Effect of Age and Resting on Hens Laying Eggs with Heavy or Light Shell Weight1

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EFFECT OF AGEAND RESTING ON HENS LAYING EGGS WITH HEAVY OR LIGHT SHELL WEIGHT^ A. G.ABDALLAH2, R. H.HARMS3, and G. B. RUSSELL Department of Dairy and Poultry Sciences, University of Florida, Gainesville, FL 32611-0930 Phone: (904) 392-1931 F M : (904) 392-3047

gnificant. lo Experiment ZA, Ew increased with no interaction between age and s

een age and shell cla f eggs from LSW hens con

strains of White Leghorns. After this time, DESCRIPTION OF PROBLEMit remained fairly constant within strains. The age of the hen at time of lay influences eggshell quality. Petersen [l] reported that eggshell quality decreased after peak egg production, whereas egg weight (EW) continued to increase. Hamilton [2] found that shell weight (SW) continued to increase between 165 and 335 days of age in ten different

Roland et al. [3] reported that E W increased with age; however, percentage shell (PS), and percentage yolk Ca decreased as hens aged, whereas SW remained constant throughout the experiment. They suggested that the decline in shell quality as the hen ages could be the result of increased EW. Roland

1 Florida Agricultural Experiment Journal Series No. R-03604 2

3

Present address: Animal Production Research Institute, Nadi AI-Sad St., Dokki, Egypt. To whom correspondence should be addressed

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Primary Audience: Nutritionists , Extension Specialists, Breeding Companies, Enn Producers

JAPR 132

EFFECT OF AGE ON EGGSHELL QUALITY

[4] found that the amount of shell deposited on the egg after three months of lay did not increase but remained fairly constant or increased slightly throughout the remainder of the laying period. This project studied the effect of age on hens laying eggs with heavy shell weight (HSW) or light shell weight (LSW) and determined whether resting affected HSW and LSW hens in the same manner.

than 5.2 g were classified as HSW hens. Hens with SW less than 4.8 g were classified as LSW hens. One hundred and eighty hens in each class were randomly assigned into replicate groups of five hens each. At four week intervals, researchers weighed all eggs from one day’s production, measured SW and EW, and calculated percentage shell and SG. At 34 wk of age the hens began receiving a diet containing 15.3% CP, 2,678 kcal ME/kg of diet, 3.9% Ca, and 0.55% total P. The experiment was conducted for sixteen weeks.

MATERIALS AND METHODS

EXPERIMENT 2A (28-44Wk) As with Experiment 1,Hy-Line W36 hens (total of 750) formed the group from which the HSW and LSW hens came. The chicks were hatched in November and reared in a floor house. At 20 wk of age, they went to individual cages and received both the artificial light to furnish 16 hr of light and the same diet as used in Experiment 1. At 28 wk of age, researchers collected eggs from all hens for four consecutive days and measured SW and EW. The average SW for the whole flock was 4.99 f 0.44 (SD)/g. Hens having SW of more

EXPERIMENT 2B (48-64 Wk) The same hens used in Experiment 2A also served in this experiment. The hens rested for ten days at the end of 44 wk of age. At 48 wk of age the eggs were collected at four week intervals and EW, SW, PS, and SG were measured as described previously for Experiment 1.The experiment was carried out for twelve weeks. EXPERIMENT 3A (26-38 Wk) A total of 840 Hy-Line W36@hens provided the HSW and LSW hens, housed in individual cages at 19 wk of age and given artificial light to furnish 16 hr of light. Hens received a diet containing 15.5% CP, 2,689 kcal ME/kg diet, 2.90% Ca, and 0.65% total F! Researchers collected eggs at 26 wk of age, from all hens for four consecutive days and measured EW and SW. The average for the whole flock was 4.96 ? 0.55 (SD)/g. Hens having SW of more than 5.40 g were classified as HSW hens; hens with SW less than 4.44 g were classified as LSW hens. One hundred and twenty in each shell class were randomly assigned into replicate groups of five hens each, where shell weight and EW were measured at two week intervals. The experiment continued for twelve weeks. EXPERIMENT 3B (40-58 Wk) The same hens used in Experiment 3A also served for this experiment. However, at 38 wk of age hens were changed to a diet containing 14.0 CP, 2,911 kcal ME/kg of diet, 3.4% Ca, and 0.55% P. Researchers collected the eggs at 40 wk of age at two week intervals and measured EW, SW, PS, and SG as described for Experiment l.The experiment was conducted for eighteen weeks.

