Young JMKenyon PRKubeil LJThompson ANTrompf JLockwood AGreer A2025-09-102025-09-102025-01-16Young JM, Kenyon PR, Kubeil LJ, Thompson AN, Trompf J, Lockwood A. (2025). The economic optimum mob size at lambing for triplet-bearing Maternal and Merino ewes across southern Australia. Animal Production Science. 65. 2.1836-0939https://mro.massey.ac.nz/handle/10179/73524Context: Lambing triplet-bearing ewes in smaller mobs significantly increases lamb survival. Aims: This paper reports economic analysis to assess the optimum mob size for triplet-bearing ewes during lambing. Methods: The analyses considered scenarios for Merino and non-Merino (Maternal) flocks where producers subdivided lambing paddocks using permanent fencing or where ewes were re-allocated within existing paddocks on the basis of pregnancy status. Key results: The optimum mob sizes for triplet-bearing ewes during lambing were affected by ewe breed, stocking rate, lamb price and the target return-on-investment if subdividing paddocks. The optimum mob size for triplet-bearing Maternal and Merino ewes was between 27% and 40% of the optimum for twin-bearing ewes and this was similar for scenarios where paddocks were subdivided, or where ewes were re-allocated within existing paddocks. At the standard lamb price of AUD$7/kg carcass weight, the economic return from adjusting the relative mob size of triplet-bearing ewes was AUD$2.05 per multiple-bearing or AUD$14.20 per triplet-bearing Maternal ewe and AUD$0.54 per multiple-bearing ewe or AUD$5.70 per triplet-bearing Merino ewe. Conclusions: Overall, these analyses demonstrated that reducing mob size at lambing can be a profitable strategy for improving survival of triplet-born lambs, depending on the current size of lambing mobs. Implications: As reported previously for single- and twin-bearing ewes, it is difficult to provide generic recommendations to producers for the optimum mob size of triplet-bearing ewes at lambing because optimum mob size was dependent on several enterprise-specific factors.(c) 2025 The Author/sCC BY-NC-ND 4.0https://creativecommons.org/licenses/by-nc-nd/4.0/lamb survivallambing paddockmarking ratemultiple-bearingnon-Merinopermanent fencingreallocationsubdivisionJournal article10.1071/AN243341836-5787journal-articleAN24334