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Pullets at the Onset of Lay1
PULLETS AT THE ONSET OF LAY' DON R. SLOAN2,R. H. HARMS, W G. SMITH Department of Poulhy Science, Universityof Florida, Gainesville, FL 32611 Phone: (904)392-1931 F a : (904) 392-8479 S. B0On;YALLA College of VeterinaryMedicine, Universityof Florih, Gainesville, FL 3261 I
Primary Audience: Nutritionists, Layer Flock Supervisors, Individual Producers. Veterinarians
DESCRIPTION OF PROBLEM Pullets coming into lay, especially during periods of hot weather, often have low feed intake and may exhibit poor peaks in production. They may also display short periods of leveling-off as they approach peak production. 1 2
1
Producers frequently initiate dietary changes to correct what they perceive as problems brought on by insufficient nutrient intake. Birds are often fed a diet which is a more nutrient-dense diet, especially in amino acids.
Florida Agricultural Experiment Station Journal Series No. R-01627 To whom correspondence should be addressed
FEED CONSUMPTION IN PULLETS
165
This change compensates for reduced feed intake [l],but generally results in a diet lower in energy, particularly if amino acid density is increased by substituting soybean meal for corn. This study was conducted to determine the benefits or detriments of increasing amino acid density above that which is normal for pullets. Developing pullets have lower nutrient requirements than laying hens [2, 3, 41. Therefore, during the early stages of a flock coming into production, birds not yet laying should eat less than birds in lay. If this assumption is true, feeding developing pullets a diet formulated for average flock consumption results in overfeeding amino acids and, in turn, reduced intake of energy. Additional increases in nutrient density may aggravate production problems by further reducing dietary energy.
production by the end of the experimental period.
RESULTS AND DISCUSSION Feed consumption for the 5 days prior to initial oviposition averaged 16.19 pounds/100 birddday (Table 1). Variation between days was small, with no clear trend of increased consumption. Average daily feed consurnption was 17.6 pounddl00 birds/day on the initial day of oviposition, a significant (P e .OS) increase over that of the 5 days prior to initial oviposition. Feed consumption for the 5 days post initial oviposition averaged 18.5 pounds/100 birds/day. This was significantly greater than both the average feed consumption on the initial day of oviposition (Pe.OS) and that of the 5 days prior to initial oviposition (P< .00l). These findings agree with our assumptions that non-laying birds consume less than laying birds, and that feed formulated for the flock average is inappropriate for birds in lay. On the initial day of oviposition, average consumption increased 1.4 pounds/100 birds/day. The average consumption for the 5 days post initial oviposition was 2.5 pounds/100 birds/day greater than the average consumption for the 5 days prior to initial oviposition. Daily consumption levels on days that eggs were produced were compared to those for days on which eggs were not produced for the 5 days post initial oviposition (Table 2). Increased consumption levels near the end of this period (noted above) paralleled an increase in individual rate of lay. Birds consumed an average of 18.9 pounds/100 birds/day on days that eggs were laid, but only
MATERIALS AND METHODS One hundred and twenty SCWL pullets, 18 weeks of age, were caged individually, and their feed consumption recorded daily [5] during a 21 day experimental period. Birds that initiated lay before 5 days or after 16 days into the experimental period were not used in comparisons. Individual egg records were maintained and feed consumption was calculated for the 5 days prior to initial oviposition, the day of initial oviposition, and the 5 days post initial oviposition. The 5 days post initial oviposition were also examined for feed consumption patterns according to whether or not an individual bird produced an egg on any of those 5 days. In addition, feed consumption was calculated for pullets that did not initiate
FEED (9)
DAYS PRIORTO OVIPOSITION
DAY OF INITIAL OVIPOSITION
DAYS POSTOVIPOSITION
I
81.9
2
I
80.9
3
I
82.7
74.1
4
73.5
3
69.4 73.7
4
I
~
2
1 Mean *Standard error of the mean BPc .05 'P < .001
I
76.9 73.5 f 1.0A
5 79.8 f 2.2B
(g)
1
5
I
=ED
85.0 88.6 83.8 & 1.2'
TABLE 2. Average feed consumption (9)on each of the 5 days post initial oviposition
I
DAYS POSTOVIPOSITION
I
2
x
I
EGG(S) PRODUCED
I
I
82.5 (24)
I
EGG(S)NOT PRODUCED
77.1 (111
I
DIFFERENCE
I
5.4
3
84.0 (27)
78.4 (8)
4
86.1 (28)
fXl.6 (7)
5.5
5
90.0 (32)
73.0 (3)
17.0
86.0 t: 1.4'
78.0 f 2.0
f SEM
BStandarderror of the mean
17.2 pounds1100 birdslday on days when no eggs were produced. Pullets that did not initiate production during the experimentalperiod consumed an average of 15.1 pounds/100 birdlday. The difference in consumption between pullets and layers, and the increase in consumption with time in lay, indicate that average consumption is an incorrect measure for birds in production. Prior to reaching 50% production, birds should receive feed that is formulated at a level which is two pounds higher than the flock average. For example, if the flock is not yet at 50% production, and is
I
5.6
I*Values in parentheses indicate the number of observations used to calculate the averagippl
1
I
I
consuming an average of 18 pounds1100 birdslday, then a less nutrient dense diet of 20 pounds/100 birdslday should be formulated for these birds. Between 50% production and peak, birds should receive feed that is formulated at a level that is one pound higher than average. At peak production and thereafter, the recommended feed formulation should be used. This strategy will result in cost savings because: 1) a higher level of energy will be available to the birds, and energy sources are less expensive than protein sources; and 2) energy deficiencies during hot weather will be minimized.
