Breed Enhancement

 

The WHSS Signet Recording Scheme is now fully established and for those members who are interested in joining the scheme or buying recorded stock here is a report on progress so far and details on how to join the scheme. New participants may qualify for funding from the Society, see the NEWS page for further details.

 

Wiltshire Horn Performance Recording Update

Achievements in 2008 / Getting involved in 2009

               

Introduction

This report provides a short overview of the achievements in performance recording Wiltshire Horn sheep during the last 12 months. The number of records within the Wiltshire analysis has now topped 5,000 and membership has increased. The high level of genetic variation observed amongst recorded animals indicates real genetic progress can be achieved through selective breeding.

 

The records collected and analysed to date will provide an excellent foundation for breeders to meet the genetic expectations of both pedigree and commercial Wiltshire Horn buyers in the future.

 

Why Performance Record?

It is important to buy rams of high genetic merit, as their genes (or breeding) are the only attribute passed from one generation to the next. This is easier said than done, because so many factors influence a ram’s appearance – including the age of the animal, whether it was reared as a single or twin and most importantly of all the amount of food it has consumed.

 

Performance recording schemes were developed to make the process of identifying superior genetics easier. Records of performance are analysed to tease out the non-genetic influences on an animals’ performance so that its true genetic potential can be assessed. The values produced are referred to as Estimated Breeding Values (EBVs); they are measures of genetic merit that enable potential ram buyers to identify rams with superior breeding.

 

EBVs are important when the traits of interest are growth rate and carcass conformation, but they are vital when it comes to maternal traits that can’t be assessed simply by looking at a ram.

 

Which traits are assessed?

EBVs are produced for a number of traits, including:-

Prolificacy (Numbers in Litter live or dead at full term).

Maternal ability (Relates to milk production. Weight at 8 weeks)

Growth rate to 21 weeks (weight at 21 weeks i.e. scan weight

Scanning for Muscle depth and fat depth at third lumbar vertebra

Mature size (live weight at first mating)

 

The Wiltshire Horn Index

Breeding indices use the data provided as EBVs, with appropriate economic weightings to produce a single figure that ranks animals for a specific breeding goal. In the case of the Wiltshire Horn the index is aiming to enhance the productivity and profitability of Wiltshire Horn sheep – taking into account lamb growth rates, maternal ability and prolificacy. Additional selection pressure can be placed on animals with superior carcass attributes.

 

The index currently being used will be reviewed and updated ahead of the 2010 recording year, placing slightly less emphasis on prolificacy and slightly more on other important traits such as carcass quality, lamb growth rate and maternal ability.

 

Why get involved?

Essentially EBVs provide important information to make informed breeding decisions and act as a valuable marketing tool.

EBVs enable breeders to make focused breeding decisions for traits of commercial, economic importance; using an independent and accurate assessment of carcass traits

And EBVs provide a way to add value to your rams

At sales – where there is increasing commercial demand for EBVs

From home – where EBVs can support the breeding claims of homebred rams

On-line – where rams and semen sales can be promoted using EBVs

 

Achievements in 2008

There has been a major increase in performance recording within the breed over the last two years, with nearly 2000 of the 5000 analysed animals being born in the last 24 months. The recording of these animals has created a firm foundation for this important breeding improvement programmeme.

 

Major differences are starting to emerge between different breeding lines, with differences in breeding potential of approximately 1.25kg and 3kg in lamb weights to 8 and 21 weeks of age emerging between Top 10% and Bottom 10% sires.

 

Importantly there is also a 2mm difference in breeding potential for muscling across the loin, which may not sound much but could equate to an extra 5-8% more muscling throughout the entire carcass of a Wiltshire Horn lamb.

 

Genetic progress across the recording population and within individual flocks is encouraging; lamb growth rates and muscling have improved, without detriment to maternal attributes.

 

NB

Signet has the ability to evaluate data relating to carcass attributes, specifically muscle and fat depth. These measures are taken on the live animal at around 21 weeks of age, using ultrasound scanning technology (similar to pregnancy scanning) across the third lumber vertebra - to get a picture of muscle and fat deposition across the loin. 

 

While the genetic ideal is always to take every possible measurement on every possible animal in a breeding programmeme, it was recognised that some Wiltshire Horn flocks would be relatively small and not able to justify the cost of ultrasound scanning, whilst others may wish to focus much more heavily on maternal attributes and early lamb growth rates. The Wiltshire Horn recording scheme was developed to try to embrace all of these views and differing breeding objectives.

