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Effects of Feeder Space on Body Weight Uniformity of Broiler Breeder Pullets During an Alternate Day Feeding Program
EDUCATION AND PRODUCTION Effects of Feeder Space on Body Weight Uniformity of Broiler Breeder Pullets During an Alternate Day Feeding Program H. P. VAN KREY and W. D. WEAVER, JR. Department of Poultry Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0332 (Received for publication June 30, 1987)
1988 Poultry Science 67:996-1000
INTRODUCTION
Quantitative feed restriction (Blair et al., 1976; Powell and Gehle, 1976; Leeson and Summers, 1985) and qualitative feed restriction programs (Waldroup et al., 1966; Harms et al., 1968; Fuller et al., 1973; Harms et al., 1979) of one form or another are commonly used to control body weight of broiler breeder flocks. Such programs are necessary to prevent excessive obesity, to reduce mortality, and to improve reproductive performance. Although these programs have generally proven to be beneficial, some problems remain. One such problem is flock weight uniformity, which can affect reproductive performance. Uniform flocks reportedly reach peak egg production at an earlier age and attain higher levels of peak egg production (North, 1984). It has been suggested that adequate feeder space should be provided to insure that all birds have access to the feed at the same time when a feed restriction program is employed (Hughes and Black, 1977; Anonymous, 1986). Inadequate feeder space is generally associated with nonuniformity of flock body weight. The objective of this study was to measure the effect of feeder space in combination with a quantitative feed restriction program during the rearing period on body weight uniformity of broiler breeder pullets. A predetermined quantity of a relatively low protein starter/developer
diet was fed on an alternate day (skip-a-day) basis. In addition, 90% of the linear feeder space recommended by the primary breeder (Anonymous, 1986) and 45% of that feeder space were tested for their effects on body weight uniformity through 20 wk of age. MATERIALS AND METHODS
A total of 616 Hubbard broiler breeder female chicks, 1 day of age, were randomly placed into 14 light controlled floor pens (2.4 m X 3.6 m). Each pen contained 44 birds. Chicks were exposed to a 24-h light regimen (15 lx) for the first 2 wk, and 8 h of light/day for the remainder of the experiment. Beaks of all birds were trimmed at 10 days of age. A 16.0% protein starter/developer diet (Table 1) was provided ad libitum for the initial 2 wk, but food intake was restricted from Weeks 2 to 20 to control body weight. Water was provided ad libitum. Each bird was weighed weekly throughout the 20-wk rearing period, and feed allocations were calculated predicated upon mean pen body weight. Growth curves and body weights recommended by the primary breeder (Anonymous, 1986) were used as a guide. To assess the effect of feeder space on body weight uniformity, 90% of the recommended linear feeder space was provided to half of the pens, and 45% of the recommended space was
996
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
ABSTRACT The effect of feeder space on body weight uniformity of adolescent broiler breeder females during a feed restriction program was evaluated. From 2 to 20 wk of age, broiler breeder pullets were fed a starter/developer diet containing 16.0% protein and 2,944 kcal ME/kg feed. Feed allocations, predicated on mean pen body weight, were fed on an every other day basis. Feeder space was 45 or 90% of that recommended for use with a feed restriction program. The mortality, feed efficiency and body weight uniformity data all support the hypothesis that it is not necessary to provide enough feeder space to enable all birds to eat simultaneously. Broiler breeder pullets provided only 45% of the recommended feeder space responded as well as, or better than, those given 90% of the recommended feeder space. (Key words: body weight, feeder space, feed restriction, broiler pullets)
FEEDER SPACE, BODY WEIGHT, AND FEED RESTRICTION
997
The criterion used for measuring body weight uniformity was that at least 85% of the birds weigh within ± 15% of the weekly mean body weight. This value was recommended by the primary breeder of the pullets used in the study (Anonymous, 1986). Data were analyzed by ANOVA (Ray et al., 1982) using a completely randomized design. The statistical model was:
TABLE 1. Composition of the starter/developer diet
RESULTS AND DISCUSSION
Ingredients
Amount
Ground yellow corn Wheat middlings Dehulled soybean meal (49% protein) Corn gluten meal (60% protein) Animal fat Dicaleium phosphate (18.5%) Limestone Iodized salt Vitamin premix 1 Trace mineral mix 2 DL-Methionine Monensin sodium premix 3
(g/kg) 646.5 162.5 112.5 37.5 2.0 17.5 10.5 2.5 5.0 .5 2.0 1.0
Total
1,000.0 4
Calculated analyses Protein, % Calcium, % Phosphorus, total, % Phosphorus, available, % Lysine, % Methionine, % Cystine, % ME, kcal/kg feed
16.0 .83 .74 .46 .66 .51 .27 2,944
'Supplied per kilogram of diet: 8,820 IU vitamin A, 3,307 IU vitamin D 3 , 5.5 IU vitamin E, 3.5 mg menadione sodium bisulfite, 1.1 mg thiamine HC1, 4.4 mg riboflavin, 8.8 mg calcium D-pantothenate, 44 mg niacin, 375 mg choline chloride, .011 mg vitamin B 1 2 , 1.1 mg folic acid, 1.1 mg pyridoxine HC1, .11 mg biotin, 992 mg DL-methionine, 125 mgethoxyquin, 5.5 mg bacitracin, and .2 mg selenium. 2 Trace mineral mix contains: 12.0% manganese, 12.0% zinc, 4.0% iron, .5% copper, .2% iodine and .045% cobalt. 3
Premix provided 99 mg monensin
diet. 'National Research Council (1984).
