SIGNIFICANT DECREASE OF SERUM VITAMIN-A LEVEL IN JAPANESE BLACK BEEF STEERS AFTER INTRODUCTION TO A FARM

Significant decrease of serum vitamin A (V.A) level in 4 out of 5 Japa nese Black beef steers on day 7 after introduction was described in th e present study. The feeder steers were fed the diets containing much more V.A than they required. In the farm where they were introduced, t he productivity was high and the frequency was low in bovine cases of death and disease. The herd management; i.e. feeding method and enviro nment of the farm were properly arranged. Results obtained from blood serum analyses revealed that health and nutritional status of the feed er steers were good on the day of introduction. The feeder steers, cli nically healthy on the day of introduction, manifested mild bronchitis and diarrhea on days 2 and 10 after introduction, respectively, and s lightly decreased dietary intake on both days. Serum V.A levels of the feeder steers were within the normal range. However, significantly de creased serum V.A level was detected in 4 feeder steers out of 5 on da y 7 after introduction. This may be attributed to stress increased V.A consumption rather than the decreased V.A intake.