Effect of Force Molting Programs on Egg Production and Quality of Laying Hens
This study was aimed to evaluate the effect of force molting programs on egg production and quality of laying hens. Total of 165 white Bovines laying hens at 72 weeks of age were divided into four groups. Birds in-group 1 (control), birds in group 2, 3 and 4 were fasted for 10, 12 and 15 days, respectively. After fasting days in each group, birds were divided into three sub groups (birds fed on a crushed yellow corn, crushed yellow corn supplemented with minerals and vitamins and birds fed on control diet) for three weeks and then birds fed on control diet until the end of the experimental period. Birds attained the peak of egg production at 138, 150 and 158 days after 10, 12 and 15 days fasting periods, respectively. The hen day egg production and egg mass for all treated groups recorded higher (p<0.01) values than those of control, while the egg weight for control group were higher (p<0.01) than those of all treated groups. On the other hand, feed conversion for all fasting groups improved (p<0.01) more than those of control group. During recovery feeding the feed consumption for birds fed layer ration increased (p<0.01) more than those of the birds fed crushed yellow corn and crushed yellow corn with minerals and vitamins. The same trend was followed for eggshell strength. From the present results it can be concluded that fasting white Bovines laying hens for 10, 12 or 15 days to induce moulting improved performance and egg quality as compared with the natural moulting, but recovery feeding after fasting did not have significant effect on hens performance.
October 20, 2010; Accepted: January 22, 2011;
Published: March 25, 2011
The requirements of the human to animal protein are increasing day by day.
Thus more researches are needed to increase production and egg quality. Force
moulting employed commercially to stop egg production in laying and breeding
hens in order to recycle them for another season of egg production. After a
molt, the hen's production rate usually peaks slightly below the previous peak
rate and egg quality is improved. The point of molting is thus to increase the
production, egg quality and profitability of flocks in their second or third
laying seasons. Feed withdrawal is the most popular and effective method in
molt induction. It has generated several concerns regarding the animal welfare
and food safety issues, eventually leading to investigation for alternative
approaches (Keshavarz and Quimby, 2002; Webster,
2003; Holt, 2003). Most commercial forced-moulting
programmes entail food withdrawal for different periods (Narahari,
2001). McCovan et al. (2006) suggest that
non-fast induced moulting treatments provide an effective method for inducing
moulting in hens and improving their well-being by minimizing discomfort due
to food deprivation. The influence of non-feed removal moulting methods on the
weight of ovary, oviduct and skeletal quality of hens was examined too (Yildiz
and Alpay, 2008). For a complete recovery of the reproductive tract the
hen's body weight must drop 30 to 35 percent during the molt. This is achieved
by withdrawing the hen's feed completely for as long as two weeks until they
go into molt, which means they lose their feathers and cease to lay eggs in
addition to losing weight (El-Azim and Ibrahim, 2005).
As well as Alodan and Mashaly (1999) reported that the
body weight of the moulted hens decreased significantly to 74.5% of their initial
body weight and that the hens were returned to a full feed layer ration ad
libitum and 16 h of light per day (California method) lost 25% of their
initial body weight by day 10 of the experiment.
Research is needed to explore the possibility of utilizing locally available protein resources, especially the greens from plants, to replace the conventional protein-rich concentrate meals. It is common practice by farmers in tropical countries to use small amounts of green feed to protect against possible vitamin deficiencies and to provide unidentified growth factors. Further researches are needed to investigate the withdrawing the hen's feed and recovery feeding on different type of diets. Thus the aim of this study was to evaluate the effect of fasting period and recovery feed on different diets as force molting programs on egg production and egg quality traits of laying hens.
MATERIALS AND METHODS
The present study was carried out at the Poultry Farm in the Department of Animal Production, Faculty of Agriculture, South Valley University (Egypt) 2008. Total of one hundred and sixty five 72 week-old white Bovans hens were used in the experiment. All birds divided into four groups (three fasting treatments and control). The first group (control) had thirty hens divided into six replicates of 5 birds each. While, forty-five hens were in each (the second, third and fourth fasting groups). The birds in groups second, third and fourth were fasted for 10, 12 and 15 days, respectively. After fasting periods the groups included three treatments (a crushed yellow corn, crushed yellow corn supplemented with minerals and vitamins and feed layer ration ad libitum) each treatment divided into 3 replicates and every replicate included 5 birds (30 birds in control group +45 birds 10 days fasting +45 birds in 12 days fasting +45 bird in 15 days fasting = 160 birds) 5 birds in each replicate were kept in wire cage of 61x55x45 cm in a closed system using controlled system. The indoor temperature was 20±2°C during the experimental period. The control group (natural molting) received 17 h of light/day from 72 weeks of age to the end of the experimental period. The fasting groups received 8 h of light/day during the fasting period and this continued until the end of the three weeks after fasting then increased by half an hour for the first week. After that it was increased one hour per week till the lighting reached 17 h per day and this was continued till the end of the experiment. The composition and calculated analysis of the experimental diet are shown in Table 1. Body weight was recorded before the fasting, the end of the fasting period and end of three weeks after fasting period and after the egg production reached 10% production.
