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Effect of Nutrient Intake on Performance of Dwarf Broiler Breeders
Effect of Nutrient Intake on Performance of Dwarf Broiler Breeders J. D. SUMMERS and S. LEESON Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada NIG 2W1 (Received for publication July 23, 1984) ABSTRACT An experiment was undertaken to test the response of dwarf broiler pullets when fed on two planes of nutrition in the growing period and fed either a 17 or 19% protein diet in the breeder house. Pullets offered 20% more feed in the growing period were heavier at 21 weeks of age and reached 50% egg production 2 weeks earlier than birds fed the regular diet. Pullets fed 20% more feed in the growing period and full-fed to 26 weeks in the laying house, gained appreciably more weight, and although they came into production faster, were less persistent in lay than birds fed the regular diet. There was no difference in egg production, egg size, or body composition of dwarfs fed 17 or 19% breeder diets. (Key words.- dwarf breeders, maturity, carcass compositions) 1985 Poultry Science 64:1599-1601 INTRODUCTION
Dwarf broiler breeders are approximately 65% of the body weight of normal breeders (Waldroup and Hazen, 1976), which, in large part, accounts for their relatively low energy requirement (Guillaume, 1971; Waldroup and Hazen, 1975). Although egg production for the dwarf and normal broiler breeder is comparable (Sherwood, 1971; Waldroup and Hazen, 1976), egg size is usually smaller for the dwarf (Jaap and Mohammadian, 1969; Chambers et al, 1972),- which results in market weight broilers weighing about 3.5% less for heterozygous males (Chambers et al, 1974). Waldroup and Hazen (1976) reported that dwarf and regular broiler breeders appeared to respond to higher dietary energy intakes with increased rates of egg production and increased egg size. To gain more information on this point the present study was initiated. MATERIALS AND METHODS
Eight-week-old dwarf broiler pullets were offered a diet containing 16% protein and 2800 kcal of metabolizable energy (ME)/kg. Two feeding schedules were used, representing the breeders recommended allowance or 120% of these values. Each treatment was tested with six replicates of 18 birds each, in floor pens. At 19 weeks of age light was immediately increased from 8 to 14 hr per day, and at 21 weeks, three pens from each growing treatment were fed practical type laying diets containing either 17 or 19% protein and similar levels of energy
(2800 kcal ME/kg). Those birds that had previously been fed according to the breeder's guide were again kept on the feeding program as recommended, while those that were fed 20% more were put on full-feed. The full-fed birds began to gain weight rapidly and, hence, at 26 weeks were returned to a daily restriction regimen. At 21 and 41 weeks of age carcass protein and fat were determined on one bird from each replicate. Data for the growing period were analyzed as overall means, whereas data for the laying treatment was analyzed as 2 x 2 factorial (Snedecor and Cochran, 1980) and resultant means subjected to a Duncan's multiple range test (Duncan, 1955). RESULTS AND DISCUSSION
At 21 weeks of age those birds fed extra feed weighed approximately 12.3% more while consuming some 19.2% more feed (Table 1). Due to the feeding schedule during the laying period, the birds fed 20% over the breeder's recommendation in the growing period also consumed approximately 15% more feed (Table 2). No other significant differences due to growing or laying treatment were noted. Pullets fed the 20% extra feed during the rearing period came up to 50% production some 2 weeks earlier than the birds fed the regular diet (Table 1). However, production did not reach as high a peak as the birds fed the regular diet (70 vs. 74%). Bornstein and Lev (1982) and Leeson and Summers (1983)
1599
1600
SUMMERS AND LEESON TABLE 1. Body weight and feed intake of dwarf breeder pullets from 8 to 21 weeks of age Average feed intake per d a y ( 8 - 2 1 wk)
21 week body weight
Growing regimen Restricted (guide) 20% over guide 1
\%>
* 1842 2068
Average energy intake per day ( 8 - 2 1 wk)
Age at 50% production
(kcal M E ) 1
(wk)
*
*
58.9 70.2
165 197
28 26
ME = Metabolizable energy.
•Means differ significantly (P<.05%).
reported that regular broiler breeders could be brought into production earlier with increased energy intake. As in the present study, the pullets brought into production earlier did not peak as high as pullets fed according to a regular feeding schedule (Leeson and Summers, 1983). Guillaume (1971) reported that the dwarf broiler breeder reguired 17 g of protein per day for optimum performance. In the present study the 17% protein diet permitted around 20 g of protein intake per day and thus may have been equal to or beyond the requirement.
