A 28-day trial investigated the effects of feeding diets containing spray-dried porcine plasma to 60 weanling pigs (21+/- 3 days of age) in two environments designed to compare disease challenge. Environments were characterized by all in-all out or continuous-flow, onsite nurseries. From day 0 to14 (Phase I) pigs were offered diets containing either 6% spray-dried porcine plasma and 2.3% blood cells or 10% dried skim milk and 7% fish meal followed by appropriate Phase II diets containing either 2.27% blood cells or 5% dried skim milk and 2.5% fish meal, respectively. From days 0 to 14, pigs offered the sprat dried plasma diets showed improved average daily weight gain in both environments. The improvements were greater as a percentage in the continuous flow nursery vs. the all in-all out nursery. As expected, average daily weight gain was greater in the all in all-out than in the continuous-flow nursery from days 0 to 21. Average daily feed disappearance was higher in pigs offered spray dried plasma from days 3 to 7. Average daily feed disappearance was also higher in the all in-all out vs. the continuous-flow up to day 21. There was no effect of diet in gain: feed ratios for any period. However, gain to feed ratios were higher in the continuous-flow nursery from days 3 to 28. Insulin-like growth factor 1 levels were higher in the all in-all out nursery on days 3 and 14. Mean body temperatures of pigs offered spray dried plasma tended to be lower 3 days post-weaning, however, this trend did not continue. Neither environment nor diet affected health score, fecal score, total serum immunoglobulin or the humoral response to vaccination against KLH at weaning. The results of this experiment showed that feeding spray dried plasma improved growth performance in pigs reared in a slow growing, continuous-flow environment and also in faster growing pigs in an all in-all out environment.