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Effect of Restricted Feeding During the Growing Period on Reproductive Performance of Large Type White Turkeys1
Effect of Restricted Feeding During the Growing Period on Reproductive Performance of Large Type White Turkeys 1 D. L. ANDERSON, J. R. SMYTH, JR. AND R. E. GLEASON2 Department of Poultry Science, University of Massachusetts, Amherst, Massachusetts (Received for publication May 28, 1962)
/CONSIDERABLE interest in recent * ^ years has centered around feeding systems which bring about a decrease in the plane of nutrition either through the restriction of a "complete" ration or the full feeding of an "incomplete" ration at some interval during the growing period. The value of these systems in feeding replacement chickens and their secondary effects on subsequent production and reproduction has been explored by several groups of investigators (Schneider et al., 1955; Sunde et al., 1954; Milby and Sherwood, 1956; Isaacks et al., 1960; and Hollands and Gowe, 1961). In general it has been demonstrated that the body weight of growing pullets is reduced, the onset of sexual maturity delayed from two to four weeks and laying house mortality reduced as a result of lowering total feed intake. These studies do not indicate consistent effects of restrictive feeding on final body weight, total feed consumption, total eggs produced, egg size, and fertility and hatchability. Similarly, there is interest in the effects of restricting the feed intake of growing turkeys on body weight of breeding stock and their subsequent reproductive performance. The early report of Scott and Payne (1941) indicated that limiting the feed in-
take of Bronze turkey females to 61 or 78% of ad libitum from 26 weeks to sexual maturity (governed by natural daylight) had no effect on maintaining body weight after the first three weeks of the breeding season. Neither egg numbers nor hatchability was influenced by reducing the feed intake to 78% of the full feed group. Feed restricted to 61% of ad libitum resulted in significantly reduced hatchability. Milby (1958) fed a low energy prebreeder ration to 26-week-old Broad Breasted White turkeys for 58 days and found a highly significant reduction in female body weight. Feed intake and cost per bird per month were, however, considerably lower for the high energy feeding program. No significant effects on subsequent egg production or hatchability were observed. Recently, Mitchell et al. (1962) reported on a similar trial in which 2 3-week-old Broad Breasted Bronze females were fed restricted quantities of a basal diet and the basal diet adjusted to contain 12% of crude fiber. Results from this study indicated no effects on total egg production, mortality, fertility or hatchability of fertile eggs. A similar lack of effect was observed with turkey hens fed ad libitum where crude fiber levels were increased to either 15 or 20% and protein concurrently reduced to 12%. The present investigation was undertaken to determine the effects of reducing the total nutrient intake of large type white turkeys at different intervals during early and late growth on subsequent feed con-
1
Contribution No. 35 from the Massachusetts Agricultural Experiment Station, Amherst, Massachusetts. "Present address: Department of Poultry Science, Texas A & M College, College Station, Texas.
8
RESTRICTED FEEDING OF TURKEYS
sumption, body weight changes, body conformation, age at sexual maturity, egg production, fertility and hatchability of fertile eggs. PROCEDURE Two replicate groups totaling 495 large type white turkey poults from the University breeding flock were used in this study. They were hatched on April 8, 1958 (replicate 1) and May 29, 1958 (replicate 2) and were brooded to 10 weeks of age with gas brooder stoves on wood shavings litter. A commercial 28% protein turkey starter ration was fed during this period. At this time the birds in each replicate were assigned to adjoining gravel ranges on the basis of body weight and sex. Range size was adjusted to allow 15 square feet of yard space per bird. At 12 weeks the birds were again weighed and assigned to ad libitum or restricted feeding treatment groups. Each treatment group in replicate 1 was comprised of 75 male and 60 female poults and replicate 2 was comprised of 60 males and 55 females per group. The pelleted complete 20% protein growing ration shown in Table 1 was fed to both replicates from 12 to 24 weeks. With the exception of energy level, this ration was formulated to contain adequate amounts of nutrients required by the growing turkey even at feed intake levels 25% below ad libitum. It was decided to attempt to limit feed intake for restricted groups to 85% of normal consumption. Two different restriction procedures were evaluated. The first procedure tried was based on a percentage of predicted intake taken from existing feed consumption and body weight tables for poults of similar age and size. This procedure proved inadequate when the actual consumption of the ad libitum was compared to the expected. The second approach, and the one adopted for use
TABLE 1.—Composition of diets Ingredients Ground yellow corn Pulverized oats Stabilized animal fat Soybean oil meal (44% protein) Menhaden fish meal (60% protein) Meat and bone scrap (50% protein) Corn distillers dried solubles Dried brewers yeast Alfalfa meal (17% protein) Ground limestone Dicalcium phosphate Manganese sulfate (feed grade) Iodized salt Dry vitamin A (10,000 I.U./gm.) Dry vitamin D3 (3,000 I.U./gm.) DL-Methionine (feed grade) Vitamin E supplement (20,000 I.U./lb.) 4-Nitrophenylarsonic acid (Histostat R )
Grower
Breeder
%
%
56.0
58.0 5.0
2.0 20.0
15.0
5.0
5.0
0 0 0 0 5 25
2.5 2.5 2.5 3.0 3.5 1.5
0.019 0.5
0.0125 0.5
0.11
0.125
0.03 0.0125
0.05
0.05
0.10
0.025
—
Riboflavin mg./lb. 1.3 Niacin mg./lb. 20.0 D-Pantothenic acid mg./lb. 3.0 Choline chloride mg./lb. 238.5 Vitamin B12 mcg./lb. 4.5 Folic acid mcg./ib. — Procaine penicillin mg./lb. 3.0 Vitamin K mg./lb. 0.5
2.0 20.0 4.0 181.6 6.0 60.0
— —
throughout this study for the restricted intake groups, was based on a variable percentage (85-100%) of the previous week's intake of the corresponding ad libitum group. The exact percentage used was extrapolated from a prediction curve representing the weekly percentage increase in feed intake of the ad libitum control. Additional consideration was also given to the stage of growth and environmental temperature. Since feed corrections were made on a weekly basis, the normally increasing consumption of the ad libitum group could then be compensated for to the extent that the over-all restriction level approached the desired 85%. To enable all birds to eat simultaneously, 8 linear inches of feeder
10
D. L. ANDERSON, J. R. SMYTH, JR. AND R. E. GLEASON
TABLE 2.—Effect of feed restriction on body weight and total feed consumption of 24-week-old male and female large type white turkeys
Treatments
Mean body wt.* (lb
Mean cumm. feed
Males
Females
(lbs.)