Guillaume (1971) and Waldroup and Hazen (1975) reported that an energy intake of around 280 kcal ME/day appeared to meet the energy requirement of the dwarf breeder. The present study is in close agreement (Table 2). The 314-kcal intake for the birds fed "20% over guide" is obviously due to these birds being full-fed from 22 to 26 weeks of age. In agreement with Waldroup and Hazen (1976) and Leeson and Summers (1983), increased energy intake resulted in an improvement in early production and egg size. Carcass composition data showed little dif-
TABLE 2. Performance of dwarf breeders from 21 to 41 weeks of age Main effects Production HDB1
Average feed per d a y
(%)
Feed:
Egg
egg
weight
mass
(g;
Body weight (41 w k s of age)
Energy intake
(g)
(kcal M E / 2 day)
Growing regimen Restricted (guide) 20% Over guide
NS3 52.2
* 97.4
NS 57.2
NS 8.1
2563
273
54.3
112.0
56.6
5.0
2736
314
Laying t r e a t m e n t 17% Protein 19% Protein
NS 52.9 53.7
NS 105.0 105.0
NS 56.7 57.2
NS 5.4 7.7
NS 2690 2602
294 294
1
HDB = Hen-day basis.
2
ME = Metabolizable energy.
3
NS = Nonsignificant.
•Significant (P<.05).
RESEARCH NOTE TABLE 3. Carcass composition of dwarf pullets (% dry matter)
Rearing Restricted (guide) 20% Over guide Laying period 17% Protein 19% Protein
Protein 21 wk 41 wk
21 wk
58.5
43.0
33.7
47.4
59.9
44.2
34.2
47.0
44.0 43.2
Eat 41 wk
46.7 47.0
ference in protein or fat c o n t e n t of pullets reared either o n a regular growing p r o g r a m o r w i t h a feed intake 2 0 % above the regular program (Table 3). This suggests t h a t a large p o r t i o n of t h e e x t r a weight gain observed (Table 2) m a y b e muscle mass. T h e r e was n o difference in carcass c o m p o s i t i o n of t h e breeders at 4 1 weeks of age w h e n fed diets containing either 17 or 19% dietary p r o t e i n . R a t h e r t h a n suggest t h a t d a t a from t h e present s t u d y indicates t h a t dwarf broiler breeders c a n n o t be b r o u g h t into p r o d u c t i o n earlier, a m o r e logical conclusion w o u l d b e t h a t broiler breeders can be b r o u g h t into p r o d u c t i o n earlier, b u t as y e t t h e p r o p e r feeding program t o follow, u p t o and past peak p r o d u c t i o n , has n o t been w o r k e d o u t . More w o r k in this area is justified as a substantial saving in feed costs and returns from " e x t r a eggs" will result if several weeks can be saved in t h e growing period. Dwarf breeders m a y b e capable of responding t o such a program.
1601 ACKNOWLEDGMENTS
Financial s u p p o r t is acknowledged from Shaver P o u l t r y Breeding Farms Ltd., Cambridge, O n t a r i o and t h e O n t a r i o Ministry of Agriculture and F o o d .
REFERENCES Bornstein, S., and Y. Lev, 1982. The energy requirements of broiler breeders during the pullet-layer transition period. Poultry Sci. 61:755—765. Chambers, J, R., A. D. Smith, I. McMillan, and G. W. Friars, 1972. Comparison of chicken broilers from normal and dwarf breeder hens. Poultry Sci. 51:1792. (Abstr.) Chambers, J. R., A. D. Smith, I. McMillan, and G. W. Friars, 1974. Comparison of normal and dwarf broiler breeder hens. Poultry Sci. 53:864—870. Duncan, D. B., 1955. Multiple Range and F tests. Biometrics 11:1-42. Guillaume, J., 1971. Some nutritional and physiological traits of the dvi chick. World's Poult. Sci. J. 27:284. Jaap, R. G., and M. Mohammadian, 1969. Sex-linked dwarfism and egg production of broiler dams. Poultry Sci. 48:344-346. Leeson, S., and J. D. Summers, 1983. Consequence of increased feed allowance for growing broiler breeder pullets as a means of demonstrating early maturity. Poultry Sci. 6 2 : 6 - 1 1 . Sherwood, H., 1971. Comparison of midget meat type breeder chickens with a normal strain. Poultry Sci. 50:1630. (Abstr.) Snedecor, G. W., and Cochran, W. G., 1980. Statistical Methods. 7th ed. Iowa State Univ. Press, Ames. Waldroup, P. W., and K. R. Hazen, 1975. Energy needs of dwarf (dw) broiler breeder hens. Poultry Sci. 54:1931-1935. Waldroup, P. W., and K. R. Hazen, 1976. A comparison of the daily energy needs of the normal and dwarf broiler hen. Poultry Sci. 55:1383 — 1393.