CONCLUSIONS AND APPLICATIONS 1. Feed consumption differs markedly between pullets yet to initiate lay and those that have
begun production. 2. Increased consumption does not begin until the initial day of oviposition. 3. Consumption varies (after production begins) between days on which eggs are produced and days on which they are not. 4. Feeding the flock average overestimates the nutritional needs of pullets; it may supply too large a quantity of amino acids, which can result in reduced energy intake by laying birds. 5. A flock coming into lay should be given a feed with an amino acid density lower than that formulated for average flock consumption.
REFERENCES AND NOTES l.Harms,RH.,C.RDouglas,RB.Christmas,B.L subsequent performance and liver and abdominal fat at
Damron, and RD. Miles, 1978. Feeding commercial layers for maximum performance. Feedstuffs 50(8):23-24. 2. Harms, RH., and C.R Douglas, 1981. Amino acid s cifications for replacement pullet feeds. Feedstuffs G(9):36-39. 3. Lteson, S., and J.D. Summer, 1982. Use of sine-stage low rotein diets for growing Leghorn pullets. $oultry Sci. 6l!1684-1691. 4. Maurice, D.V., B.L. Hughes, J.E Jones, and J.M. Weber, 1982.Theeffect ofreverse protein andlow protein feeding regimens in the rearing period on pullet growth,
the end of lay. Poultry Sci. 61:2421-2429. 5. Roland, D.A., Sr., D.R Sloan, and R.H. Harms, 1971. An easy and ine ensive system for measuring feed consumption. Poultry%. 501227-1228. 6. Data were subjected to anal is of variance and standard error of means calculated F A S Institute, 1982 SAS user's Guide; Statistics, version 5. SAS Inst., Cary, NC.)
I
Primary Audience: Nutritionists, Layer Flock Supervisors, Individual Producers. Veterinarians
DESCRIPTION OF PROBLEM Pullets coming into lay, especially during periods of hot weather, often have low feed intake and may exhibit poor peaks in production. They may also display short periods of leveling-off as they approach peak production. 1 2
1
Producers frequently initiate dietary changes to correct what they perceive as problems brought on by insufficient nutrient intake. Birds are often fed a diet which is a more nutrient-dense diet, especially in amino acids.
Florida Agricultural Experiment Station Journal Series No. R-01627 To whom correspondence should be addressed
FEED CONSUMPTION IN PULLETS
165
This change compensates for reduced feed intake [l],but generally results in a diet lower in energy, particularly if amino acid density is increased by substituting soybean meal for corn. This study was conducted to determine the benefits or detriments of increasing amino acid density above that which is normal for pullets. Developing pullets have lower nutrient requirements than laying hens [2, 3, 41. Therefore, during the early stages of a flock coming into production, birds not yet laying should eat less than birds in lay. If this assumption is true, feeding developing pullets a diet formulated for average flock consumption results in overfeeding amino acids and, in turn, reduced intake of energy. Additional increases in nutrient density may aggravate production problems by further reducing dietary energy.
production by the end of the experimental period.
