeding Grasshoppers to Turkeys
Feeding Grasshoppers to Turkeys T. T. MILBY AND ROBERT PENQUITE
Oklahoma Agricultural and Mechanical College, Stillwater, Oklahoma (Received for publication January 22, 1940)
turkeys were first domesticated, SINCE growers have followed the practice of
EXPERIMENTAL In the summer of 1937 several hundred pounds of live grasshoppers were again caught in fields in the vicinity of Stillwater. About one-third of the live grasshoppers were placed in a large pressure cooker and cooked at 15 pounds pressure for 45 minutes. They were then spread out in a layer one to two inches thick on wire-bottom trays and dried in the sun. They were thoroughly air-dry within three or four days and had a pronounced oily appearance when dry. When dry they were ground to a powder. The remaining grasshoppers were immediately placed in a sharp freezer at a temperature of 0°F. to 10°F. After remaining in the freezer for several days half of the grasshoppers were spread out to dry on trays as were the cooked grasshoppers. They did not have the oily appearance of the cooked grasshoppers and a decidedly stronger odor was noticeable. The very strong, almost putrid, odor of the grasshoppers prepared the previous year was not present.
[332]
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
letting the young birds range for most of their food with only a feeding of grain at night to induce the birds to come home to roost. Granted that losses are frequently high with this system of management, good turkeys have been and are being produced. The food of turkeys so reared consists largely of insects and tender green feed. In many parts of the country the most abundant insect is the grasshopper and periodically it becomes sufficiently numerous to cause considerable crop damage. Farmers have used young turkeys to help keep down the pest and at the same time make a profitable growth. On the other hand those concerned with the marketing of turkeys have discouraged this method of rearing. They have claimed that it produces tough, stringy birds with an undesirable flavor when cooked. A search of the literature fails to show experimental work to support either side of the argument. McHargue (1917) reported that on a dry basis grasshoppers contained 75.3 percent protein, 7.2 percent fat, and 5.6 percent ash. Analysis of the protein of grasshoppers showed that it contained about the same amount of the important amino acids, arginine, cystine, and lysine as roast beef and the white meat of turkey. He suggested that grassshoppers when they were plentiful could be dried and ground into a meal which would be a high grade protein supplement for poults. Previous work at this station (1936) directed by Lawrence Morris indicated that dried ground grasshoppers were toxic to
turkey poults six weeks of age when fed at levels of 8 and 16 percent of the ration. Analysis of the dried grasshoppers showed 72.15 percent protein, 5.95 percent ash, and 6.38 percent fat. These grasshoppers were killed by putting them in burlap sacks in a glass covered box (ordinary cold frame) in the sun for several hours. The dead insects were then spread about one inch deep on screen frames and allowed to dry in the sun. This required about three days at a temperature of about 100°F.
333
FEEDING GRASSHOPPERS TO TURKEYS TABLE 1.—Species and sex determination of grasshoppers, 1937 Sample II (361)
Sample I (343) Species M. differentialis M. mexicanus M. pacardii M. femur-rubrum M. bivittatus Unidentified Total
% females
% of total
% females
% of total
54.0 59.3 51.5 50.0 91.7 53.3 55.7
61.5 15.7 9.6 5.3 3.5 4.4 100.0
52.0 67.2 55.3 41.7 77.8 60.0 55.4
63.4 16.1 10.5 3.3 2.5 4.2 100.0
TABLE 2.—Chemical analyses of grasshoppers
1. 2. 3. 4. 5.
Sample
Ash
Fat
Fiber
Protein
N.F.E.