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EXPERIMENT 1(52-64 Wk) A total of 450 Hy-Line W36@ [5] hens provided thebase to select groups ofHSW and LSW hens. The chicks were hatched in August and reared in a floor house. At 20 wk of age, they were housed in an open-side house in individual cages and given artificial light to furnish 16 hr of light. They had previously received a diet containing 15.5% CP, 2,689 kcal ME/kg of diet, 3.35% Ca, and0.63% total P. At 34 wk of age the hens began receiving a diet containing 15.3% CP, 2,678 kcaVkg diet, 3.9% Ca, and 0.55% total €! At 52 wk of age, eggs were collected for four consecutive days; egg weight (EW) and shell weight (SW) were measured. The average SW for the entire flock was 5.65 f 0.64 (SD)/g. Hens having more SW than 5.92 g were classified as HSW hens. Hens with SW less than 5.38 g were classified as LSW hens. One hundred and twenty hens made up each class, housed in groups of five hens each. All eggs and shells from one day’s production were weighed and PS was calculated (shell weight/egg weight x 100) each week. Also, specific gravity (SG) was calculated using the equation of Harms et ai. [6]. The experiment lasted for twelve weeks.

Research Report ABDALLAH et al.

133

The data from all experiments were subjected to the ANOVA using General Linear Models [7].

with age of the hen; however, neither changed for the HSW hens (Table 1).Agex shell classes interactions for PS and SG were not significant. The data from this experiment agrees with a previous report by Hamilton [2], who found that SW did not change significantly after 335 days of age. Also, the data agrees with Roland el al. [3], who found that amount of the shell deposited on the egg after three months of lay did not increase but remained fairly constant throughout the remainder of the laying period. The lack of an age x shell class interaction indicated that the change with age was the same for HSW and LSW hens.

RESULTS AND DISCUSSION

EXPERIMENT 2A (2&44Wk) Egg weight increased significantly from 28 to 40 wk with both HSW and LSW hens (Table 2). Age x shell classes interaction for EW was not significant (Table 2). Shell weight increased significantly for both HSW and

TABLE 1. Egg weight, shell weight, percent shell, and specific gravity of e g g s from hens laying e g g s with heavy shell weight (HSW) or light shell weight (LSW) (Experiment 1 )

62

68.3a

62.Sab

6.24a

5.40a

9.14bc

8.HbC

8Bbc

790bC

63

69.1a

63Aa

6.19a

5.57

8.9gbC

8.7fiabc

808'

79PbC

64

68.1a

63.1a

6.Ma

5.41a

9.31abc

8.5Yd

82Fbc

786bcd

STATETICAL ANALYSIS

PROBABILITY

Age Shell classesB

0.0001

0.4000

0.0001

0.0001

0.0001

0.0001

0.0001

0.0001

Age x shell classes

0.653

0.772

0.772

0.771

Ia-dMeanswithin a column with no common superscript differ significantly ( P c .05).

I

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EXPERIMENT 1(32-64 Wk) Egg weight from HSW increased to 54 wk and remained constant thereafter. The EW from LSW hens increased with the age from 52 to 57 wk of age (Table 1).Eggs from HSW hens were significantlyheavier than eggs from LSW hens. Age x shell classes interaction for EW proved insignificant. Shell weight from both HSW and LSW hens did not change significantly from 52 to 64 wk of age. The eggs from HSW hens had significantlyhigher shell weight than eggs from LSW hens (Table 1). The age x shell classes interaction for SW was not significant. Percentage shell and SG from LSW decreased

JAPR EFFECT OF AGE ON EGGSHELL QUALITY

134

AGE

EGG WEIGHT

LSW

HSW

SHELL WEIGHT HSW

LSW

PERCENT SHELL LSW

LSW

SPECIFIC GRAVITYA HSW

LSW

Age Shell classesB

o.Ooo1

o.Ooo1

o.Ooo1

o.Ooo1

o.Ooo1

o.Ooo1

0.0001

0.0001

Age x shell classes

0.1631

o.Ooo1

0.0001

o.Ooo1

LSW hens from 28 to 44 wk of age (Table 2). Age x shell classes interactions for SW, PS, and SG were significant because of an increase in SW of eggs from LSW hens (0.55 g) greater than for those from HSW hens (0.25 g) from 28 to 36 wk of age. Percentage shell and SG significantly increased with age from 28 to 44 wk (Table 2). The age x shell classes analysis indicates that changes between 28 and 36 wk differs for the HSW and LSW hens. This finding was different from the results in Experiment 1. EXPERIMENT 2B (48-64 Wk) Egg weight increased significantly between 48 and 52 wk in both HSW and LSW hens (Table 3). This EW change may be explained by the fact that the hens had been rested prior to the start of this experiment. There was no significant increase in EW from 52 to 60 wk. Age x shell classes interaction for EW was not significant. Shell weight significantly increased from 48 to 60 wk of age for both HSW and LSW hens. Age x shell classes interaction for SW was not significant. The improvement in SW from 52 to 60 wk of age was attributed to resting the hens. Christmas and Harms [lo] and Christmasetal. [ll]also found that resting hens significantlyimproved eggshell quality.

