- Email: [email protected]
Nutrient Restriction After 21 Weeks of Age and Its Effect on Performance of Leghorn Pullets1
Nutrient Restriction After 21 Weeks of Age and Its Effect on Performance of Leghorn Pulletsl C. R. DOUGLAS, H. R. WILSON, T. S. POWELL2 AND R. H. HARMS
Department of Poultry Science, Florida Agricultural Experiment Station, Gainesville, Florida 32611 (Received for publication July 13, 1976)
POULTRY SCIENCE 56: 506-511, 1977
Wright et al. (1968) used a 9% protein grower diet from 8 to 18 weeks of age for satisfactorily delaying maturity of Leghorn-type pullets. Commercial egg producers occasionally find it advantageous, due to housing difficulty, and other reasons, to delay onset of production in pullets which are approaching sexual maturity. Jackson (1970) reported that feeding free choice corn, hen-size grit and water to pullets from 20 to 30 weeks of age, had no adverse effects upon production, feed conversion, egg quality or egg weight after the birds were placed on a complete laying feed. The work reported herein was undertaken to study the effects of severe nutrient restriction from 21 to 26 or 27 weeks of age upon subsequent laying house performance.
INTRODUCTION
V
ARIOUS methods have been studied to delay sexual maturity of broiler breeders. Couch et al. (1957) reported that if sufficient fiber were included in the feed, pullets would not be able to consume enough energy to meet their requirements, thereby, delaying maturity. A grower diet deficient in lysine was proposed by Singsen et al. (1964) to delay sexual maturity in meat-type pullets, while Waldroup et al. (1966) used a low protein diet successfully to delay maturity. Voitle et al. (1970) found a "skip-a-day" feeding program to be satisfactory for delaying maturity in broiler breeders. While nutrient restriction to delay sexual maturity in Leghorn-type pullets has been shown to give satisfactory results (Lillie and Denton, 1966; Wright et al., 1968), this practice has not been widely accepted nor is there complete agreement as to its overall value.
EXPERIMENTAL PROCEDURE Two experiments were conducted using Kimber K-137 Leghorn-type pullets which were grown from one day to 21 weeks of age in floor pens using peanut hulls as litter. Pullets were hatched in August and Sep-
1. Fla. Agr. Exp. Sta. Journal Series No. 6177. 2. Present address Central Soya Co., Inc., Decatur, Indiana 46733. 506
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
ABSTRACT Two experiments were conducted using Leghorn-type pullets to study the effects of severe feed restriction after 21 weeks of age upon subsequent performance. All pullets were grown from one day to six weeks of age on a 21.6% protein starter diet and from seven to 21 weeks of age on a 14% protein grower diet. At 21 weeks of age, the following four treatments were applied: 1) No feed 1 week; 9% protein grower 4 or 5 weeks; 16% protein layer thereafter. 2) No feed 1 week; 16% protein layer thereafter. 3) Alternate weeks of no feed and 9% protein grower until pullets were 26 or 27 weeks of age then 16% protein layer thereafter. 4) Controls—16% protein layer at 21 weeks of age and thereafter. Sexual maturity, as measured by days of age at 50% egg production was delayed 6.5, 14.5 and 33.5 days with treatments 2, 1 and 3, respectively, when compared to control treatment 4. Withholding feed for one week resulted in an average weight loss of 267 grams (19.2%). Mature body weight was not affected by treatment. There were no significant differences noted in laying hen mortality due to treatment. After the second month of production, no significant differences were found in hen-day egg production through the end of the laying period.