RESULTS AND DISCUSSION Feed consumption for the 5 days prior to initial oviposition averaged 16.19 pounds/100 birddday (Table 1). Variation between days was small, with no clear trend of increased consumption. Average daily feed consurnption was 17.6 pounddl00 birds/day on the initial day of oviposition, a significant (P e .OS) increase over that of the 5 days prior to initial oviposition. Feed consumption for the 5 days post initial oviposition averaged 18.5 pounds/100 birds/day. This was significantly greater than both the average feed consumption on the initial day of oviposition (Pe.OS) and that of the 5 days prior to initial oviposition (P< .00l). These findings agree with our assumptions that non-laying birds consume less than laying birds, and that feed formulated for the flock average is inappropriate for birds in lay. On the initial day of oviposition, average consumption increased 1.4 pounds/100 birds/day. The average consumption for the 5 days post initial oviposition was 2.5 pounds/100 birds/day greater than the average consumption for the 5 days prior to initial oviposition. Daily consumption levels on days that eggs were produced were compared to those for days on which eggs were not produced for the 5 days post initial oviposition (Table 2). Increased consumption levels near the end of this period (noted above) paralleled an increase in individual rate of lay. Birds consumed an average of 18.9 pounds/100 birds/day on days that eggs were laid, but only
MATERIALS AND METHODS One hundred and twenty SCWL pullets, 18 weeks of age, were caged individually, and their feed consumption recorded daily [5] during a 21 day experimental period. Birds that initiated lay before 5 days or after 16 days into the experimental period were not used in comparisons. Individual egg records were maintained and feed consumption was calculated for the 5 days prior to initial oviposition, the day of initial oviposition, and the 5 days post initial oviposition. The 5 days post initial oviposition were also examined for feed consumption patterns according to whether or not an individual bird produced an egg on any of those 5 days. In addition, feed consumption was calculated for pullets that did not initiate
FEED (9)
DAYS PRIORTO OVIPOSITION
DAY OF INITIAL OVIPOSITION
DAYS POSTOVIPOSITION
I
81.9
2
I
80.9
3
I
82.7
74.1
4
73.5
3
69.4 73.7
4
I
~
2
1 Mean *Standard error of the mean BPc .05 'P < .001
I
76.9 73.5 f 1.0A
5 79.8 f 2.2B
(g)
1
5
I
=ED
85.0 88.6 83.8 & 1.2'
TABLE 2. Average feed consumption (9)on each of the 5 days post initial oviposition
I
DAYS POSTOVIPOSITION
I
2
x
I
EGG(S) PRODUCED
I
I
82.5 (24)
I
EGG(S)NOT PRODUCED
77.1 (111
I
DIFFERENCE
I
5.4
3
84.0 (27)
78.4 (8)
4
86.1 (28)
fXl.6 (7)
5.5
5
90.0 (32)
73.0 (3)
17.0
86.0 t: 1.4'
78.0 f 2.0
f SEM
BStandarderror of the mean
17.2 pounds1100 birdslday on days when no eggs were produced. Pullets that did not initiate production during the experimentalperiod consumed an average of 15.1 pounds/100 birdlday. The difference in consumption between pullets and layers, and the increase in consumption with time in lay, indicate that average consumption is an incorrect measure for birds in production. Prior to reaching 50% production, birds should receive feed that is formulated at a level which is two pounds higher than the flock average. For example, if the flock is not yet at 50% production, and is
I
5.6
I*Values in parentheses indicate the number of observations used to calculate the averagippl
1
I
I
consuming an average of 18 pounds1100 birdslday, then a less nutrient dense diet of 20 pounds/100 birdslday should be formulated for these birds. Between 50% production and peak, birds should receive feed that is formulated at a level that is one pound higher than average. At peak production and thereafter, the recommended feed formulation should be used. This strategy will result in cost savings because: 1) a higher level of energy will be available to the birds, and energy sources are less expensive than protein sources; and 2) energy deficiencies during hot weather will be minimized.
CONCLUSIONS AND APPLICATIONS 1. Feed consumption differs markedly between pullets yet to initiate lay and those that have
begun production. 2. Increased consumption does not begin until the initial day of oviposition. 3. Consumption varies (after production begins) between days on which eggs are produced and days on which they are not. 4. Feeding the flock average overestimates the nutritional needs of pullets; it may supply too large a quantity of amino acids, which can result in reduced energy intake by laying birds. 5. A flock coming into lay should be given a feed with an amino acid density lower than that formulated for average flock consumption.
REFERENCES AND NOTES l.Harms,RH.,C.RDouglas,RB.Christmas,B.L subsequent performance and liver and abdominal fat at
Damron, and RD. Miles, 1978. Feeding commercial layers for maximum performance. Feedstuffs 50(8):23-24. 2. Harms, RH., and C.R Douglas, 1981. Amino acid s cifications for replacement pullet feeds. Feedstuffs G(9):36-39. 3. Lteson, S., and J.D. Summer, 1982. Use of sine-stage low rotein diets for growing Leghorn pullets. $oultry Sci. 6l!1684-1691. 4. Maurice, D.V., B.L. Hughes, J.E Jones, and J.M. Weber, 1982.Theeffect ofreverse protein andlow protein feeding regimens in the rearing period on pullet growth,
the end of lay. Poultry Sci. 61:2421-2429. 5. Roland, D.A., Sr., D.R Sloan, and R.H. Harms, 1971. An easy and ine ensive system for measuring feed consumption. Poultry%. 501227-1228. 6. Data were subjected to anal is of variance and standard error of means calculated F A S Institute, 1982 SAS user's Guide; Statistics, version 5. SAS Inst., Cary, NC.)
I