Age x shell classes interaction for PS and SG proved insignificant (Table 3). The lack of a change in EW, PS, and SG Cor the HSW and LSW hens is similar to the results in Experiment 1. Also, the age x shell classes interactions for EW, SW, PS, and SG were not significant. The difference in ES measurements for LSW and HSW continued after resting. EXPERIMENT 3A (26-38 Wk) Shell weight increased significantly (P< .OOOl) from 26 to 36 wk of age (Table 4). Age x shell classes interaction for SW was significant (P c .OOl) because of the large increase (0.50 g) in SW for the LSW hens as compared to no increase for the HSW hens. The age x shell classes interaction during the early portion of production was the same as that observed inExperiment 2A. Even with the large increase in SW with the LSW hens, the SW was still significantly different (P < .001) for the two groups of hens. EXPERIMENT 3B (40-58 Wk) Egg weight for both groups of hens varied greatly but were not significantly different at 40 vs. 48 wk (Table 5). Egg weight for both HSW and LSW hens significantly increased from 50 to 54 wk of age (Table 5). The EW

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PROBABILITY

STATISI'ICAL ANALYSIS

Research Report ABDALLAH et af.

135

TABLE 3.Egg weight, shell weight, percent shell, and specific gravity of e g g s from hens laying e g g s with heavy shell weight (HSW)or light shell weight (LSW) (Experiment 28)

hens were force rested at the end of week 44.

BSpecificgravityvalues were coded 1.OXXX. 'Shell classes (heavy and light shell weight) dMeans within a column with no common superscripts differ significantly (P c .OS).

SHELL WEIGIIT

AGE MSW Wk

LSW g

26

5.40b

4MC

28

5.30b

4.73c

30

SAa

4.82bC

32

5.26b

4.8Pb

34 36 38

I I

5.54a 5.52a

I I

5.40b

4.92ab

I I

4.94a

Age Shell classesA

o.Oo01

Age x shell classes

0.0001

a-c

4.90ab

0.0001

Means within a column with no common superscripts differ significantly (P < .OS).

I

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'%e

JAPR EFFECT OF AGE ON EGGSHELL QUALITY

136

Between 28 and 36 wk of age in Experiment 2A, a large increase in SW was observed. A similar increase in SW for LSW hens appeared at 22 and 34 wk of age in Experiment 3A (Table 4). These findings agree with the data reported by Harms and Miles [12], who found that SW increased from 5.1 to 5.6 g during a seven-day period during the onset of "Fatty Liver Syndrome." In this study, the increase in SW was greater with the LSW hens than with the HSW hens. Egg weight and SW increased from 48 to 56 wk in Experiments 2B and 3B. The increased EW and SW in Experiment 2B occurred after the hens had rested. The HSW were more adversely affected by a reduction in the Ca in the diet than were LSW hens [13]. Removing the Mn from the feed resulted in significantly reducing SW from HSW hens, but did not affect SW from LSW hens [14]. Therefore, it does not appear that the difference between LSW and HSW hens resuIts from their individual nutritional requirements.

TABLE 5. Egg weight, shell weight, percent shell, and specific gravity of eggs from hens laying eggs with heavy shell weight (HSW) and light shell weight (LSW) (Experiment 38)

AGE

1

EGG WEIGHT

I

SHELL WEIGIIT

I

PERCENTSIIELL

SPECIFIC GRAVITYA

40

61.9&

S6.9d

5.62'

5.0SCd

9.1OCd

8.90b

816ak

8WbC

42

60.3'

56.2d

5.40d

4.93d

9.Wd

8.80bC

808'

800bC

44

60.6'

56.3d

5.43Cd

4.91'

9.00d

8.74'

809'

796bC

46

621b

56.9

S.7lb

5.12a

9.22a

9.06ab

822a

814a

48

61.SbC

S6.f

5.53Cd

4.9SCd

9.00d

8.76'

812bC

797bC

*Specific gravity values were coded LOXXX.

BShell classes (heavy and light shell weight) a-c

I

Means within a column with no common superscripts dilfer significantly (P < .OS).

