Table 2.

Effects of antibiotic feeding program on the growth performance of nursery pigs

	Antibiotic feeding program
Item	Control	TIACTC†	CAROTC‡	SEM	P-value
No. of pens	30	30	30	—	—
Phase 1 (days 0 to 14)
BW, kg
Day 0 (start)	6.7	6.6	6.7	0.45	1.00
Day 14	11.7b	12.2a	12.1a	1.10	0.01
ADG, kg	0.36b	0.39a	0.38a	0.046	<0.001
ADFI, kg	0.46b	0.48a	0.49a	0.053	<0.001
G:F, kg:kg	0.780b	0.812a	0.775b	0.0120	<0.001
Morbidity and mortality
No. of pigs	7	12	10	—	—
Percentage of pigs	0.93	1.60	1.33	0.361	0.43
Phase 2 (days 14 to 35)
BW, kg
Day 14	11.7b	12.2a	12.1a	1.10	0.01
Day 35 (end)	25.0b	25.7a	26.0a	1.91	<0.001
ADG, kg	0.62c	0.64b	0.66a	0.039	<0.001
ADFI, kg	0.94b	0.98a	1.00a	0.078	<0.001
G:F, kg:kg	0.663	0.656	0.663	0.0116	0.11
Morbidity and mortality
No. of pigs	8	7	5	—	—
Percentage of pigs	1.08	0.96	0.69	0.372	0.61
Overall (days 0 to 35)
ADG, kg	0.52b	0.54a	0.55a	0.042	<0.001
ADFI, kg	0.75c	0.78b	0.79a	0.068	<0.001
G:F, kg:kg	0.692	0.695	0.690	0.0055	0.39
Morbidity and mortality
No. of pigs	15	19	15	—	—
Percentage of pigs	2.00	2.53	2.00	0.575	0.73

^a,b,cMeans within a row with different superscripts are significantly different (P < 0.05).

^†39 mg/kg (35 g/ton) tiamulin + 441 mg/kg (400 g/ton) chlortetracycline fed from days 0 to 14 followed by 39 mg/kg (35 g/ton) tiamulin fed from days 14 to 35.

^‡28 mg/kg (25 g/ton) carbadox + 441 mg/kg (400 g/ton) oxytetracycline fed from days 0 to 14 followed by 55 mg/kg (50 g/ton) carbadox fed from days 14 to 35.