NUTRIENT RESTRICTION OF PULLETS
507
TABLE 1.—Percent composition and calculated analyses of diets Ingredients
Starter 62.85 31.00 2.50 1.00
Low protein (9%) grower 94.15 — 3.00 0.50
Experiment 1 Treatment 1—No feed 1 week; 9% protein grower (Table 1) 5 weeks; 16% protein layer (Table 1) thereafter. Treatment 2—No feed 1 week; 16% protein layer thereafter. Treatment 3—No feed 1 week; 9% protein grower 1 week; No feed 10 days; 9% protein grower 2 weeks; No feed 1 week; 16% protein layer thereafter. Treatment 4—Controls—16% protein layer. Experiment 2 Treatment 1—No feed 1 week; 9% protein grower 4 weeks; 16% protein layer. Treatment 2—No feed 1 week; 16% protein layer. Treatment 3—Alternate weeks of no feed and 9%
protein grower until pullets were 26 weeks of age when placed on 16% protein layer. Treatment 4—Control—16% protein layer. An attempt was made in Experiment 1, Treatment 3, to feed or withhold feed from pullets to produce specific body weights. However, in order to make the experimental plan more simple, in Experiment 2, alternate weeks of feed and no feed were used for Treatment 3. Birds received water ad libitum. Performance was evaluated using egg production, feed intake, body weight, egg weight, age at sexual maturity, and mortality. Where appropriate, the data were subjected to the analysis of variance as outlined by Steele and Torrie (1960) with significant differences among treatment means determined by the multiple range test of Duncan (1955). RESULTS AND DISCUSSION Sexual maturity (age at 50% production) was delayed an average of 6.5 days for both experiments when feed was withheld for one week followed by the layer diet (Table 3). A delay of 14.5 days or two weeks was observed using Treatment 1 when the birds were given no feed for one week then the low protein grower for four or five additional weeks. When feed was withheld every other
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
Layer Yellow corn 69.85 Soybean meal (50% protein) 19.00 Alfalfa meal (20% protein) 2.50 Limestone 6.00 Defluorinated phosphate (18% P; 32% Ca.) 1.90 1.90 1.45 1.90 Iodized salt 0.25 0.25 0.40 0.25 Micro-ingredients' _ 0.50 _ __ 0.50 __ __ 0.50 __ __ 0.50 Crude" prot"ein"(%) 2L6~ i4~0~ 9~3~ 16~3" M.E. kcal./kg. 2944 3133 3274 2893 Calcium (%) 1.10 1.07 0.72 2.86 Total phosphorus (%) 0.73 0.66 0.54 0.75 'Supplies per kg. of diet: 6600 I.U. vit. A; 2200 I.C.U. Vit. D 3 ; 22 meg. vit. B l 2 ; 4.4 mg. riboflavin; 40 mg. niacin; 13 mg. pantothenic acid; 2.2 mg. menadione dimethylpyrimidinol; 499.4 mg. choline chloride; 125 mg. ethoxyquin; 50 mg. iron; 6 mg. copper; 1.1 mg. iodine; 35 mg. zinc; 60 mg. manganese; 198 meg. cobalt. temberfor Experiments 1 and 2, respectively. Heat for the brooding period was supplied by infra-red heat lamps. Feed and water were supplied ad libitum. A 21.6% protein starter diet was fed for the first six weeks with a 14% protein grower diet being fed from six to 21 weeks of age (Table 1). Natural light was unsupplemented during the growing period. Pullets were housed at 21 weeks of age in 25.4 x 45.7 cm. cages with two birds per cage. Seven and six replicates of 10 birds each were used in Experiment 1 and 2, respectively. Experimental treatments (Table 2) were applied at 21 weeks of age as follows:
Grower 81.60 12.25 2.50 1.00
508
DOUGLAS, WILSON, POWELL AND HARMS
TABLE 2.—Feeding regime of pullets subjected to various dietary restriction treatments' Treatments
21
Weeks of age 24
22
23
25
26
27
G L G L
G L N L
L L L L
(Experiment 2) G L G L
G L N L
L L L L
L L L L
1 2 3 4
N N N L
G L G L
(Experiment 1) G G L L 2 N G L L
1 2 3 4
N N N L
G L G L
G L N L
TABLE 3.—Sexual maturity and egg production of pullets subjected to various dietary restriction treatments Egg production (% hen day)' Exp, . 2
Days to 50% production
Exp. 1
Treatments 2
Exp. 1
Exp. 2
12 Periods 3
3-12 Periods
10 Periods
3-10 Periods
1 2 3 4
181 177 204 172
188 176 203 168
54.9b 56.6ab 52.2b 61.9a
61.3a 60.2a 62.8a 64.4a
64.5a 66.6a 61.0a 68.5a
72.2a 73.9a 74.2a 72.7a
1 Means within the same column having 2 See Table 2 for treatment description. 3
different letters are significantly different (P < .05).
Each period = 28 days.
