الفهرس 
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Abstract
SUMMARY
The present study was carried out using data of 7226 chick of Dokki-4 chickens
(as a native breed) in the Poultry Research farm at Inshas (Sharkia Governorate),
Animal and Poultry Production Research Institute, Ministry of Agriculture, Egypt,
in two consecutive generations in the period from March 1979 to June 1981. Data of
individual body weight (BW) at hatch and biweekly thereafter up to 16 weeks of
age were collected on all individuals of the first aad second generation. Daily gain
(DG) and relative growth rate (RG) between intervals ofhatch-4, 4-8, 8-12 and 12-
16 weeks were also computed.
Restricted Maximum Likelihood (REML) procedure (i.e. sire model and dam
model) and Derivative Free Restricted Maximum Likelihood (DFREML) procedure
(i.e. single-trait and multi-trait animal models) were used for analysis of such data.
The results obtained could be summarized as:
1. Means and variation:
Means of BW and DG of Dokki-4 chicks increased with advancing of age.
However, RG was high (135.40%) at the early stages (hatch-4 weeks), then
decreased generally with the advancement of age which reached 33.57% during the
period of 12-16 weeks. Percentages of phenotypic variation (V%) are tended to
increase with the chick advanced in age for growth traits. The V% for DG and RG
during the period ofhatch-4 weeks was 20.4~o and 750/0, respectively.
2. Non-genetic aspects:
Means of BW, DG and RG of DoklO-4 chicks at different ages were slightly
heavier in the first generation than those f the second generation. Also, males were
heavier and higher in their growth than females’ at all different ages. Difference
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between means of the two generations d the two sexes was highly significant
(P<O.O1) for most growth traits.
3. Variance components:
Variance components due to dam effect (O”~) estimated by dam model are large
(6.80/0) at all ages comparable to sire effect ( O”~) (3.1 0/0) estimated by sire model.
Percentages of direct additive geneti variance (~) for BW and RG traits
estimated by multi-trait AM appeared to e higher than those estimated by singletrait
AM. The average percentages of O”~ ere 11.2% and 8.2% when using singletrait
AM vs 13.90/0and 8.8% when usin multi-traits AM for BW and RG traits,
respectively. I
Percentages of Common environmen I variance (O”~) when using single-trait
AM for BW were large at hatch (25.30/0 but declined gradually at the chick grew
older (14.20/0 at 16 weeks). The percenta es of O”~ for BW traits obtained by multitrait
AM were higher (22.00/0)than those obtained by single-trait AM (17.4%).
4. Heritability:
Generally, estimates of heritability based on sire components of variance (h;),
dam components of variance (h;), direct additive genetic variance when using
single-trait (h~s) and multi-trait (h~) wete highest at younger ages (from hatch to 4
weeks of age) than at later ages (12-16 weeks of age) for all growth traits. The
average estimates of h; were 0.35, 0.23 and 0.18 for BW, DG and RG traits,
respectively. While the average estimates of h; were 0.14, 0.11 and 0.11 for the
same order. Estimates of heritability resulting from multi-traits AM were somewhat
larger (ranged from 0.14 and 0.09) than those obtained by single-trait analysis
(ranged from 0.11 and 0.08) for BW and AM traits, respectively.
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5. Correlation among growth traits:
Estimates of Genetic correlation (rG) ong BW were tended to increase in
value as the intervals between the two age get larger, and most of these associations
among growth traits at different ages were .gh and indicated that the genetic factors
of all growth traits studied were closely additively related. It ranged from 0.17 to
0.84 among BW, -0.35 to 0.65 among DG and -0.65 to 0.48 among RG traits.
All estimates of Common environmental correlation (re:) among BW and among
DG traits are positive and have moderate f high magnitude, and tended to decrease
relatively in value as the intervals betwe -n the two ages get larger. The average
estimates of r, among BW, DG and RG re 0.65, 0.27 and -0.28, respectively.
Estimates of Environmental (rE) and henotypic (rp) correlations among BW
and among DG traits were positive and enerally moderate or high. The average
estimates of rE among BW, DG and R were 0.42, 0.15 and -0.16, respectively.
While the average estimates of rs were .45,0.17 and -0.17 among BW, DG and
RG, respectively.
6. Evaluation of birds: . I
Number of iterations required to reac~ convergence rate, CPU-time consumed
and storage required could be affected by the number of equations (number of
birds), the number of non-zero elements, the number of traits.
Results of Dokki-4 chicks, generally, recorded higher ranges in estimates of
predicted breeding value (PBV) of birds with records, transmitting ability for sires
(PSTA) and dams (PDTA) for BW when using multi-traits AM than those singletrait
AM. The average of ranges in estimates of PBV obtained from multi-traits vs
single-trait AM were 86.58 vs 67.95 grams, 4.17 vs 3.96 grams and 12.66 vs 10.71
0/0 for BW, DG and RG traits, respectively.
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·,-,.
The average of ranges in estimates of PSTA obtained by multi-traits AM vs
single~traitAM were 36.97 vs 32.54 grams, 2.06 vs 2.11 grams and 5.14 vs 5.17 0/0
for BW, DG and RG traits, respectively. While the average of ranges of PDTA
when multi-trait AM using vs single-trait AM were 21.59 vs 15.83 grams, 0.87 vs
0.91 grams and 2.35 vs 1.99 % for BW, DG and RG, respectively.
In general, the accuracy of predictions (i.e. PBV, PSTA and PDTA) obtained by
- - . multi-traits AM was larger than those estimates obtained by single-trait AM for
most of growth traits.
7. Rank correlation of predictions:
For data of birds (birds with records), estimates of rank correlation among most
. ranks of PBV estimates estimated by single-trait or multi-traits AM for BW and DG
traits were moderate or high. Most estimates of rank correlation were significant
(P<O.Ol).
Most estimates of rank correlations among estimates of PBV, PSTA and PDTA
estimated by single-trait andlor multi-traits AM were high and highly significant
(P<O.Ol)for BW at 8 weeks and the following ages.