Mixed Females Males Gravid females Calculated wet basis
3.92 3.77 3.62 7.13 1.63
18.39 15.84 16.51 5.49 7.65
10.85 9.64 8.60
62.82 57.06 58.60 74.83 26.13
4.02 13.69 12.67
Most of the individuals among the grasshoppers used in this study were immature and practically no gravid females were present. Some of the grasshoppers were caught in fields that had been treated with poison recently. Analysis of grasshoppers from these fields for arsenic was negative. A chemical analysis of three samples from the frozen grasshoppers is given in Table
4.51
1.67
that this analysis corresponds to that of the grasshoppers fed in 1936. The composition of the rations fed is given in Table 3. The grain mixture consisted of equal parts of yellow cornmeal, wheat bran, and wheat shorts and the protein concentrate of equal parts of meat scraps, cottonseed meal, and dried buttermilk. The protein concentrate of the mash
TABLE 3.—Composition of rations, grasshopper feeding Lot Number
11
12
13
14
Grain mixture Alfalfa leaf meal Salt Pulverized oyster shell Cod liver oil concentrate Protein concentrate Dried grasshoppers (cooked) Dried grasshoppers (not cooked) Frozen grasshoppers
69 10 1 1 1/6 21
78 10 1 1 1/6
78 10 1 1 1/6
78 10 1 1 1/6 10.5
12
—
— —
— —
•
—
— —
12
—
4 lbs. daily
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
2. The calculated analysis, on a wet basis, is an average of the three samples. Assuming 10 percent moisture in air-dry samples, 100 pounds of live grasshoppers made about 45 pounds of dry material. An analysis is also given for gravid females, collected in the fall of 1937. It is interesting to note
A species and sex analysis of two samples containing 343 and 361 individuals taken from different fields is given in Table 1. The two samples were very similar. Females outnumbered males, and the most common species, M. differentialis, made up over 60 percent of both samples.
334
T. T. MILBY AND ROBERT PENQUITE
TABLE 4.—Analysis of variance, weights at beginning of experiment Source of variation
Degrees of freedom
Sum of squares
Total Between means of lots Between means of groups Interaction Within (error)
79
20.807
•3 3
.104 16.684
.035* 5.561f
9 64
.678 3.342
.075* .052
Mean square
* Not significant, f Highly significant.
ment is given in Table 4. The analysis indicates that the grouping accounted for
most of the variation in weight. The sex difference in weight is very great at this age, but the poults cannot be accurately sexed. With small numbers in the lots, abnormal sex ratios could easily produce apparent differences or obscure real differences in growth. Since growth of an individual tends to remain fairly constant over a short period of time, the prediction value of initial weight is made use of in this experimental setup. The analysis of the weights at the end of the experiment is given in Table 5. There TABLE 5.—Analysis of variance, weights at end of experiment Mean square
Source of variation
Degrees of freedom
Sum of squares
Total Between means of lots Between means of groups Interaction Within (error)
79
80.390
3
9.129
3.043t
3 9 64
42.675 4.744 23.840
14.225f .527* .372
* Not significant, t Highly significant.
was a highly significant difference between the means of the lots indicating that the rations induced different growth rates. Analyses were made separating the birds by sex and ignoring the grouping but are not reported here. They indicated that the differences between lots were barely significant because of the great variability within lots. This is a natural consequence of the method of distributing the poults so the analysis given in Table 5 is the more valid test. The poults in lot 14 made the greatest gains so lot 14 was omitted and the analysis made for the three remaining lots. The analysis given in Table 6 indicates that the differences between the means are not significant. The poults fed grasshopper meal, lots 12 and 13, grew as well as the control lot.
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
was replaced by the dried, ground grasshoppers on an equivalent crude protein basis. The daily allowance of 4 pounds of frozen grasshoppers for lot 14 was eagerly consumed and the birds would probably have eaten a larger quantity if it had been available. Eighty Bronze poults, 12 weeks of age, were divided into four groups according to size. The poults in each of the four groups were distributed at random into the four lots. The birds were weighed at weekly intervals. Sufficient grasshopper meal was available to continue the experiment for five weeks. A representative male and female from each lot were killed, dressed, and stored undrawn in a sharp freezer for a cooking test to be conducted later. A small amount of grasshopper meal remaining from the tests of the previous year was mixed according to the formula used for lots 12 and 13 and at the conclusion of the regular experiment was fed to a group of 12 poults for a period of two weeks. The old meal was fed to determine whether or not it would exhibit the toxic properties that it possessed in the previous trials. RESULTS The analysis of variance of the weights of the birds at the beginning of the experi-
FEEDING GRASSHOPPERS TO TURKEYS
Calculated analysis of the ration actually consumed by the poults in lot 14 shows that it was higher in protein than the rations consumed by the other birds. The birds ate 21 percent grasshoppers on a dry TABLE 6.—Analysis of variance, weight at end of experiment, lot 14 omitted Source of variation
Degrees of Sum of squares freedom 59
54.508
2
.579
.290*
3 6 48
29.594 4.028 20.308
9.865f .671* .423
* Not significant, t Highly significant.
