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Debeaking of Caged Layers1
Debeaking of Caged Layers1 R. C. HARGREAVES2 AND L. R. CHAMPION Department of Poultry Science, Michigan State University, East Lansing, Michigan (Received for publication February 25, 1965)
D
1
Journal Article No. 3583, Michigan Agricultural Experiment Station. " In partial fulfillment of the M.S. degree in Poultry Science. Present address: 20° "U" Street, Bakersfield, California.
•
/
FIG. 1. Control
taken to determine what, if any, limitations should be applied to the degree of debeaking used in commercial practice. EXPERIMENTAL PROCEDURE Single Comb White Leghorns (M.S.U. pure line) were debeaked at 18 weeks of age and placed in 1-bird and 3-bird cages. The dimensions of the 1-bird cages were 8 inches X 16 inches; that of the 3-bird cages was 12 inches X 18 inches. Other pullets from the same strain were debeaked at 24 weeks of age and placed in 21-bird, 3 X 4 ft. cages. Three degrees of debeaking were used: approximately one-half, three-fourths, and all of the distance between the tip of the beak and the nostrils (see Figures 1-4). Non-debeaked birds served as the controls. The birds with all of the beak removed are referred to as "entirely debeaked." Both upper and lower mandibles were removed with one stroke of the electric debeaker, with the throat held back in such a manner
1223
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
EBEAKING research has amply supported the use of milder forms of debeaking. Removing one-half of the upper or both mandibles just prior to or during egg production has not significantly affected egg production (Morgan, 1957; Bray et al., 1960; Xoles et al., 1962). Debeaking one-half of the upper beak has, however, been reported to significantly reduce body weight (Bray et al., 1960) and feed wastage (Bauermann, 1959). Noles et al. (1962) found that feed efficiency was significantly affected by block debeaking one-half, but the effects were completely reversed from one year's trial to the next; it significantly reduced mortality in one trial but not in the other. Debeaking two-thirds of the upper beak and one-third of the lower beak at 8 weeks of age significantly retarded age at sexual maturity, reduced body weight gains and decreased feed consumption for the first 20 weeks of lay but had no effect on egg production (Slinger and Pepper, 1964). In the same experiment, debeaking at 20 weeks of age significantly reduced feed consumption only during the first 4 weeks following debeaking and did not significantly affect the other measurements. Thus, previous research has clearly indicated that debeaking pullets within reasonable limits did not adversely affect egg production. The limits, however, were not established. The present research was under-
1224
R. C. HARGEEAVES AND L. R. CHAMPION TABLE 1.—Composition of diet
as to leave the lower mandible slightly longer than the upper mandible. Twenty-four cages were used for each debeaking treatment in the 1-bird cages, 12 cages for each treatment in the 3-bird cages, and one cage for each treatment in the 21-bird cages. The birds were fed on all-mash laying ration ad libitum. The composition of the ration is given in Table 1. Egg production records were started at initial egg production for the birds in 1-bird cages and at 24 weeks of age for the birds in 3-bird and 21-bird cages. Feed consumption was measured weekly from four replicates of each treatment in the 1-bird and 3-bird cages and from each of
Percent
Ground yellow corn Ground oats Wheat bran Flour middlings Alfalfa meal (17% dehyd.) Dried skim milk White fish meal Meat scraps Soybean meal (44% piul.) Ground oyster shell Hour Steamed bone meal Salt Fish oil (400 D, 2,000 A)
34.5 20.0 15.0 10.0 3.0 2.0 2.5 3.0 C
5.0 1.5 0.6 0.4
the four treatments in colony cages through the first 20 weeks of lay, beginning at 25 weeks of age. From the twentieth week of lay to the end of the experiment (500 days of age) feed consumption was measured in 28 day periods. All eggs were collected for five continuous days at the end of each 28-day period and weighed to the nearest gram. Body weights and beak lengths were measured at the end of each 28-day period. Statistical analyses were based on a modified form of analysis of variance (Guenther, 1964). All significant differences were further tested by use of Tukey's method for multiple comparisons (Guenther, 1964).
