Sheep Breeding Bulletin Extra

Transcription

1 Sheep Breeding Bulletin Extra Summer 2014 In this issue Ultrasound scanning Maternal initiatives Interpreting EBVs Ram selection there is more to an animal than what you see Rams with superior breeding enable producers to improve flock productivity. However, it is difficult to identify rams with superior breeding by eye alone as a ram s appearance is influenced by many factors both genetic and non-genetic. Increasing interest in recorded rams By Samuel Boon, EBLEX Breeding Specialist EBLEX recently asked Signet clients in England what impact they thought performance recording was making to their business. Over 95% of responding clients felt that commercial interest in performance recorded stock has increased in the ten years since the Better Returns Programme (BRP) was established. Nearly all felt the initiative has had a significant impact. Between them the respondents were selling nearly 1000 rams per year. Most now had over 50% of their buyers asking for Estimated Breeding Values (EBVs). In this survey nearly 70% of those rams were sold off farm and 30% by auction. With nearly 700 flocks annually recording their lambs, there is a vast choice in the breed and type of recorded ram available to the commercial producer and the difference between the average ram and the highest EBV recorded ram is increasing every year. Maternal breeds Recording is not all about terminal sire breeds many lambs from maternal breeds are currently recorded through Signet. Important developments to their breeding evaluations are provided in this publication. For the latest breeding information go to When selecting rams at a sale to breed faster growing progeny, the biggest rams might be those with the best genes for growth or they might be the best-fed or oldest rams on sale. When selecting rams for maternal attributes, such as their genetic potential for prolificacy and milk production, a visual inspection tells you virtually nothing. This is why EBVs are an important tool, as they provide an unbiased assessment of genetic potential, taking into account non-genetic influences on performance, such as age, rear-type and feeding regime. Estimated Breeding Values indicate exactly where an animal ranks within the breed for specific traits of economic importance enabling buyers to select rams on the basis of their breeding potential, not just their appearance. What you see when assessing a ram is a combination of genetic and non-genetic influences. Estimated Breeding Values provide the best indicator of genetic potential.

2 Which breeds performance record with Signet? Over 30 sheep breeds performance record with Signet. The breeds where the evaluation contains more than 1000 lambs per annum are shown in Table 1. Improving lamb growth rates The use of weight recording in the selective breeding of terminal sire breeds has had a massive impact on the genetic potential of the UK flock for lamb growth rate. Farmers with performance recorded flocks weigh their lambs twice in their lifetime, at eight weeks of age and at scanning (at around 21 weeks of age), to assess their performance. These weights are analysed to produce EBVs for these important growth traits. Commercial producers are now able to buy rams whose progeny grow faster and more efficiently and are capable of being taken to heavier weights without becoming over-fat. This change in genetic potential for growth rate can be seen in Figure 1 for the Charollais, Hampshire Down, Meatlinc, Suffolk and Texel breeds. Direct comparisons between the breeds should be made with caution, as some evaluations are based on the whole breed, whilst others are a subset of recorded animals but the overall upward trend is striking. Large genetic gains have been achieved in all five breeds. This means the average recorded ram is more valuable to the commercial producer than ever before. Within the Texel, Suffolk and Hampshire Down breeds, all of the lamb births notified to the Breed Society are included in the analyses with a subset of their members (shown with an asterix) actively involved in performance recording. This table also shows the large number of maternal breeds that are now recording, notably the Lleyn, whose involvement has increased substantially in recent years. Breed No. of flocks in 2013 No. of lambs No. of early weights submitted No. of lambs ultrasound scanned Texel 1364 (196*) Suffolk 759 (69*) Lleyn Composite Charollais Dorset Scotch Blackface Hampshire Down 192 (63*) Easycare Welsh Mountain Romney Marsh Bluefaced Leicester Meatlinc North Country Cheviot Park Beulah Shropshire Others Grand Total * The number in brackets indicates the number of weight recording clients. Table 1: Numerically largest sheep breeds that performance record with Signet Relative rates of genetic gain in growth rate since 1999 * Denotes where the whole breed is being analysed. Figure 1: The change in genetic potential for growth rate for the Charollais, Hampshire Down, Meatlinc, Suffolk and Texel breeds