basis and 79 percent mash. The higher protein content of the ration is probably the factor which enabled these poults to make more rapid growth than the others. The pounds of feed required to produce a pound of gain were 3.82 and 3.85 for lots 11 and 14 respectively. The lots fed the dried, ground grasshoppers required 4.16 and 4.32 pounds of feed per pound of gain. There is no test for significance of these differences but they would seem to indicate that the protein of grasshoppers is not as well utilized as the protein in a mixture of dried milk, meat scraps, and cottonseed meal. The poults grew as well but only by eating more feed. Of the 80 turkeys in the experiment only one died, in lot 14, during the third week of the trial. The cause of death is not known. There were certainly no indications of the toxic effect produced by the grasshopper meal the previous year. The old grasshopper meal did not cause any mortality during the two weeks it was fed but while the 12 poults on the control ration gained .96 pounds each, the poults fed the grasshopper meal lost .19 pounds each. Only two of the 12 poults made any
gain at all. Apparently the old grasshopper meal still retained its toxic properties. After several months the birds that had been placed in cold storage were thawed out, drawn, and cooked under uniform conditions by the Home Economics Department. They were scored while warm for flavor and odor by several judges. While the two turkeys from the control ration were judged to be the best, there were no undesirable flavors or odors in any of the birds. SUMMARY In 1936 grasshoppers were killed by exposure to sunlight in a glass covered box, dried in the sun, and ground to a meal. This meal, when fed to turkey poults six weeks of age at levels of 8 and 16 percent, induced poor growth and heavy mortality. Postmortem examination of the poults failed to show any symptoms of disease. The following summer, 1937, grasshoppers were prepared in three different ways: (1) cooked in a steam pressure cooker at 15 pounds pressure for 45 minutes, sun dried and ground, (2) frozen at 0°F. to 10°F., sun dried, and ground, (3) frozen at 0°F., to 10°F., and fed whole immediately after thawing. The entire protein supplement of a turkey starting mash was replaced on an equivalent protein basis with grasshopper meal prepared by the two above mentioned methods. The frozen whole grasshoppers were fed at the rate of 4 pounds daily to 20 poults along with a ration containing one-half the usual protein supplement. Poults 12 weeks of age were fed the above rations for five weeks. No significant reduction in growth resulted from feeding the rations containing grasshopper meal. The growth of the poults fed frozen whole grasshoppers was significantly greater than that of the poults fed the control ration, possibly because they consumed more protein.
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
Total Between means of lots Between means of groups Interaction Within (error)
Mean square
335
336
T. T. MILBY AND ROBERT PENQUITE
Representative poults from each lot were killed and stored undrawn at 0°F. to 10°F. for several months. They were then cooked under uniform conditions and scored for flavor and odor. There were no undesirable flavors or odors in any of the birds. Chemical analyses and identification of species were made of the grasshoppers collected for the trials. The average crude protein content was 62.8 percent on an air-dry basis.
