L.PDS.2101 - PDS - Managing growth of ewe weaners

Summary

The reproductive rate of the sheep flock is a key profit driver in any business. Increasing profit in these enterprises is limited by the mismanagement of ewe weaners during puberty. This is not entirely the fault of managers. Climate change has had a profound impact on pasture growth in the tablelands and pastoral belts, which has significantly reduced the quantity and quality of feed usually allocated to weaners. This levy Producer Demonstration Site aimed to demonstrate that differential nutritional management of ewe weaners in a self-replacing flock improves retention rate of replacement ewes leading to increased net reproductive rate of the ewe flock.

This project was developed during a period of drought, with the aim of calculating the cost-benefit of feeding a supplement to ewe weaners that were below target weight. The project area of Hay and Booligal experienced high rainfall and had minimal need for supplementary feed during the project period. Due to the seasons experienced there was very little variation in the weight of the weaners within the first year of the demonstration and data collection activities.

Seasonal impacts to the project extended past optimal rainfall, all properties involved were on the Lower Lachlan River floodplain and as such had significant parts of their properties either inundated or cut off by flood water in 2022. This resulted in the inability for tagging and weight data collection on the 2022 drop could occur.

This project was placed on hold in late 2022, with the intention of recommencing in spring 2023. Seasonal conditions continued to impact the projects ability to deliver on its objectives and milestones, as a result the project was terminated in late 2023.

Objectives

By September 2023 in the Hay and Booligal regions of NSW

1. Six Merino producers will have demonstrated the benefits of increasing weaner nutrition and weight gain during puberty on their lifetime net reproductive rate (NRR) of Merino ewes.
a. A treatment group of ewe lambs will be differentially managed (ME intake to suit required growth rate). The ewe weaners below benchmark weight for age will be allocated better quality pasture, where available, or offered supplementary feed in order to meet required “catch up” growth rates.
b. A control group will be weaned “traditionally” – run in one mob.
2. A benefit cost analysis will demonstrate the advantages of the system of better meeting weaners nutritional needs, as well as identifying the cost benefits of early supplementary feeding (before weight loss occurs). We will use ear tags to identify underweight weaners in each, then compare future reproductive rate in both treatment and control sheep.
3. 100% of core producers and 50% of observer producers will have adopted improved weaner management strategies. These producers will be able to identify nutritionally challenged weaners and react accordingly.
4. 100% of core producers and 70% of observer producers will have increased their knowledge and skills in relation to weaner management through a variety of extension activities such as field days and workshops. A number of field days will be held both during the PDS to demonstrate the life-long productivity gains from running more fertile sheep.
Follow up measurements in years 3 and 4 will be taken to track the effects of improving net reproductive rate throughout the life of the ewe.

MLA action

MLA continues to deliver the Producer Demonstration Site (PDS) program, supporting livestock producers working in peer-to-peer groups to pursue new skills, knowledge and management practices applicable to their own commercial livestock production systems.