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1. A dose-response experiment was conducted with male Korean native ducklings (KND) to evaluate the total sulphur amino acid (TSAA) requirement from hatch to 21 d of age. 2. A completely randomised design with 7 dietary TSAA concentrations (0.62%, 0.65%, 0.68%, 0.71%, 0.74%, 0.77% and 0.80%) were used with 6 replications per treatment. 3. Body weight (BW) and feed intake were measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). One duckling per pen (n = 6) was killed by cervical dislocation to weigh empty body and drumsticks at the conclusion of experiment. 4. BW was improved significantly with increasing TSAA content, in a non-linear manner. A significant decrease of FCR was shown with increasing TSAA contents. TSAA requirement was determined by taking a mean value after fitting the data to both a linear-plateau and a quadratic-plateau model. Estimated TSAA requirements were 0.70%, 0.70%, 0.66% and 0.70% for the maximum BW, ADG and ADFI and for the minimum FCR, respectively. Increasing TSAA content improved quantity of full body weight (FBW), empty body weight (EBW) and drumstick weight (DSW), but there was no effect on proportion of DSW in relation to EBW and proportion of EBW to FBW. 5. In conclusion, the growth of male KND during 1 to 21 d of age was improved with increasing TSAA content, suggesting optimal TSAA requirements estimated by two analysis models.

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This study aimed to evaluate carcass characteristics and meat quality of cross-bred (Brahman × Lai Sind, BL) bulls and cross-bred (Red Angus × Lai Sind, AL) bulls. A total of 30 bulls, 15 head/crossbred genotype were fattened for 90 days before slaughtering at 24 months of age. Carcass traits and meat quality were accordingly measured in 30 slaughtered animals. Results showed that the slaughter weight, carcass weight, carcass dressing, meat percentage, loin muscle area were higher for AL bulls than for BL bulls (p<0.05). The color of the meat was not affected by genotype with exception of L* at 48, 168 and 336 hours after slaughter, and this value was higher in AL than in BL bulls (p<0.05). The pH of the meat was not different between genotypes (p>0.05) but decreased quickly at 24 hours after slaughter (p<0.05), then maintained not significantly during storage times. The drip loss, cooking loss and tenderness of the meat were affected by cattle genotype and these values were lower in AL bulls than in BL bulls (p<0.05). In conclusion, crossbred (Red Angus × Lai Sind) bulls were higher carcass characteristics, and were better meat quality than crossbred (Brahman × Lai Sind) bulls.