TABLE 4.—Egg weights of birds subjected to various dietary restriction treatments (Experiment 2)' Weeks of age Treatment 3
26
30
34
38
42
46
1 2 3 4
44.0b 51.0a
54.6b 55.0b 55.8ab 56.9a
57.0 56.5 56.8 57.5
57.0 56.0 57.1 58.0
58.0 56.7 58.0 59.9
58.1 57.1 58.4 59.2
52.3a
1 Each value is 2 Means within 3
the average of all eggs laid on two consecutive days. the same column having different letters are significantly different (P < .05). See Table 2 for treatment descriptions.
week alternating with low protein grower (Treatment 3), a few birds began laying approximately three days after being given feed; however, when feed was again withheld production ceased in about three days. This resulted in a delay in reaching 50% production of 33.5 days or approximately 5 weeks. Rate of increase in production was essentially the same for all treatment groups when all birds were placed on the 16% layer diet. This
suggests that even though a few birds on a low nutritional level lay for a brief period, continuous production could be delayed for as long as desired by use of alternate weeks of no feed and a low protein feed. In Experiment 1, egg production through 12 periods was significantly higher for the controls than for the birds given the grower after 21 weeks of age (Table 3). While the trend was the same in Experiment 2, dif-
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
•N = No feed; G = 9% Protein Grower; L = 16% Protein Layer. This period was for 10 days while all other periods were for 7 days.
2
509
NUTRIENT RESTRICTION OF PULLETS
1700
r
1500
-
1300
22
23
24
Age
25
26
27
o
Treatment 2
A
Treatment 3
o
Treatment 4
•
28
(weeks)
FIG. 1. Average body weight of pullets subjected to various dietary restriction treatments (See Table 2). (Experiment 1).
1700
r
21
22
23
24
25
26
27
Treatment
1
o
Treatment
2
*
Treatment
3
a
Treatment
4
•
28
Age (weeks) FIG. 2. Average body weight of pullets subjected to various dietary restriction treatments. (Experiment 2).
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
21
Treatment 1
510
DOUGLAS, WILSON, POWELL AND HARMS
TABLE 5.—Feed efficiency (grams feed/egg) of birds subjected to various dietary restriction treatments (Experiment 2) Treatments 2
Laying periods'
1
2
3
4
1-10 3-10
148 136
139 132
145 131
140 133
1 2
Each period = 28 days. See Table 2 for treatment descriptions.
Withholding feed for one week resulted in body weight loss of 267 grams (Fig. 1 and Fig. 2). By the 28th week, body weight of birds subjected to Treatment 1, 2 and 3 were essentially the same with the control birds remaining heavier (Fig. 2). It is suggested that the heavier body weight of the control birds was responsible for the increase in egg weights. This is consistent with recent findings of Douglas and Harms (1976), who reported that birds with heavier body weights at 20 weeks of age laid heavier eggs throughout the laying period. In Experiment 2, due to severe feed restriction, birds on Treatment 3 had consumed only 59 grams of feed per bird per day from
REFERENCES Couch, J. R., R. E. Isaacks, B. L. Reid, W. P. Crawford and J. H. Quisenberry, 1957. Feeding and management of replacement broiler stock. Feed Age, 7(10): 34. Douglas, C. R., and R. H. Harms, 1976. The influence
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
ferences were not statistically significant. When the first two laying periods were omitted, production was essentially the same for all treatments. In Experiment 1 when the birds were 29 weeks of age, a significantly lower egg weight was found for birds on Treatment 3 (53.3, 54.9, 48.0 and 53.5 grams, respectively, for Treatments 1 through 4). In order to more critically evaluate the influence of treatment on egg weight, data were collected in Experiment 2 for a greater number of periods (Table 4). Although the control birds laid heavier eggs than the restricted birds, the differences were not significant after 30 weeks of age. The delay in maturity resulting from alternate weeks without feed eliminated most small and medium eggs through 26 weeks. This could be an important economic factor when small eggs are selling at below cost.
22 through 29 weeks while the average consumption of all other birds was 88 grams. This was about 30 percent less feed than that consumed by birds on the other treatments. This lowered feed intake was a result of birds having access to feed every other week. The fact that feed intake was reduced by only 30% would indicate that they overconsumed on the weeks when feed was given. This allowed birds to gain rapidly after 26 weeks of age and explains the reason for body weight being essentially equal at 28 weeks of age. It was possible to determine feed intake by treatment only, therefore no statistical analysis was possible. When the entire laying period was considered in Experiment 2, feed efficiency was somewhat poorer for birds on Treatment 3 than for the controls (Table 5). However, when the first two laying periods were omitted, the situation was reversed with controls showing slightly poorer feed conversion than birds on Treatment 3. This would be expected since egg production followed this same pattern. There were no significant differences in mortality among treatment groups in either experiment. Results from these studies indicate that sexual maturity can satisfactorily be delayed in Leghorn-type pullets by using alternate weekly periods of withholding feed with weekly periods of feeding a low protein feed, after pullets have reached 21 weeks of age. The reduction in numbers of undersized eggs should be economically beneficial in periods when prices for these sizes are especially low. The system should also be a beneficial management tool when unexpected delay in onset of egg production is desired.