2t
24.8 25.5
15.8 16.8
53.8 61.3
Mean
25.2
16.3
57.6
21.1 21.8
14.8 15.6
45.0 49.8
21.4
15.2
47.4
Replicate groups i**
Ad libitum
1 2
Restricted
Mean
* Mean weight of both replicates at 12 weeks; males, 9.6 lbs.; females, 7.3 lbs. ** July 2-September 24, 1958. t August 21-November 13, 1958.
space was supplied per bird in the restricted groups and one-half of the daily feed allotment was fed in the morning (9:00 A.M.) and the remainder in the afternoon (3:00 P.M.). Body weight data were collected at 4week intervals starting at 10 weeks of age, and breast width, shank length and body depth measurements were made at 24 weeks. Due to lack of pen space it was necessary to eliminate replicate 2 from the study at this time. The females from replicate 1 were transferred from range at 24 weeks and subdivided on the basis of body weight and previous treatment into 3 blocks of 4 groups containing 9 birds each. They were then placed in open-front breeder pens allowing 10 square feet of floor space per bird and assigned to the following experimental treatments: Percentage of ad libitum feed intake 12-24 wks. 24-40 wks. Treatment Treatment Treatment Treatment
A: B: C: D:
100 100 85 85
100 85 100 85
A representative sample of 20 males from both treatment groups in replicate 1
was similarly housed and placed on ad libitum feeding. At 25 weeks of age they were exposed to 14 hours of light daily. Following two weeks on this light program attempts to collect semen were initiated and continued at weekly intervals until 31 weeks of age to determine the average age of first measurable semen sample. These data were used as a measure of age at sexual maturity in this study. The pelleted complete grower ration was replaced at 40 weeks by the complete allmash breeder ration (Table 1) which was fed to all treatment groups ad libitum until the end of the trial on June 3. Artificial lighting was supplied to the females on January 16, 1959 to equal a total of 14 hours of light daily. All pens were trapnested 7 days a week and egg production, fertility and hatchability records were collected. The birds were artificially inseminated with pooled semen samples from a randomized lot of treatment group males at approximately 3 to 4-week intervals. Eggs were saved for 10 days prior to the scheduled setting dates. Feed consumption records were obtained bi-weekly and body weight data monthly throughout the breeding season. Variance analyses were employed in conjunction with appropriate transformation procedures on the percentage data according to the methods outlined by Snedecor (1956). EXPERIMENTAL RESULTS
The effects of restricting the total feed intake of growing turkeys from 12 to 24 weeks on mean body weight and total feed consumption are shown in Table 2. Feed intake levels of 83.6% of ad libitum in replicate 1 and 81.2% in replicate 2 resulted in a statistically significant reduction in body weight at 24 weeks. Although the restricted group in replicate 2 was subjected to a slightly greater percentage reduction in total feed intake, the absolute
RESTRICTED FEEDING OF TURKEYS TABLE 3.—Effect
Body Measure (cm.)
11
of feed restriction on body conformation at 24 weeks in large type white male and female turkeys Male
Female
Replicate Groups
Ad libitum
Restricted
Ad libitum
Restricted
1 2
16.5 17.3
16.3 16.8
13.2 13.7
13.0 13.7
Mean
16.9
16.6
13.4
13.4
1 2
23.7 23.0
22.8 21.7
18.7 17.8
19.0 17.4
Mean
23.4
22.2
18.2
18.2
1 2
11.4 13.0
9.6 11.4
10.4 13.0
9.6 12.2
Mean
12.2
10.5
11.7
10.9
Shank length
Body depth
Breast width
quantity consumed was 10.7% greater than replicate 1 due in part to the normally decreasing fall temperatures in this latitude. This was undoubtedly a factor which contributed to the significant differences found in mean body weights between replicates at 24 weeks. Unfortunately there was a greater degree of apparent feed restriction imposed on the males than on the females as indicated by a significant treatment-sex interaction and evidenced by the 15.1% and 6.8% lower body weights in the restricted groups for the males and females respectively. Variance analyses of the body conformation data summarized in Table 3 revealed a significant (P < .05) depression in breast width of both males and females in the restricted intake groups. No significant treatment effects on shank length or body depth,
criteria used as indicators of skeletal development, were observed in either replicate. In an attempt to determine the influence of restricted feed intake during different growth intervals on productive and reproductive performance, the females from replicate 1 were subjected to the design involving treatment reversal shown above from 24 to 40 weeks of age. The body weights and feed consumptions at 40 and 60 weeks are summarized in Table 4. Despite the fact that the feed intake of the females in treatment groups B and D were identical at 40 weeks, the apparent rate of body gain was slightly better in group D. Similarly, group C (allowed free access to feed after 24 weeks) gained relatively more during this 16-week period than the ad libitum females (group A) even though
TABLE 4.—Effect of feed restriction on body weight and feed consumption of large type white turkey hens (24-60 wks.) Mean body wt. (lbs) Treatment A B C D
Mean feed consumed (lbs.)
24 wks.
40 wks.*
44 wks.
60 wks.
24-40 wks.
40-60 wks.
15.9 15.9 14.9 14.9
21.1 18.3 20.6 17.7
20.3 18.9 19.8 18.6
17.0 16.2 16.8 16.5
56.7 47.9 56.5 47.6
64.7 67.5 64.4 70.4
* All treatment groups placed on ad libitum feeding at 40 weeks of age.