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continued to increase from the LSW hens until 58 wk of age. However, the age x shell classes interaction was not significant (P = SO), and the two classes continued to remain significantly different ( P e .OOOl). The age x shell classes effect was not significant (P = .488). Shell weight declined from 40 to 44 wk of age with both HSW and LSW hens (Table 5). However, the two groups remained significantly different (P = .oOOl) and increased during 44 to 46 wk. After 52 wk, SW increased until 56 wk for HSW and to 58 wk for LSW hens (Table 5). The age x shell classes effect was not significant (P = .27). However, the SW of HSW differed markedly from that of LSW hens (P < .OOOl); percentage shell and SG during 40 to 48 wk followed the same trend. Percentage shell increased from 48 to 58 wk of age with both HSW and LSW hens (Table 5). The 3.5% increase in SP from 48 to 58 wk was not as great as the 6% increase in SW. The difference between the HSW and LSW hens in SP was significant (P = .0001) during this period. Specific gravity values followed the same trend as shell percentage.

Research Report ABDALLAH et al.

137

CONCLUSIONS AND APPLICATIONS 1. Hens that lay eggs with poor shell quality at an early age continue to lay eggs with poor

~

REFERENCES AND NOTES 1. Petersen, C.F., 1965. Factors influencing eggshell quality: A review. World’s Poultry Sci. J. 21:110-138.

cant. Means were separated by Duncan’s multiple range test [9].

2. Ilamilton, R.M.G., 1978. Observations on the changes in physical characteristics that influence eggshell guality in ten strains of white leghorns. Poultry Sci. 71192-1197. 3. Roland, D.k, Sr., D.R. Sloan, and R.11. Ilarms, 1975. The ability of hens to maintain calcium deposition in the eggshell and egg yolk as the hen ages. Poultry Sci. 54: 1720-1723.

8. SAS Institute, 1990. SAS@ Institute User’s Guide: Statistics, 1990 Edition. SAS Institute, Inc., Caw, NC.

4. Roland, D.A., 1979. Factors influencingshell quality of aging hens. PoultIy Si.58:774-777.

5. Hy-Line International, Dallas Center, IA 50063. 6. Harms, RII., A.F. Rossi, D.R. Sloan, R.D. Miles, and R.B. Chrislmas, 1990.A method for estimatingshell weight and corrective specific gravity for egg weight in eggshell quality studies. Poultly Sci 69:48-52. ’ .The data were subjected to the 7. ANOVA using the General Linear Models procedure of SA@ software [8]. All experimental data was analyzed by factorial design of treatments. The following model was used: YiJk = ,L4 +Ti -I- Pj -I-(TP),j 4- eljk; where, I( = the overall mean, Ti = the effect of the a e, PJ - the the effect of shell classes (HSW and LSW), &P)J effect of interaction between the age of hen and shell classes, and ei~k= the random error term. Differences with probability of < .05 were considered signifi-

9. Duncan, D.B., 1955. Multiple range and multiple F tests. Biometrics 11:1-42.

10. Chrislmas, R.B. and R.H. Harms, 1983. The performance of four strains of laying hens subjected to various post-rest combinations of calcium and phosphorus afterforcerest inwinter orsummcr. PoultrySci.6218161822.

11. Chrislmas, R.B., R.11. Ilarms, and O.M. Junqueira, 1985. Performance of Single Comb White Leghorn hens subjected to 4 or 10-day feed withdrawal force rest procedures. PoultIy Sci. 64:2321-2324. 12. Harms, R.11. and R.D. Miles, 1989. The influence of fatty liver syndrome on the calcium status of the laying hen. Nutr. Reports Intl. 39697-702.

13. Abdallah, A.C., R.11. Harms, and 0.El-Ilusseiny, 1993. Performance of hens laying eggs with heavy or light shell weight when fed diets with different calcium and phosphorus levels. Poultry Sci. 72:1881-1901. 14. Abdallah, A.C., R.11. IIarnis, 1I.R. Wilson, and 0. El-Ilusseiny, 1994. Effect of removing trace minerals from the diet of hens laying eggs with heavy or light shell weight. PoultIy Sci. 73:295-301.

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shells throughout their laying career. 2. There is a significant interaction of age x shell classes with young hens. 3. There is no significant interaction of age x shell classes with old hens. 4. Poultry breeders should use eggshell weight after 40 wk of age to get an accurate measurement of hens’ abilities to deposit calcium on the shell. 5. The failure of hens to lay eggs with heavy SW at an early age may explain eggshell problems that occur between 40 and 48 wk of age after EW increases. 6. Hens laying eggs with poor shells continue to lay eggs with poor shells after they have been force rested.