Increasing lambing percentages through better use of pregnancy scanning technology - L.LSM.0021 - Final Report

Summary

The project aimed to improve lamb survival and reproductive rate in Australian sheep through better adoption of pregnancy scanning, encouraging more producers to precision-manage flocks to better met the nutritional requirements of ewes of different litter sizes, including empty ewes. Pregnancy scanning for litter size enables:

• The selling of empty ewes at scanning or at the following shearing.
• Better allocation of feed according to ewe litter size.
• Allocating multiple bearing ewes to the best lambing paddocks and/or reduce mob size.
• Preparing the lambing feed budget in advance.
• Earlier detection of any reproductive failure.
• More rapid re-mating of empty ewes.
• More accurate selection of replacement ewes.

Objectives

Key objectives were to:

1. Have conducted the following activities with the aim of increasing adoption of pregnancy scanning by 10% (by 2032):

a) Conducted an extensive benefit cost analysis on the value of scanning across a range of sheep producing regions and enterprise types.
b) Developed a detailed business case for pregnancy scanning, including information suitable for inclusion in MLA and AWI extension packages tailored to different production environments, producer skill levels and resource availability (e.g. livestock identification systems and labour availability).
c) Conducted a series of case studies and surveys to create a better understanding of barrier to adoption of pregnancy scanning and develop solutions to overcome these barriers.

2. Have designed and implemented strategies to improve the skills base of pregnancy scanners and encouraged the trialling and adoption of innovations in scanning technology by:

a) Creating a scanning image library (videos of real-time assessments) using three experienced pregnancy scanners and a human sonographer / radiologist as a tool for benchmarking.
i. Created a series of training materials and information resources for pregnancy scanners, including content covering.
ii. Images and anatomical references to identify single and multiple pregnancies at different stages of the gestation.
iii. Ovine reproduction physiology.
iv. Foetal losses and causes of loss.

b) Conducted workshops for scanners, including use of benchmarking material, as part of a regular (bi-annual) conference.

Key findings

• Pregnancy scanning to identify multiple-bearing, single-bearing and empty ewes and implementing optimal nutritional management and paddock allocation is profitable in all agricultural regions, lambing times and flock types.

• The average increase in profitability is $5.75/ewe scanned. The highest value is for flocks scanning just prior to the most significant feed deficit each year because decisions can be made to more effectively manage ewe nutrition during this feed shortage.

• Pregnancy scanning for pregnancy status only is generally about half as profitable as scanning for litter size. It is however a good introduction to the benefits and practicalities of scanning.

• Scanning at the correct time improves accuracy – scan for multiples (litter size) 80-90 days after the rams go in (based on the industry recommended five-week joining period) and by correct ewe preparation – ewes should be off feed and water for a minimum of six hours before scanning.

• Scanning for pregnancy status is 97–98% accurate, whereas the agreement between fetal numbers identified at scanning and the number of lambs born is lower (85%–88%), partly due to unobserved lamb loss rather than scanning errors.

Benefits to industry

• Scanning for multiples (litter size), which enables precision management of lambing groups, as well as optimal management of dry ewes, is profitable in all winter and summer rainfall regions in southern Australia, in all genotypes and at all times of lambing investigated. The average profit was $5.75 per ewe scanned.

• Pregnancy scanning for multiples has a 400% return on investment and can and should be a vital tool for improving reproductive rate and lamb (and ewe) survival rates, via the following:

- Selling of empty ewes at scanning or at the following shearing.
- Better allocation of feed in favour of multiple-bearing rather than single-bearing ewes and especially empty ewes.
- Allocating multiple bearing ewes to the best lambing paddocks and/or reduce mob size to enhance lamb survival.
- Ability to prepare the lambing feed budget in advance.
- Earlier detection of any reproductive failure.
- Ability to more rapidly re-mate empty ewes.
- More accurate selection of replacements by accounting for birth type.

Future research

• Extending the collation of pregnancy scanning data nationally, for benchmarking purposes, as already carried out on a regional basis in Western Australia, would add value to the current investment in pregnancy scanning technology.
• Projects addressing the logistical reasons given by some sheep producers for not scanning (especially for multiples), including not having enough paddocks and unwillingness to lamb down small mobs of twin or multiple-bearing ewes should be initiated.
• The feasibility of using machine learning (and/or deep learning) to aid in pregnancy scanning is worth investigation. This could help not only in ultimately increasing the capacity for scanning more sheep, but could potentially aid in further improving scanning accuracy, particularly for more fecund sheep and could aid in identification of fetal and uterine abnormalities.
• Extending the economic analysis and business case for pregnancy scanning to the pastoral/rangeland areas of Australia.
• Improvement of scanning accuracies for triplets and higher order litters and associated optimisation of management for ewes bearing triplets or more.
• Where the average flock litter size is 1.5 or more, sheep producers should be encouraged to request that scanning operators specifically look for and identify ewes carrying triplets, in addition to identifying twin and single bearing ewes and empty ewes.
• Video images of pregnancy scanning already collected during the L.LSM.0021 project, augmented by a number of additional scanning images, could be packaged in such a way as to provide an on-line learning package for novice scanners.
• A working group (to include pregnancy scanners, consultants and scientists) be established to:
o provide recommendations on the future training needs for pregnancy scanners and how they can be best met, and
o plan conduct future workshops for scanners and provide a focus for interaction between scanners, scientists, consultants, producers, MLA and AWI and government.