12
D. L. ANDERSON, J. R. SMYTH, JR. AND R. E. GLEASON TABLE 5.—Effect
of feed restriction during growth on egg production, fertility and hatchability of fertile eggs from large type white turkeys Hatchabilitj' of fertile eggs
Treatment
A
B
C
D
Replicate pens
Egg Numbers Feb. 1June 3
Fertility (%)
Average all hatches
Setting dates 2/24
3/10
4/9
5/6
1 2 3
53.7 56.1 55.8
84.5 83.3 85.8
50.0 50.0 53.7
54.1 72.9 65.4
36.1 47.1 57.7
45.0 44.8 57.9
46.3 53.7 58.7
Mean
55.2
84.5
51.2
64.1
47.0
49.2
52.9
1 2 3
61.7 52.3 56.6
85.1 89.4 84.4
47.6 51.1 43.9
62.7 73.2 67.3
46.9 55.6 40.0
47.2 41.7 48.6
51.1 55.4 50.0
Mean
56.9
86.3
47.5
67.7
47.5
45.8
52.2
1 2 3
55.8 61.1 49.2
82.7 92.3 88.7
59.5 60.0 70.6
65.7 76.7 68.9
75.0 57.9. 66.7
59.1 46.7 66.7
64.8 60.3 68.2
Mean
55.3
87.9
63.4
70.4
66.5
57.5
64.4
1 2 3
61.9 58.1 52.0
94.7 89.5 94.7
34.9 49.1 62.7
72.5 77.1 77.8
63.4 55.9 61.1
46.3 48.3 66.7
54.3 57.6 67.1
Mean
57.5
93.0
48.9
75.8
60.1
53.8
59.7
total feed consumption did not differ. The effect on body weight of an approximate 16% decrease in total feed intake from 24 to 40 weeks was not altered materially by the previous plane of nutrition (group A versus B and group C versus D). It is interesting to note that the mean body weight at 60 weeks, although not significantly different, maintained essentially the same relationship between treatment groups as that found at 40 weeks even though the mean feed consumption was 2.8 and 5.7 pounds per bird more in groups B and D respectively. Determination of days to first measurable semen sample in males from replicate 1 resulted in mean values of 205.1 and 197.4 days of age for the restricted and ad libitum groups respectively. When analyzed by Students "t" test the mean difference of 7.7 days was found to be highly significant. (P < .01). It thus appears that
the large type white turkey males used in this study were retarded in sexual maturity to a significant degree when subjected to approximately a 16% reduction in total feed intake during the second 12 weeks of growth. On the other hand, the females in treatment groups C and D which were restricted in total feed intake during the 12 to 24week period demonstrated a significant (P < .05) improvement in hatchability of fertile eggs (Table 5). Restricting the feed intake of females from 24 to 40 weeks had no effect on the hatchability of eggs laid by birds previously in the ad libitum groups. The improvement in hatchability for the 12 to 2 4-week restricted birds was less (4.7%), however, when restriction was continued from 24 to 40 weeks. In this respect it should be noted that with the exception of the hatch set on February 24, the average hatchability of the remaining
RESTRICTED FEEDING OF TURKEYS
settings in treatment group D was essentially identical to those in treatment group C which had been restricted during the second 12 weeks of growth only. Regardless of the slight depression just indicated, the average hatchability of group D was 6.8 and 7.5% higher than treatments A and B respectively. The differences in fertility (Table 5) although not statistically significant, showed a marked trend toward higher fertility in those groups (C and D) restricted during the 12 to 24-week period. No statistically significant differences between treatment groups in total number of eggs laid per bird were observed during the 20-week breeding period. DISCUSSION Restricting the energy or total feed intake of different classes of livestock has resulted in variable and conflicting reports on age at sexual maturity, fertility, reproductive ability and length of reproductive life span. Reid (1959) has reviewed the major effects of plane of nutrition on carcass growth and conformation of livestock and indicates the importance of the rate of maturation of different tissues on their response to limited energy intake. The results of the present study indicate that the turkey is apparently not an exception to the trends found generally applicable in other species. The significantly reduced body weight without significant skeletal changes (Table 3) when average total feed intake was reduced by 16% demonstrates the nutritional adequacy (energy excepted) of the ration used in this study and supports previously reported data on the priority of bone growth over tissue growth or fat deposition. The relationship of differences in rate of tissue maturation is further exemplified by the significant differences in breast width within sexes observed at 24 weeks as a result of restricted feed intake which was
13
due probably to variations in fat accumulation and/or tissue protein gains. Since the major nutrient limitation imposed upon the restricted fed groups was in total energy intake it would be reasonable to assume that these differences were more likely the result of different degrees of intra-muscular fat deposition rather than differences in tissue growth. The increase in total feed consumption recorded at 60 weeks in those groups (B and D) on restricted feed intake just prior to egg production was largely associated with heavy overconsumption during the first four weeks of the breeding period. The concurrent body weight increases of these groups during this interval followed by sharply declining body weights thereafter are in close agreement with the data reported by Scott and Payne (1941). Thus it is evident that turkey females deprived of sufficient caloric intake during the holding period (24 to 40 weeks) will attempt to restore a part of this loss during the early weeks of production with no apparent adverse effects on egg numbers. This does not appear to be the case with birds maintained on restricted feed intake prior to 24 weeks. Under these conditions (Table 4) no compensatory overconsumption was observed but instead a markedly improved feed utilization for growth was evident which may possibly be related to maintenance energy requirements since body size differences were consistent throughout the period. In contrast to the lack of effect on egg numbers, the depression in hatchability observed at the end of the first production month (Table 5, groups B and D) indicates that the maturing turkey females in this study in initially attempting to overcome depressed body weight and maintain normal egg formation stimulated by hormonal activity after lighting were unable to simultaneously maintain maximum
