Summer and Winter Seasons Coincide with Changes in the Nutritional Needs and Corresponding Alterations of Blood Biochemical Parameters of Korean Hanwoo Beef Cattle

摘要

The effects of programmed feeding on the production performance as well as blood biochemical parameters (total bilirubin, total cholesterol, AST, ALT, BUN, cortisol and insulin) during the summer and winter seasons were determined. Twenty-four Hanwoo beef cows (350-450 kg) were divided into three treatment groups based on the targeted average daily gain (0.2, 0.4 and 0.6 kg/day). Results have shown that during the summer season, cows that were fed to gain 0.6 kg/day were able to have the highest feed efficiency amongst all the three groups. On the other hand, during the winter season, cows which were projected to gain 0.4 kg/day had the highest feed efficiency. Results showed that all blood biochemistry measurements fell within normal range for both summer and winter seasons except for total bilirubin (both summer and winter season) and total cholesterol (winter season, 0.4 kg/day and 0.6 kg/day). In addition, cortisol levels during the winter season were significantly higher (four to five-folds). Findings of this study can help in providing the optimum amount of feeds to Hanwoo cows.