Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item The economic optimum mob size at lambing for triplet-bearing Maternal and Merino ewes across southern Australia(CSIRO Publishing, 2025-01-16) Young JM; Kenyon PR; Kubeil LJ; Thompson AN; Trompf J; Lockwood A; Greer AContext: 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.Item Decreasing Mob Size at Lambing Increases the Survival of Triplet Lambs Born on Farms across Southern Australia(MDPI (Basel, Switzerland0, 2023-06-09) Lockwood A; Allington T; Blumer SE; Boshoff J; Clarke BE; Hancock SN; Kearney GA; Kenyon PR; Krog J; Kubeil LJ; Refshauge G; Trompf JP; Thompson AN; Dailey RIndustry consultation in Australia revealed that the potential impact of the mob size of ewes during lambing on the survival of triplet-born lambs was an important research priority. Previous research has demonstrated that smaller mob sizes at lambing improve the survival of single- and especially twin-born lambs, regardless of ewe stocking rate. Therefore, we hypothesised that lambing triplet-bearing ewes in smaller mobs, regardless of stocking rate, will increase the survival of their lambs. Research sites were established on 12 commercial sheep farms across southern Australia between 2019 and 2021. One farm used Merinos whilst the remainder of the farms used non-Merino breeds, consisting of composite ewes joined to composite or terminal sires. Three of the farms were used in two years of the experiment. Adult, triplet-bearing ewes were randomly allocated into one of two treatments, 'High' or 'Low' mob size, at an average of 135 days from the start of joining. Ewe and lamb survival were assessed between allocation to treatments and lamb marking. Lamb survival was significantly greater for lambs born in the Low (65.6%) compared with the High (56.6%) mob size treatments (p < 0.001). There was no effect of mob size at lambing on the mortality of triplet-bearing ewes. Analysis of the effect of the actual mob sizes showed that reducing the mob size at lambing by 10 triplet-bearing ewes increased the survival of their lambs to marking by 1.5% (p < 0.001). This study has shown that the survival of triplet-born lambs can be improved by lambing triplet-bearing ewes in smaller mobs regardless of stocking rate when ranging from 0.7-13 ewes/ha.