Physiological and Behavioural Patterns Associated with Prolonged Lambing Events in Sheep

Abstract

<p>Dystocia is one of the most important issues faced by sheep producers nationally and internationally. In Australia specifically, dystocia directly and indirectly accounts for 50-75% of all neonatal lamb mortalities. Similar figures have been reported in flocks in New Zealand and the UK. Dystocia has been the subject of research for decades" however, the outcome studied is almost always 'number of lambs dead', therefore excluding dystocic events that did not result in death. This thesis is comprised of a series of experimental manuscripts investigating dystocia and its effect on maternal behaviour pre- and post-birth" assessing on-animal accelerometers to identify differences in eutocic and dystocic ewe activity pre-birth" and using pen-side blood analysis techniques to identify maternal blood markers that may be indicative of a dystocic event before and after birth.</p> <p>Dystocia has a marked effect on the behaviour of the ewe in the hours before birth. Dystocic ewes are significantly more active overall – identified by accelerometer data alongside traditional observation and annotation methods – but reach the peak in their activity 3 h before birth, whereas eutocic ewes reach the peak in activity at birth. There is also a significant difference in ewe behaviour after birth, with dystocic ewes performing fewer maternal care behaviours and more avoidance behaviours. Finally, there are multiple blood markers seen to be different in eutocic and dystocic ewes before and immediately after birth" however they are cohort-dependent.</p><p>Dystocia is a complex and multifaceted problem, and requires a multifaceted approach in order to appropriately address the underlying issues and develop practical detection and prevention strategies.</p>