There is little direct evidence that litter-mate size has an effect on the weight gain and
survival of low-birth-weight piglets. Low-birth-weight piglets fostered into litters with
similar-sized litter-mates had improved survival and weight gain relative to low-birthweight
piglets that were not fostered (Marcatti Neto, 1986), although Aherne (1999) found
no such effect. Low-birth-weight piglets raised with much-heavier litter-mates had slightly
lower survival rates, but showed no tendency towards lower weight gains or less-successful
suckling behavior than low-birth-weight piglets raised with slightly heavier litter-mates
(Milligan et al., 2001b). Our purpose was to examine the effect of neonatal weight and
within-litter neonatal-weight variation on pre-weaning mortality, weight gain, and variation
in weaning weights.