Egg production was recorded daily per hen in each cage during the experimental
period and hen day egg production for each group was calculated every week.
For each hen, after force molting period feed consumption was recorded and calculated
weekly. Feed conversion ratio as g feed/g egg mass was calculated weekly. Egg
quality measurements were determined monthly using 9 eggs per group till the
end of the experiment. The Haugh unit was measured for the internal quality
of the eggs. The height, correlated with the weight, determines the Haugh unit.
|| Composition and calculated analysis of the experimental diets
|*Vitamins and minerals premix provided per kilogram of the
diet: Vit A, 1000 IU; D3 2000 ICU; Vit E, 10 mg; Vit K, 1 mg; B1, 10 mg;
B2, 5 mg; B6, 1500 mg; B12, 10 mg Pantothenic acid, 10 mg; Nicotinic acid,
30 mg; Folic acid, 1mg; Biotin, 50 mcg; Chloride, 500 mg; copper, 10 mg;
iron, 50 mg; Manganese, 60 mg; Zinc, 50 mg and Selenium, 0.1 mg
The higher the number, the better the quality of the egg (fresher, higher quality
eggs have thicker whites). The test was introduced by Haugh
(1937) and is considered the most significant measure of egg quality.
Data were analyzed using a two way Analysis of Variance (ANOVA) to analyze
the differences between treatment groups using SAS (1985)
General Linear Models procedures. Means were compared using Duncans multiple
range tests. Level of significance used in all results was p<0.05 (Duncan,
1955). The statistical model used for analyzing data obtained was:
||Observed value of the concerned trait
||Observed mean for the concerned trait
||The fixed effect due fasting period
The fixed effect due to the type of diet
||The fixed effect due to the interaction. (Fasting period x type diet)
RESULTS AND DISCUSSION
Egg production: Effect of fasting periods on egg production values is
presented in Table 2. When feed was withheld to induce a force
molt, some eggs were laid for several days before egg production dropped to
|| Egg production affected by force molting
Egg production was reduced to zero by 5th, 4th and 5th days for hens subjected
to 10, 12 and 15 days fasting periods, while the number of days out of egg production
were 15, 17 and 20 days for hens subjected 10, 12 and 15 days of fasting, respectively.
The present results showed that bird reached to 50% egg production at 43, 45
and 57 days after the fasting phase with 10, 12 and 15 days of fasting, respectively.
These results means that the 10 days fasting group reached to 50% egg production
at 2 and 14 days earlier than the 12 and 15 days group, while the 12 days fasting
group reached to 50% egg production at 12 days earlier than the 15 days group.
These results are in agreement with the findings of Carey
and Brake (1983) who reported that peak of egg production was attained at
138, 150 and 158 days, while the egg production percentage was peaked at 73,
78 and 76%, respectively after deprivation periods in all 10, 12 and 15 days
fasting periods in that order. The differences of peak production was 5% between
the 10 and 12 days fasting group in favour of 12 days fasting group, while it
was found to be 3% between the 10 and 15 days fasting group, in favour of 15
days. The difference obtained for peak of egg production percentage was 2% between
the 12 and 15 days fasting group in favour of 12 days fasting group.
