Effects of prostaglandin f2 alpha treatment of pseudopregnant pigs on nestbuilding and interactions with newborn piglets

Previous studies showed that prostaglandin (PG)F2 alpha treatment stimulate d nest building behaviors in prepartum and pseudopregnant pigs. This experi ment studied behaviors of PGF2 alpha -treated pseudopregnant nulliparous pi gs (gilts) exposed to newborn piglets. Penned pseudopregnant gilts (days 46 -53) were injected with either 10 mg PGF2 alpha (n = 8) or saline (n = 8) i m, and behavior was recorded for 2 h (period A). Between 2 and 6 h (period B), gilts were given two male piglets (< 12 h old) and a novelty object (ho use brick) and recordings continued. During period A, PGF2<alpha> animals s howed greater frequencies of standing, pawing, rooting, lifting, and carryi ng straw (indices of nest building) and scratching than saline treated anim als. During period B, one PGF2 alpha- and two saline-treated gilts attacked piglets, which were removed from the pen and the gilts excluded from furth er analysis. There were no treatment differences in period B in gilt postur e, nest building behavior, or interactions with piglets or novelty object, except for a reduced frequency to trap piglets beneath their bodies and an increased frequency to attempt to escape from the pen in PGF2 alpha -treate d animals. Piglet position relative to the gifts' head and udder was unaffe cted by treatment. Gilts in both groups approached and nosed piglets more w ithin the first 30 min of period B than subsequently. PGF2 alpha -induced n est building had only a weak impact upon subsequent interactions between gi lts and piglets, suggesting that mechanisms controlling porcine nest buildi ng and maternal behavior in this model were not directly linked. (C) 2001 A cademic Press.