Dwarf broiler breeders are approximately 65% of the body weight of normal breeders (Waldroup and Hazen, 1976), which, in large part, accounts for their relatively low energy requirement (Guillaume, 1971; Waldroup and Hazen, 1975). Although egg production for the dwarf and normal broiler breeder is comparable (Sherwood, 1971; Waldroup and Hazen, 1976), egg size is usually smaller for the dwarf (Jaap and Mohammadian, 1969; Chambers et al, 1972),- which results in market weight broilers weighing about 3.5% less for heterozygous males (Chambers et al, 1974). Waldroup and Hazen (1976) reported that dwarf and regular broiler breeders appeared to respond to higher dietary energy intakes with increased rates of egg production and increased egg size. To gain more information on this point the present study was initiated. MATERIALS AND METHODS
Eight-week-old dwarf broiler pullets were offered a diet containing 16% protein and 2800 kcal of metabolizable energy (ME)/kg. Two feeding schedules were used, representing the breeders recommended allowance or 120% of these values. Each treatment was tested with six replicates of 18 birds each, in floor pens. At 19 weeks of age light was immediately increased from 8 to 14 hr per day, and at 21 weeks, three pens from each growing treatment were fed practical type laying diets containing either 17 or 19% protein and similar levels of energy
(2800 kcal ME/kg). Those birds that had previously been fed according to the breeder's guide were again kept on the feeding program as recommended, while those that were fed 20% more were put on full-feed. The full-fed birds began to gain weight rapidly and, hence, at 26 weeks were returned to a daily restriction regimen. At 21 and 41 weeks of age carcass protein and fat were determined on one bird from each replicate. Data for the growing period were analyzed as overall means, whereas data for the laying treatment was analyzed as 2 x 2 factorial (Snedecor and Cochran, 1980) and resultant means subjected to a Duncan's multiple range test (Duncan, 1955). RESULTS AND DISCUSSION
At 21 weeks of age those birds fed extra feed weighed approximately 12.3% more while consuming some 19.2% more feed (Table 1). Due to the feeding schedule during the laying period, the birds fed 20% over the breeder's recommendation in the growing period also consumed approximately 15% more feed (Table 2). No other significant differences due to growing or laying treatment were noted. Pullets fed the 20% extra feed during the rearing period came up to 50% production some 2 weeks earlier than the birds fed the regular diet (Table 1). However, production did not reach as high a peak as the birds fed the regular diet (70 vs. 74%). Bornstein and Lev (1982) and Leeson and Summers (1983)
1599
1600
SUMMERS AND LEESON TABLE 1. Body weight and feed intake of dwarf breeder pullets from 8 to 21 weeks of age Average feed intake per d a y ( 8 - 2 1 wk)
21 week body weight
Growing regimen Restricted (guide) 20% over guide 1
\%>
* 1842 2068
Average energy intake per day ( 8 - 2 1 wk)
Age at 50% production
(kcal M E ) 1
(wk)
*
*
58.9 70.2
165 197
28 26
ME = Metabolizable energy.
•Means differ significantly (P<.05%).
reported that regular broiler breeders could be brought into production earlier with increased energy intake. As in the present study, the pullets brought into production earlier did not peak as high as pullets fed according to a regular feeding schedule (Leeson and Summers, 1983). Guillaume (1971) reported that the dwarf broiler breeder reguired 17 g of protein per day for optimum performance. In the present study the 17% protein diet permitted around 20 g of protein intake per day and thus may have been equal to or beyond the requirement.