Hen Day Egg Production (HDP): There is insufficient information conducted
to evaluate force molting on hen day egg production. The hen day of egg production
as affected by the interaction between the recovery feeding and fasting period
values are presented in Table 3. The HDP of all fasting groups
increased (p<0.05) by about 49, 48 and 46% in groups 2, 3 and 4, respectively
as compared with control group. However, no significant differences due to recovery
feeding or interaction between fasting period lengths were detected among the
four groups. These results are in agreement with the findings of
Hassanabadi and Kermanshahi (2007) who found that there were no differences
observed between feed removal treatment and nonfeed removal treatment for postmoult
hen day production
Egg Weight (EW) and Egg Mass (EM): The Egg Weight (EW) and Egg Mass
(EM) as affected by the fasting period and recovery feeding are presented in
Table 3. The birds of control group had higher (p<0.01)
Egg Weight (EW) by about 2 to 3% than those of all fasting groups but there
were no significant differences among fasting treatments. Similar results were
obtained by Christmas et al. (1985) who indicated
that there was no significant difference in egg weight due to fasting treatments
of 4 and 10 days. Birds in fasting groups 2, 3 and 4 had higher (p<0.01)
egg mass (51, 50 and 48%, respectively) than those of control group. While,
non-significant differences were observed in EW and EM due to recovery feeding
or interaction between fasting period lengths of the four groups. Hassanabadi
and Kermanshahi (2007) who found that there were no differences observed
between feed removal treatment and nonfeed removal treatment for postmoult egg
||Effect of fasting periods and recovery feeding on hen day
egg production (HDP)(%), egg weight (gm), Egg Mass (EM), Feed Consumption
(FC)and Feed Conversion Ratio (FCR) in white Bovans layer
|a-c Means with different supper scripts in the same column
are significantly different (YC) = Crushed yellow corn. (YCM) = Crushed
yellow corn with minerals and vitamins, (LR) = Layer Ration
Feed Consumption (FC) and Feed Conversion Ratio (FCR): The FC and FCR
as affected by recovery feeding and fasting periods are presented in Table
3. Differences observed in feed consumption due to fasting periods were
not significant. The present results indicated that the feed conversion of birds
in fasting groups had significant (p<0.01) differences as compared with control
group. These results are in agreement with that of Mohamed
(1990) who observed no significant differences in feed consumption between
7 and 10 days fasting treatment groups. Hassanabadi and
Kermanshahi (2007) who found that there were no differences observed between
feed removal treatment and nonfeed removal treatment for feed intake, feed efficiency.
Egg quality: There were no significant differences in egg component
percentages due to fasting period length or recovery feeding or fasting period
length (Table 4). No significant differences were observed
in values of Yolk Percentage (YP) between the eggs of birds fed crushed Yellow
Corn (YC), Yellow Corn with Minerals and vitamins (YCM) and Layer Ration (LR)
groups. No significant differences were observed for albumen percentage, shell
percentage. Also, there were no significant different on the egg quality indices
such as egg shape index, shell strength, shell thickness, Haugh units and egg
yolk index among treatments. These results due to length of fasting or recovery
feeding are presented in Table 5 and 6.
The eggshell strength produced by birds fed (LR) was higher (p<0.05) by about
7 and 9% than those eggs produced by hens fed YC and YCM, respectively. Christmas
et al. (1985) found that forced molting by fasting for 4 and 10 days
improved the egg quality. Non-feed removal molting programme based particularly
on grain barley had positive effect on egg quality traits in laying hens (Petek
et al., 2008).
|| Effect of fasting periods and recovery feeding on yolk, shell
and albumin percentage in white Bovans layer
|(YC) = Crushed Yellow corn, (YCM) = Crushed yellow corn with
minerals and vitamins, (LR) = Layer Ration, Significance level = p>0.05
||Effect of fasting periods and recovery feeding on shape index,
shell strength (Newtan) and shell thickness (Micron) in white Bovans layer
|Significance level = p>0.05, (YC) = Crushed yellow corn,
(YC) = Crushed yellow corn, (MYC) = Crushed yellow corn with minerals and
vitamins, (LR) = layer ration
|| Effect of fasting periods and recovery feeding on yolk index,
Haugh unit in white Bovans layer
|(YC) = Crushed yellow corn, (YC) = Crushed yellow corn, (MYC)
= Crushed yellow corn with minerals and vitamins
From the present result it can be concluded that fasting white Bovans laying
hens for 10, 12 or 15 days to induce molting improved performance and egg quality
as compared with the natural molting, but recovery feeding after fasting did
not have significant effect on hens performance.
From the present result it can be concluded that fasting white Bovans laying hens for 10, 12 or 15 days to induce molting improved performance and egg quality as compared with the natural molting, but recovery feeding after fasting did not have significant effect on hens performance.
In this study, fasting groups were the best between control groups. These fasting groups of hens had significantly higher egg production and egg mass when compared with other group. More studies still needed to improve egg production and egg quality in laying hens.
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