|
Japanese Black steers
|
Backgrounded at about 20,000 IU vitamin A/day, low vitamin A (no extra supplementation) diet was fed from 15 to 23 months of age
|
Maintaining a low level of serum vitamin A (≤ 20 μg/dL) before 23 months of age may contribute to higher marbling scores
|
[6]
|
|
Black yearling steers
|
Backgrounded at 1364 IU vitamin A/kg DM, then 0, 1103, 2205, 4410, or 8820 IU supplemental vitamin/kg DM was fed for 142 or 143 days
|
Little effect was observed for performance, marbling, or lipogenic enzyme activity in adipose tissue
|
[8]
|
|
Korean native steers
|
Backgrounded at 8890 IU vitamin A/kg DM, then 8890 (Con), 3890 (T1), or 890 (T2) IU restricted vitamin A/kg DM was fed for 240 days
|
Marbling scores in the vitamin A-restricted groups were not significantly higher than in the control group but showed a trend for a higher yield grade
|
[9]
|
|
Feedlot heifers
|
Backgrounded at 3640 IU vitamin A/kg DM, then 3640 or 0 IU vitamin A/kg DM was fed for 218 days
|
Vitamin A restriction increased the degree of marbling without affecting backfat thickness
|
[60]
|
|
Holstein steers
|
Backgrounded at 2700 IU vitamin A/kg DM, then 2200 or 950 IU of vitamin A/kg DM was fed for 112 days or 243 days (2200 IU for 112 days and 950 IU for latter 131 days)
|
Feeding the restricted vitamin A 243 days increased IMF without affecting subcutaneous or visceral fat deposition
|
[61]
|
|
Feedlot heifers
|
Backgrounded at < 1300 IU vitamin A/kg DM, then 0 or 2700 IU supplemental vitamin A/kg DM was fed for 168 days
|
The percentage of carcasses grading ≥ Choice−was not different between treatment groups
|
[62]
|
|
Feedlot heifers
|
Backgrounded at < 1100 IU vitamin A/kg DM, then 0 or 2700 IU supplemental vitamin A/kg DM was fed for 112 or 227 days
|
Vitamin A restriction did not affect USDA yield grade or marbling score
|
[63]
|
|
Angus steers
|
Backgrounded at a low β-carotene and vitamin A cereal-based ration (no detailed data), then 0 or 60,000 IU supplemental vitamin A/100 kg of BW/day was fed for 308 days
|
There was greater IMF in longissimus thoracis et lumborum and greater seam fat, but there ws no significant change in marbling score
|
[64]
|
