LPP Dual purpose crops for lamb production in southern QLD and northern NSW

The Livestock Productivity Partnership was a collaborative arrangement between MLA and various research organisations including CSIRO. The data within this record is from an LPP project involving CSIRO as the only research organisation. \nLineage: The project consisted of a single livestock systems trial with a 2x2 factorial replicated design which took place over three production cycles beginning in 2018 and concluding in 2022. The factors were (1) lambing time, where ewes lambed in spring (August/September) or in autumn (May/June), and (2) feed regime, where the sheep had access to pasture only, or to dual purpose crop (DPC) grazing on one quarter of the allocated grazing land. The land devoted to DPC was equally divided between long season winter wheat (variety Manning) and long season Canola (variety Edimax). Cropping was not successful across all years for a variety of reasons. \nDuring 2018 the field site was constructed for the experiment. Eight farmlets (A-H) were delineated by blocks 70m wide and 560m long (3.92 ha), running approximately North/South. The facility was situated on the CSIRO Chiswick property in Uralla local government area in NSW. The site was located against the Big Ridge road, and is referred to as the "Top East strip plots". The farmlets could be divided into multiple plots using electric fencing, and this was used to facilitate controlled grazing of the area by sheep. Usually, 0.49 ha blocks were utilised for grazing and/or cropping, but two adjacent blocks were utilised where feed on offer (FOO) was low.\nBefore the commencement of the trial, in autumn 2018 the area was fertilised with single superphosphate and lime, and over-sowing was attempted by direct drilling annual ryegrass, white clover, subterranean clover and French Serradella. This over-sowing was mostly unsuccessful because of low rainfall in 2018.\nThe site has a sloping aspect with the farmlets in the Western side being much flatter than those on the Eastern side. Therefore it was decided to conduct the replicates in two blocks (replicate 2 containing farmlets E, F, G, H, and replicate 1 containing farmlets A, B, C, D).\nIn October, 2018, two hundred Merino ewes (New England fine wool type) were selected for the trial from a mob of approximately four hundred. The animals retained had liveweights between forty and fifty-two kg. The ewes were divided into groups using a random stratified method so that all the group mean weights were within 0.8 kg. Ten groups were created, each containing 20 ewes. Five groups were assigned for autumn lambing, and five for spring lambing. Of these ten groups, there were eight groups of ewes entered into the trial and two groups of spare ewes designated for autumn or spring lambing. These spares were used to substitute ewes at mating each year for deaths or culls so that grazing pressure was constant throughout the trial. In each experimental group at the beginning of the trial there were twelve 2014-drop and eight 2015-drop individuals. \nAutumn lambing ewes were administered with a melatonin implant (Regulin© APVMA 38233) to induce oestrus on the day of drafting, and the ewes were kept in a single mob until the 5th of December, 2018 when they were introduced to the farmlets. Also at the time of drafting, five White Suffolk rams were administered with Regulin and kept separated from the ewes until being introduced to the plots on the 5th of December with the autumn lambing ewes. Mating proceeded until the 17th of January, 2019. The use of Regulin is necessary to stimulate oestrus during times of the year when daylength is not decreasing.\nSpring lambing ewes were kept in a single mob with the autumn lambing ewes until being placed on the farmlets on the 5th of December. These ewes were to be mated later (March 2019), also using white Suffolk rams, but we did not use Regulin in these ewes as oestrus is maximal close to the autumn equinox when daylight periods are decreasing.\nThe timing of the subsequent production cycles was similar to the first year and dates are provided in the dataset.