Crossbred New Zealand White meat type 8 male and 16 female rabbits aged 3.5 to 4.5 months weighing 9.5 to 13.0 kg were used in a 128 day trial to study the effects of concentrate supplementation on growth and reproductive performance of rabbit under rural condition. Rabbits were divided according to live weight into two treatment groups, i.e. T 1 (conventional diet) and T 2 (conventional diet + concentrate 75 g/d per rabbit) with four replications per treatment in a Complete Randomized Design (CRD). All animals had free access to locally available green grasses. Results showed that, average daily live weight gain was significantly (p<0.01) higher in T 2 (13.02 ± 0.43 g/d) than T 1 (5.30 ± 0.43 g/d) group. Litter weight at birth was better (p<0.05) in T 2 (180.38 ± 16.37g) than T 1 (137.19 ± 16.37g) group. Litter size at weaning differed (p<0.05) and the mean values were 1.37 ± 0.30 for T 1 and 2.37 ± 0.27 for T 2 group. Kit weight at weaning was superior (p<0.01) in T 2 (408.12 ± 3.85g) than T 1 (310.62 ± 3.56g) group. Kit mortality up to weaning was higher (p<0.01) in T 1 (45.0 ± 10.07 %) than T 2 (26.92 ± 10.7 %) group. These results indicate that, supplementation of concentrate in addition to conventional feeding may improve growth and reproductive performance of rabbit under rural condition.

The productive and reproductive efficiency of Red Chittagong cattle (RCC) reared at the Bangladesh Livestock Research Institute (BLRI) farm was evaluated. A total of 46 RCC of different categories were considered under this study. Parameters studied were birth weight, weight at 3, 6 months of age and adult body weight, growth rate, daily milk yield, lactation length, lactation yield, age at puberty, weight at puberty, age at first calving, post partum estrus period, service per conception, calving interval and gestation length of RCC were collected and recorded. The birth weight differed significantly (p<0.01) between male and female and the average birth weight of RCC calves at farm level was 14.87 kg. The growth rates and adult body weight also differed significantly (p<0.05 and p<0.01) between male and female except in growth rate from 3 to 6 months of age. The average daily milk yield, milk yield per lactation and lactation length of RCC were 2.24 kg, 526.81 kg and 238 days, respectively. The age at puberty, service per conception, post partum estrus period and calving interval of RCC heifers and cows were 15 months, 1.15, 40 days and 11 months, respectively. It can be concluded that the RCC is a genetically and economically superior variety of Bangladesh.DOI: http://dx.doi.org/10.3329/pa.v18i2.18166 Progress. Agric. 18(2): 109 - 114, 2007

Heritability and genetic correlation of economic traits of Bangladesh Livestock Research Institute (BLRI) Cattle Breed-1 (BCB-1) were estimated with Residual Maximum Likelihood (REML) principle. The BCB-1 is a native cattle breed developed by BLRI through selective breeding among indigenous cattle of Bangladesh. Data asserted from performance record sheets of 500 animals maintained during 1992 to 2005 were analyzed for estimation of genetic parameters. The heritabilities were estimated with single trait animal model for age at service and age at first calving and those of single trait repeatability model for other traits. However, two traits animal models were used for estimation of genetic correlations among different traits. The model includes sex, season and year of birth, parity, generation and additive genetic merit of each individual. The estimated heritabilities were higher for lactation milk yield (LMY, 0.404) and age at first calving (AFC, 0.404) followed by moderate estimates of daily milk yield (DMY, 0.257), lactation length (LL, 0.333), peak milk yield (PMY, 0.335), milk yield per day of calving interval (MYCI, 0.227), age at first service (AFS, 0.316), calving interval (CI, 0.273), and post partum heat period (PPHP, 0.276). The genetic correlations of lactation milk yield were high with DMY (+0.797), LL (+0.797) and MYCI (+0.876), moderate with CI (+0.399), PPHP (+0.205) and DP (-0.404) and low with AFS (-0.048) and AFC (-0.025). The moderate to high heritabilities for along with high genetic correlations among most of the milk yield traits emphasized continuation of selective breeding program for maximization of genetic improvement of this breed. The information generated in the present study may also be used in planning breeding program for other indigenous cattle germplasm of the country.

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Bangladesh has a great demand of beef but it has been facing demand and supply mismatches due to insufficient production and supply of beef, low carcass yield of native cattle and recent no-cattle export policy of a long bordered neighboring country. Thus, the present work was undertaken with an objective to develop market beef cattle of average >150 Kg carcass weight by 24 months with an average FCR of <6.50 under on farm feeding and management condition. Aiming at developing breeding bulls the native dams of BCB-1 (BLRI Cattle Breed 1) were inseminated with the imported frozen semen of Brahman, Simmental, Charolais and Limousin. The crossbred progeny of different assorted F1 genotypes were being selected and their production and breeding performance were evaluated and compared with BCB-1. All pregnant (> 6 months of gestation period) cows were in pre-natal care, and all calves were raised in a single plane of nutrition and management. All crossbred progeny performed better than BCB-1 in terms of live weights and average daily gains. Among the crossbreds, Charolais×BCB-1 had the highest (p<0.001) birth weight (27.5±1.52 kg) followed by Brahman×BCB-1 (24.1±1.23), Simmental×BCB-1 (21.9±1.78), Limousin×BCB-1 (19.8±1.39) and BCB-1×BCB-1 (18.4±1.09), and the genotypes differences were highly significant (p<0.001). In average growth curve, Simmental cross grew faster followed by Charolais, Limousin, Brahman crosses and purebred BCB-1. The genotype×environment interaction was only observed in birth weight. Purebred BCB-1 had the lowest daily DM intake and showed the lowest FCR in all ages compare to other crosses. Calf scour and alopecia occurred in all genotypes. In this breeding program, calf mortality was found as 5.26%. Simmental×BCB-1 is performing as the best among the five genotypes in terms of growth up to 12 month of age.