•HH FIG. 3. Debeaked three-fourths.
1
FIG. 4. Entirely debeaked.
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
FIG. 2. Debeaked one-half.
ingredient
DEBEAKING OF CAGED LAYERS TABLE 2.—Effect
TABLE 3.—Effect of debeaking on egg production, feed consumption, egg weight and mortality
of debeaking on sexual maturity
,• . . . T-, i Debeaking 6 treatment
Average number of J, , clays to cfirst egg
Debeaking treatment
Control i
178 178 181 Entire 234 Standard error of means=7.10
Control
i
Entire Standard error of means
RESULTS AND DISCUSSION
itO
l#5
Average Feed Egg total consumption weight egg (lbs. /bird/ (grams) production day) 188 179 173 127
0.29.1 0.273 0.252 0.227
53.5 53.6 53.7 53.7
6.26
0.010
0.224
Mortality
(%)
10.6 17.4 18.8 18.0
tirely debeaked birds was significantly (P < 0.01) lower than that of any of the other three treatments. One would suspect that the difference in age at sexual maturity could have caused most of the difference in egg production. Figure S, however, reveals that the difference in egg production persisted throughout the experiment. Feed consumption is also reported in Table 3. No significant interaction was found, so the various treatments were combined for analysis. Differences in feed consumption between the controls and birds debeaked three-fourths or entirely were highly significant (P < 0.01) between en-
56
55
I
Age ( w e e k s )
FIG. 5. Effect of debeaking on egg production.
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
The effect of debeaking on age at sexual maturity is shown in Table 2. Debeaking one-half or three-fourths did not significantly affect age at sexual maturity. Entire debeaking, however, caused a highly significant (P < 0.01) delay in age at sexual maturity. Analysis of variance did not reveal any significant interaction in egg production between debeaking treatments and cage population size, so the egg records from the different cage groups were combined. The combined averages are shown in Table 3. Debeaking one-half or three-fourths did not cause any significant difference in egg production, but the egg production of en-
1225
1226
R. C. HARGREAVES AND L. R. CHAMPION
TABLE 4.—Effect of debeaking on feed efficiency (lbs. feed/dozen eggs) Debeaking treatment
Cage population size 1-bird
3-bird
21-bird
5.70 6.30 Control 6.02 5.57 5.81 J 5.58 4.81 5.43 5.72 6.61 6.10 Entire 6.70 Standard error of means = 0,,174
TABLE 5.—Effect of debeaking on average body weight gain (lbs.) to 500 days of age Debeaking
Control i J Entire
SUMMARY AND CONCLUSIONS An experiment was carried out to deterTABLE 6.—Effect of debeaking on average beak length (cm) 1-bird cages
Cage population size
1.64 1.40 1.15 0.89
1.47 1.37 1.11 0.86
0.90 1.20 1.30 0.70
Control } } Entire
Weeks after Be fore 0 6 10 18 1.8 1.8 1.8 1.8 1.9 1.8 0.7 0.8 0.9 1.1 1.8 0.4 0.6 0.6 0.6 1.8 0.0 0.4 0.4 0.5 Standard error of means
debeaking 26 34 42 1.8 1.9 2.0 1.1 1.0 1.1 0.6 0.6 0.7 0.5 0.5 0.5 =0.019
50 1.8 1.0 0.5 0.5
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
tirely debeaked birds and birds debeaked one-half. In feed efficiency, highly significant (P < 0.01) interaction was found between levels of debeaking and cage population size. Feed efficiency figures are given in Table 4. Birds in entirely debeaked treatments consumed significantly more feed per dozen eggs than birds in most other treatments. Egg weights listed in Table 3 were not significantly different among any of the treatments. Highly significant (P < 0.01) interaction in average body weight gains was found between debeaking treatments and cage population size. As shown in Table 5, the average body weight gain decreased with an increase in severity of debeaking among birds in 1-bird and 3-bird cages, but in 21-bird cages average body weight gain was greatest among birds debeaked one-half and three-fourths. The body weight gains of controls in 1-bird and 3-bird cages were significantly (P < 0.05) higher than gains of birds debeaked one-half, and highly significantly (P < 0.01) higher than
