Effects of prostaglandin f2α treatment of pseudopregnant pigs on nest building and interactions with newborn piglets

Previous studies showed that prostaglandin (PG)F2 alpha treatment stimulated nest building behaviors in prepartum and pseudopregnant pigs. This experiment studied behaviors of PGF2 alpha -treated pseudopregnant nulliparous pigs (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) im, 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 (house brick) and recordings continued. During period A, PGF2<alpha> animals showed greater frequencies of standing, pawing, rooting, lifting, and carrying straw (indices of nest building) and scratching than saline treated animals. During period B, one PGF2 alpha- and two saline-treated gilts attacked piglets, which were removed from the pen and the gilts excluded from further analysis. There were no treatment differences in period B in gilt posture, 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 -treated animals. Piglet position relative to the gifts' head and udder was unaffected by treatment. Gilts in both groups approached and nosed piglets more within the first 30 min of period B than subsequently. PGF2 alpha -induced nest building had only a weak impact upon subsequent interactions between gilts and piglets, suggesting that mechanisms controlling porcine nest building and maternal behavior in this model were not directly linked. (C) 2001 Academic Press.