Acoustic analysis of the distress vocalisation of the neonate lamb — ASN Events

Acoustic analysis of the distress vocalisation of the neonate lamb (#517)

Christine Morton 1 , Geoffrey Hinch 1 , Paul McDonald 1 , Alison Small 2
  1. University of New England, ARMIDALE, NSW, Australia
  2. Agriculture Flagship, CSIRO, Armidale, NSW, Australia

The neonate distress cry demonstrates a similar acoustic structure across a range of mammalian species and is highly effective in attracting and compelling parental care. Evidence of the same neural circuitry across mammalian and bird species, and alignment of critical periods of vocal behaviour, has been used to support the evolutionary theory that the infant cry pathway has remained unchanged or converged toward a similar configuration to ensure reproductive success within a range of environments and social situations (Lingle et al, 2012). In support of this premise, distress vocalisation features including latency, vocalisation rate, fundamental frequency and other acoustic parameters are now commonly recognised to reflect neurobehavioral integrity in both the human and rodent neonate. Using a translational approach, the aims of this study were to investigate the acoustic parameters of neonate lamb distress vocalisations associated with cognitive functioning and maternal-infant behaviour. Following an initial study where delayed vocalisation was found to be associated with poor vigour-related behaviours in the first 12 hours post partum (Morton et al, 2014), further studies were undertaken to investigate the relationship of acoustic signal characteristics with markers indicative of fetal distress, and the impact of deficient signals on maternal response. The results of these studies indicate that lambs with delayed vocal responses emit fewer, and often inappropriate signals, with acoustic parameters reflecting low vocal intensity and stability, which were less likely to be preferred by ewes in a 2 choice test (p<0.05). Delayed vocalisation latency was also associated with elevated plasma glucose (r=0.45, p<0.005), longer parturition (r=0.61, p<0.01) and heavier birth weight (r=0.33, p<0.05). The results support the hypothesis that delayed vocalisation responsiveness in neonate lambs is associated with fetal distress; poor signal efficiency; and suboptimal maternal arousal. Compromised vocal cues, and in particular distress vocalisation latency, may be used as an indicator of deficient neurobehavioural status in the neonate. This research has important implications for understanding failed maternal-young interactions in ungulate species.

  1. Lingle, S., et al (2012). What makes a cry a cry? A review of infant distress vocalizations. Current Zoology, 58(5), 698-726.
  2. Morton, C. et al (2014). Vocalisation latency of neonate lambs as an indicator of vigour. Proc. 48th Congress Int. Soc. An. Ethol., pp 139