Oxfords - Making genetic progress


Why are we breeding sheep?

Breeding sheep is about turning your time, effort, breeding expertise and information into premium prices for your sheep. Your customers are looking for sheep that will add value to their progeny with superior genetics. To do this it is important that you understand the objectives of your customers and use it to inform your breeding program. One objective is producing pedigree sheep that meet the breed standards and can be sold to other pedigree breeders to achieve higher prices. You can also add value through the extra performance that the genetics of your rams bring to your customers flock, both commercial and pedigree. To do this you need to identify the animals within your flock with the best genetics.

Estimated Breeding Values (EBVs)

In any group of animals, we see variation in type and performance. What we see and measure in animals is caused by variations in the animal’s genetics and environment. In a breeding program we need to look at the variation due to genetics, so we can select the best animals for breeding and sale.

EBVs use an animal’s performance and pedigree information, which is analysed in a Best Linear Unbiased Predictor (BLUP) evaluation to calculate an animal’s genetic merit in a specific trait. These can be used to directly compare animals within the flock, across the breed and across years.

EBVs help to further inform your breeding decisions and should be used alongside your experience and knowledge to help select the breeding animals.


Performance recorded Oxford flocks

Six members from across the country are now performance recording their Oxford Down flocks in the Signet Sheepbreeder service. (Please ask the secretary for contact details)

  • J W S Brown Redhouse Flock No 1189 (Pembrokeshire)

  • M F S Brown Monkstone Flock No 985 (Pembrokeshire)

  • J A Porter Sundown Flock No 1242 (Norfolk)

  • L Rumming Lydiard Flock No 1288 (Wiltshire)

  • R J Steele Weeton Flock No 1225 (Yorkshire)

  • D Webb Whittington Flock No 1352 (Gloucestershire)

The scheme involves the recording of several key performance traits: 8-week weight, Scan weight, Muscle depth, Fat depth, Mature size, Maternal ability and Prolificacy. By analysis of pedigree and performance records a range of Estimated Breeding Values (EBVs) and Breeding Indexes are generated to help breeders identify genetically superior rams and ewes.

What is the Terminal Sire Evaluation?

The Terminal Sire Evaluation was launched in 2018 and included Signet’s 13 largest performance recording terminal breeds (Meatlinc, Texel, Suffolk, Charollais, Dorset, Hampshire Down, Bleu du Maine, Vendeen, Southdown, Beltex, Blue Texel, Shropshire). This update used the initial findings from RamCompare project, so breeders can identify and select rams that will sire the most profitable commercial progeny. All breeds are analysed together in a monthly run, of over 3 million records.

This winter, Oxford Downs and two other terminal breeds were added to the evaluation to benefit from this new approach. The key benefits for the Oxfords being part of the Terminal Sire Evaluation are:

· Monthly runs which adds extra flexibility to recording your flock and means that information is more timely helping breeders to make the most informed breeding decisions early in the season.


· Carcarse traits (Muscle and Fat Depth EBVs) have been moved to a weight adjusted basis. To give a better reflection of carcase composition, as it shows the muscling and fat levels of animals at a fixed weight. This not only means this trait has a higher heritability (less environmental variation) but can be assessed independently of growth too.

· Opportunity to include commercial and crossbred data, accounting for the impact of hybrid vigour to identify the animals with the best genetic merit.


These changes mean that Oxfords are benefitting from the same evaluation as all terminal sire breeds. Along with the changes to the EBVs, the Index has also been updated. Indexes allow selection at a population to make progress in a balance of traits to progress the overall genetic merits of the breed.

Oxfords have two new breeding Indexes; the Terminal Sire Index for rams that sire slaughter generation lambs and focuses on producing fast growing lambs with good carcase conformation and optimum fat class. The second, the Maternal Index to identify the best rams that will sire productive females balancing; milking ability, optimum prolificacy and growth.

Making genetic progress

To make progress it is important to firstly establish breeding objectives that meet your customers’ requirements and on farm objectives. It is then important to use these objectives to shape your breeding program and selection of animals.

Selection pressure is how breeders can drive genetic progress. Selection pressure is the proportion of animals that are selected from a generation to be used for breeding. The higher the selection pressure the higher the average genetic merit of the animals used for breeding will be, which then means the lamb crop has a higher genetic merit. Only selecting a few animals from a large population for breeding will not guarantee progress, selection needs to be informed to identify the animals with the best genetics; to do this we use EBVs. Ram selection offers the best opportunity to add genetics to a flock and be the most selective, making the most informed ram selection decisions is the best way to drive genetic progress in a flock.

How to get involved and begin recording your flock

You can benefit from performance recording even if you don’t record your own flock, use the information available on Signetdata.com to help select rams with the best genetic merit.


The greatest benefit you will see from performance recording your flock is the ability to produce accurate EBVs for your sheep. These will help your marketing and selection decisions. Signet membership also provides reports and services, such as an inbreeding calculator and a sheep for sale listing.

Getting started recording your flock is easy, to begin contact with Ed Brant:

ed.brant@ahdb.org.uk or Tel: 07810 789501.


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