Amniotic fluid is important for the maintenance of maternal responsiveness and the establishment of maternal selectivity in sheep

Abstract

Amniotic fluid (AF) is important for the establishment of maternal behaviour in inexperienced ewes, but its role in experienced mothers remains to be studied. Here, the maintenance of post-partum maternal responsiveness and the establishment of exclusive bonding was investigated in multiparous ewes when AF was removed from the neonate or/and physical contact with the young was precluded for the first 4 h post partum. Maintenance of maternal responsiveness and establishment of exclusive bonding were measured by the proportion of mothers accepting their own lamb and alien lambs that had been either washed or not washed, and by comparing an acceptance score for each type of lamb. The acceptance score was computed by summing standardised variables of acceptance (low bleats, acceptance at udder, nursing and licking time) and subtracting standardised variables of rejection (high-pitched bleats, rejection at the udder and aggressive behaviour). Washing the neonate reduced its acceptance score, but the proportion of mothers rejecting their own lamb was reduced only when washing the neonate and prevention of physical contact for 4 h were combined (7/15 v. 0/10 in controls, P 5 0.02). In addition, washing the neonate increased the acceptance score of the washed alien lamb, but not of the unwashed alien. However, washing and privation of physical contact did not increase significantly the proportion of mothers accepting an alien lamb at 4 h post partum. We conclude that AF is important in experienced ewes for the establishment of maternal responsiveness, as already found in primiparous mothers. In addition, our results indicate that AF also carries some chemosensory information facilitating exclusive bonding.

Maternal behaviour of Awassi sheep and behaviour of thelambs during the first hour after parturition

“…It is known that amniotic fluids are crucial for the establishment of a bond between a mother and her newborn. This fluid carries some chemosensory information that facilitates exclusive bonding (19). At this point, sniffing and licking behaviours come into play.…”

Maternal experience in Romanov sheep impairs mother-lamb recognition during the first 24 hours postpartum

“…In a comparison of maternal behavior between Romanov, Ile de France, and Préalpes du Sud ewes and their lambs within 3 hours after birth, Poindron et al (1984b) found no major differences in multiparous dams. In contrast, primiparous Romanov ewes showed lower problems for lamb licking and less aggressive behavior to newborns compared with the other 2 breeds.…”

“…Most studies of Romanov ewes have been based on productivity, and only 2 reports were found supporting the assumptions of high maternal ability (Poindron et al, 1984b;Ricordeau et al, 1976). In a comparison of maternal behavior between Romanov, Ile de France, and Préalpes du Sud ewes and their lambs within 3 hours after birth, Poindron et al (1984b) found no major differences in multiparous dams.…”

“…Lack of maternal experience in ewes impairs or delays the normal maternal selective bonding process (Otal et al, 2009;Poindron et al, 2010). This lack of maternal experience also affects dam behavior during the first hours after parturition (Lévy et al, 1993;Lévy et al, 1996).…”

Sensory factors involved in mother-young bonding in sheep: a review

“…Likewise, a mother may accept an alien lamb within four hours of giving birth if the young animal is impregnated with amniotic fluid. Interestingly, this suggests that the source of the amniotic fluid (i.e., whether it comes from the biological mother or another ewe) is not important, and that what truly matters is that the amniotic fluid contains attractive chemical cues that serve to facilitate individual recognition of the lamb (Poindron et al 1980;Levy et al 1983;Poindron et al 1984;Arteaga-Castaneda et al 2007;Poindron et al 2010). Keller et al (2003) have demonstrated that the presence of individual olfactory cues in amniotic fluids may also explain why about 30% of mothers display maternal selectivity from the very moment at which the foetus is expelled.…”