gains of three-fourths and entirely debeaked birds. The differences in body weight gain between entirely debeaked birds and birds in any of the other treatments were highly significant (P < 0.01). In 21-bird cages, on the other hand, the birds debeaked one-half and three-fourths attained the highest average body weight gain. The differences between these two treatments and the controls and entirely debeaked were highly significant (P < 0.01). The average body weight gain of the birds debeaked one-half and three-fourths were not significantly different from each other. At 500 days of age the average body weight gain of the controls was significantly (P < 0.05) greater than that of the entirely debeaked birds in 21bird cages. Beak length measurements were made primarily on birds in 1-bird cages (Table 6). The only change in beak length over the period of the experiment that was significantly different from that of the controls occurred among the entirely debeaked birds. This change was highly significant (P < 0.01). By 18 weeks after debeaking the average beak length of the entirely debeaked birds was no longer significantly different from the average beak length of birds debeaked three-fourths. Visual observations, however, showed the presence of the usual horny covering on the beaks of birds debeaked three-fourths, while the beaks of the entirely debeaked birds had a leathery covering.
1227
DEBEAKING OF CAGED LAYERS
significantly greater body weight gains than in the controls. REFERENCES Bauermann, J. F., 1959. An investigation of the effect of debeaking on feed wastage and fertility of Single Comb White Leghorn chickens. Poultry Sci. 38: 1189. Bray, D. J., S. F. Ridlen and J. A. Gesell, 1960. Performance of pullets debeaked at various times during the laying year. Poultry Sci. 39: 1546-1550. Guenther, W. C , 1964. Analysis of Variance, Prentice-Hall, Inc., Inglewood Cliffs, N. J. Morgan, W., 1957. Effect of day-old debeiking on the performance of pullets. Poultry Sci. 36: 208-211. Noles, R. K., J. C. Driggers, C. K. Laurent and W. O. Page, 1962. Floor space requirements of Single Comb White Leghorn hens. Poultry Sci. 4 1 : 887-891. Slinger, S. J., and W. F. Pepper, 1964. Effects of debeaking and feeding whole grain on the reproductive performance of pullets. Poultry Sci. 43 : 356-362.
Logical Steps to Metric Conversion D O U G L A S V.
FROST
Abbott Laboratories, North Chicago, Illinois (Received for publication March 5, 1965)
I
NABILITY to change, beyond already successful changes, marks the decline, both of species and of nations. "Opennessto-change" has been attributed to democracy alone. But in some instances, such as this, democracies may suffer most from inertia. The adoption of decimal currency by the United States in its infancy (1786) was a change from which the whole world benefits. This was the first large scale public use of the decimal system and was an important outcome of the American Revo* Presented in part at the Metric Association Meeting (A.A.A.S.), December 28, 1963.
lution. England and Australia are only now forsaking their awkward currency. All English speaking countries will again for their own good, finally go metric. The slow trend toward simplification in man's historical use of numbers is seen below: History o) the Practical Use of Numbers Finger-counting Prehistory Sexagesimal system Sumeria3000 B.C. Babylonia Roman numerals Rome 500 B.C.1500 A.D.** Zero invented India 600 A.D. Arabia **In his fine book Science Awakening (Oxford University Press, 1961), Van der Waerden
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
mine the effects that several degrees of debeaking would have on reproductive performance. Block debeaking just in front of the nostrils caused highly significant changes in production characteristics: age to sexual maturity was prolonged, egg production was decreased, feed consumption was decreased, feed efficiency was poorer and body weight gains were smaller. Intermediate forms of debeaking did not cause any significant loss in egg production. Debeaking three-fourths of the beak resulted in a significant drop in feed consumption. A corollary improvement in feed efficiency was obscured by interactions with cage population size. Debeaking both one-half and three-fourths resulted in significantly smaller body weight gains than in the controls in 1-bird and 3-bird cages, but in the 21-bird cages debeaking one-half and three-fourths resulted in
D
1
Journal Article No. 3583, Michigan Agricultural Experiment Station. " In partial fulfillment of the M.S. degree in Poultry Science. Present address: 20° "U" Street, Bakersfield, California.