sodium/kg
Yy = Jl + Ti + e;:
where (x = the overall mean, T ; = treatments, and e;j = variation among pens treated alike. Percentage data were transformed to arc sine \f% before being analyzed by ANOVA.
Percentages of pullets that were culled or died were similar for both feeder space treatments. The mortality/cull values were 5 and 6% for the birds exposed to 45 and 90% of the recommended feeder space, respectively. Body weights for the two groups, at 4-wk intervals, are presented in Table 2. In general, weekly mean body weights were slightly, but consistently higher than those recommended by the primary breeder (Anonymous, 1986). This was true for the birds exposed to 90% of the recommended feeder space and for those exposed to 45% of the recommended feeder space. This was not an unexpected result, however, as the quantity of feed made available to each pen was calculated weekly to insure that the birds attained a predetermined body weight. Pullets exposed to 45% of the recommended feeder space were consistently more efficient at feed conversion than those exposed to 90% of the linear feeder space recommended by the parent breeder; the difference was significant (P=£.05) for the 2 to 16-wk period (Table 3). The cause of this greater efficiency is unclear. Siegel et al. (1961) found that decreasing feeder space approximately 20% did not affect feed conversion of growing broilers. Wilson et al. (1985) showed that increasing feeder space 100% significantly decreased the feed efficiency of bobwhite quail, but the effect was attributed to increased feed wastage with increased feeder space. Feed wastage did not occur in our study and, therefore, was not a factor contributing to the result obtained. Body weight uniformity data, at 4-wk intervals, are presented in Table 4. Feeder space significantly affected the percentage of the popu-
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
provided to the remainder of the pens. Feeder space was regulated by varying the number of identical feeding troughs made available to the birds. Thus, during Weeks 1 to 5, seven pens of females were provided with a single trough feeder, which yielded 5.5 cm of feeder space/ bird, and seven pens were provided with two trough feeders, which yielded 11.0 cm of feeder space/bird. After 5 wk of age, trough feeder space was increased to 6.9 cm and 13.8 cm to the two groups of pens, respectively. The recommended feeder space during the rearing period (2 to 20 wk of age) is 15.38 cm/bird. No adjustment in feeder space was made when a bird died.
VAN KREY AND WEAVER, JR.
998
TABLE 2. Mean body weights (± SB) of broiler breeder pullets aged 4 to 20 wk fed on a restricted feeding schedule, at two different levels of feeder space1 Percentage of
Age (wk)
feeder space 2 ' 3
4
8
12
16
20
45% 90%
453 ± 14.7 446 + 15.0
821 ± 25.3 825 ± 25.7
1,639 ± 36.0 1,614 ± 37.5
2,058 ± 40.8 2,062 ±41.5
Recommended weight 3
410
800
(g) 1,287 ± 33.4 1,258 ± 34.3 1,200
1,550
2,050
2 Feeder space was 5.5 or 11.0 cm/bird to 5 wk of age, and 6.9 or 13.8 cm thereafter, which represents 45% and 90% of the recommended feeder space at each age interval. 3
Anonymous (1986).
