الفهرس 
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Abstract
SUMMARY
The present study was carried out using data records of 2945 does of New
Zealand White rabbits collected at ZIKA Nucleus Breeding Farm (Schweizerhof
Untergronningen in Germany) over 14 consecutive years of production started in
1982. Lifetime production traits measured per doe were (total number born alive,
total number born, total number weaned, number of litters produced by the doe and
length of lifetime production). Linear mixed models were used for analysing these
data. Variance components and heritabilities were estimated for these traits using
Restricted Maximum Likelihood procedure (REML). For animals with and without
records, transmitting abilities estimated for traits of the study were estimated using
single-trait and multi-trait Animal Models. The result obtained could be summarized
as:
(i) Means and Variation
The mean performance of lifetime production (productive life) traits were 39.2,
42.0, 31.2 bunnies for total number born alive, total number born and total number
weaned, respectively. Also it was 8.1 months for length of lifetime production and
4.8 litters for number of litters produced by doe during that period. The percentages
of phenotypic variation (Yolo) for all these traits are relatively high and ranged from
31.5 to 43.3%.
(ii) Non-genetic aspects
Year-season of birth of doe in this study had non-significant effect on all traits
studied. Litter size in which the doe was born constituted a highly
significant(p<O.OOI) source of variation in total number born alive, total number
born and total number weaned.
(iii) Random components of variance and heritabilities
Percentages of sire variance component (dls) relative to total phenotypic
variance (ds + ~e) were low and ranged from 1.4 to 3.3%. The sire heritabilities
(h2s) where also low and ranged from 0.05 to 0.13. Percentages of d-d relative to
(t:?e + a2s) for L T were low (2.4%), while they are moderately low for litter-size
traits (TNBA, TNB and TNW) and NL. Low dam heritability (0.09) was observed
for length of lifetime production of doe, while moderate estimates were recorded for
litter-size traits (i. e. TNBA, TNB and TNW) and NLwhere the estimates ranged
from 0.16 to 0.21.
(iv) Sire evaluation for lifetime production traits
Predicted Transmitting ability estimates for all animals with and without
records were estimated for four traits being TNBA, TNB, TNW and LT. The
BLUP estimates obtained for lifetime production traits took into account the
relationship coefficient matrix among animals. For list of all sires with record, multitrait
Animal Model generally recorded higher ranges in estimates of STA for all
traits than those ranges estimated by single-trait Animal Model. The ranges in
estimates of STA obtained from multi-trait vs single-trait Animal Model were 8.7 vs
4.9 bunnies for TNBA, 7.5 vs 4.1 bunnies for TNB, 8.0 vs 5.9 bunnies for TNW
and 1.60 vs 1.42 months for LT.
The top 5% of sires recorded higher ranges of transmitting abilities for all
traits studied when estimated by multi-trait Animal Model than those estimated by
single-trait Animal Model. The numbers of sires with positive transmitting ability
when using multi-trait Animal Model were larger than those of sires with positive
estimates obtained from applying single trait Animal Model was applied. For the top
5% of sires (with records), the percentages of sires common between single-trait
and multi-trait Animal Models were relatively moderate and ranged from 19.0 to
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52.4% for different traits studied. On the other hand, the percentage of sires
remaining in the same position when using the two models were very low and
ranged from 0.0 to 2.4% ..
Results of transmitting ability obtained by multi-trait and single-trait Animal
Models for animals without records (paternal grand sires and maternal grand sires)
had the same trend obtained for animals (sires) with records. Also, the percentages
of paternal grand sires or maternal grand sires which are common between singletrait
Animal Model and multi-trait Animal Model were moderate or high and ranged
from 15.4 to 69.2%.
(v) Dam evaluation for lifetime production traits
For dams with available records, dam transmitting ability (DTA) values were
predicted by using both animals models used. For the list of all dams with records,
using multi-trait Animal Model resulted in higher ranges in estimates ofDTA for all
traits than those resulted from single-trait Animal Model. The ranges of estimates of
DTA obtained by multi-trait vs single-trait Animal Model were 21.08 vs 10.8
bunnies for TNBA, 20.6 vs 11.8 bunnies for TNB, 11.3 vs 7.1 bunnies for TNW
and 1.01 vs 0.82 months for LT. Similar to the list of all dams, the ranges in DTA
for the top 30% of dams estimated by multi-trait Animal Model for all lifetime
production traits studied were nearly double to those estimated by single-trait
Animal Model. In both multi-trait and sinlge-trait Animal Models, the ranges in
DTA othe top 30% of the dams seem to be of the same trend when all dams were
considered. The numbers of dams with positive transmitting ability estimates and
their percentages estimated by multi-trait Animal Model where higher than those
obtained from single-trait Animal Model. However, the percentages of dams with
positive values of DTA obtained from multi-trait Animal Model vs those obtained
by single-trait Animal Model were 97.3 vs 49.2% for TNBA, 97.4 vs 48.2% for
TNB, 99.4 vs 50.8% for TNW and 87.2 vs 50.9% for LT.
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For the top 30% of dams for all lifetime production traits, percentages of dams
with records common in both single-trait and multi-trait Animal Models were
moderate or high and ranged from 53.1 to 69.0%. The percentages of dams
remaining in the same position were almost equal to zero.
The minimum and maximum estimates of transmitting ability values and their
ranges for animals without records (dams of dams and sires of dams) showed the
same trend obtained as that of dams with records.
Number of animals with positive transmitting ability values and their
percentages for lifetime production traits indicate that multi-trait Animal Model gave
much higher values of transmitting ability single-trait Animal Model. The positive
estimates obtained for dams of dams ranged from 44.2 to 47.7% when using singletrait
vs 60.3 to 87.1% when using multi-trait, while the respective estimates
recorded for sires of dams ranged from 43.2 to 45.9% and from 68.6 to 92.4%. For
the top 30% of animals without records percentages of dams of dams and sires of
dam common when using the two Animal Models were high and ranged from 50.5
to 77.4% for dams of dams and from 33.0 to 59.6% for sires of dams.
(vi) Rank correlation:
For both data sets of sires and dams (animals with and without records),
estimates of rank correlation among ranks of transmitting ability estimated by
single-trait Animal Model were high and near to unity for lifetime litter-size traits
(TNB~ TNB and TNW). The estimates ranged from 0.88 to 0.98 (P < 0.001) for
both sets of animals.
Most correlations among ranks of transmitting ability value estimated by
single-trait Animal Model and those estimated by multi-trait Animal Model were
relatively moderate or low where 67 estimates out of 96 were of less than 0.4. This
means that effectiveness of single-trait Animal Model is not similar to that of multitrait
Animal Model in evaluating animals for lifetime production traits in rabbits of
the study.