 

Where flocks are able to ultrasound scan their flock the EBVs for muscle depth and fat depth for their lambs will reflect measurements on these animals and their relatives. Unscanned lambs are still assigned muscle depth and fat depth EBVs in the analysis, as their breeding potential for these traits can be predicted based on other measurements. The most important of these correlated traits is live weight, with heavier animals tending to have the genetic potential to be more heavily muscled and slightly fatter.  Where relatives have been ultrasound scanned in previous years and in other flocks this will also contribute towards predictions for muscle depth and fat depth.

 

Interestingly, muscling is an attribute that can be quite successfully improved by selecting for growth. The main reason for ultrasound scanning lambs is to find fast growing, well muscled sheep that are not overfat. If as a breed the decision is reached that fatness is a relatively minor concern, then the importance of ultrasound scanning relative to simply selecting for growth rate would decrease.

 

Current Membership

The following Wiltshire Horn breeders are now involved in performance recording their flocks.

 

N & M J Ashwin, Bristol, 01454 632313 - C W Tweed, Co Antrim, 028 2858 3405 - Jean Burke, Cornwall,  01726 882204 - George Gruzelier, Cornwall,  01579 326158  - Tim White, Wiltshire,  01747 820796 - St Just Farms, Wiltshire, 01722 718216 - York King Ltd, Wiltshire,  07979 904886 - Paul Morgan, Somerset, 01934 741771 - A & J Mogridge, Essex, 01279 876421- Divine Ovine, Perth & Kinross, 01738 840999 - S.E.W. Temple, Lancs, 01524 37695 - Tim Patchett, Wiltshire, 01985 844824 - Jim Primrose, Dorset, 01258 821352 - Richard Ling, Devon, 01548 559068 - Jim Briggs, Cornwall, 01726 845100                                        

                                                                                                                                                                                              

Please feel free to contact them if you wish to know more about the scheme or are interested in buying recording stock next year.

 

Plans for 2009

Increasing flock genetic linkage

One of the challenges in analysing a large number of lambs that are reared in a number of different flocks, under different management conditions is that the genetic linkage (shared genetics) required to enable good comparisons to be made between flocks is going to be more limited. Recording breeders are aware of this challenge and plans to share rams and exchange breeding lines in 2009 are already underway.

New Pedigree Leaflets available from EBLEX  A series of new leaflets are being produced by EBLEX to support breeders with recorded flocks and to help them talk to their clients about performance records. Pedigree Pointers 1 & 2 is on “Flock Connectedness” and “Accuracy Values”. For copies please contact Signet directly. 

High Five Listing In 2009 Signet plans to produce a list of the Top Five Recorded Ram Lambs in every Recording Wiltshire Horn flock in the country and to make this available via the Society as a guide to both commercial and pedigree breeders that are interested in purchasing a recorded Wiltshire Horn ram.   This report has provided a useful way to promote recording in other breeds and it is hoped the same will be true for Wiltshire Horns.

Additional Focus - Ewe Mature Size Another undoubtedly important trait is mature size. Increasing lamb growth rates will inevitably increase ewe mature size on commercial farms. On some farms this is not a major issue, with larger ewes commanding a premium as breeding animals or at culling time, on others it creates an unwelcome cost due to increased feed costs and lower stocking rates. Whatever your view, if the trait isn’t measured you can’t assess how it is changing and more importantly you can’t select the sheep with the right mature size genetics for your farm – or more importantly that of your customers. 

All Signet recorded flocks are being encouraged to submit mature weights for their shearlings ewes to enhance the accuracy of the mature size EBV produced for Wiltshire Horn sheep.                                           

New Traits – Worm Resistance Some flocks are involved in collected faecal egg count data for lambs at around 21 weeks of age to identify those shedding high worm egg counts onto the pasture and those that are genetically more resistance to worms. This work is at an early stage, but if more breeders get involved it may be possible to produce a FEC (worm resistance) EBV in due course.

New Traits - Shedding Signet is working with Wiltshire Horn breeders to put together a project that investigates the genetics associated with shedding. It will aim to identify the optimum time and way to score Wiltshire Horn sheep to identify those that shed out completely and do so relatively early in the season, it will then go on to identify whether these are the animals that will produce the highest percentage of shedding progeny in a cross breeding programme.

Researching Recorded Stock. It is now possible to research details of all Wiltshire Horn Sheep included in the Signet Recording rogramme on the Basco website.  http://www.egenes.co.uk/bascosearchsheep/search/quick

So why get involved?…….  EBVs are an important tool to support breeding decisions and a valuable aid when marketing rams; Breeders can access funding towards the cost of recording; The more flocks that get involved the more value the scheme is to individual breeders, commercial ram buyers and the breed as a whole; Working with other flocks might help to take your flock forwards In 2009 new breeding reports will highlight leading breeding lines; Your flock might contain something special - this is your chance to identify it and promote it!  

For more information contact Sam Boon at Signet Tel: 01908 844 195