. 2020 Jul 20;34(5):2132–2141. doi: 10.1111/jvim.15862

TABLE 3.

Estimated daily vitamin E intake (mean ± SD, IU/d) of all horses (n = 331) separated into groups based on fresh, green pasture access (P, >6 h/d and NP, ≤6 h/d) and vitamin E form and amount, with contingencies (column totals) of vitamin E supplementation groups versus plasma alpha‐tocopherol concentration groups

	Vitamin E supplementation groups
	P				NP
	InE/NonE	SynE	NatE	NatE+SynE	InE/NonE	SynE	NatE	NatE+SynE
E intake (IU/d)	106 ± 122	1129 ± 1291	2317 ± 3518	2121 ± 794^{^}	205 ± 154	1020 ± 93	3460 ± 3362^{#,^}	1895 ± 1317^{^}
Plasma (E)
Deficient <1.5 μg/mL	13 (16.1%)^a	4 (6.20%)^a	1 (5.30%)^a	0^a	19 (32.2%)^a	10 (19.6%)^a	3 (8.60%)^a	1 (8.30%)^a
Marginal 1.5‐2 μg/mL	19 (27.2%)^a	9 (13.9%)^a,b	3 (15.8%)^a	1 (11.1%)^a	14 (23.7%)^a,b	10 (19.6%)^a	10 (28.6%)^a	0^a
Adequate >2 μg/mL	49 (56.8%)^a	52 (80.0%)^b	15 (79.0%)^a	8 (88.9%)^a	26 (44.1%)^b	31 (60.8%)^a	22 (62.9%)^a	11 (91.7%)^a

Notes: Supplementation groups are horses receiving <500 IU of vitamin E daily (InE/NonE) and those receiving ≥500 IU as either >90% synthetic source (SynE); >90% natural source (NatE); or a combination of both at <90% each (NatE+SynE). Superscript symbols ^{#, ^} indicate statistically significant differences in daily dietary vitamin E intake between supplementation groups for horses receiving ≥500 IU/d with (P) or without (NP) adequate pasture access. Superscript ^# indicates a significant difference from the SynE‐P group (P = .01) and ^{^} indicates a significant difference from the SynE‐NP group (P = .02 for NatE+SynE‐P, P = .04 for NatE+SynE‐NP and P = .003 for NatE‐NP). Superscript letters ^{a, b} denote statistical significance (P < .05) between supplementation groups (down a column).