1998 年 60 巻 1 号 p. 101-102
Significant decrease of serum vitamin A (V.A) level in 4 out of 5 Japanese Black beef steers on day 7 after introduction was described in the present study. The feeder steers were fed the diets containing much more V.A than they required. In the farm where they were introduced, the productivity was high and the frequency was low in bovine cases of death and disease. The herd management; i.e. feeding method and environment of the farm were properly arranged. Results obtained from blood serum analyses revealed that health and nutritional status of the feeder steers were good on the day of introduction. The feeder steers, clinically healthy on the day of introduction, manifested mild bronchitis and diarrhea on days 2 and 10 after introduction, respectively, and slightly decreased dietary intake on both days. Serum V.A levels of the feeder steers were within the normal range. However, significantly decreased serum V.A level was detected in 4 feeder steers out of 5 on day 7 after introduction. This may be attributed to stress-increased V.A consumption rather than the decreased V.A intake.