14
D. L. ANDERSON, J. R. SMYTH, JR. AND R. E. GLEASON
hatchability during this interval. These data suggest the desirability of removing females from restricted feeding several weeks before lighting to minimize possible depression in early hatchability. The lack of a significant effect on hatchability, egg numbers or fertility in the groups maintained on reduced feed intake during the holding period (24 to 40 weeks) are in agreement with the data reported by Milby (1958) and Mitchell et al. (1962), even though the periods of restriction in the latter studies were of considerably shorter duration. In contrast to these observations, the limiting of feed intake of large type turkey females from 12 to 24 weeks of age resulted in an improvement (P < 0.05) in hatchability of fertile eggs which was apparently independent of the subsequent feeding program. Thus it is evident that the large type white females used in this study responded to feed restriction during the second 12 weeks of growth in a manner quite different with regard to feed consumption, body weight gain and hatchability of fertile eggs than hatchmates maintained on limited intake during the 24 to 40-week holding period. It appears possible that the differences in growth and feed utilization found may be due in part to an improved utilization of nutrients (known or unknown) as a result of adaptation to decreased total nutrient intake. If this were the case, it is also conceivable that such an adaptation, if sustained, could result in increased utilization and deposition of a nutrient or nutrients in the egg thus explaining the consistent and significant improvement in hatchability observed. SUMMARY The effect of restricting the total feed intake of large type turkey males and females for different intervals during the growing period on subsequent feed consumption, body weight changes, body con-
formation, age at sexual maturity, egg production, fertility and hatchability of fertile eggs has been investigated. Restricting feed from 12 to 24 weeks and/or 24 to 40 weeks of age resulted in significantly reduced body weight. Body conformation changes measured at 24 weeks appeared to be related to differences in breast fleshing as evidenced by a significant reduction in breast width (P < 0.05). Since the ration used in this study was designed to be nutritionally complete (energy excepted) at levels of intake 25% below ad libitum, the data suggest that these differences were primarily the result of changes in fat accumulation rather than changes in tissue protein. No significant effects on shank length or body depth were observed. The feed saving realized from 16% restriction during the 24 to 40-week period was partly lost due to marked overconsumption during the first month of the breeding season. In contrast, improved growth and feed conversion was noted in the absence of overconsumption in turkeys restricted from 12 to 24 weeks of age only. Hatchability of fertile eggs was significantly (P < 0.05) improved in those groups restricted during the 12 to 24-week growing period. In contrast, neither egg numbers nor fertility were significantly affected by the interval of restriction. A delay of 7.7 days to first measurable semen yield in males restricted from 12 to 24 weeks was found to be highly significant (P < 0.01). These data indicate that the interval of feed restriction during growth had an important influence on the productive and reproductive performance of large type white turkeys in these studies. ACKNOWLED GMENTS The authors are indebted to Mr. Francis Vlach for technical assistance during the course of this study.
RESTRICTED FEEDING OF TURKEYS REFERENCES Hollands, K. G., and R. S. Gowe, 1961. The effect of restricted and full-feeding during confinement rearing on first and second year laying house performance. Poultry Sci. 40: S74-S83. Isaacks, R. E., B. L. Reid, R. E. Davies, J. H. Quisenberry and J. R. Couch, 1960. Restricted feeding of broiler type replacement stock. Poultry Sci. 39: 339-346. Milby, T. T., 1958. The effects of a low energy pre-breeder diet on weight gains and subsequent reproductive performance of turkeys. Poultry Sci. 37: 1227. Milby, T. T., and D. H. Sherwood, 1956. The influence of feed intake during the growing period on the subsequent performance of laying hens. Poultry Sci. 35: 863-869. Mitchell, R. H., C. R. Creger, R. E. Davies, R. L. Atkinson, T. M. Ferguson and J. R. Couch, 1962. The effect of restricted feeding on Broad Breasted Bronze turkeys during the holding pe-
IS
riod on subsequent reproductive performance. Poultry Sci. 4 1 : 91-98. Reid, J. T., 1959. Plane of nutrition and livestock performance. Proceedings of the Cornell Nutrition Conference for Feed Manufacturers, pp. 56-64. Schneider, A. J., B. B. Bohren and V. L. Anderson, 1955. The effect of restricted feeding on several genetically controlled characters in the fowl. Poultry Sci. 34: 691-702. Scott, H. M., and L. F. Payne, 1941. The influence of restricted food intake on the reproductive performance of breeding turkeys. Poultry Sci. 20: 395-401. Snedecor, G. W., 1956. Statistical Methods. The Iowa State College Press, Ames, Iowa. Sunde, M. L., W. W. Cravens, H. R. Bird and J. G. Halpin, 1954. The effect of complete and incomplete growing diets on subsequent performance of the laying hen. Poultry Sci. 3 3 : 779-784.
Effect of Ethylene Dibromide in the Diet on the Growth of Chicks1 GEORGE K. MORRIS 2 AND HENRY L. FULLER Poultry Department, University of Georgia, Athens, Georgia (Received for publication May 28, 1962)
E
THYLENE dibromide is used extensively as a component of a grain fumigant mixture. Its toxicity was encountered by poultrymen who observed a reduction in egg size when hens were fed grain treated with a fumigant containing 1
Journal Paper No. 239 of the College Experiment Station, University of Georgia, College of Agriculture Experiment Stations. This study was conducted in part with funds from the Agricultural Marketing Service, United States Department of Agriculture, under contract number 12-25-010-1083. The Agricultural Marketing Service neither restricts nor is responsible for the opinions or conclusions of the authors. 2 Present address: Department of Chemistry, University of Georgia, Athens, Georgia.
