Table 6.

Effects of dietary treatment and group size on medical treatments and removals, day 0–41

	Diet1						Group Size2
Item	NC	PC	ZA	DR	SEM	P value	Large	Small	SEM	P value
Medical treatments, proportion3,5	0.814a	0.506b	0.719ab	0.923a	0.152	0.024	0.759	0.722	0.136	0.706
Removals, proportion4,5	0.086	0.062	0.073	0.059	0.017	0.666	0.087	0.053	0.0121	0.0486

¹NC = negative control; PC = positive control: NC + dietary antibiotics; ZA = NC+ ZnO + dietary acidifier; DR = NC + Bacillus-based direct-fed microbial + 5% resistant starch.

²Group size treatments: pigs were housed in groups of either 31 (large group) or 11 (small group) pigs per pen.

³Medical treatments calculated as total number of medical treatments administered per pen divided by number of pigs allotted to pen (31 or 11).

⁴Removals calculated as total number of pigs removed from study (found dead or removed for illness or injury) divided by number of pigs allotted to pen (31 or 11).

⁵Means within a row without a common superscript differ significantly (P < 0.05). Interaction P value for medical treatments and removals not significant. (P > 0.10).