Interpretive Summary: Level of feeding and stage of maturity affects diet digestibility and protein and fat deposition in cross-bred lambs
By: Thomas P Keogh, Shawn R McGrath, Maxwell B Allworth, Victor H Oddy
Understanding animal responses to changes in nutrition will assist to create more efficient red meat production systems. Complex interactions exist due to the quality, physical characteristics and level of feeding of the diet, and the nutritional history of the animal. The resultant changes to body composition and the partitioning of energy to tissues has important implications for producers. A replicated trial used CT scans of live animals to investigate body compositional changes at different stages of animal maturity and different feeding levels. Given that fat deposition has been shown to increase at greater energy intake, it was expected that the contribution of fat to empty body gain would be smaller at lower feeding levels; however, lambs at later stages of maturity and lower levels of intake deposited greater amounts of fat as a proportion of empty body gain. Results are likely confounded by the response of visceral lean tissue mass to changes in nutrient supply. Irrespective of this, nutritional history had no effect on the rate or composition of gain at different levels of feeding, potentially demonstrating an inexistence of compensatory growth. A greater understanding of lean tissue responses to dietary changes is necessary for the increased precision of predictive growth models.
Read the full article in the Journal of Animal Science.