Table 1.

Timeline of events for control (CONT) and zilpaterol (ZH) steers fed 0, 28, or 56 d after ad libitum or maintenance intake level

Block	Block 1	Block 2	Block 1	Block 2	Block 1	Block 2
Harvest day	Day 0	Day 0	Day 28	Day 28	Day 56	Day 56
n	4	4	8	8	16	16
Pre-allocation period, d
Weighed at commercial feedyard	1	1	1	1	1	1
Transported to research sitea	2	2	2	2	2	2
Weighed at research site	3–4	3–4	3–4	3–4	3–4	3–4
Penned as block	3	3	3	3	3	3
Pretreatment feeding, d
Intermediate energy ration	3–5	3–5	3–5	3–5	3–5	3–5
High energy finishing ration	6–24	6–52	6–24	6–52	6–24	6–52
Allocation period, d
Weigh daysb	23–24	51–52	23–24	51–52	23–24	51–52
Assigned to pairs, randomized to treatment, and penned individually	25	53	25	53	25	53
Treatment period, d
Start of maintenance or continuation of ad libitum intake			29	57	29	57
Harvest	29	57	57	85	85	113
Fabrication	30	58	58	86	86	114
Zilpaterol hydrochloride supplementation or control					61–80	89–108
Treatment weigh days, db
Day −1 and day 0	28	56	28–29	56–57	28–29	56–57
Day 11			39	67	39	67
Day 21			49	77	49	77
Day 27 and 28			56	84	56–57	84–85
Day 55					112	112

^aTransportation duration of 23 h.

^bAll weights taken off feed and water for 9 h.