Guillaume (1971) and Waldroup and Hazen (1975) reported that an energy intake of around 280 kcal ME/day appeared to meet the energy requirement of the dwarf breeder. The present study is in close agreement (Table 2). The 314-kcal intake for the birds fed "20% over guide" is obviously due to these birds being full-fed from 22 to 26 weeks of age. In agreement with Waldroup and Hazen (1976) and Leeson and Summers (1983), increased energy intake resulted in an improvement in early production and egg size. Carcass composition data showed little dif-
TABLE 2. Performance of dwarf breeders from 21 to 41 weeks of age Main effects Production HDB1
Average feed per d a y
(%)
Feed:
Egg
egg
weight
mass
(g;
Body weight (41 w k s of age)
Energy intake
(g)
(kcal M E / 2 day)
Growing regimen Restricted (guide) 20% Over guide
NS3 52.2
* 97.4
NS 57.2
NS 8.1
2563
273
54.3
112.0
56.6
5.0
2736
314
Laying t r e a t m e n t 17% Protein 19% Protein
NS 52.9 53.7
NS 105.0 105.0
NS 56.7 57.2
NS 5.4 7.7
NS 2690 2602
294 294
1
HDB = Hen-day basis.
2
ME = Metabolizable energy.
3
NS = Nonsignificant.
•Significant (P<.05).
RESEARCH NOTE TABLE 3. Carcass composition of dwarf pullets (% dry matter)
Rearing Restricted (guide) 20% Over guide Laying period 17% Protein 19% Protein
Protein 21 wk 41 wk
21 wk
58.5
43.0
33.7
47.4
59.9
44.2
34.2
47.0
44.0 43.2
Eat 41 wk
46.7 47.0
ference in protein or fat c o n t e n t of pullets reared either o n a regular growing p r o g r a m o r w i t h a feed intake 2 0 % above the regular program (Table 3). This suggests t h a t a large p o r t i o n of t h e e x t r a weight gain observed (Table 2) m a y b e muscle mass. T h e r e was n o difference in carcass c o m p o s i t i o n of t h e breeders at 4 1 weeks of age w h e n fed diets containing either 17 or 19% dietary p r o t e i n . R a t h e r t h a n suggest t h a t d a t a from t h e present s t u d y indicates t h a t dwarf broiler breeders c a n n o t be b r o u g h t into p r o d u c t i o n earlier, a m o r e logical conclusion w o u l d b e t h a t broiler breeders can be b r o u g h t into p r o d u c t i o n earlier, b u t as y e t t h e p r o p e r feeding program t o follow, u p t o and past peak p r o d u c t i o n , has n o t been w o r k e d o u t . More w o r k in this area is justified as a substantial saving in feed costs and returns from " e x t r a eggs" will result if several weeks can be saved in t h e growing period. Dwarf breeders m a y b e capable of responding t o such a program.
1601 ACKNOWLEDGMENTS
Financial s u p p o r t is acknowledged from Shaver P o u l t r y Breeding Farms Ltd., Cambridge, O n t a r i o and t h e O n t a r i o Ministry of Agriculture and F o o d .
REFERENCES Bornstein, S., and Y. Lev, 1982. The energy requirements of broiler breeders during the pullet-layer transition period. Poultry Sci. 61:755—765. Chambers, J, R., A. D. Smith, I. McMillan, and G. W. Friars, 1972. Comparison of chicken broilers from normal and dwarf breeder hens. Poultry Sci. 51:1792. (Abstr.) Chambers, J. R., A. D. Smith, I. McMillan, and G. W. Friars, 1974. Comparison of normal and dwarf broiler breeder hens. Poultry Sci. 53:864—870. Duncan, D. B., 1955. Multiple Range and F tests. Biometrics 11:1-42. Guillaume, J., 1971. Some nutritional and physiological traits of the dvi chick. World's Poult. Sci. J. 27:284. Jaap, R. G., and M. Mohammadian, 1969. Sex-linked dwarfism and egg production of broiler dams. Poultry Sci. 48:344-346. Leeson, S., and J. D. Summers, 1983. Consequence of increased feed allowance for growing broiler breeder pullets as a means of demonstrating early maturity. Poultry Sci. 6 2 : 6 - 1 1 . Sherwood, H., 1971. Comparison of midget meat type breeder chickens with a normal strain. Poultry Sci. 50:1630. (Abstr.) Snedecor, G. W., and Cochran, W. G., 1980. Statistical Methods. 7th ed. Iowa State Univ. Press, Ames. Waldroup, P. W., and K. R. Hazen, 1975. Energy needs of dwarf (dw) broiler breeder hens. Poultry Sci. 54:1931-1935. Waldroup, P. W., and K. R. Hazen, 1976. A comparison of the daily energy needs of the normal and dwarf broiler hen. Poultry Sci. 55:1383 — 1393.