511
NUTRIENT RESTRICTION OF PULLETS
and Procedures of Statistics. McGraw-Hill Book Co., Inc. New York, N.Y. Voitle, R. A., H. R. Wilson and R. H. Harms, 1970. The effect of body weight restriction of broiler breeder pullets on subsequent performance. Poultry Sci. 49: 1448. 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: 393-402. Wright, C. F., B. L. Damron, P. W. Waldroup and R. H. Harms, 1968. The performance of laying hens fed normal and low protein diets between 8 and 18 weeks of age. Poultry Sci. 47: 635-638.
The Chick's Requirement for 25-Hydroxycholecalciferol and Cholecalciferolx JAMES L .
M C N A U G H T O N , 2 ELBERT J. DAY AND B E N C.
DILWORTH
Poultry Science Department, Mississippi Agricultural and Forestry Experiment Station, State University, Mississippi State, MS 39762
Mississippi
(Received for publication July 16, 1976)
ABSTRACT Three experiments were conducted to compare the effect of 25-hydroxycholecalciferol (25-OHDj) and cholecalciferol (D3) on three week weight gains, feed utilization and tibia ash of broiler cockerels. In Experiment 1, vitamin D levels of 198 and 330 I.C.U./kg. from both vitamin D sources were fed at phosphorus levels of .40%, .45%, .50% and .55% furnished by sodium phosphate monobasic (SPM). Feeding 25-OHD3 compared to D 3 significantly increased tibia ash if phosphorus levels were below .45%. No significant differences in tibia ash were found due to phosphorus levels when 25-OHD3 was fed; however, when D 3 was fed a significantly larger tibia ash was found by feeding phosphorus above .40%. Chicks in Experiment 2 were fed .45% total phosphorus with either SPM or defluorinated phosphate as the phosphorus source and 25-OHD3 or D 3 at dietary levels of 198 or 330 I.C.U./kg. Chicks fed SPM with either vitamin D source had improved weight gains and tibia ash if the diet contained a vitamin D level of 198 I.C.U./kg. Phosphorus source responses were equal if the diet contained 330 I.C.U./kg. of vitamin D. In Experiment 3, both vitamin D sources were fed at dietary levels of 66, 132, 198, 330 and 396 I.C.U./kg. in diets containing .45% total phosphorus with defluorinated phosphate as the phosphorus source. Tibia ash statistically equal to the maximum response was achieved with 132 I.C.U./kg. of 25-OHD3or 198 I.C.U./kg. of D3. The potency of 25-OHD3 was found to be 1.5 times greater than D 3 based on requirement levels of both vitamin D sources. POULTRY SCIENCE 56: 511-516,
INTRODUCTION
V
ARIOUS biologically active metabolites of cholecalciferol have been isolated
1. Journal article number 3342 from M.A.F.E.S. 2. Present address, U.S.D.A. South Central Poultry Research Laboratory, Box 5367, Mississippi State, Mississippi 39762.