lation deviating at least 15% from the mean weight during Week 12 but this difference was no longer significant by the end of Week 16. By 20 wk of age, body weight uniformity was generally acceptable according to standards developed by the primary breeder (80 to 85% of the flock within 15% of the mean body weight). Birds with only 45% of the recommended feeder space showed greater uniformity throughout the
rearing period, suggesting that feeder space may not be critical for maintaining body weight uniformity when using skip-a-day feeding. Thus, it may not be necessary to provide space for all birds to eat at the same time. Based on feed efficiency and body weight data, birds appeared to adjust when less feeder space was available. The results of this experiment regarding body weight uniformity are not consistent with those'
TABLE 3. Mean feed efficiencies (gain:feed, ± SE) of broiler breeder pullets aged 2 to 20 wk at two feeder space levels1
TABLE 4. Effect of feeder space on variation in body weights of broiler breeder pullets at various ages. Percentage of population within 85% of the mean body weight
Percentage of recommended feeder space 2 ' 3 45%
Age
Percentage of recommended feeder space 1 ' 2
90%
Age (wk)
2 2 2 2 2
to to to to to
4 8 12 16 20
.474 .367 .335 .301 .273
± .004 + .003 ± .002 ± .002 ± .002
.466 .370 .335 .294 .268
± .006 + .004 ± .002 ± .002* ± .002
1
Birds were fed a predetermined amount of feed on a skip-a-day schedule. 2 Feeder space was 5.5 or 11.0 cm/bird to 5 wk of age, and 6.9 or 13.8 cm thereafter, which represents 45% and 90% of the recommended feeder space at each age interval. 3
45%
90%
97.7 50.8 57.4 67.0 72.1 80.8
97.1 46.9 51.0 57.5* 66.5 75.8
(g/g)
Anonymous (1986).
*Means within a row are significantly different (P«.05).
(wk)
0 4
12 16 20
'Feeder space was 5.5 or 11.0 cm/bird to 5 wkof age, and 6.9 or 13.8 cm thereafter, which represents 45% and 90% of the recommended feeder space at each age interval. 2
Anonymous (1986).
*Means within a row are significantly different (P«.05).
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
1 From 0 to 2 wk of age, birds were fed daily amounts of feed based on commercial feed recommendations and performance goals. From 2 to 20 wk of age, birds were fed a predetermined amount of feed on a skip-a-day schedule.
FEEDER SPACE, BODY WEIGHT, AND FEED RESTRICTION
that the increased feed depth along with the diminished social effects would facilitate momentary accessibility to food for all birds. The increased depth of the feed would also facilitate food bolting which could decrease time to initial satiation in the more successful birds. This would afford the less successful birds an opportunity to eat before the effects of any initial satiation diminished. Thus, feed would be more uniformly distributed amongst the birds exposed to relatively less feeder space. Data obtained in this experiment suggest that feeder space adequate to allow all birds to eat simultaneously is not a prerequisite to attaining uniform body weights in broiler breeder females on a skip-a-day feeding program. In fact, the data indicate that less feeder space may be advantageous when employing such a feed restriction program. Relative ease of food availability from the feed trough may also be a factor. These concepts should be investigated. ACKNOWLEDGMENTS
Research supported in part by the Virginia Poultry Industry-Virginia Polytechnic Institute and State University Research Check-Off Program. The authors wish to thank Hubbard Farms, Inc., Walpole, NH, for providing the breeding stock. REFERENCES Al-Rawi, B. J., J. V. Craig, and A. W. Adams, 1976. Agonistic behavior and egg production of caged layers: Genetic strain and group size. Poultry Sci. 55:796807. Anonymous, 1986. Hubbard Management Guide for Breeder Pullets. Hubbard Farms, Inc., Walpole, NH. Blair, R., M. M. MacCowan, and W. Bolton, 1976. Effects of food regulation during the growing and laying stages on the productivity of broiler breeders. Br. Poult. Sci. 17:215-223. Cunningham, D. L., and A. van Tienhoven, 1984. The effects of management program and social rank on behavior and productivity of White Leghorn layers in cages. Poultry Sci. 63:25-30. Fuller, H. L., W. M. Kirkland, and L. W. Chaney, 1973. Methods of delaying sexual maturity of pullets. 2. Restricting energy consumption. Poultry Sci. 52:228236. Guhl, A. M., 1953. Social Behavior of Domestic Fowl. Kansas Exp. Stn. Tech. Bull. 73, Manhattan, KS. Harms, R. H., B. L. Damron, and H. R. Wilson, 1968. Performance of broiler breeder pullets as influenced by composition of grower and layer diets. Br. Poult. Sci. 9:359-366. Harms, R. H., R. A. Voitle, and H. R. Wilson, 1979. Performance of broiler breeder pullets grown on various grower programs. Nutr. Rep. Int. 20:561-566.
