الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 172 |  |  |
| | | from | 172 | | |
Abstract
5. SUMMARY
This study was carried out in Gizereit El-Sheir Experimental
station at El-Kanater El-Khairia, that belongs to the
Animal Production Research Institute, Agricultural Research
Center, Ministry of Agriculture at Dokki, Egypt. Data were
collected on 1966 purebred progeny of Baladi Red (548), Bauscat
(620) and New Zealand White (798) rabbits produced during
two consecutive years of production (1985/1986 & 1986/1987)
to investigate some genetic and non-genetic effects on weaning
and post weaning body weights up to 16 weeks of age,
daily gain from weaning up to 16 weeks of age during different
age intervals (4-8, 8-10, 10-12, 12-14, 14-16 and 4-16
weeks), post weaning viability in rabbits up to different
ages till 16 weeks and carcass traits of rabbits of the three
breeds slaughtered at 12 and 16 weeks of age.
Body weight:
Dam effects contributed signi·ficantly (P(O. 01 or P(O. 001)
in the variance of body weight at different ages from weaning
up to 16 weeks.
Year-of-birth effects aD body
(P(0.05, P(OO, P(O.OOI or P(O.OOOl) at
weight were significant
some ages and noosignificant
in others.
Body weight of rabbits varied with month of birth at all
ages but without any definable trend; the differences were
generally significant (P(O.05 or P(O.OI) in the three breeds.
Body weight of rabbits varied from parity to another but
did not show any consistent pattern, the differences were
-.l46-
~~~~~~~~~~~~---_.~---_._-_._--_ ... __ .~-----------------
significant (P(O.05 or P<O.OOl) at all ages studied in Bauscat
and New Zealand White rabbits and mostly so in Baladi
Red.
Litter size at birth, constituted a significant (P(O.05
or P<O.Ol) source of variance in body weight of rabbits at
all ages stUdied. ;
Sex differences in body weight at all ages of the study
were in favour of females but were small and non-significant.
Body weights at different ages varied significantly
(P(O.01 or P<O.OOl or P<O.0001) with breed, Bauscat rabbits
always excelled the other two breeds.
Daily gain:
Changes in the average daily gain with advance of postweaning
age intervals up to 16 weeks did Dot show similar
trend in the three breeds of the study.
Dam effects contributed significantly (P(O.05, P(O.Ol,
P<O.OOI or P(O.0001) to average daily gain from weaning up to
16 weeks of age.
Average post-weaning daily gain during different age
intervals varied with year-af-birth effects, the differences
were significant in some age intervals and non-significant in
others.
Average post-weaning daily gain varied with month of
birth. parity and litter size at birth but without definable
trend, the differences were significant (P(O.05, P(O.01,
P<O.OOI or P<O.OOOl) during same age intervals and nonsignificant
during others.
Sex differences in post weaning daily gain during differeDt
age intervals were in favour of feLales but ~eI~ lifuited
and non-significant.
Average post-weaning daily gain during different age
intervals from weaning up to 16 weeks varied with breed group
significantly (P<O.05, P<O.OI or P<O.OOOl), Bauscat rabbits
showed the best performance.
Post-weaning viability:
Post-weaning viability of rabbits decreased as age
advanced.
Post-weaning viability of young rabbits up to 16 weeks
was significantly (P<O.OOI or P<O.OOOI) influenced by their
dams’ effects.
Year differences in post-weaning viability were generally
significant (P<O.Ol, P<O.OOI or p<O.OOOl).
Month-of-birth effects on .post-weaning viability were
significant (P<O.01, P<O.OOI or P<O.0001), but without any
definable pattern.
Parity effects on post-weaning viability showed no definable
trend and were non-significant.
Female rabbits recorded higher post weaning viability
than males up to all ages studied but the differences were
small and non-significant •
Differences in viability due to breed effects were 5i9-
nificant (P<O.OI or P<O.OOl) up to ten, 12 and 14 weeks of
age; New Zealand White rabbits were the most viable as compared
with the other two breeds.
-148-
~~L~a~~ trai ts:
Estimates of the means showed that the averages of all
carcass traits increased as age advanced except that of
dressing percentage.
Carcass traits when measured at 12 and 16 weeks of age
varied with year of birth, the diff~rences were in favour of
rabbits born in the first year (1985/86). The differences
were significant (P(O.05 or P(O.01 or P(O.001) for some
traits and non-significant for others at both ages.
Carcass traits varied with month of birth and parity, the
differences were significant (P(O.05, P(O.Ol, P(O.OOI or
P(O.0001) in some traits and non-significant in others at
both ages.
Carcass traits varied with sex, but the differences at
both 12 and 16 weeks of age were mostly non-significant.
Dauscat rabbits recorded the heaviest fasted weight while
Baladi Red gave the heaviest carcass weight and highest
dressing percent both at the two ages (12 and 16 weeks of
age) .
Carcass traits varied with breed, the differences were
significant (P(O.05 or P(O.Ol or P(O.OOI or P(O.OOOl) in
dressing percent as well as in weights of carcass, front
part, shoulder, chest, spleen, head, blood, stomach, intestine+
caecua, tail and bladder at 12 weeks of age, in weights
of non-eapty carcass as well as loin, lungs and kidneys at 16
weeks of age and in fasted weight as well as weights of
liver, heart and feet at both 12 and 16 weeks.
A positive significant (P(O.OOI or P(O.OOOl) linear association
between body weight at slaughter and carcass traits
was observe