1977
(Blunt et al., 1968a; DeLuca, 1973; Holick et al., 1971; and Suda et al., 1970a). The molecular structure of these metabolities are 25-hydroxycholecalciferol (25-OHD 3 ); 24, 25-dihydroxycholecalciferol; 25, 26-dihydroxycholecalciferol; and 1, 25-dihydroxycholecalciferol. Blunt et al. (1968b) found 25-OHDj to be more active than cholecalciferol (D 3 ) in promoting intestinal calcium
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
of protein level of the grower diet upon subsequent egg size. Poultry Sci. 55: 1593. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Jackson, D., 1970. All corn diet for layers. Animal Nutrition and Health, 25: 8. Lillie, R. J., and C. A. Denton, 1966. Effect of nutrient restriction on White Leghorns in the grower and subsequent layer periods. Poultry Sci. 45: 810-818. Singsen, E. P., J. Nagel, S. G. Patrick and L. D. Matterson, 1964. The effect of a lysine deficiency on growth characteristics, age at sexual maturity, and reproductive performance of meat-type pullets. Poultry Sci. 43: 1362. Steel, R. G. D., and J. H. Torrie, 1960. Principles
Department of Poultry Science, Florida Agricultural Experiment Station, Gainesville, Florida 32611 (Received for publication July 13, 1976)
POULTRY SCIENCE 56: 506-511, 1977
Wright et al. (1968) used a 9% protein grower diet from 8 to 18 weeks of age for satisfactorily delaying maturity of Leghorn-type pullets. Commercial egg producers occasionally find it advantageous, due to housing difficulty, and other reasons, to delay onset of production in pullets which are approaching sexual maturity. Jackson (1970) reported that feeding free choice corn, hen-size grit and water to pullets from 20 to 30 weeks of age, had no adverse effects upon production, feed conversion, egg quality or egg weight after the birds were placed on a complete laying feed. The work reported herein was undertaken to study the effects of severe nutrient restriction from 21 to 26 or 27 weeks of age upon subsequent laying house performance.
INTRODUCTION
V
ARIOUS methods have been studied to delay sexual maturity of broiler breeders. Couch et al. (1957) reported that if sufficient fiber were included in the feed, pullets would not be able to consume enough energy to meet their requirements, thereby, delaying maturity. A grower diet deficient in lysine was proposed by Singsen et al. (1964) to delay sexual maturity in meat-type pullets, while Waldroup et al. (1966) used a low protein diet successfully to delay maturity. Voitle et al. (1970) found a "skip-a-day" feeding program to be satisfactory for delaying maturity in broiler breeders. While nutrient restriction to delay sexual maturity in Leghorn-type pullets has been shown to give satisfactory results (Lillie and Denton, 1966; Wright et al., 1968), this practice has not been widely accepted nor is there complete agreement as to its overall value.
EXPERIMENTAL PROCEDURE Two experiments were conducted using Kimber K-137 Leghorn-type pullets which were grown from one day to 21 weeks of age in floor pens using peanut hulls as litter. Pullets were hatched in August and Sep-
1. Fla. Agr. Exp. Sta. Journal Series No. 6177. 2. Present address Central Soya Co., Inc., Decatur, Indiana 46733. 506
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
ABSTRACT Two experiments were conducted using Leghorn-type pullets to study the effects of severe feed restriction after 21 weeks of age upon subsequent performance. All pullets were grown from one day to six weeks of age on a 21.6% protein starter diet and from seven to 21 weeks of age on a 14% protein grower diet. At 21 weeks of age, the following four treatments were applied: 1) No feed 1 week; 9% protein grower 4 or 5 weeks; 16% protein layer thereafter. 2) No feed 1 week; 16% protein layer thereafter. 3) Alternate weeks of no feed and 9% protein grower until pullets were 26 or 27 weeks of age then 16% protein layer thereafter. 4) Controls—16% protein layer at 21 weeks of age and thereafter. Sexual maturity, as measured by days of age at 50% egg production was delayed 6.5, 14.5 and 33.5 days with treatments 2, 1 and 3, respectively, when compared to control treatment 4. Withholding feed for one week resulted in an average weight loss of 267 grams (19.2%). Mature body weight was not affected by treatment. There were no significant differences noted in laying hen mortality due to treatment. After the second month of production, no significant differences were found in hen-day egg production through the end of the laying period.