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
of Vaughters et al. (1987), which showed that high body weight variability at 4 wk of age also resulted in high variability at 20 wk of age. Although body weights were highly variable at 4 wk of age and throughout much of the rearing period in the present experiment (Table 4), body weight variability had decreased considerably by 20 wk of age. Presumably, the fact that feed allocations were predicated on mean weekly body weight led to improved uniformity by the end of the 20-wk rearing period. Also, results of Vaughters et al. (1987) are based on experimentation with males, in contrast to only females in the present study, which may have been a factor in the differences observed. Social status has long been known to affect ingestive behavior of chickens maintained in floor pens (Guhl, 1953; Tindell and Craig, 1959), even when small groups of chickens are hungry and have limited access to feeders (Lowry and Abplanalp, 1972). However, AlRawi et al. (1976) found that social rank did not affect time spent at the feeder when chickens were maintained in colony cages. They suggested that when chickens are held in colony cages at a high density, the importance of social stress changes, and caged birds do not behave like those held in floor pens. An analogous situation exists when broiler breeders in floor pens are placed on a skip-a-day feed restriction program. All semblance of social order disappears during the period of frenetic feeding immediately after food is made available. As a result, all birds are able to consume at least some feed despite very limited feeder space. This observation generally agrees with the report of Cunningham and van Tienhoven (1984), in which it was shown when hens were maintained in colony cages and feed was restricted, birds low in the social order spent significantly less time eating, but still obtained sufficient food to maintain body weight. Why body weight uniformity should be better in pullets exposed to limited feeder space is equivocal. A possible explanation might be related to both social behavior and feed accessibility. Although behavioral traits were not measured in the present experiment, it seems logical that immediately after feed provision, the degree of disorder and duration of this disorder would be relatively greater in pens with less feeder space. It may also be significant that in pens with 45% of the recommended feeder space, initial feed depth was twice as great as in the remaining pens. It seems plausible, therefore,
999
1000
VAN KREY AND WEAVER, JR. Whatley, 1982. SAS User's Guide. SAS Inst. Inc., Cary, NC. Siegel, P. B., H. S. Siegel, C. Y. Kramer, and C. E. Howes, 1961. Influence of and interactions between feeder and water allowance, sex, and crossbred on broiler performance. Poultry Sci. 40:201-206. Tindell, D., and J. V. Craig, 1959. Effects of social competition on laying house performance in the chicken. Poultry Sci. 38:95-105. Vaughters, P. D., G. M. Pesti, and B. Howarth, Jr., 1987. Effects of feed composition and feeding schedule on growth and development of broiler breeder males. Poultry Sci. 66:134-146. Waldroup, P. W., B. L. Damron, and R. H. Harms, 1966. The effect of low protein and high fiber grower diets on the performance of broiler pullets. Poultry Sci. 45:393^102. Wilson, H. R., D. R. Ingram, C. R. Douglas, and P. A. Skewes, 1985. Feeder space for brooding bobwhite quail. Poultry Sci. 64:2007-2009.
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
Hughes, B. O., and A. J. Black, 1977. Diurnal patterns of feeding and activity in layer hens in relation to dietary restriction and cage shape. Br. Poult. Sci. 18:353-360. Leeson, S., and J. D. Summers, 1985. Effect of cage vs. floor rearing and skip-a-day vs. every-day feed restriction on performance of dwarf broiler breeders and their offspring. Poultry Sci. 64:1742-1749. Lowry, D. C , and H. Abplanalp, 1972. Social dominance difference, given limited access to common food, between hens selected and unselected for increased egg production. Br. Poult. Sci. 13:365-376. National Research Council, 1984. Nutrient Requirements of Domestic Animals. 1. Nutrient Requirements of Poultry. Natl. Acad. Sci., Washington, DC. North, M. O., 1984. Commercial Chicken Production Manual. AVI Pub. Co., Inc., Westport, CT. Powell, T. S., and M. H. Gehle, 1976. Effect of various pullet restriction methods on performance of broiler breeders. Poultry Sci. 55:502-509. Ray, A. A., J. P. Sail, M. Saffer, S. P. Joyner, and J. K.