ethylene dibromide (EDB), ethylene dichloride (EDC) and carbon tetrachloride (CTC). A number of workers (Bondi et al., 1955; Morgan, 1958; Bierer and Vickers, 1959; and Caylor and Laurent, 1959) showed that EDB caused a reduction in egg size and numbers laid, when fed to hens alone or in combination with EDC and CTC. Fuller and Morris (1962) administered these fumigant components directly into the crop of hens and established toxic levels under condition of controlled intake. Dosages of 0.5 mg. EDB/day/hen for 12 weeks (equivalent to 5 p.p.m. of the diet) were found to decrease egg weights, but the dosage required to depress egg pro-
/CONSIDERABLE interest in recent * ^ years has centered around feeding systems which bring about a decrease in the plane of nutrition either through the restriction of a "complete" ration or the full feeding of an "incomplete" ration at some interval during the growing period. The value of these systems in feeding replacement chickens and their secondary effects on subsequent production and reproduction has been explored by several groups of investigators (Schneider et al., 1955; Sunde et al., 1954; Milby and Sherwood, 1956; Isaacks et al., 1960; and Hollands and Gowe, 1961). In general it has been demonstrated that the body weight of growing pullets is reduced, the onset of sexual maturity delayed from two to four weeks and laying house mortality reduced as a result of lowering total feed intake. These studies do not indicate consistent effects of restrictive feeding on final body weight, total feed consumption, total eggs produced, egg size, and fertility and hatchability. Similarly, there is interest in the effects of restricting the feed intake of growing turkeys on body weight of breeding stock and their subsequent reproductive performance. The early report of Scott and Payne (1941) indicated that limiting the feed in-
take of Bronze turkey females to 61 or 78% of ad libitum from 26 weeks to sexual maturity (governed by natural daylight) had no effect on maintaining body weight after the first three weeks of the breeding season. Neither egg numbers nor hatchability was influenced by reducing the feed intake to 78% of the full feed group. Feed restricted to 61% of ad libitum resulted in significantly reduced hatchability. Milby (1958) fed a low energy prebreeder ration to 26-week-old Broad Breasted White turkeys for 58 days and found a highly significant reduction in female body weight. Feed intake and cost per bird per month were, however, considerably lower for the high energy feeding program. No significant effects on subsequent egg production or hatchability were observed. Recently, Mitchell et al. (1962) reported on a similar trial in which 2 3-week-old Broad Breasted Bronze females were fed restricted quantities of a basal diet and the basal diet adjusted to contain 12% of crude fiber. Results from this study indicated no effects on total egg production, mortality, fertility or hatchability of fertile eggs. A similar lack of effect was observed with turkey hens fed ad libitum where crude fiber levels were increased to either 15 or 20% and protein concurrently reduced to 12%. The present investigation was undertaken to determine the effects of reducing the total nutrient intake of large type white turkeys at different intervals during early and late growth on subsequent feed con-
1
Contribution No. 35 from the Massachusetts Agricultural Experiment Station, Amherst, Massachusetts. "Present address: Department of Poultry Science, Texas A & M College, College Station, Texas.
8
RESTRICTED FEEDING OF TURKEYS
sumption, body weight changes, body conformation, age at sexual maturity, egg production, fertility and hatchability of fertile eggs. PROCEDURE Two replicate groups totaling 495 large type white turkey poults from the University breeding flock were used in this study. They were hatched on April 8, 1958 (replicate 1) and May 29, 1958 (replicate 2) and were brooded to 10 weeks of age with gas brooder stoves on wood shavings litter. A commercial 28% protein turkey starter ration was fed during this period. At this time the birds in each replicate were assigned to adjoining gravel ranges on the basis of body weight and sex. Range size was adjusted to allow 15 square feet of yard space per bird. At 12 weeks the birds were again weighed and assigned to ad libitum or restricted feeding treatment groups. Each treatment group in replicate 1 was comprised of 75 male and 60 female poults and replicate 2 was comprised of 60 males and 55 females per group. The pelleted complete 20% protein growing ration shown in Table 1 was fed to both replicates from 12 to 24 weeks. With the exception of energy level, this ration was formulated to contain adequate amounts of nutrients required by the growing turkey even at feed intake levels 25% below ad libitum. It was decided to attempt to limit feed intake for restricted groups to 85% of normal consumption. Two different restriction procedures were evaluated. The first procedure tried was based on a percentage of predicted intake taken from existing feed consumption and body weight tables for poults of similar age and size. This procedure proved inadequate when the actual consumption of the ad libitum was compared to the expected. The second approach, and the one adopted for use
TABLE 1.—Composition of diets Ingredients Ground yellow corn Pulverized oats Stabilized animal fat Soybean oil meal (44% protein) Menhaden fish meal (60% protein) Meat and bone scrap (50% protein) Corn distillers dried solubles Dried brewers yeast Alfalfa meal (17% protein) Ground limestone Dicalcium phosphate Manganese sulfate (feed grade) Iodized salt Dry vitamin A (10,000 I.U./gm.) Dry vitamin D3 (3,000 I.U./gm.) DL-Methionine (feed grade) Vitamin E supplement (20,000 I.U./lb.) 4-Nitrophenylarsonic acid (Histostat R )
Grower
Breeder
%
%
56.0
58.0 5.0
2.0 20.0
15.0
5.0
5.0
0 0 0 0 5 25
2.5 2.5 2.5 3.0 3.5 1.5
0.019 0.5
0.0125 0.5
0.11
0.125
0.03 0.0125
0.05
0.05
0.10
0.025
—
Riboflavin mg./lb. 1.3 Niacin mg./lb. 20.0 D-Pantothenic acid mg./lb. 3.0 Choline chloride mg./lb. 238.5 Vitamin B12 mcg./lb. 4.5 Folic acid mcg./ib. — Procaine penicillin mg./lb. 3.0 Vitamin K mg./lb. 0.5
2.0 20.0 4.0 181.6 6.0 60.0
— —
throughout this study for the restricted intake groups, was based on a variable percentage (85-100%) of the previous week's intake of the corresponding ad libitum group. The exact percentage used was extrapolated from a prediction curve representing the weekly percentage increase in feed intake of the ad libitum control. Additional consideration was also given to the stage of growth and environmental temperature. Since feed corrections were made on a weekly basis, the normally increasing consumption of the ad libitum group could then be compensated for to the extent that the over-all restriction level approached the desired 85%. To enable all birds to eat simultaneously, 8 linear inches of feeder
10
D. L. ANDERSON, J. R. SMYTH, JR. AND R. E. GLEASON
TABLE 2.—Effect of feed restriction on body weight and total feed consumption of 24-week-old male and female large type white turkeys
Treatments
Mean body wt.* (lb
Mean cumm. feed
Males
Females
(lbs.)
