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Data Driven Decision Making: Flock Management

15 November 2023

“You can’t manage what you can’t don’t measure!”


This article has been written as a continuation of a series of webinars on flock management between Sheep Specialist, Daniel Stout, and Farmer Duncan Nelless from Thistleyhaugh.

You can view the recording of the webinar below: 


The emphasis of the webinar was on the benefits of historical and current data to inform farm management decisions. The subject matter looked at was the main KPI’s for sheep flocks, performance to weaning, finishing lambs, breeding ewe hoggs and the value of high genetic merit (EBV) terminal sires.  

Performance Recording’s Purpose 

When recording data to measure flock performance you must have clear objectives on your key profit drivers, to calculate KPIs and generate value from the time and investment spent. In the webinar, Duncan revealed his main reasons for data recording: 

  1. Take control of breeding objectives
  2. Stop making genetic mistakes. 
  3. Identify poor performance. 
  4. Inform where to invest in the business. 

A farm business which has a sound understanding of its position and direction and is often a very successful business. Whilst external forces such as market prices, weather fluctuations, inflation etc are items that cannot be controlled but a business can have strong control and knowledge over genetics, health and financials and this is what Duncan focuses on. 

On the 50 rams tested at Thistleyhaugh for the Ramcompare project, there was a 10-day (~10%) difference in finishing speed from the top and bottom rams due to the genetic potential of sires.

For the commercial flock we should endeavour to record data in the ewes, tups and lambs. In the flock we should be pregnancy scanning, tracking mortality, weighing and BCS at key times and recording data on lambing traits. In lambs we should be tracking losses and weighing to see if DLWG are optimal, analysing data on sales profile and carcasses. In rams having performance data allows us to make informed purchase and sale decisions giving us confidence in sire performance 

Why Should You Performance Record Your Flock?   

Performance recording allows you to better inform investment and management decisions by:

  • Identifying poor performance of animals faster, intervene faster and mitigate lost performance.   
  • Empowering you to make far better use of land and labour resources than you might off gut feel.  
  • Helping the farmer understand if their feeding regimes are working, as well as the parasite challenge burden. Some management groups are 60g/day behind average of the flock.  

Data led decisions generate gains for the farmer, Thistleyhaugh’s lamb performance progress shows this below. As yourself whether you are making the data work so you can see its worth on the business like it is seen below? 


Two Ways To Use Data 

We can use data in reflection to review past performance to inform future management but also current monitored data for reactive adaptive management. Software can help make the most from large data sets and take some of the manual number crunching out for us. Farmax for example allows for long term and short-term modelling which provides feed budgeting forecasts and scenario analysis for pasture-based farmers. See the supply (in green) and demand of pasture (in grey) for Thistleyhaugh’s livestock so far this year. Looking at this data we can see there is still more opportunity to be made from grass


When we don’t use data to make our management decisions it can be costly and we also can mistakenly jump to conclusions as to why something is not performing without the facts. Often we look straight for a (often expensive) remedy in a bottle, but the main issue might simply be feed quality and poor pasture management. The key driver of lamb growth: is forage quality and quantity, worm burden, trace elements are secondary key drivers. All these things can be proven through testing. So: 1. Analyse forage, 2. do FEC tests for worms, fluke, coccidia etc and 3. Blood test for mineral and diseases. It pays to know what’s going on! 

Better Finishing Lamb Performance Through Data 

We have limited ability to judge weight by eye and zero ability to assess growth rates, so regular weighing is the only way to monitor performance. 

Accurate weights are essential, so make sure you do the following before collecting your data: 

  • Calibrate scales regularly.  
  • Consider gut fill – time of day, weather, handling duration.  

 Lambs don’t grow just because they are weighed:  

  • Handling causes growth check, gut fill and weather can also influence weights.  
  • Tie in weights with other management tasks.  
  • Analyse and review data to make more informed decisions and generate value.  

Consider Targeted selective treatment. Studies from SRUC and Moredun showed a 40% saving in wormer using this method over conventional routine worming with no difference in performance. Lambs will have higher weights when healthy. Data recording at Thistleyhaugh has highlighted time and time again the value of ‘clean’ grazing.  

Getting Started With Data Driven Management 

If you are wanting to get into performance recording: 

  • Ensure you know your purpose for doing so
  • Seek help for understanding EBVS 
  • Make sure you know how to calculate your KPIs  

Contact your local consultant for help in the process. There is more material on the software available to help record data.


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