1988 Poultry Science 67:996-1000
INTRODUCTION
Quantitative feed restriction (Blair et al., 1976; Powell and Gehle, 1976; Leeson and Summers, 1985) and qualitative feed restriction programs (Waldroup et al., 1966; Harms et al., 1968; Fuller et al., 1973; Harms et al., 1979) of one form or another are commonly used to control body weight of broiler breeder flocks. Such programs are necessary to prevent excessive obesity, to reduce mortality, and to improve reproductive performance. Although these programs have generally proven to be beneficial, some problems remain. One such problem is flock weight uniformity, which can affect reproductive performance. Uniform flocks reportedly reach peak egg production at an earlier age and attain higher levels of peak egg production (North, 1984). It has been suggested that adequate feeder space should be provided to insure that all birds have access to the feed at the same time when a feed restriction program is employed (Hughes and Black, 1977; Anonymous, 1986). Inadequate feeder space is generally associated with nonuniformity of flock body weight. The objective of this study was to measure the effect of feeder space in combination with a quantitative feed restriction program during the rearing period on body weight uniformity of broiler breeder pullets. A predetermined quantity of a relatively low protein starter/developer
diet was fed on an alternate day (skip-a-day) basis. In addition, 90% of the linear feeder space recommended by the primary breeder (Anonymous, 1986) and 45% of that feeder space were tested for their effects on body weight uniformity through 20 wk of age. MATERIALS AND METHODS
A total of 616 Hubbard broiler breeder female chicks, 1 day of age, were randomly placed into 14 light controlled floor pens (2.4 m X 3.6 m). Each pen contained 44 birds. Chicks were exposed to a 24-h light regimen (15 lx) for the first 2 wk, and 8 h of light/day for the remainder of the experiment. Beaks of all birds were trimmed at 10 days of age. A 16.0% protein starter/developer diet (Table 1) was provided ad libitum for the initial 2 wk, but food intake was restricted from Weeks 2 to 20 to control body weight. Water was provided ad libitum. Each bird was weighed weekly throughout the 20-wk rearing period, and feed allocations were calculated predicated upon mean pen body weight. Growth curves and body weights recommended by the primary breeder (Anonymous, 1986) were used as a guide. To assess the effect of feeder space on body weight uniformity, 90% of the recommended linear feeder space was provided to half of the pens, and 45% of the recommended space was
996
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
ABSTRACT The effect of feeder space on body weight uniformity of adolescent broiler breeder females during a feed restriction program was evaluated. From 2 to 20 wk of age, broiler breeder pullets were fed a starter/developer diet containing 16.0% protein and 2,944 kcal ME/kg feed. Feed allocations, predicated on mean pen body weight, were fed on an every other day basis. Feeder space was 45 or 90% of that recommended for use with a feed restriction program. The mortality, feed efficiency and body weight uniformity data all support the hypothesis that it is not necessary to provide enough feeder space to enable all birds to eat simultaneously. Broiler breeder pullets provided only 45% of the recommended feeder space responded as well as, or better than, those given 90% of the recommended feeder space. (Key words: body weight, feeder space, feed restriction, broiler pullets)
FEEDER SPACE, BODY WEIGHT, AND FEED RESTRICTION
997
The criterion used for measuring body weight uniformity was that at least 85% of the birds weigh within ± 15% of the weekly mean body weight. This value was recommended by the primary breeder of the pullets used in the study (Anonymous, 1986). Data were analyzed by ANOVA (Ray et al., 1982) using a completely randomized design. The statistical model was:
TABLE 1. Composition of the starter/developer diet
RESULTS AND DISCUSSION
Ingredients
Amount
Ground yellow corn Wheat middlings Dehulled soybean meal (49% protein) Corn gluten meal (60% protein) Animal fat Dicaleium phosphate (18.5%) Limestone Iodized salt Vitamin premix 1 Trace mineral mix 2 DL-Methionine Monensin sodium premix 3
(g/kg) 646.5 162.5 112.5 37.5 2.0 17.5 10.5 2.5 5.0 .5 2.0 1.0
Total
1,000.0 4
Calculated analyses Protein, % Calcium, % Phosphorus, total, % Phosphorus, available, % Lysine, % Methionine, % Cystine, % ME, kcal/kg feed
16.0 .83 .74 .46 .66 .51 .27 2,944
'Supplied per kilogram of diet: 8,820 IU vitamin A, 3,307 IU vitamin D 3 , 5.5 IU vitamin E, 3.5 mg menadione sodium bisulfite, 1.1 mg thiamine HC1, 4.4 mg riboflavin, 8.8 mg calcium D-pantothenate, 44 mg niacin, 375 mg choline chloride, .011 mg vitamin B 1 2 , 1.1 mg folic acid, 1.1 mg pyridoxine HC1, .11 mg biotin, 992 mg DL-methionine, 125 mgethoxyquin, 5.5 mg bacitracin, and .2 mg selenium. 2 Trace mineral mix contains: 12.0% manganese, 12.0% zinc, 4.0% iron, .5% copper, .2% iodine and .045% cobalt. 3
Premix provided 99 mg monensin
diet. 'National Research Council (1984).
