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Immunogenetic influences on Litter Traits, viability and growth in Broiler Rabbits
A detailed investigation into the genetic and environmental factors influencing litter traits, growth and viability among three temperate broiler breeds of rabbits namely New Zealand white, Grey Giant and Soviet Chinchilla, maintained at rabbit research station under the Centre for Advanced Stud...
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| Muut tekijät: | |
| Aineistotyyppi: | Ph.D Thesis |
| Kieli: | Undetermined |
| Julkaistu: |
Mannuthy
Department of Animal Genetics and Breeding, College of Veterinary and Animal Sciences
1999
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| Yhteenveto: | A detailed investigation into the genetic and environmental factors
influencing litter traits, growth and viability among three temperate broiler
breeds of rabbits namely New Zealand white, Grey Giant and Soviet
Chinchilla, maintained at rabbit research station under the Centre for
Advanced Studies in Animal Genetics and Breeding of Kerala Agricultural
University was undertaken. The effect of breed and sire on litter traits,
growth and viability were assessed. Association among these traits were
estimated. In an attempt to ascertain the genetics of humoral immune
response of broiler rabbits, antibody response to chicken RBC was analysed.
The influence of breed, sex and sire on humoral immune response was
ascertained. Heritability of humoral immune response was worked out. The
interrelationship between humoral immune response, growth and viability
was estimated.
Litter size at birth averaged 4.37 ±0.15 among rabbits. The effect of
breed and sires within breed was not significant on this trait. Grey Giant
rabbits had highest litter size at birth.
Overall mean for litter weight at birth was 227.36 ± 6.81 g. Breed
and sire effects were not significant on litter weight at birth. Grey Giant
breed had highest litter weight at birth of 236.70 ± 14.74 g.
2
Breed differences were significant (P:5 0.05) for the litter size at
weaning among broiler rabbits. Grey Giant had largest weaning litter size
of 1.96±0.25 followed by New Zealand White (1.87 ±0.24) and Soviet
Chinchilla (1.18 ± 0.21). The effect of sires on this trait was not significant.
The effect of breed on litter weight at weaning was significant
(P:5 0.05). Grey giant had heaviest litter weight at weaning with a mean of
1084.15 g New Zealand White and Grey Giant had weaning litter weight of
1073.88 g and 707.96 g respectively. Sire component of variance was not
significant for this trait.
Pre-weaning mortality among the three breeds of broiler rabbits
averaged 76.20%. The influence of breed on preweaning mortality was
significant (P :50.05). New Zealand White rabbits had least preweaning
mortality and Grey Giant suffered from maximum preweaning losses.
Preweaning mortality among the litters of various sire groups were not
differed significantly.
Phenotypic correlation coefficient among litter size traits and litter
weight traits studied were positive and highly significant (p:5 0.01). Litter
size traits had highly significant (P:5 0.01) positive correlation with litter
weight traits. Pre-weaning mortality had a highly significant (P:50.01)
negative correlations of (-)0.27, (-)0.85 and (-)0.81 respectively with litter
weights at birth and at weaning and litter size at weaning. Association
between litter size at birth and preweaning mortality was significant
(P:5 0.05) and negative.
3
Genetic correlations of litter size at birth with litter weight at birth and
litter weight at weaning were highly significant (P:=:; 0.01) and positive.
Litter weight at birth had a highly significant (P:=:; 0.01) genetic correlation
with litter size at weaning.
Overall mean of body weight at weaning was 611.73 g among
rabbits. Effect of breed and sire was not significant on this trait. Grey
Giant, New Zealand White and Soviet Chinchilla respectively had weaning
weight in grams of 641.92, 614.33 and 564.36.
Body weight at 12 week averaged 1168.41 g in broiler rabbits.
Though the breed effect was not significant, Soviet Chinchilla had heaviest
body weight at 12 week with a mean of 1237.66 g followed by New
Zealand White (1132.97 g) and Grey Giant (1121.19 g). The effect of sire
was significant(p :=:;0.05) for the variation body weight at 12 week.
Effect of breed, sire and sex on Forssman antibody titre to chicken
RBC was not significant. Forssman antibody titre (1 + loge) averaged 0.11
in the population.
Antibody response to chicken RBC peaked 7 day post immunisation
with a mean of 4.208 and dwindled to a mean of 3.454 and 2.932
respectively on 14 and 21 day post immunisation.
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4
The effect of breed was not significant on 7 and 14 day post-
immunisation antibody titres to chicken RBC. However, 21 day post-
immunisation antibody titres to chicken RBC was significantly (P::; 0.05)
influenced by the breed. Soviet chinchilla rabbits consistently had higher
antibody titres with a mean of 4.3715,3.6320 and 3.2903 at 7, 14 and 21
day post-immunisation. Though not significant, males had higher antibody
titres to chicken RBC compared to females. sire had significant effect on
7th day (P = 0.0486), 14th day (P = 0.0218) and 21 st day (P = 0.0047) post-
immunisation antibody titres. Heritability estimates were high for the
immune response traits.
Phenotypic correlation between 7, 14 and 21 day postimmunisation
antibody titres were highly significant (P::; 0.01). Association of Forssman
antibody titre with postimmunisation antibody titres were not significant.
Body weight at weaning had significant (P::; 0.05) negative correlation
of (-)0.18 and (-)0.19 respectively, with 14 and 21 day postimmunisation
antibody levels to chicken RBC.
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