3 Which ram breed has the biggest influence? Analysis of the 2013 Sheep Breed Survey, which is funded by EBLEX and HCC, is nearing completion and there are some interesting provisional results (Table 2). From the 8331 holdings that returned the survey, a total of rams were recorded. Breeds accounting for more than 1% of sires are reported here and the dominance of the Texel is evident. Their market share has increased by 5% in the past ten years. Within the maternal breeds, the percentage of Lleyn rams has doubled a remarkable achievement for a breed that hardly featured in breed surveys in the 1970s and 1980s. Amongst the rams, 95% were purebred and 5% were crossbred. Most of the crossbreds were terminal sire breeds, many of which contained some Beltex genetics. Nearly a quarter of rams are homebred, a percentage that increases markedly in the hill sector. Ewe longevity research On average, flocks within the UK have a 20 25% replacement rate due to various factors including culling policy and death rate. It is expensive to replace breeding ewes, so genetic solutions to increase their productive lifespan on farm are likely to be financially beneficial. EBLEX has recently agreed to fund a research project with SRUC (Scotland s Rural College) to find the best way to include productive lifespan in sheep breeding evaluations. Breed Pure Crossbred Total 1996 % 2003 % 2013% (provisional) Texel % 24% 29% Suffolk % 23% 13% Charollais % 7.5% 9% Bluefaced Leicester % 7.5% 7% Scotch Blackface % 7% 6% Welsh Mountain % 6% 5% Lleyn <1% 2% 4% Beltex <1% 1% 3% Cheviot Hill Type % 3% 3% Swaledale % 3% 3% Cheviot (Unspecified) % 1% 2% Table 2: The number of recorded rams in Great Britain in 2013, split into breeds. Preliminary findings reported at Sheep Breeders Round Table, Nottingham, November 2013 The project will initially involve three breeds the Poll Dorset, Lleyn and Texel. This research has a potential value to the industry of 4.35 million, purely through lengthening the profitable lifetime of breeding ewes. Further financial gains could also be made by reducing the amount of grazing required for replacement ewe lambs.

4 Ultrasound scanning guides selection process Ram breeders can assess the carcase attributes of their lambs by ultrasound scanning, which measures muscle and fat depth in the live animal. Carcase traits, like muscling across the loin are harder to identify than traits such as growth rate, so ultrasound is an invaluable tool. The measurements taken by the machine allow breeders to identify animals with superior muscling within the carcase and the right amount of fat to suit the taste of modern consumers. New scanning equipment Signet recently invested in new scanning equipment that uses the latest scanning software. The SonoScape machines provide a sharper and clearer image that allows muscle and fat layers to be more clearly defined. How is it done? At around 21 weeks of age, lambs are scanned by an accredited Signet technician. The scanning technique involves parting the wool at the third lumbar vertebra at 90 degrees to the backbone and then applying liquid paraffin oil to give a contact. The transducer is adjusted until a clear image of the third lumbar transverse process, the eye muscle and the fat layers can be seen on the screen. A single measurement is taken of muscle depth at the deepest point and three measures of fat depth are taken at 1cm intervals (Figure 2). How does the producer benefit? The raw data provided by ultrasound scanning is analysed to produce EBVs for Muscle Depth and Fat Depth. These EBVs allow producers to select the ram with the right breeding potential for their farming system. The purchase of rams with good carcase trait EBVs can significantly improve the carcase conformation of slaughter lambs. Pedigree flocks can benefit too, as the purchase of an ultrasound scanned stock ram with superior EBVs, reduces the risk of introducing a new bloodline into the flock with inferior genes. EBVs or raw data? When buying a ram, it is important to use the EBVs generated from the ultrasound scanning data, rather than the raw data itself. This is because the raw data has not been adjusted for on-farm effects such as feeding, age or how the animal was reared. It is not necessarily easy to tell whether a high muscle depth measurement is due to a ram s genes for muscling or the environment in which it was being kept. Figure 2: Measurement points during ultrasound scanning for muscle and fat depths Farmers wishing to enhance the carcase quality of their lambs should look for rams that have been ultrasound scanned to generate Muscle Depth and Fat Depth EBVs.