sodium/kg
Yy = Jl + Ti + e;:
where (x = the overall mean, T ; = treatments, and e;j = variation among pens treated alike. Percentage data were transformed to arc sine \f% before being analyzed by ANOVA.
Percentages of pullets that were culled or died were similar for both feeder space treatments. The mortality/cull values were 5 and 6% for the birds exposed to 45 and 90% of the recommended feeder space, respectively. Body weights for the two groups, at 4-wk intervals, are presented in Table 2. In general, weekly mean body weights were slightly, but consistently higher than those recommended by the primary breeder (Anonymous, 1986). This was true for the birds exposed to 90% of the recommended feeder space and for those exposed to 45% of the recommended feeder space. This was not an unexpected result, however, as the quantity of feed made available to each pen was calculated weekly to insure that the birds attained a predetermined body weight. Pullets exposed to 45% of the recommended feeder space were consistently more efficient at feed conversion than those exposed to 90% of the linear feeder space recommended by the parent breeder; the difference was significant (P=£.05) for the 2 to 16-wk period (Table 3). The cause of this greater efficiency is unclear. Siegel et al. (1961) found that decreasing feeder space approximately 20% did not affect feed conversion of growing broilers. Wilson et al. (1985) showed that increasing feeder space 100% significantly decreased the feed efficiency of bobwhite quail, but the effect was attributed to increased feed wastage with increased feeder space. Feed wastage did not occur in our study and, therefore, was not a factor contributing to the result obtained. Body weight uniformity data, at 4-wk intervals, are presented in Table 4. Feeder space significantly affected the percentage of the popu-
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
provided to the remainder of the pens. Feeder space was regulated by varying the number of identical feeding troughs made available to the birds. Thus, during Weeks 1 to 5, seven pens of females were provided with a single trough feeder, which yielded 5.5 cm of feeder space/ bird, and seven pens were provided with two trough feeders, which yielded 11.0 cm of feeder space/bird. After 5 wk of age, trough feeder space was increased to 6.9 cm and 13.8 cm to the two groups of pens, respectively. The recommended feeder space during the rearing period (2 to 20 wk of age) is 15.38 cm/bird. No adjustment in feeder space was made when a bird died.
VAN KREY AND WEAVER, JR.
998
TABLE 2. Mean body weights (± SB) of broiler breeder pullets aged 4 to 20 wk fed on a restricted feeding schedule, at two different levels of feeder space1 Percentage of
Age (wk)
feeder space 2 ' 3
4
8
12
16
20
45% 90%
453 ± 14.7 446 + 15.0
821 ± 25.3 825 ± 25.7
1,639 ± 36.0 1,614 ± 37.5
2,058 ± 40.8 2,062 ±41.5
Recommended weight 3
410
800
(g) 1,287 ± 33.4 1,258 ± 34.3 1,200
1,550
2,050
2 Feeder space was 5.5 or 11.0 cm/bird to 5 wk of age, and 6.9 or 13.8 cm thereafter, which represents 45% and 90% of the recommended feeder space at each age interval. 3
Anonymous (1986).