2t
24.8 25.5
15.8 16.8
53.8 61.3
Mean
25.2
16.3
57.6
21.1 21.8
14.8 15.6
45.0 49.8
21.4
15.2
47.4
Replicate groups i**
Ad libitum
1 2
Restricted
Mean
* Mean weight of both replicates at 12 weeks; males, 9.6 lbs.; females, 7.3 lbs. ** July 2-September 24, 1958. t August 21-November 13, 1958.
space was supplied per bird in the restricted groups and one-half of the daily feed allotment was fed in the morning (9:00 A.M.) and the remainder in the afternoon (3:00 P.M.). Body weight data were collected at 4week intervals starting at 10 weeks of age, and breast width, shank length and body depth measurements were made at 24 weeks. Due to lack of pen space it was necessary to eliminate replicate 2 from the study at this time. The females from replicate 1 were transferred from range at 24 weeks and subdivided on the basis of body weight and previous treatment into 3 blocks of 4 groups containing 9 birds each. They were then placed in open-front breeder pens allowing 10 square feet of floor space per bird and assigned to the following experimental treatments: Percentage of ad libitum feed intake 12-24 wks. 24-40 wks. Treatment Treatment Treatment Treatment
A: B: C: D:
100 100 85 85
100 85 100 85
A representative sample of 20 males from both treatment groups in replicate 1
was similarly housed and placed on ad libitum feeding. At 25 weeks of age they were exposed to 14 hours of light daily. Following two weeks on this light program attempts to collect semen were initiated and continued at weekly intervals until 31 weeks of age to determine the average age of first measurable semen sample. These data were used as a measure of age at sexual maturity in this study. The pelleted complete grower ration was replaced at 40 weeks by the complete allmash breeder ration (Table 1) which was fed to all treatment groups ad libitum until the end of the trial on June 3. Artificial lighting was supplied to the females on January 16, 1959 to equal a total of 14 hours of light daily. All pens were trapnested 7 days a week and egg production, fertility and hatchability records were collected. The birds were artificially inseminated with pooled semen samples from a randomized lot of treatment group males at approximately 3 to 4-week intervals. Eggs were saved for 10 days prior to the scheduled setting dates. Feed consumption records were obtained bi-weekly and body weight data monthly throughout the breeding season. Variance analyses were employed in conjunction with appropriate transformation procedures on the percentage data according to the methods outlined by Snedecor (1956). EXPERIMENTAL RESULTS
The effects of restricting the total feed intake of growing turkeys from 12 to 24 weeks on mean body weight and total feed consumption are shown in Table 2. Feed intake levels of 83.6% of ad libitum in replicate 1 and 81.2% in replicate 2 resulted in a statistically significant reduction in body weight at 24 weeks. Although the restricted group in replicate 2 was subjected to a slightly greater percentage reduction in total feed intake, the absolute
RESTRICTED FEEDING OF TURKEYS TABLE 3.—Effect
Body Measure (cm.)
11
of feed restriction on body conformation at 24 weeks in large type white male and female turkeys Male
Female
Replicate Groups
Ad libitum
Restricted
Ad libitum
Restricted
1 2
16.5 17.3
16.3 16.8
13.2 13.7
13.0 13.7
Mean
16.9
16.6
13.4
13.4
1 2
23.7 23.0
22.8 21.7
18.7 17.8
19.0 17.4
Mean
23.4
22.2
18.2
18.2
1 2
11.4 13.0
9.6 11.4
10.4 13.0
9.6 12.2
Mean
12.2
10.5
11.7
10.9
Shank length
Body depth
Breast width
quantity consumed was 10.7% greater than replicate 1 due in part to the normally decreasing fall temperatures in this latitude. This was undoubtedly a factor which contributed to the significant differences found in mean body weights between replicates at 24 weeks. Unfortunately there was a greater degree of apparent feed restriction imposed on the males than on the females as indicated by a significant treatment-sex interaction and evidenced by the 15.1% and 6.8% lower body weights in the restricted groups for the males and females respectively. Variance analyses of the body conformation data summarized in Table 3 revealed a significant (P < .05) depression in breast width of both males and females in the restricted intake groups. No significant treatment effects on shank length or body depth,
criteria used as indicators of skeletal development, were observed in either replicate. In an attempt to determine the influence of restricted feed intake during different growth intervals on productive and reproductive performance, the females from replicate 1 were subjected to the design involving treatment reversal shown above from 24 to 40 weeks of age. The body weights and feed consumptions at 40 and 60 weeks are summarized in Table 4. Despite the fact that the feed intake of the females in treatment groups B and D were identical at 40 weeks, the apparent rate of body gain was slightly better in group D. Similarly, group C (allowed free access to feed after 24 weeks) gained relatively more during this 16-week period than the ad libitum females (group A) even though
TABLE 4.—Effect of feed restriction on body weight and feed consumption of large type white turkey hens (24-60 wks.) Mean body wt. (lbs) Treatment A B C D
Mean feed consumed (lbs.)
24 wks.
40 wks.*
44 wks.
60 wks.
24-40 wks.
40-60 wks.
15.9 15.9 14.9 14.9
21.1 18.3 20.6 17.7
20.3 18.9 19.8 18.6
17.0 16.2 16.8 16.5
56.7 47.9 56.5 47.6
64.7 67.5 64.4 70.4
* All treatment groups placed on ad libitum feeding at 40 weeks of age.