•
/
FIG. 1. Control
taken to determine what, if any, limitations should be applied to the degree of debeaking used in commercial practice. EXPERIMENTAL PROCEDURE Single Comb White Leghorns (M.S.U. pure line) were debeaked at 18 weeks of age and placed in 1-bird and 3-bird cages. The dimensions of the 1-bird cages were 8 inches X 16 inches; that of the 3-bird cages was 12 inches X 18 inches. Other pullets from the same strain were debeaked at 24 weeks of age and placed in 21-bird, 3 X 4 ft. cages. Three degrees of debeaking were used: approximately one-half, three-fourths, and all of the distance between the tip of the beak and the nostrils (see Figures 1-4). Non-debeaked birds served as the controls. The birds with all of the beak removed are referred to as "entirely debeaked." Both upper and lower mandibles were removed with one stroke of the electric debeaker, with the throat held back in such a manner
1223
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
EBEAKING research has amply supported the use of milder forms of debeaking. Removing one-half of the upper or both mandibles just prior to or during egg production has not significantly affected egg production (Morgan, 1957; Bray et al., 1960; Xoles et al., 1962). Debeaking one-half of the upper beak has, however, been reported to significantly reduce body weight (Bray et al., 1960) and feed wastage (Bauermann, 1959). Noles et al. (1962) found that feed efficiency was significantly affected by block debeaking one-half, but the effects were completely reversed from one year's trial to the next; it significantly reduced mortality in one trial but not in the other. Debeaking two-thirds of the upper beak and one-third of the lower beak at 8 weeks of age significantly retarded age at sexual maturity, reduced body weight gains and decreased feed consumption for the first 20 weeks of lay but had no effect on egg production (Slinger and Pepper, 1964). In the same experiment, debeaking at 20 weeks of age significantly reduced feed consumption only during the first 4 weeks following debeaking and did not significantly affect the other measurements. Thus, previous research has clearly indicated that debeaking pullets within reasonable limits did not adversely affect egg production. The limits, however, were not established. The present research was under-
1224
R. C. HARGEEAVES AND L. R. CHAMPION TABLE 1.—Composition of diet
as to leave the lower mandible slightly longer than the upper mandible. Twenty-four cages were used for each debeaking treatment in the 1-bird cages, 12 cages for each treatment in the 3-bird cages, and one cage for each treatment in the 21-bird cages. The birds were fed on all-mash laying ration ad libitum. The composition of the ration is given in Table 1. Egg production records were started at initial egg production for the birds in 1-bird cages and at 24 weeks of age for the birds in 3-bird and 21-bird cages. Feed consumption was measured weekly from four replicates of each treatment in the 1-bird and 3-bird cages and from each of
Percent
Ground yellow corn Ground oats Wheat bran Flour middlings Alfalfa meal (17% dehyd.) Dried skim milk White fish meal Meat scraps Soybean meal (44% piul.) Ground oyster shell Hour Steamed bone meal Salt Fish oil (400 D, 2,000 A)
34.5 20.0 15.0 10.0 3.0 2.0 2.5 3.0 C
5.0 1.5 0.6 0.4
the four treatments in colony cages through the first 20 weeks of lay, beginning at 25 weeks of age. From the twentieth week of lay to the end of the experiment (500 days of age) feed consumption was measured in 28 day periods. All eggs were collected for five continuous days at the end of each 28-day period and weighed to the nearest gram. Body weights and beak lengths were measured at the end of each 28-day period. Statistical analyses were based on a modified form of analysis of variance (Guenther, 1964). All significant differences were further tested by use of Tukey's method for multiple comparisons (Guenther, 1964).
•HH FIG. 3. Debeaked three-fourths.
1
FIG. 4. Entirely debeaked.
