L.LSM.0020 - Refining body condition score for region, season, breed and responsiveness
Did you know, the body condition score for region, season, breed and responsiveness has been refined?
| Project start date: | 24 June 2019 |
| Project end date: | 14 September 2022 |
| Publication date: | 08 August 2023 |
| Project status: | Completed |
| Livestock species: | Sheep |
| Relevant regions: | National |
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Download Report
(1.8 MB)
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Summary
The focus of this project was to refine current advice on body condition score targets for ewes across a wide range of regions, breeds and season of mating. This involved identifying the reproductive responsiveness to variation in body condition score and liveweight. The project included Merino, Maternal, Composite and Shedding flocks in the analysis.
Objectives
- Completed Ausfarm modelling for six regions of NSW and a minimum of twelve flocks across SA and Victoria. The modelling will produce gross margin results for reproduction response rate to higher body condition score (BCS) for a range of conditions including breed and season of mating within each of the regions. The regions examined included:
a. Central Northern NSW (summer dominant)
b. Southern Tablelands (winter dominant)
c. Riverina (winter dominant)
d. Central Western Tablelands
e. Western NSW
f. SA (region to be agreed with MLA & AWI)
g. VIC (region to be agreed with MLA & AWI) - Completed detailed on-farm assessments of 30,000 individual ewe BCS’s and analysed their relationship with pregnancy scanning results.
- Collated on-farm data on the number of lambs scanned and utilised Ausfarm modelling to incorporate this information into an analysis on the range of reproduction responses observed and formatted the results for incorporation into adoption packages.
- Submitted a final report to MLA detailing the range of reproduction responses observed and the implications for optimising BCS by season, breed and region.
- A secondary output will be to have successfully submitted three journal articles to Animal Production Science on the trials and outcomes of the project.
Key findings
On-farm monitoring of pregnancy rate and litter size demonstrate curved, rate-limiting relationships with both body condition score (BCS) and liveweight. The nature of the relationships differed between breeds and seasons of mating, indicating a biological optimum BCS around 3.5 and decreases in fertility and scanning rate in animals more forward in condition. Similarly, optimum liveweights were around 60-70 kg and decreases in pregnancy rate and litter size were observed in ewes heavier than this range.
The farm system modelling demonstrated increased profitability under high reproduction levels and decreases in profit with higher grain price. The riskiness of the systems tested are also defined in profit terms. Detailed results are provided per location as additional materials to this report.
Benefits to industry
Awareness of rate-limitations associated with BCS or liveweight beyond BCS 3.5 or 70 kg liveweight will help sheep producers understand the value in setting upper and lower BCS targets for pre-mating ewe management for their own flock. The results should also stimulate producers into testing the relationships within their own flock.
The riskiness of the farm systems modelled are defined in profit terms and allow producers to understand the profit implications of altering their farm systems to achieve higher or lower reproduction rates, or by changing the season of mating, or under higher grain price scenarios.
MLA action
MLA will use the finding of this research project to inform future investment.
Future research
Development of a Microsoft Excel software program to test response curves for individual producers would be helpful in establishing targets within a flock.
The fertility and scanning rate of shedder/hair sheep was low and more research is needed for these breeds. Capturing data that fairly represents the breed requires investigations to occur within flock over multiple mating cycles, using multiple flocks located in high and low rainfall environments.
Modern Australian sheep breeds include mixed breed composite and shedding/hair sheep and these genotypes are not truly available in the Grazplan farm system decision support software packages, (Grazfeed, GrassGro and Ausfarm). Future R&D is required to define parameter sets for these breeds to enable more accurate evaluation in modelling software.
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For more information Contact Project Manager: Joe Gebbels |
