The effects of crossfostering pigs on survival and growth.

Data from 254 crossfostered pigs and 753 noncrossfostered pigs of Duroc and Landrace first-parity litters were used to assess the phenotypic effects of crossfostering on baby pigs. Differences between crossfostered and noncrossfostered pigs in the recipient litter were analyzed. Phenotypic correlations were calculated for selected individual pig traits (n = 1007, combined foster and nonfoster data). Birth weight was correlated positively with improved birth vigor (r = .40; P less than .01), survival to 21 d (r = .34; P less than .01) and weight at 21 d (r = .37; P less than .01). Improved birth vigor was correlated positively with pig survival to 21 d (r = .70; P less than .01) and to weaning (r = .66; P less than .01). These correlations indicate that baby pig size and strength are related and that these two characteristics influence survival and performance. Pigs that were not crossfostered (adjusted for birth vigor) had a 4.8% (P less than .10) higher rate of survival to 21 d and a 6.8% (P less than .05) higher rate of survival to weaning (42 d). However, crossfostered pigs had greater birth vigor (P less than .01). Unadjusted for vigor, crossfostered pigs had an 11.3% (P less than .01) higher rate of survival to 21 d and an 8.6% (P less than .05) higher rate of survival to weaning than noncrossfostered pigs. These results indicate that when average-strength pigs were crossfostered, livability was reduced. However, crossfostered pigs that were stronger than average had greater livability than pigs that were not crossfostered.(ABSTRACT TRUNCATED AT 250 WORDS)