Pregnancy scanning in extensive sheep flocks

Summary

This Producer Demonstration Site (PDS) is designed to demonstrate that pregnancy scanning for foetal number and foetal age together with wet and drying ewes at marking can be used to both optimise the management of breeding ewes as well as identify and retain ewes with proven reproductive performance and increase the national reproduction rate in extensive sheep flocks with an extended joining period.

Objectives

By June 2023, in the western division (Hay) of New South Wales:

1. Benchmark the reproductive performance of breeding ewe flocks (n=6) and identify the environment and management constraints to net reproduction rate (NRR, lambs weaned/ewes joined) at the beginning of the demonstration.

2. Demonstrate the use of pregnancy scanning as a management tool to improve NRR by up to 10% through:

   i. identify and differentially manage single and twin bearing ewes

   ii. identify and cull twice dry ewes (maidens and adults) from the breeding flock

   iii. identify early- and late- ewes to draft into mobs for differential management

   iv. wetting and drying ewes at marking and use simple ear notches (or coloured tags) to identify high/poor performing ewes

   v. improved lambing management for those flocks with extended joining periods.

3. To have the six core group members trained in condition scoring sheep and understand the key factors limiting the reproductive performance of their sheep flocks and the key management interventions available to overcome them:

   i. the impact of length of joining on the ability to implement pregnancy scanning and improve lambing and weaning management

   ii. using pregnancy scanning to identify ewes for differential nutritional management, allocation of lambing paddocks and optimised lambing mob size

   iii. wet and dry ewes at marking to quantify ewe reproductive performance and inform ewe selection and culling decisions

   iv. the potential of eID to collect and use data for informed decision marking

4. To have half of the observer producers understand the range of factors that can impact on the reproductive performance of their flocks and recognise the key management interventions that could be used to improve the reproductive performance of their flocks.

5. That 75 % of core producers and 30 % of observer producers will routinely adopt the key practices demonstrated by this project.

Progress

The four producers demonstration sites for “Pregnancy scanning in extensive sheep flocks” (near Wilcannia, Anabranch South, Hay and Carrathool NSW) have completed the data collection for their first breeding cycle, despite each property being impacted in some way by floodwaters since Sep-22.

Data capture for the second breeding cycle commenced pre-joining where possible in late 2022 and will continue into 2023. Good joining results were reported despite the difficulties imposed by floodwaters. Feed is abundant at each property following the flooding with all producers expecting continuation of better than average seasonal conditions.

This demonstration site project is managed by Laura Broughton and Sue Hatcher.