Predictive growth models are unable to properly account for the effects of changes to body composition on the energetic efficiency of lamb growth and improving these models has been limited by the realities of data collection. By tracking changes in individual animal body composition, it is likely that better predictions of the effects of genetics, nutrition, and management on lamb growth can be made. The computerized tomography (CT) scanning of lambs enables the analysis of changes in body composition over time, potentially supporting better model development and testing. A repeatable method for analyzing lamb CT scans was developed and results were compared with 2 existing lamb growth models. Lean tissue mass derived from CT scans aligned with model predictions but fat mass estimated using CT scans was greater than model predictions, particularly for lambs fed at later stages of maturity. Further verification is needed by combining CT scanning and comparative slaughter, especially with respect to the weight of internal organs and the stomach and intestinal contents to better inform predictive growth models.

Read the full article in the Journal of Animal Science.