ASSESSMENT OF GROWTH AND REPRODUCTIVE TRAITS IN DIALLEL CROSSING OF THREE RABBIT BREEDS
ASSESSMENT OF GROWTH AND REPRODUCTIVE TRAITS IN DIALLEL CROSSING OF THREE RABBIT BREEDS
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Date
2010-08
Authors
KABIR, Mohammed
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Abstract
A study was conducted to assess the growth and reproductive performance of three breeds of
rabbit in a full diallel crossing scheme. Data generated from 162 purebred kits born in 36
litters and 408 crossbred kits from 72 litters were used. The purebred kits comprised 38
Chinchilla (CHC), 54 New Zealand White (NZW) and 70 California White (CAW) kits. The
crossbred groups comprised 217 „main cross‟ kits and 191 „reciprocal cross‟ kits. Birth and
weaning traits considered included gestation length, litter size at birth and weaning, litter
weight at birth and weaning, preweaning mortality and weaning sex ratio while growth traits
included weekly body weight (BW) and body linear measurements: ear length (EL), body
length (BL), nose to shoulder (NTS), shoulder to tail-drop (STT), heart girth (HG), tail length
(TL), length of front leg (LFL) and length of back leg (LBL). Results of litter size at birth for
CHC, NZW and CAW breeds were 6.05, 6.89 and 7.33, respectively. The litter sizes at 21
and 35 days of age were 4.61, 5.5 and 5.94, and 4.58, 5.39 and 5.86 for CHC, NZW and
CAW breeds, respectively. Results for Litter weight for CHC, NZW and CAW breeds were
163.68g, 149.25g and 155.94g at birth, 952.13g, 1041.02g and 1067.29g at 21 days of age
and 1596.93g, 1764.05g and 1838.40g at 35 days of age, respectively. The respective birth
weights for individual kits for CHC, NZW and CAW breeds were 27.05g, 21.66g and 21.27g
while the values at 21 and 35 days of age were 206.53g, 189.27g and 179.68g, and 348.67g,
327.28g and 313.72g for CHC, NZW and CAW breeds, respectively. The above results
revealed that the CHC breed produced kits that were individually heavier at birth and at
weaning than the kits from NZW and CAW breeds. The relatively high performing ability of
the CHC breed was confirmed by the results of the general combining ability (GCA) on
growth traits which indicated that CHC breed showed significantly (P<0.05) high superiority
over NZW and CAW breeds for 8 traits (BW, EL, BL, TL, NTS, STT, LFL and LBL).
Nevertheless, heritability estimates for litter size from birth to weaning were high (0.49–0.64)
in the CHC breed, while the estimates for litter weight were moderate to high (0.34–0.52). In
the NZW and CAW breeds moderate to high estimates of heritability for litter size and litter
weight (0.33–0.46 and 0.28–0.41, and 0.31–0.42 and 0.32–0.41, respectively) were observed
from birth to weaning. In the crosses however, the results of specific combining ability
(SCA) indicated that the CHC x NZW cross was the best combination regarding the use of
sire and dam breed to exploit non-additive genetic variance in 6 of the 9 examined body
measurement traits. It was observed also that the CHC breed performed generally well in
crosses with either NZW or CAW. Cross performance was however low for NZW x CAW
cross, implying poor manifestation of non-additive gene action. Moderate to high coefficients
of genetic correlation in the CHC breed for growth traits (0.43±0.03–0.88±0.24; 0.27±0.04–
0.85±0.15; 0.20±0.02–0.83±0.14) at 6, 8 and 10 weeks of age respectively, were observed.
Positive and significantly high association for HG, BL, NTS, STT and BW indicated that
absolute height and frame size were complementary. Beside, selection for increased
measurement for any trait and in any of the breeds studied herein, would mean positive and
significant influence on the others and therefore, increased skeletal stature with concormitant
increase in other absolute body measurements. It was concluded that rabbit farmers in the
Guinea Savannah zone of Nigeria would operate more profitably if they keep Chinchilla does
with optimal feeding levels especially after weaning so as to attain faster growth and market
weight. The progeny from CHC x NZW combination proved the best among the crossbreds,
probably due to high exploitation of heterosis from both parents
Description
A DISSERTATION SUBMITTED TO THE POSTGRADUATE SCHOOL
AHMADU BELLO UNIVERSITY IN PARTIAL
FULFILLMENT OF THE REQUIREMENT FOR THE
AWARD OF DOCTOR OF PHILOSOPHY
IN ANIMAL SCIENCE
DEPARTMENT OF ANIMAL SCIENCE
FACULTY OF MEDINE
AHMADU BELLO UNIVERSITY
ZARIA, NIGERIA
Keywords
ASSESSMENT,, GROWTH,, REPRODUCTIVE TRAITS,, DIALLEL CROSSING,, THREE RABBIT BREEDS.