When grasshoppers are abundant, may prove to be a valuable protein for turkeys if properly prepared for ing and adequately supplemented other feedstuffs.
they feed feedwith
REFERENCES
McHargue, J. S., 1917. A study of proteins of certain insects with reference to their value as food for poultry. J. Ag. Res. 10:633-637. Oklahoma Agr. Exp. Sta. biennial report, 1934-36. Pp. 77-79. Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
Oklahoma Agricultural and Mechanical College, Stillwater, Oklahoma (Received for publication January 22, 1940)
turkeys were first domesticated, SINCE growers have followed the practice of
EXPERIMENTAL In the summer of 1937 several hundred pounds of live grasshoppers were again caught in fields in the vicinity of Stillwater. About one-third of the live grasshoppers were placed in a large pressure cooker and cooked at 15 pounds pressure for 45 minutes. They were then spread out in a layer one to two inches thick on wire-bottom trays and dried in the sun. They were thoroughly air-dry within three or four days and had a pronounced oily appearance when dry. When dry they were ground to a powder. The remaining grasshoppers were immediately placed in a sharp freezer at a temperature of 0°F. to 10°F. After remaining in the freezer for several days half of the grasshoppers were spread out to dry on trays as were the cooked grasshoppers. They did not have the oily appearance of the cooked grasshoppers and a decidedly stronger odor was noticeable. The very strong, almost putrid, odor of the grasshoppers prepared the previous year was not present.
[332]
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
letting the young birds range for most of their food with only a feeding of grain at night to induce the birds to come home to roost. Granted that losses are frequently high with this system of management, good turkeys have been and are being produced. The food of turkeys so reared consists largely of insects and tender green feed. In many parts of the country the most abundant insect is the grasshopper and periodically it becomes sufficiently numerous to cause considerable crop damage. Farmers have used young turkeys to help keep down the pest and at the same time make a profitable growth. On the other hand those concerned with the marketing of turkeys have discouraged this method of rearing. They have claimed that it produces tough, stringy birds with an undesirable flavor when cooked. A search of the literature fails to show experimental work to support either side of the argument. McHargue (1917) reported that on a dry basis grasshoppers contained 75.3 percent protein, 7.2 percent fat, and 5.6 percent ash. Analysis of the protein of grasshoppers showed that it contained about the same amount of the important amino acids, arginine, cystine, and lysine as roast beef and the white meat of turkey. He suggested that grassshoppers when they were plentiful could be dried and ground into a meal which would be a high grade protein supplement for poults. Previous work at this station (1936) directed by Lawrence Morris indicated that dried ground grasshoppers were toxic to
turkey poults six weeks of age when fed at levels of 8 and 16 percent of the ration. Analysis of the dried grasshoppers showed 72.15 percent protein, 5.95 percent ash, and 6.38 percent fat. These grasshoppers were killed by putting them in burlap sacks in a glass covered box (ordinary cold frame) in the sun for several hours. The dead insects were then spread about one inch deep on screen frames and allowed to dry in the sun. This required about three days at a temperature of about 100°F.
333
FEEDING GRASSHOPPERS TO TURKEYS TABLE 1.—Species and sex determination of grasshoppers, 1937 Sample II (361)
Sample I (343) Species M. differentialis M. mexicanus M. pacardii M. femur-rubrum M. bivittatus Unidentified Total
% females
% of total
% females
% of total
54.0 59.3 51.5 50.0 91.7 53.3 55.7
61.5 15.7 9.6 5.3 3.5 4.4 100.0
52.0 67.2 55.3 41.7 77.8 60.0 55.4
63.4 16.1 10.5 3.3 2.5 4.2 100.0
TABLE 2.—Chemical analyses of grasshoppers
1. 2. 3. 4. 5.
Sample
Ash
Fat
Fiber
Protein
N.F.E.