lation deviating at least 15% from the mean weight during Week 12 but this difference was no longer significant by the end of Week 16. By 20 wk of age, body weight uniformity was generally acceptable according to standards developed by the primary breeder (80 to 85% of the flock within 15% of the mean body weight). Birds with only 45% of the recommended feeder space showed greater uniformity throughout the
rearing period, suggesting that feeder space may not be critical for maintaining body weight uniformity when using skip-a-day feeding. Thus, it may not be necessary to provide space for all birds to eat at the same time. Based on feed efficiency and body weight data, birds appeared to adjust when less feeder space was available. The results of this experiment regarding body weight uniformity are not consistent with those'
TABLE 3. Mean feed efficiencies (gain:feed, ± SE) of broiler breeder pullets aged 2 to 20 wk at two feeder space levels1
TABLE 4. Effect of feeder space on variation in body weights of broiler breeder pullets at various ages. Percentage of population within 85% of the mean body weight
Percentage of recommended feeder space 2 ' 3 45%
Age
Percentage of recommended feeder space 1 ' 2
90%
Age (wk)
2 2 2 2 2
to to to to to
4 8 12 16 20
.474 .367 .335 .301 .273
± .004 + .003 ± .002 ± .002 ± .002
.466 .370 .335 .294 .268
± .006 + .004 ± .002 ± .002* ± .002
1
Birds were fed a predetermined amount of feed on a skip-a-day schedule. 2 Feeder space was 5.5 or 11.0 cm/bird to 5 wk of age, and 6.9 or 13.8 cm thereafter, which represents 45% and 90% of the recommended feeder space at each age interval. 3
45%
90%
97.7 50.8 57.4 67.0 72.1 80.8
97.1 46.9 51.0 57.5* 66.5 75.8
(g/g)
Anonymous (1986).
*Means within a row are significantly different (P«.05).
(wk)
0 4
12 16 20
'Feeder space was 5.5 or 11.0 cm/bird to 5 wkof age, and 6.9 or 13.8 cm thereafter, which represents 45% and 90% of the recommended feeder space at each age interval. 2
Anonymous (1986).
*Means within a row are significantly different (P«.05).
Downloaded from http://ps.oxfordjournals.org/ at Penn State University (Paterno Lib) on December 4, 2015
1 From 0 to 2 wk of age, birds were fed daily amounts of feed based on commercial feed recommendations and performance goals. From 2 to 20 wk of age, birds were fed a predetermined amount of feed on a skip-a-day schedule.
FEEDER SPACE, BODY WEIGHT, AND FEED RESTRICTION
that the increased feed depth along with the diminished social effects would facilitate momentary accessibility to food for all birds. The increased depth of the feed would also facilitate food bolting which could decrease time to initial satiation in the more successful birds. This would afford the less successful birds an opportunity to eat before the effects of any initial satiation diminished. Thus, feed would be more uniformly distributed amongst the birds exposed to relatively less feeder space. Data obtained in this experiment suggest that feeder space adequate to allow all birds to eat simultaneously is not a prerequisite to attaining uniform body weights in broiler breeder females on a skip-a-day feeding program. In fact, the data indicate that less feeder space may be advantageous when employing such a feed restriction program. Relative ease of food availability from the feed trough may also be a factor. These concepts should be investigated. ACKNOWLEDGMENTS
Research supported in part by the Virginia Poultry Industry-Virginia Polytechnic Institute and State University Research Check-Off Program. The authors wish to thank Hubbard Farms, Inc., Walpole, NH, for providing the breeding stock. REFERENCES Al-Rawi, B. J., J. V. Craig, and A. W. Adams, 1976. Agonistic behavior and egg production of caged layers: Genetic strain and group size. Poultry Sci. 55:796807. Anonymous, 1986. Hubbard Management Guide for Breeder Pullets. Hubbard Farms, Inc., Walpole, NH. Blair, R., M. M. MacCowan, and W. Bolton, 1976. Effects of food regulation during the growing and laying stages on the productivity of broiler breeders. Br. Poult. Sci. 17:215-223. Cunningham, D. L., and A. van Tienhoven, 1984. The effects of management program and social rank on behavior and productivity of White Leghorn layers in cages. Poultry Sci. 63:25-30. Fuller, H. L., W. M. Kirkland, and L. W. Chaney, 1973. Methods of delaying sexual maturity of pullets. 2. Restricting energy consumption. Poultry Sci. 52:228236. Guhl, A. M., 1953. Social Behavior of Domestic Fowl. Kansas Exp. Stn. Tech. Bull. 73, Manhattan, KS. Harms, R. H., B. L. Damron, and H. R. Wilson, 1968. Performance of broiler breeder pullets as influenced by composition of grower and layer diets. Br. Poult. Sci. 9:359-366. Harms, R. H., R. A. Voitle, and H. R. Wilson, 1979. Performance of broiler breeder pullets grown on various grower programs. Nutr. Rep. Int. 20:561-566.