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
FIG. 2. Debeaked one-half.
ingredient
DEBEAKING OF CAGED LAYERS TABLE 2.—Effect
TABLE 3.—Effect of debeaking on egg production, feed consumption, egg weight and mortality
of debeaking on sexual maturity
,• . . . T-, i Debeaking 6 treatment
Average number of J, , clays to cfirst egg
Debeaking treatment
Control i
178 178 181 Entire 234 Standard error of means=7.10
Control
i
Entire Standard error of means
RESULTS AND DISCUSSION
itO
l#5
Average Feed Egg total consumption weight egg (lbs. /bird/ (grams) production day) 188 179 173 127
0.29.1 0.273 0.252 0.227
53.5 53.6 53.7 53.7
6.26
0.010
0.224
Mortality
(%)
10.6 17.4 18.8 18.0
tirely debeaked birds was significantly (P < 0.01) lower than that of any of the other three treatments. One would suspect that the difference in age at sexual maturity could have caused most of the difference in egg production. Figure S, however, reveals that the difference in egg production persisted throughout the experiment. Feed consumption is also reported in Table 3. No significant interaction was found, so the various treatments were combined for analysis. Differences in feed consumption between the controls and birds debeaked three-fourths or entirely were highly significant (P < 0.01) between en-
56
55
I
Age ( w e e k s )
FIG. 5. Effect of debeaking on egg production.
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
The effect of debeaking on age at sexual maturity is shown in Table 2. Debeaking one-half or three-fourths did not significantly affect age at sexual maturity. Entire debeaking, however, caused a highly significant (P < 0.01) delay in age at sexual maturity. Analysis of variance did not reveal any significant interaction in egg production between debeaking treatments and cage population size, so the egg records from the different cage groups were combined. The combined averages are shown in Table 3. Debeaking one-half or three-fourths did not cause any significant difference in egg production, but the egg production of en-
1225
1226
R. C. HARGREAVES AND L. R. CHAMPION
TABLE 4.—Effect of debeaking on feed efficiency (lbs. feed/dozen eggs) Debeaking treatment
Cage population size 1-bird
3-bird
21-bird
5.70 6.30 Control 6.02 5.57 5.81 J 5.58 4.81 5.43 5.72 6.61 6.10 Entire 6.70 Standard error of means = 0,,174
TABLE 5.—Effect of debeaking on average body weight gain (lbs.) to 500 days of age Debeaking
Control i J Entire
SUMMARY AND CONCLUSIONS An experiment was carried out to deterTABLE 6.—Effect of debeaking on average beak length (cm) 1-bird cages
Cage population size
1.64 1.40 1.15 0.89
1.47 1.37 1.11 0.86
0.90 1.20 1.30 0.70
Control } } Entire
Weeks after Be fore 0 6 10 18 1.8 1.8 1.8 1.8 1.9 1.8 0.7 0.8 0.9 1.1 1.8 0.4 0.6 0.6 0.6 1.8 0.0 0.4 0.4 0.5 Standard error of means
debeaking 26 34 42 1.8 1.9 2.0 1.1 1.0 1.1 0.6 0.6 0.7 0.5 0.5 0.5 =0.019
50 1.8 1.0 0.5 0.5
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
tirely debeaked birds and birds debeaked one-half. In feed efficiency, highly significant (P < 0.01) interaction was found between levels of debeaking and cage population size. Feed efficiency figures are given in Table 4. Birds in entirely debeaked treatments consumed significantly more feed per dozen eggs than birds in most other treatments. Egg weights listed in Table 3 were not significantly different among any of the treatments. Highly significant (P < 0.01) interaction in average body weight gains was found between debeaking treatments and cage population size. As shown in Table 5, the average body weight gain decreased with an increase in severity of debeaking among birds in 1-bird and 3-bird cages, but in 21-bird cages average body weight gain was greatest among birds debeaked one-half and three-fourths. The body weight gains of controls in 1-bird and 3-bird cages were significantly (P < 0.05) higher than gains of birds debeaked one-half, and highly significantly (P < 0.01) higher than
gains of three-fourths and entirely debeaked birds. The differences in body weight gain between entirely debeaked birds and birds in any of the other treatments were highly significant (P < 0.01). In 21-bird cages, on the other hand, the birds debeaked one-half and three-fourths attained the highest average body weight gain. The differences between these two treatments and the controls and entirely debeaked were highly significant (P < 0.01). The average body weight gain of the birds debeaked one-half and three-fourths were not significantly different from each other. At 500 days of age the average body weight gain of the controls was significantly (P < 0.05) greater than that of the entirely debeaked birds in 21bird cages. Beak length measurements were made primarily on birds in 1-bird cages (Table 6). The only change in beak length over the period of the experiment that was significantly different from that of the controls occurred among the entirely debeaked birds. This change was highly significant (P < 0.01). By 18 weeks after debeaking the average beak length of the entirely debeaked birds was no longer significantly different from the average beak length of birds debeaked three-fourths. Visual observations, however, showed the presence of the usual horny covering on the beaks of birds debeaked three-fourths, while the beaks of the entirely debeaked birds had a leathery covering.