Mixed Females Males Gravid females Calculated wet basis
3.92 3.77 3.62 7.13 1.63
18.39 15.84 16.51 5.49 7.65
10.85 9.64 8.60
62.82 57.06 58.60 74.83 26.13
4.02 13.69 12.67
Most of the individuals among the grasshoppers used in this study were immature and practically no gravid females were present. Some of the grasshoppers were caught in fields that had been treated with poison recently. Analysis of grasshoppers from these fields for arsenic was negative. A chemical analysis of three samples from the frozen grasshoppers is given in Table
4.51
1.67
that this analysis corresponds to that of the grasshoppers fed in 1936. The composition of the rations fed is given in Table 3. The grain mixture consisted of equal parts of yellow cornmeal, wheat bran, and wheat shorts and the protein concentrate of equal parts of meat scraps, cottonseed meal, and dried buttermilk. The protein concentrate of the mash
TABLE 3.—Composition of rations, grasshopper feeding Lot Number
11
12
13
14
Grain mixture Alfalfa leaf meal Salt Pulverized oyster shell Cod liver oil concentrate Protein concentrate Dried grasshoppers (cooked) Dried grasshoppers (not cooked) Frozen grasshoppers
69 10 1 1 1/6 21
78 10 1 1 1/6
78 10 1 1 1/6
78 10 1 1 1/6 10.5
12
—
— —
— —
•
—
— —
12
—
4 lbs. daily
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
2. The calculated analysis, on a wet basis, is an average of the three samples. Assuming 10 percent moisture in air-dry samples, 100 pounds of live grasshoppers made about 45 pounds of dry material. An analysis is also given for gravid females, collected in the fall of 1937. It is interesting to note
A species and sex analysis of two samples containing 343 and 361 individuals taken from different fields is given in Table 1. The two samples were very similar. Females outnumbered males, and the most common species, M. differentialis, made up over 60 percent of both samples.
334
T. T. MILBY AND ROBERT PENQUITE
TABLE 4.—Analysis of variance, weights at beginning of experiment Source of variation
Degrees of freedom
Sum of squares
Total Between means of lots Between means of groups Interaction Within (error)
79
20.807
•3 3
.104 16.684
.035* 5.561f
9 64
.678 3.342
.075* .052
Mean square
* Not significant, f Highly significant.
ment is given in Table 4. The analysis indicates that the grouping accounted for
most of the variation in weight. The sex difference in weight is very great at this age, but the poults cannot be accurately sexed. With small numbers in the lots, abnormal sex ratios could easily produce apparent differences or obscure real differences in growth. Since growth of an individual tends to remain fairly constant over a short period of time, the prediction value of initial weight is made use of in this experimental setup. The analysis of the weights at the end of the experiment is given in Table 5. There TABLE 5.—Analysis of variance, weights at end of experiment Mean square
Source of variation
Degrees of freedom
Sum of squares
Total Between means of lots Between means of groups Interaction Within (error)
79
80.390
3
9.129
3.043t
3 9 64
42.675 4.744 23.840
14.225f .527* .372
* Not significant, t Highly significant.
was a highly significant difference between the means of the lots indicating that the rations induced different growth rates. Analyses were made separating the birds by sex and ignoring the grouping but are not reported here. They indicated that the differences between lots were barely significant because of the great variability within lots. This is a natural consequence of the method of distributing the poults so the analysis given in Table 5 is the more valid test. The poults in lot 14 made the greatest gains so lot 14 was omitted and the analysis made for the three remaining lots. The analysis given in Table 6 indicates that the differences between the means are not significant. The poults fed grasshopper meal, lots 12 and 13, grew as well as the control lot.
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
was replaced by the dried, ground grasshoppers on an equivalent crude protein basis. The daily allowance of 4 pounds of frozen grasshoppers for lot 14 was eagerly consumed and the birds would probably have eaten a larger quantity if it had been available. Eighty Bronze poults, 12 weeks of age, were divided into four groups according to size. The poults in each of the four groups were distributed at random into the four lots. The birds were weighed at weekly intervals. Sufficient grasshopper meal was available to continue the experiment for five weeks. A representative male and female from each lot were killed, dressed, and stored undrawn in a sharp freezer for a cooking test to be conducted later. A small amount of grasshopper meal remaining from the tests of the previous year was mixed according to the formula used for lots 12 and 13 and at the conclusion of the regular experiment was fed to a group of 12 poults for a period of two weeks. The old meal was fed to determine whether or not it would exhibit the toxic properties that it possessed in the previous trials. RESULTS The analysis of variance of the weights of the birds at the beginning of the experi-
FEEDING GRASSHOPPERS TO TURKEYS
Calculated analysis of the ration actually consumed by the poults in lot 14 shows that it was higher in protein than the rations consumed by the other birds. The birds ate 21 percent grasshoppers on a dry TABLE 6.—Analysis of variance, weight at end of experiment, lot 14 omitted Source of variation
Degrees of Sum of squares freedom 59
54.508
2
.579
.290*
3 6 48
29.594 4.028 20.308
9.865f .671* .423
* Not significant, t Highly significant.