12
D. L. ANDERSON, J. R. SMYTH, JR. AND R. E. GLEASON TABLE 5.—Effect
of feed restriction during growth on egg production, fertility and hatchability of fertile eggs from large type white turkeys Hatchabilitj' of fertile eggs
Treatment
A
B
C
D
Replicate pens
Egg Numbers Feb. 1June 3
Fertility (%)
Average all hatches
Setting dates 2/24
3/10
4/9
5/6
1 2 3
53.7 56.1 55.8
84.5 83.3 85.8
50.0 50.0 53.7
54.1 72.9 65.4
36.1 47.1 57.7
45.0 44.8 57.9
46.3 53.7 58.7
Mean
55.2
84.5
51.2
64.1
47.0
49.2
52.9
1 2 3
61.7 52.3 56.6
85.1 89.4 84.4
47.6 51.1 43.9
62.7 73.2 67.3
46.9 55.6 40.0
47.2 41.7 48.6
51.1 55.4 50.0
Mean
56.9
86.3
47.5
67.7
47.5
45.8
52.2
1 2 3
55.8 61.1 49.2
82.7 92.3 88.7
59.5 60.0 70.6
65.7 76.7 68.9
75.0 57.9. 66.7
59.1 46.7 66.7
64.8 60.3 68.2
Mean
55.3
87.9
63.4
70.4
66.5
57.5
64.4
1 2 3
61.9 58.1 52.0
94.7 89.5 94.7
34.9 49.1 62.7
72.5 77.1 77.8
63.4 55.9 61.1
46.3 48.3 66.7
54.3 57.6 67.1
Mean
57.5
93.0
48.9
75.8
60.1
53.8
59.7
total feed consumption did not differ. The effect on body weight of an approximate 16% decrease in total feed intake from 24 to 40 weeks was not altered materially by the previous plane of nutrition (group A versus B and group C versus D). It is interesting to note that the mean body weight at 60 weeks, although not significantly different, maintained essentially the same relationship between treatment groups as that found at 40 weeks even though the mean feed consumption was 2.8 and 5.7 pounds per bird more in groups B and D respectively. Determination of days to first measurable semen sample in males from replicate 1 resulted in mean values of 205.1 and 197.4 days of age for the restricted and ad libitum groups respectively. When analyzed by Students "t" test the mean difference of 7.7 days was found to be highly significant. (P < .01). It thus appears that
the large type white turkey males used in this study were retarded in sexual maturity to a significant degree when subjected to approximately a 16% reduction in total feed intake during the second 12 weeks of growth. On the other hand, the females in treatment groups C and D which were restricted in total feed intake during the 12 to 24week period demonstrated a significant (P < .05) improvement in hatchability of fertile eggs (Table 5). Restricting the feed intake of females from 24 to 40 weeks had no effect on the hatchability of eggs laid by birds previously in the ad libitum groups. The improvement in hatchability for the 12 to 2 4-week restricted birds was less (4.7%), however, when restriction was continued from 24 to 40 weeks. In this respect it should be noted that with the exception of the hatch set on February 24, the average hatchability of the remaining
RESTRICTED FEEDING OF TURKEYS
settings in treatment group D was essentially identical to those in treatment group C which had been restricted during the second 12 weeks of growth only. Regardless of the slight depression just indicated, the average hatchability of group D was 6.8 and 7.5% higher than treatments A and B respectively. The differences in fertility (Table 5) although not statistically significant, showed a marked trend toward higher fertility in those groups (C and D) restricted during the 12 to 24-week period. No statistically significant differences between treatment groups in total number of eggs laid per bird were observed during the 20-week breeding period. DISCUSSION Restricting the energy or total feed intake of different classes of livestock has resulted in variable and conflicting reports on age at sexual maturity, fertility, reproductive ability and length of reproductive life span. Reid (1959) has reviewed the major effects of plane of nutrition on carcass growth and conformation of livestock and indicates the importance of the rate of maturation of different tissues on their response to limited energy intake. The results of the present study indicate that the turkey is apparently not an exception to the trends found generally applicable in other species. The significantly reduced body weight without significant skeletal changes (Table 3) when average total feed intake was reduced by 16% demonstrates the nutritional adequacy (energy excepted) of the ration used in this study and supports previously reported data on the priority of bone growth over tissue growth or fat deposition. The relationship of differences in rate of tissue maturation is further exemplified by the significant differences in breast width within sexes observed at 24 weeks as a result of restricted feed intake which was
13
due probably to variations in fat accumulation and/or tissue protein gains. Since the major nutrient limitation imposed upon the restricted fed groups was in total energy intake it would be reasonable to assume that these differences were more likely the result of different degrees of intra-muscular fat deposition rather than differences in tissue growth. The increase in total feed consumption recorded at 60 weeks in those groups (B and D) on restricted feed intake just prior to egg production was largely associated with heavy overconsumption during the first four weeks of the breeding period. The concurrent body weight increases of these groups during this interval followed by sharply declining body weights thereafter are in close agreement with the data reported by Scott and Payne (1941). Thus it is evident that turkey females deprived of sufficient caloric intake during the holding period (24 to 40 weeks) will attempt to restore a part of this loss during the early weeks of production with no apparent adverse effects on egg numbers. This does not appear to be the case with birds maintained on restricted feed intake prior to 24 weeks. Under these conditions (Table 4) no compensatory overconsumption was observed but instead a markedly improved feed utilization for growth was evident which may possibly be related to maintenance energy requirements since body size differences were consistent throughout the period. In contrast to the lack of effect on egg numbers, the depression in hatchability observed at the end of the first production month (Table 5, groups B and D) indicates that the maturing turkey females in this study in initially attempting to overcome depressed body weight and maintain normal egg formation stimulated by hormonal activity after lighting were unable to simultaneously maintain maximum
14
D. L. ANDERSON, J. R. SMYTH, JR. AND R. E. GLEASON
