Investigations into the use of in-paddock technologies to study growth, supplement intake and metabolic responses of grazing beef cattle

Abstract

The present thesis utilised novel ‘in-paddock’ technologies, such us walk-over-weighing scales (WOW) and electronic feeders (EF), to measure cattle liveweight (LW) and supplement intake, respectively. This approach was also combined with metabolomics (i.e. quantification of the abundance of small metabolites in animal fluids) to monitor, describe and understand the variability in LW, liveweight change (LWC), and the intake of molasses-lick blocks (MLB) of grazing beef cattle. Chapter 3 demonstrated that the length of the interval between LW measures (ILW) can impact LW and LWC calculations in three cattle categories (calves, weaners and cows). Chapter 4 assessed the ability of WOW and EF to capture temporal relationships between LW, LWC, MLB intake, and feeding behaviour with forage type, quantity and quality. Results indicated that changes MLB intake are useful to monitor changes in forage quantity and quality. Similarly, in Chapter 5, the large variability in MLB intake amongst individual animals was positively correlated with LWC and feeding behaviour was useful to predict MLB intake without the need of measuring MLB disappearance. Chapters 6 and 7 investigated associations between LWC and MLB intake with the metabolome of animals. Chapter 6 revealed that changes in abundance of several metabolites involved in protein and energy metabolism are associated with body growth of animals over time. Chapter 7 characterised the metabolic profile of individual animals with superior growth, particularly under growth recovery. Results from the present thesis suggest that data streams obtained from in paddock technologies and the metabolome of animals can be used to enhance management, productivity and welfare of grazing beef cattle.