NUTRIENT RESTRICTION OF PULLETS
507
TABLE 1.—Percent composition and calculated analyses of diets Ingredients
Starter 62.85 31.00 2.50 1.00
Low protein (9%) grower 94.15 — 3.00 0.50
Experiment 1 Treatment 1—No feed 1 week; 9% protein grower (Table 1) 5 weeks; 16% protein layer (Table 1) thereafter. Treatment 2—No feed 1 week; 16% protein layer thereafter. Treatment 3—No feed 1 week; 9% protein grower 1 week; No feed 10 days; 9% protein grower 2 weeks; No feed 1 week; 16% protein layer thereafter. Treatment 4—Controls—16% protein layer. Experiment 2 Treatment 1—No feed 1 week; 9% protein grower 4 weeks; 16% protein layer. Treatment 2—No feed 1 week; 16% protein layer. Treatment 3—Alternate weeks of no feed and 9%
protein grower until pullets were 26 weeks of age when placed on 16% protein layer. Treatment 4—Control—16% protein layer. An attempt was made in Experiment 1, Treatment 3, to feed or withhold feed from pullets to produce specific body weights. However, in order to make the experimental plan more simple, in Experiment 2, alternate weeks of feed and no feed were used for Treatment 3. Birds received water ad libitum. Performance was evaluated using egg production, feed intake, body weight, egg weight, age at sexual maturity, and mortality. Where appropriate, the data were subjected to the analysis of variance as outlined by Steele and Torrie (1960) with significant differences among treatment means determined by the multiple range test of Duncan (1955). RESULTS AND DISCUSSION Sexual maturity (age at 50% production) was delayed an average of 6.5 days for both experiments when feed was withheld for one week followed by the layer diet (Table 3). A delay of 14.5 days or two weeks was observed using Treatment 1 when the birds were given no feed for one week then the low protein grower for four or five additional weeks. When feed was withheld every other
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
Layer Yellow corn 69.85 Soybean meal (50% protein) 19.00 Alfalfa meal (20% protein) 2.50 Limestone 6.00 Defluorinated phosphate (18% P; 32% Ca.) 1.90 1.90 1.45 1.90 Iodized salt 0.25 0.25 0.40 0.25 Micro-ingredients' _ 0.50 _ __ 0.50 __ __ 0.50 __ __ 0.50 Crude" prot"ein"(%) 2L6~ i4~0~ 9~3~ 16~3" M.E. kcal./kg. 2944 3133 3274 2893 Calcium (%) 1.10 1.07 0.72 2.86 Total phosphorus (%) 0.73 0.66 0.54 0.75 'Supplies per kg. of diet: 6600 I.U. vit. A; 2200 I.C.U. Vit. D 3 ; 22 meg. vit. B l 2 ; 4.4 mg. riboflavin; 40 mg. niacin; 13 mg. pantothenic acid; 2.2 mg. menadione dimethylpyrimidinol; 499.4 mg. choline chloride; 125 mg. ethoxyquin; 50 mg. iron; 6 mg. copper; 1.1 mg. iodine; 35 mg. zinc; 60 mg. manganese; 198 meg. cobalt. temberfor Experiments 1 and 2, respectively. Heat for the brooding period was supplied by infra-red heat lamps. Feed and water were supplied ad libitum. A 21.6% protein starter diet was fed for the first six weeks with a 14% protein grower diet being fed from six to 21 weeks of age (Table 1). Natural light was unsupplemented during the growing period. Pullets were housed at 21 weeks of age in 25.4 x 45.7 cm. cages with two birds per cage. Seven and six replicates of 10 birds each were used in Experiment 1 and 2, respectively. Experimental treatments (Table 2) were applied at 21 weeks of age as follows:
Grower 81.60 12.25 2.50 1.00
508
DOUGLAS, WILSON, POWELL AND HARMS
TABLE 2.—Feeding regime of pullets subjected to various dietary restriction treatments' Treatments
21
Weeks of age 24
22
23
25
26
27
G L G L
G L N L
L L L L
(Experiment 2) G L G L
G L N L
L L L L
L L L L
1 2 3 4
N N N L
G L G L
(Experiment 1) G G L L 2 N G L L
1 2 3 4
N N N L
G L G L
G L N L
TABLE 3.—Sexual maturity and egg production of pullets subjected to various dietary restriction treatments Egg production (% hen day)' Exp, . 2
Days to 50% production
Exp. 1
Treatments 2
Exp. 1
Exp. 2
12 Periods 3
3-12 Periods
10 Periods
3-10 Periods
1 2 3 4
181 177 204 172
188 176 203 168
54.9b 56.6ab 52.2b 61.9a
61.3a 60.2a 62.8a 64.4a
64.5a 66.6a 61.0a 68.5a
72.2a 73.9a 74.2a 72.7a
1 Means within the same column having 2 See Table 2 for treatment description. 3
different letters are significantly different (P < .05).
Each period = 28 days.