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of Vaughters et al. (1987), which showed that high body weight variability at 4 wk of age also resulted in high variability at 20 wk of age. Although body weights were highly variable at 4 wk of age and throughout much of the rearing period in the present experiment (Table 4), body weight variability had decreased considerably by 20 wk of age. Presumably, the fact that feed allocations were predicated on mean weekly body weight led to improved uniformity by the end of the 20-wk rearing period. Also, results of Vaughters et al. (1987) are based on experimentation with males, in contrast to only females in the present study, which may have been a factor in the differences observed. Social status has long been known to affect ingestive behavior of chickens maintained in floor pens (Guhl, 1953; Tindell and Craig, 1959), even when small groups of chickens are hungry and have limited access to feeders (Lowry and Abplanalp, 1972). However, AlRawi et al. (1976) found that social rank did not affect time spent at the feeder when chickens were maintained in colony cages. They suggested that when chickens are held in colony cages at a high density, the importance of social stress changes, and caged birds do not behave like those held in floor pens. An analogous situation exists when broiler breeders in floor pens are placed on a skip-a-day feed restriction program. All semblance of social order disappears during the period of frenetic feeding immediately after food is made available. As a result, all birds are able to consume at least some feed despite very limited feeder space. This observation generally agrees with the report of Cunningham and van Tienhoven (1984), in which it was shown when hens were maintained in colony cages and feed was restricted, birds low in the social order spent significantly less time eating, but still obtained sufficient food to maintain body weight. Why body weight uniformity should be better in pullets exposed to limited feeder space is equivocal. A possible explanation might be related to both social behavior and feed accessibility. Although behavioral traits were not measured in the present experiment, it seems logical that immediately after feed provision, the degree of disorder and duration of this disorder would be relatively greater in pens with less feeder space. It may also be significant that in pens with 45% of the recommended feeder space, initial feed depth was twice as great as in the remaining pens. It seems plausible, therefore,
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VAN KREY AND WEAVER, JR. Whatley, 1982. SAS User's Guide. SAS Inst. Inc., Cary, NC. Siegel, P. B., H. S. Siegel, C. Y. Kramer, and C. E. Howes, 1961. Influence of and interactions between feeder and water allowance, sex, and crossbred on broiler performance. Poultry Sci. 40:201-206. Tindell, D., and J. V. Craig, 1959. Effects of social competition on laying house performance in the chicken. Poultry Sci. 38:95-105. Vaughters, P. D., G. M. Pesti, and B. Howarth, Jr., 1987. Effects of feed composition and feeding schedule on growth and development of broiler breeder males. Poultry Sci. 66:134-146. Waldroup, P. W., B. L. Damron, and R. H. Harms, 1966. The effect of low protein and high fiber grower diets on the performance of broiler pullets. Poultry Sci. 45:393^102. Wilson, H. R., D. R. Ingram, C. R. Douglas, and P. A. Skewes, 1985. Feeder space for brooding bobwhite quail. Poultry Sci. 64:2007-2009.
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Hughes, B. O., and A. J. Black, 1977. Diurnal patterns of feeding and activity in layer hens in relation to dietary restriction and cage shape. Br. Poult. Sci. 18:353-360. Leeson, S., and J. D. Summers, 1985. Effect of cage vs. floor rearing and skip-a-day vs. every-day feed restriction on performance of dwarf broiler breeders and their offspring. Poultry Sci. 64:1742-1749. Lowry, D. C , and H. Abplanalp, 1972. Social dominance difference, given limited access to common food, between hens selected and unselected for increased egg production. Br. Poult. Sci. 13:365-376. National Research Council, 1984. Nutrient Requirements of Domestic Animals. 1. Nutrient Requirements of Poultry. Natl. Acad. Sci., Washington, DC. North, M. O., 1984. Commercial Chicken Production Manual. AVI Pub. Co., Inc., Westport, CT. Powell, T. S., and M. H. Gehle, 1976. Effect of various pullet restriction methods on performance of broiler breeders. Poultry Sci. 55:502-509. Ray, A. A., J. P. Sail, M. Saffer, S. P. Joyner, and J. K.