Increased Dietary Protein to Energy Ratio in Pre-Weaning Lambs Increases Average Daily Gain and Cortical Bone Thickness in the Tibia

Gibson MJAdams BRBack PJDittmer KEHerath HMGPPain SJKenyon PRMorel PCHBlair HTRogers CW2024-06-272024-06-272022-12Gibson MJ, Adams BR, Back PJ, Dittmer KE, Herath HMGP, Pain SJ, Kenyon PR, Morel PCH, Blair HT, Rogers CW. (2022). Increased Dietary Protein to Energy Ratio in Pre-Weaning Lambs Increases Average Daily Gain and Cortical Bone Thickness in the Tibia. Ruminants. 2. 4. (pp. 478-486).https://mro.massey.ac.nz/handle/10179/70035The objective of this study was to examine if diets differing in crude protein (CP) to metabolizable energy (ME) ratio (CP:ME) pre-weaning altered peripheral quantitative computed tomography (pQCT) measures of bone mass and strength in lambs. The left hind leg of lambs were available at the completion of a trial designed to examine the effect that altering the CP:ME ratio in milk replacer had on growth and body composition of pre-weaned lambs reared artificially. Treatments consisted of either normal commercial milk replacer (CMR, n = 10) containing 240 g/kg CP and 21.89 MJ/kg ME, high protein milk replacer (HPM, n = 9) containing CMR with additional milk protein concentrate to reach 478.7 g/kg CP and 19.15 MJ/kg ME or a mix of normal milk replacer and milk protein concentrate adjusted twice-weekly to match optimal CP:ME requirements (MB, n = 8) based on maintenance plus 300 g/d liveweight gain. At 22 kg live weight, lambs were euthanized and the tibia including the surrounding muscle was collected and scanned using pQCT at the mid-diaphysis. Lambs on the HPM and MB diets had a greater average daily gain (p < 0.01). There were limited differences in bone morphology and muscle mass, though notably the higher protein diets (MB and HPM) were associated with greater cortical thickness (p < 0.05) and, therefore, potentially greater peak bone mass at maturity This finding demonstrates that pre-weaning diets, and the protein content in particular, may influence the developmental potential of long bones and attainment of peak bone mass at maturity.(c) 2022 The Author/sCC BY 4.0https://creativecommons.org/licenses/by/4.0/bone morphologyartificial rearingtibialambbone strengthcrude proteinIncreased Dietary Protein to Energy Ratio in Pre-Weaning Lambs Increases Average Daily Gain and Cortical Bone Thickness in the TibiaJournal article10.3390/ruminants20400342673-933Xjournal-article478-486