1227
DEBEAKING OF CAGED LAYERS
significantly greater body weight gains than in the controls. REFERENCES Bauermann, J. F., 1959. An investigation of the effect of debeaking on feed wastage and fertility of Single Comb White Leghorn chickens. Poultry Sci. 38: 1189. Bray, D. J., S. F. Ridlen and J. A. Gesell, 1960. Performance of pullets debeaked at various times during the laying year. Poultry Sci. 39: 1546-1550. Guenther, W. C , 1964. Analysis of Variance, Prentice-Hall, Inc., Inglewood Cliffs, N. J. Morgan, W., 1957. Effect of day-old debeiking on the performance of pullets. Poultry Sci. 36: 208-211. Noles, R. K., J. C. Driggers, C. K. Laurent and W. O. Page, 1962. Floor space requirements of Single Comb White Leghorn hens. Poultry Sci. 4 1 : 887-891. Slinger, S. J., and W. F. Pepper, 1964. Effects of debeaking and feeding whole grain on the reproductive performance of pullets. Poultry Sci. 43 : 356-362.
Logical Steps to Metric Conversion D O U G L A S V.
FROST
Abbott Laboratories, North Chicago, Illinois (Received for publication March 5, 1965)
I
NABILITY to change, beyond already successful changes, marks the decline, both of species and of nations. "Opennessto-change" has been attributed to democracy alone. But in some instances, such as this, democracies may suffer most from inertia. The adoption of decimal currency by the United States in its infancy (1786) was a change from which the whole world benefits. This was the first large scale public use of the decimal system and was an important outcome of the American Revo* Presented in part at the Metric Association Meeting (A.A.A.S.), December 28, 1963.
lution. England and Australia are only now forsaking their awkward currency. All English speaking countries will again for their own good, finally go metric. The slow trend toward simplification in man's historical use of numbers is seen below: History o) the Practical Use of Numbers Finger-counting Prehistory Sexagesimal system Sumeria3000 B.C. Babylonia Roman numerals Rome 500 B.C.1500 A.D.** Zero invented India 600 A.D. Arabia **In his fine book Science Awakening (Oxford University Press, 1961), Van der Waerden
Downloaded from http://ps.oxfordjournals.org/ at University of California, San Diego on June 3, 2015
mine the effects that several degrees of debeaking would have on reproductive performance. Block debeaking just in front of the nostrils caused highly significant changes in production characteristics: age to sexual maturity was prolonged, egg production was decreased, feed consumption was decreased, feed efficiency was poorer and body weight gains were smaller. Intermediate forms of debeaking did not cause any significant loss in egg production. Debeaking three-fourths of the beak resulted in a significant drop in feed consumption. A corollary improvement in feed efficiency was obscured by interactions with cage population size. Debeaking both one-half and three-fourths resulted in significantly smaller body weight gains than in the controls in 1-bird and 3-bird cages, but in the 21-bird cages debeaking one-half and three-fourths resulted in