TABLE 4.—Egg weights of birds subjected to various dietary restriction treatments (Experiment 2)' Weeks of age Treatment 3
26
30
34
38
42
46
1 2 3 4
44.0b 51.0a
54.6b 55.0b 55.8ab 56.9a
57.0 56.5 56.8 57.5
57.0 56.0 57.1 58.0
58.0 56.7 58.0 59.9
58.1 57.1 58.4 59.2
52.3a
1 Each value is 2 Means within 3
the average of all eggs laid on two consecutive days. the same column having different letters are significantly different (P < .05). See Table 2 for treatment descriptions.
week alternating with low protein grower (Treatment 3), a few birds began laying approximately three days after being given feed; however, when feed was again withheld production ceased in about three days. This resulted in a delay in reaching 50% production of 33.5 days or approximately 5 weeks. Rate of increase in production was essentially the same for all treatment groups when all birds were placed on the 16% layer diet. This
suggests that even though a few birds on a low nutritional level lay for a brief period, continuous production could be delayed for as long as desired by use of alternate weeks of no feed and a low protein feed. In Experiment 1, egg production through 12 periods was significantly higher for the controls than for the birds given the grower after 21 weeks of age (Table 3). While the trend was the same in Experiment 2, dif-
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
•N = No feed; G = 9% Protein Grower; L = 16% Protein Layer. This period was for 10 days while all other periods were for 7 days.
2
509
NUTRIENT RESTRICTION OF PULLETS
1700
r
1500
-
1300
22
23
24
Age
25
26
27
o
Treatment 2
A
Treatment 3
o
Treatment 4
•
28
(weeks)
FIG. 1. Average body weight of pullets subjected to various dietary restriction treatments (See Table 2). (Experiment 1).
1700
r
21
22
23
24
25
26
27
Treatment
1
o
Treatment
2
*
Treatment
3
a
Treatment
4
•
28
Age (weeks) FIG. 2. Average body weight of pullets subjected to various dietary restriction treatments. (Experiment 2).
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
21
Treatment 1
510
DOUGLAS, WILSON, POWELL AND HARMS
TABLE 5.—Feed efficiency (grams feed/egg) of birds subjected to various dietary restriction treatments (Experiment 2) Treatments 2
Laying periods'
1
2
3
4
1-10 3-10
148 136
139 132
145 131
140 133
1 2
Each period = 28 days. See Table 2 for treatment descriptions.
Withholding feed for one week resulted in body weight loss of 267 grams (Fig. 1 and Fig. 2). By the 28th week, body weight of birds subjected to Treatment 1, 2 and 3 were essentially the same with the control birds remaining heavier (Fig. 2). It is suggested that the heavier body weight of the control birds was responsible for the increase in egg weights. This is consistent with recent findings of Douglas and Harms (1976), who reported that birds with heavier body weights at 20 weeks of age laid heavier eggs throughout the laying period. In Experiment 2, due to severe feed restriction, birds on Treatment 3 had consumed only 59 grams of feed per bird per day from
REFERENCES Couch, J. R., R. E. Isaacks, B. L. Reid, W. P. Crawford and J. H. Quisenberry, 1957. Feeding and management of replacement broiler stock. Feed Age, 7(10): 34. Douglas, C. R., and R. H. Harms, 1976. The influence
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
ferences were not statistically significant. When the first two laying periods were omitted, production was essentially the same for all treatments. In Experiment 1 when the birds were 29 weeks of age, a significantly lower egg weight was found for birds on Treatment 3 (53.3, 54.9, 48.0 and 53.5 grams, respectively, for Treatments 1 through 4). In order to more critically evaluate the influence of treatment on egg weight, data were collected in Experiment 2 for a greater number of periods (Table 4). Although the control birds laid heavier eggs than the restricted birds, the differences were not significant after 30 weeks of age. The delay in maturity resulting from alternate weeks without feed eliminated most small and medium eggs through 26 weeks. This could be an important economic factor when small eggs are selling at below cost.
22 through 29 weeks while the average consumption of all other birds was 88 grams. This was about 30 percent less feed than that consumed by birds on the other treatments. This lowered feed intake was a result of birds having access to feed every other week. The fact that feed intake was reduced by only 30% would indicate that they overconsumed on the weeks when feed was given. This allowed birds to gain rapidly after 26 weeks of age and explains the reason for body weight being essentially equal at 28 weeks of age. It was possible to determine feed intake by treatment only, therefore no statistical analysis was possible. When the entire laying period was considered in Experiment 2, feed efficiency was somewhat poorer for birds on Treatment 3 than for the controls (Table 5). However, when the first two laying periods were omitted, the situation was reversed with controls showing slightly poorer feed conversion than birds on Treatment 3. This would be expected since egg production followed this same pattern. There were no significant differences in mortality among treatment groups in either experiment. Results from these studies indicate that sexual maturity can satisfactorily be delayed in Leghorn-type pullets by using alternate weekly periods of withholding feed with weekly periods of feeding a low protein feed, after pullets have reached 21 weeks of age. The reduction in numbers of undersized eggs should be economically beneficial in periods when prices for these sizes are especially low. The system should also be a beneficial management tool when unexpected delay in onset of egg production is desired.
