• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.13-24
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• 2016

Sixty Hanwoo steers(15 months of age; 409±29.2 kg of BW) were used to evaluate the effects of dietary vitamins A and D restriction on carcass characteristics. Steers were allotted randomly to 1 of 4 treatments: Control(diet supplemented with vitamins A, D and E), -A (diet supplemented with vitamins D and E), -D(diet supplemented with vitamins A and E) and -AD(diet supplemented with vitamin E only). Steers were fed the experimental diet for a period of 8 months(until 23 months of age), and then supplemented with vitamins A and D at 0.05% of the diet(as fed-basis) from 24 to 26 months of age, and at 0.1% of the diet from 27 to 31 months of age(harvesting time). Dietary restriction of vitamins A and D did not affect DM intake, daily gain and feed conversion ratio. But the concentration of serum retinol was significantly(P<0.05) decreased by vitamin A restriction with the lowest concentration being seen at 23 months of age(345.0 ㎍/L and 326.7㎍/L for control and -D treatment versus 169.3 ㎍/L and 175.4 ㎍/L for -A and -AD treatments). The serum concentration of 25(OH)D₃ was also decreased significantly(P<0.05) by vitamin D restriction and the lowest concentration was seen at 18 months of age(53.7ng/ml and 61.8ng/ml for control and - A treatment versus 24.0 ng/ml and 24.5 ng/ml for -D and -AD treatments). After the restriction period of vitamins A and D, the concentrations of retinol and 25(OH)D₃ for - A, -D and -AD treatments were recovered at those of control. Dietary restriction of vitamins A and D did not affect carcass weight, backfat thickness, ribeye area, quality grade and yield grade. But marbling score was significantly increased by vitamin A restriction compared with control(6.73, 6.87 and 5.73 for -A, -AD and control, respectively). The results of the present study suggested that dietary vitamin A restriction could improve marbling score in Hanwoo steers.