Twenty 35-wk-old chickens, including 10 Single Comb White Leghorn (SCWL) and 10 Rhode Island Red (RIR) hens, were used to examine the effects of egg and yolk weights on egg yolk antibody (IgY) production in the two strains of chickens immunized with BSA. The SCWL chickens had a greater (P < 0.01) percentage hen-day production and greater egg and yolk weights than did the RIR chickens. However, the anti-BSA antibody activities determined by ELISA in the serum and the egg yolk were similar (P > 0.05) between the SCWL and RIR chickens. Similarities between the two strains of hens were also observed in protein and total IgY contents (expressed as the percentage of wet weight of yolk) and the percentage of BSA-specific antibody in the total IgY. It was concluded that both the SCWL and RIR chickens immunized with BSA can produce egg yolk IgY containing similar proportions of BSA-specific antibodies. Therefore, the egg yolk weight and the percentage hen-day production, both of which are greater in the SCWL hens, are considered to be important factors for the efficient production of IgY.

This study was conducted to determine the optimum substitution level of dried leftover food (DLF) in formula feed for Hanwoo (Korean Native Cattle) steers. A total of forty growing steers were assigned to 5 treatments based on substitution level of DLF (at 0, 25, 50, 75 and 100% level of formula feed). The experiment was carried out with growing steers from 6 months of age to 24 months of age. Average daily gain (ADG) was not affected by DLF substitution level up to 75% of formula feed. However ADG decreased at 100% substitution level. Daily feed intakes were similar among treatments but the amount of feed per 1 kg gain increased with increasing substitution level of DLF. Dressing percentage was around 62% in all treatments without any significant differences. Proportion of quality beef higher than grade 1 was the greatest from animals fed 25% substitution level of DLF. Economic efficiency for Hanwoo steer operator was the highest with 50% substitution level of DLF.

The present study was carried out to determine the effects of feeding levels of barley grain in diets of Hanwoo on the growth performance and carcass characteristics of Hanwoo. Twenty Hanwoo bull calves (initial mean body wt. 99 kg) were randomly divided to examine the effects of 5 feeding levels of barley grains (addition levels: 0, 0 and 40% for FII40; 0, 0 and 60% for FII60; 0, 20 and 40% for F2040; and 0, 20 and 60% for F2060 during the growing, early fattening and late fattening periods, respectively) on growth performance and meat quality. Body weight was not affected by the feeding level of barley grains through the whole experimental period, although the body weight of Hanwoo bulls fed FII40 diet at 24 months old of age tended to be lower (591.5 kg) than that of other animals (606.2 614.6 kg). However, body weight gain in the bulls of the FII60 diet was slightly increased (P<.19). The feeding levels of barley grains did not influence on fasting body weight, carcass weight, carcass rate, lean meat, retailed cut, KPH fat and bone yield. The lean meat yield (89.82%) and fat yield (20.28%) tended to increase in Hanwoo bulls fed the F2060 compared with other treatments. Feeding of the diets of FII40 resulted in the higher marbling scores as 3.75, respectively than other diets.