hatchability during this interval. These data suggest the desirability of removing females from restricted feeding several weeks before lighting to minimize possible depression in early hatchability. The lack of a significant effect on hatchability, egg numbers or fertility in the groups maintained on reduced feed intake during the holding period (24 to 40 weeks) are in agreement with the data reported by Milby (1958) and Mitchell et al. (1962), even though the periods of restriction in the latter studies were of considerably shorter duration. In contrast to these observations, the limiting of feed intake of large type turkey females from 12 to 24 weeks of age resulted in an improvement (P < 0.05) in hatchability of fertile eggs which was apparently independent of the subsequent feeding program. Thus it is evident that the large type white females used in this study responded to feed restriction during the second 12 weeks of growth in a manner quite different with regard to feed consumption, body weight gain and hatchability of fertile eggs than hatchmates maintained on limited intake during the 24 to 40-week holding period. It appears possible that the differences in growth and feed utilization found may be due in part to an improved utilization of nutrients (known or unknown) as a result of adaptation to decreased total nutrient intake. If this were the case, it is also conceivable that such an adaptation, if sustained, could result in increased utilization and deposition of a nutrient or nutrients in the egg thus explaining the consistent and significant improvement in hatchability observed. SUMMARY The effect of restricting the total feed intake of large type turkey males and females for different intervals during the growing period on subsequent feed consumption, body weight changes, body con-
formation, age at sexual maturity, egg production, fertility and hatchability of fertile eggs has been investigated. Restricting feed from 12 to 24 weeks and/or 24 to 40 weeks of age resulted in significantly reduced body weight. Body conformation changes measured at 24 weeks appeared to be related to differences in breast fleshing as evidenced by a significant reduction in breast width (P < 0.05). Since the ration used in this study was designed to be nutritionally complete (energy excepted) at levels of intake 25% below ad libitum, the data suggest that these differences were primarily the result of changes in fat accumulation rather than changes in tissue protein. No significant effects on shank length or body depth were observed. The feed saving realized from 16% restriction during the 24 to 40-week period was partly lost due to marked overconsumption during the first month of the breeding season. In contrast, improved growth and feed conversion was noted in the absence of overconsumption in turkeys restricted from 12 to 24 weeks of age only. Hatchability of fertile eggs was significantly (P < 0.05) improved in those groups restricted during the 12 to 24-week growing period. In contrast, neither egg numbers nor fertility were significantly affected by the interval of restriction. A delay of 7.7 days to first measurable semen yield in males restricted from 12 to 24 weeks was found to be highly significant (P < 0.01). These data indicate that the interval of feed restriction during growth had an important influence on the productive and reproductive performance of large type white turkeys in these studies. ACKNOWLED GMENTS The authors are indebted to Mr. Francis Vlach for technical assistance during the course of this study.
RESTRICTED FEEDING OF TURKEYS REFERENCES Hollands, K. G., and R. S. Gowe, 1961. The effect of restricted and full-feeding during confinement rearing on first and second year laying house performance. Poultry Sci. 40: S74-S83. Isaacks, R. E., B. L. Reid, R. E. Davies, J. H. Quisenberry and J. R. Couch, 1960. Restricted feeding of broiler type replacement stock. Poultry Sci. 39: 339-346. Milby, T. T., 1958. The effects of a low energy pre-breeder diet on weight gains and subsequent reproductive performance of turkeys. Poultry Sci. 37: 1227. Milby, T. T., and D. H. Sherwood, 1956. The influence of feed intake during the growing period on the subsequent performance of laying hens. Poultry Sci. 35: 863-869. Mitchell, R. H., C. R. Creger, R. E. Davies, R. L. Atkinson, T. M. Ferguson and J. R. Couch, 1962. The effect of restricted feeding on Broad Breasted Bronze turkeys during the holding pe-
IS
riod on subsequent reproductive performance. Poultry Sci. 4 1 : 91-98. Reid, J. T., 1959. Plane of nutrition and livestock performance. Proceedings of the Cornell Nutrition Conference for Feed Manufacturers, pp. 56-64. Schneider, A. J., B. B. Bohren and V. L. Anderson, 1955. The effect of restricted feeding on several genetically controlled characters in the fowl. Poultry Sci. 34: 691-702. Scott, H. M., and L. F. Payne, 1941. The influence of restricted food intake on the reproductive performance of breeding turkeys. Poultry Sci. 20: 395-401. Snedecor, G. W., 1956. Statistical Methods. The Iowa State College Press, Ames, Iowa. Sunde, M. L., W. W. Cravens, H. R. Bird and J. G. Halpin, 1954. The effect of complete and incomplete growing diets on subsequent performance of the laying hen. Poultry Sci. 3 3 : 779-784.
Effect of Ethylene Dibromide in the Diet on the Growth of Chicks1 GEORGE K. MORRIS 2 AND HENRY L. FULLER Poultry Department, University of Georgia, Athens, Georgia (Received for publication May 28, 1962)
E
THYLENE dibromide is used extensively as a component of a grain fumigant mixture. Its toxicity was encountered by poultrymen who observed a reduction in egg size when hens were fed grain treated with a fumigant containing 1
Journal Paper No. 239 of the College Experiment Station, University of Georgia, College of Agriculture Experiment Stations. This study was conducted in part with funds from the Agricultural Marketing Service, United States Department of Agriculture, under contract number 12-25-010-1083. The Agricultural Marketing Service neither restricts nor is responsible for the opinions or conclusions of the authors. 2 Present address: Department of Chemistry, University of Georgia, Athens, Georgia.
ethylene dibromide (EDB), ethylene dichloride (EDC) and carbon tetrachloride (CTC). A number of workers (Bondi et al., 1955; Morgan, 1958; Bierer and Vickers, 1959; and Caylor and Laurent, 1959) showed that EDB caused a reduction in egg size and numbers laid, when fed to hens alone or in combination with EDC and CTC. Fuller and Morris (1962) administered these fumigant components directly into the crop of hens and established toxic levels under condition of controlled intake. Dosages of 0.5 mg. EDB/day/hen for 12 weeks (equivalent to 5 p.p.m. of the diet) were found to decrease egg weights, but the dosage required to depress egg pro-