Table 2 Studies reporting vitamin A restriction and the ADH1C genotype in cattle

Angus-cross steers (n = 130; 50 TT, 50 TC, 30 CC)

Backgrounded at 549 IU vitamin A/kg DM then fed 0 or 2200 supplemental IU vitamin A/kg DM

Un-supplemented steers had greater marbling scores and IMF than supplemented steers. There was a significant treatment × genotype interaction for IMF. With no vitamin A supplementation, TT steers had 23% greater IMF than CC steers. Un-supplemented TT steers had 24% greater IMF than supplemented TT steers

[106]

Angus-cross steers (n = 117; 45 TT, 45 TC, 27 CC)

Backgrounded at 3360 IU vitamin A/kg DM, then fed 550, 1100, or 1650 total IU vitamin A/kg DM

A treatment × genotype interaction was observed for IMF; TT steers on the 1650 IU/kg DM treatment had higher IMF relative to CT and CC steers on the same treatment

[107]

Korean native steers (n = 136; 102 TT, 34 TC)

Backgrounded at 890 IU vitamin A/kg DM, then fed 930 IU total vitamin A/kg DM

Marbling scores were greater for the TC genotype than the TT genotype following a vitamin A-restricted diet

[110]

Black Angus steers

(n = 2000; TT and TC), mixed breed

Backgrounded on 3360 IU vitamin A/kg DM, then fed 1100 or 2200 IU total vitamin A/kg DM

There was not a significant vitamin A × ADH1C interaction for marbling score

[111]