Browsing by Author "Holdsworth, Sophia Ellen"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Behavioural effects of a thoracic squeeze on healthy neonatal mammals of precocial species : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Physiology at Massey University, Manawatū, New Zealand
    (Massey University, 2020) Holdsworth, Sophia Ellen
    Some neonatal farm mammals that are apparently healthy do not behave normally after birth and without intervention, often die. Recently, a thoracic squeeze has been applied to these neonates, which observed their entrance into a ‘non-responsive state’, from which they rapidly recover when the squeeze is released to express normal healthy behaviours. In addition, healthy newborn foals also become non-responsive during application of the thoracic squeeze. To date, there have been no systematic studies into the effects of the thoracic squeeze on healthy neonates of other precocial mammalian species. This preliminary research aimed to describe the responses of healthy newborn piglets and calves to a standardised application of the thoracic squeeze, and evaluate the effectiveness of the method of squeeze application in eliciting a non-responsive state. Neonatal piglets and calves were squeezed around the chest with either a soft fabric rope or a modified inflation cuff. Physiological parameters were monitored for abnormal changes, while induction behaviour and neural reflex activity were measured. Behavioural data indicated that the thoracic squeeze was effective at eliciting a non-responsive state in all piglets in the study and maintaining this state in half of all the piglets induced, with reduced or absent reflexes in nearly all piglets. In contrast, 81% of the calves were induced into a lower-responsive state, with half of all calves squeezed maintaining this state for the full observation period and present reflexes observed for nearly all calves. Furthermore, the cuff appeared to be more effective at inducing both piglets and calves into a non-responsive or lower-responsive state than the rope, with a faster application and removal. These findings suggest that the non-responsive state reported in foals can be generalised to neonates of other precocial species. The thoracic squeeze has been demonstrated to be inherently safe and effective at inducing and maintaining a non-responsive state in neonates. This pilot study provides a foundation for further research using the inflation cuff to explore the mechanisms underlying the thoracic squeeze and ways in which the squeeze can be effectively applied in an industry context.
  • Thumbnail Image
    Item
    Characterising the responses of farm mammals to a thoracic squeeze and the relationship to tonic immobility : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Manawatū, New Zealand
    (Massey University, 2023) Holdsworth, Sophia Ellen
    Applying compression to the thorax of newborn farm mammals causes immobility accompanied by reduced responsiveness. Traditionally, this response was proposed to arise in neonatal foals due to the ‘thoracic squeeze’ mimicking the compression occurring during birth. Recent findings regarding the responses to the squeeze suggest a link to Tonic Immobility (TI). TI is a temporary and reversible state of reduced responsiveness and immobility with characteristic physiological changes. It is elicited by the collective actions of handling and sustained physical contact with additional pressure (restraint) and may be facilitated by inversion. TI is reported in young and adult animals of numerous species. The aim of this thesis was to examine whether responses to the thoracic squeeze are consistent with TI. First, behavioural responses to a squeeze were explored in lambs, with a focus on determining whether responses persisted beyond the neonatal period. Cortisol responses of healthy neonatal piglets to the squeeze were then investigated to explore similarities in Hypothalamic-Pituitary-Adrenal responses between the squeeze and TI. The final study examined electroencephalographic (EEG) responses of healthy neonatal piglets to a thoracic squeeze under light anaesthesia, to determine whether the squeeze causes changes in brain activity or exerts anti-nociceptive effects such as those reported during TI. The results demonstrated that responses to a thoracic squeeze persist beyond the neonatal period in lambs, and responses are generalised across multiple mammalian species. Furthermore, cortisol responses of piglets to a thoracic squeeze followed a similar pattern to that previously observed during TI in other species. Also consistent with some TI studies, the initial handling and restraint required to apply the squeeze appeared to induce the cortisol response in piglets. No inferences could be made about the effects of a thoracic squeeze on state of awareness in neonatal piglets, or the squeeze’s effect on nociception due to methodological limitations. Nevertheless, the results of this research support the hypothesis that the thoracic squeeze may be classified as a stimulus for inducing TI. Further work is required to characterise the effects of the squeeze on awareness and nociception and to explore the affective experiences of animals subjected to the squeeze.