basis and 79 percent mash. The higher protein content of the ration is probably the factor which enabled these poults to make more rapid growth than the others. The pounds of feed required to produce a pound of gain were 3.82 and 3.85 for lots 11 and 14 respectively. The lots fed the dried, ground grasshoppers required 4.16 and 4.32 pounds of feed per pound of gain. There is no test for significance of these differences but they would seem to indicate that the protein of grasshoppers is not as well utilized as the protein in a mixture of dried milk, meat scraps, and cottonseed meal. The poults grew as well but only by eating more feed. Of the 80 turkeys in the experiment only one died, in lot 14, during the third week of the trial. The cause of death is not known. There were certainly no indications of the toxic effect produced by the grasshopper meal the previous year. The old grasshopper meal did not cause any mortality during the two weeks it was fed but while the 12 poults on the control ration gained .96 pounds each, the poults fed the grasshopper meal lost .19 pounds each. Only two of the 12 poults made any
gain at all. Apparently the old grasshopper meal still retained its toxic properties. After several months the birds that had been placed in cold storage were thawed out, drawn, and cooked under uniform conditions by the Home Economics Department. They were scored while warm for flavor and odor by several judges. While the two turkeys from the control ration were judged to be the best, there were no undesirable flavors or odors in any of the birds. SUMMARY In 1936 grasshoppers were killed by exposure to sunlight in a glass covered box, dried in the sun, and ground to a meal. This meal, when fed to turkey poults six weeks of age at levels of 8 and 16 percent, induced poor growth and heavy mortality. Postmortem examination of the poults failed to show any symptoms of disease. The following summer, 1937, grasshoppers were prepared in three different ways: (1) cooked in a steam pressure cooker at 15 pounds pressure for 45 minutes, sun dried and ground, (2) frozen at 0°F. to 10°F., sun dried, and ground, (3) frozen at 0°F., to 10°F., and fed whole immediately after thawing. The entire protein supplement of a turkey starting mash was replaced on an equivalent protein basis with grasshopper meal prepared by the two above mentioned methods. The frozen whole grasshoppers were fed at the rate of 4 pounds daily to 20 poults along with a ration containing one-half the usual protein supplement. Poults 12 weeks of age were fed the above rations for five weeks. No significant reduction in growth resulted from feeding the rations containing grasshopper meal. The growth of the poults fed frozen whole grasshoppers was significantly greater than that of the poults fed the control ration, possibly because they consumed more protein.
Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015
Total Between means of lots Between means of groups Interaction Within (error)
Mean square
335
336
T. T. MILBY AND ROBERT PENQUITE
Representative poults from each lot were killed and stored undrawn at 0°F. to 10°F. for several months. They were then cooked under uniform conditions and scored for flavor and odor. There were no undesirable flavors or odors in any of the birds. Chemical analyses and identification of species were made of the grasshoppers collected for the trials. The average crude protein content was 62.8 percent on an air-dry basis.
When grasshoppers are abundant, may prove to be a valuable protein for turkeys if properly prepared for ing and adequately supplemented other feedstuffs.
they feed feedwith
REFERENCES
McHargue, J. S., 1917. A study of proteins of certain insects with reference to their value as food for poultry. J. Ag. Res. 10:633-637. Oklahoma Agr. Exp. Sta. biennial report, 1934-36. Pp. 77-79. Downloaded from http://ps.oxfordjournals.org/ at Kainan University on April 27, 2015