511
NUTRIENT RESTRICTION OF PULLETS
and Procedures of Statistics. McGraw-Hill Book Co., Inc. New York, N.Y. Voitle, R. A., H. R. Wilson and R. H. Harms, 1970. The effect of body weight restriction of broiler breeder pullets on subsequent performance. Poultry Sci. 49: 1448. 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: 393-402. Wright, C. F., B. L. Damron, P. W. Waldroup and R. H. Harms, 1968. The performance of laying hens fed normal and low protein diets between 8 and 18 weeks of age. Poultry Sci. 47: 635-638.
The Chick's Requirement for 25-Hydroxycholecalciferol and Cholecalciferolx JAMES L .
M C N A U G H T O N , 2 ELBERT J. DAY AND B E N C.
DILWORTH
Poultry Science Department, Mississippi Agricultural and Forestry Experiment Station, State University, Mississippi State, MS 39762
Mississippi
(Received for publication July 16, 1976)
ABSTRACT Three experiments were conducted to compare the effect of 25-hydroxycholecalciferol (25-OHDj) and cholecalciferol (D3) on three week weight gains, feed utilization and tibia ash of broiler cockerels. In Experiment 1, vitamin D levels of 198 and 330 I.C.U./kg. from both vitamin D sources were fed at phosphorus levels of .40%, .45%, .50% and .55% furnished by sodium phosphate monobasic (SPM). Feeding 25-OHD3 compared to D 3 significantly increased tibia ash if phosphorus levels were below .45%. No significant differences in tibia ash were found due to phosphorus levels when 25-OHD3 was fed; however, when D 3 was fed a significantly larger tibia ash was found by feeding phosphorus above .40%. Chicks in Experiment 2 were fed .45% total phosphorus with either SPM or defluorinated phosphate as the phosphorus source and 25-OHD3 or D 3 at dietary levels of 198 or 330 I.C.U./kg. Chicks fed SPM with either vitamin D source had improved weight gains and tibia ash if the diet contained a vitamin D level of 198 I.C.U./kg. Phosphorus source responses were equal if the diet contained 330 I.C.U./kg. of vitamin D. In Experiment 3, both vitamin D sources were fed at dietary levels of 66, 132, 198, 330 and 396 I.C.U./kg. in diets containing .45% total phosphorus with defluorinated phosphate as the phosphorus source. Tibia ash statistically equal to the maximum response was achieved with 132 I.C.U./kg. of 25-OHD3or 198 I.C.U./kg. of D3. The potency of 25-OHD3 was found to be 1.5 times greater than D 3 based on requirement levels of both vitamin D sources. POULTRY SCIENCE 56: 511-516,
INTRODUCTION
V
ARIOUS biologically active metabolites of cholecalciferol have been isolated
1. Journal article number 3342 from M.A.F.E.S. 2. Present address, U.S.D.A. South Central Poultry Research Laboratory, Box 5367, Mississippi State, Mississippi 39762.
1977
(Blunt et al., 1968a; DeLuca, 1973; Holick et al., 1971; and Suda et al., 1970a). The molecular structure of these metabolities are 25-hydroxycholecalciferol (25-OHD 3 ); 24, 25-dihydroxycholecalciferol; 25, 26-dihydroxycholecalciferol; and 1, 25-dihydroxycholecalciferol. Blunt et al. (1968b) found 25-OHDj to be more active than cholecalciferol (D 3 ) in promoting intestinal calcium
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
of protein level of the grower diet upon subsequent egg size. Poultry Sci. 55: 1593. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Jackson, D., 1970. All corn diet for layers. Animal Nutrition and Health, 25: 8. Lillie, R. J., and C. A. Denton, 1966. Effect of nutrient restriction on White Leghorns in the grower and subsequent layer periods. Poultry Sci. 45: 810-818. Singsen, E. P., J. Nagel, S. G. Patrick and L. D. Matterson, 1964. The effect of a lysine deficiency on growth characteristics, age at sexual maturity, and reproductive performance of meat-type pullets. Poultry Sci. 43: 1362. Steel, R. G. D., and J. H. Torrie, 1960. Principles