5 Assessing carcase attributes using Computed Tomography Computed Tomography (CT) scanning is an important tool for identifying animals with superior genes for muscling. It provides a welfare-friendly way of assessing the total muscle, fat and bone yield in a live sheep using X-ray image analysis. CT images provide the best possible predictor of carcase composition, including muscling in different parts of the carcase such as the gigot. This type of scanning detects different tissue densities. On the image shown in Figure 3, air appears as black, fat as dark grey, muscle as light grey and bone as white. Breeders particularly interested in improving the hindquarter of their stock should look carefully at the Gigot EBVs for high-indexed terminal sires. Some breeders will display the CT images of their lambs at sales. CT scanned animals can also be identified because they have higher accuracy values for the Gigot EBV. Why buy a CT scanned ram? CT information is used to enhance the accuracy of the EBVs produced for recorded rams, influencing predictions of muscle and fat weights in the carcase. Producers seeking the very best and potentially most profitable breeding stock, are advised to seek out high EBV rams that have been through a CT scanner. Figure 3: Gigot CT image of a 55kg lamb New way to present Fat Depth EBVs The orientation of this particular EBV on the charts has caused much debate over the past few years. Leaner animals have traditionally been reported as above average or superior. However, it is important to recognise that in practice producers require stock with an optimum level of fatness. Old chart presentation This optimum will vary with ewe breed and farming system. Therefore, ram selection decisions using the Fat Depth EBV have to be made carefully to ensure lambs have the optimum amount of carcase fat at the point of slaughter. Change of orientation This year Signet has changed the orientation of the Fat Depth EBVs published on the sale charts often displayed at shows. Figure 4: EBV chart with old presentation of Fat Depth (mm) New chart presentation Producers see this change as logical, with more fat being presented on the same side of the chart as more growth, more muscle and more milk. The breed benchmarks have also changed. Breeding Indexes are unaffected. An example is shown to the right for a Lleyn ram with a positive Fat Depth EBV. Figure 5: EBV chart with new presentation of Fat Depth (mm)

6 Maternal sheep breeding initiatives Signet is working with several breeders to promote the importance of performance recording within maternal breeds. Enhanced maternal valuations for Dorset and Lleyn breeds Estimated Breeding Values are calculated using knowledge of the heritability of different traits (the degree to which variation between animals is influenced by their genes) and the relationships (correlations) between these traits. Periodically these genetic parameters are reviewed to ensure they are appropriate for the sheep/breed being analysed. In 2014 EBLEX funded SRUC to review the genetic parameters used in the evaluation of Dorset and Lleyn sheep. Results As a result of the research, a new way of calculating the Maternal Ability EBV has been developed. The Maternal Ability EBV is an assessment of the genetic influences on lamb growth to eight weeks of age that can be attributed to its mother, the main one being milk production. In the Dorset breed the most striking finding was that the heritability of maternal ability had risen significantly. The new evaluation is doing a better job of attributing lamb weight gain to the genetic potential of the ewe to produce milk and care for her lamb, rather than confounding this influence with the lamb s genetic ability to grow. Lleyn case studies After meeting with the Lleyn Sheep Society, Signet produced a new leaflet containing four case studies relating to performance recorded Lleyn flocks. It explains how performance records can help selection decisions in a purebred flock. In the Lleyn breed the biggest increase was seen in the Scan Weight EBV, indicating that previous evaluations were probably under-estimating the rates of genetic gain being achieved for lamb growth rate. Implication for Breeding Indexes In the Dorset breed, the Terminal Sire Breed Indexes have been modified to place less emphasis on leaner breeding lines and more emphasis on those with superior muscling. This follows earlier work in 2012 on the maternal index to increase the emphasis placed on prolificacy. In the Lleyn breed, discussions will take place with breeders this autumn regarding a proposed update to their Breeding Indexes. What does this mean for commercial producers? When selecting a ram to breed female replacements it is important to use EBVs to assess maternal characteristics, as a visual inspection of the ram says nothing about his genes for milk production and prolificacy. More accurate EBVs mean producers can make more informed breeding decisions, allowing them to exploit the elite genetics present in both of these breeds.

7 Each case study shows a breeder using performance recording in a different way to improve the profitability of their flock. The timing of this publication coincided with the establishment of a new Performance Recording Lleyn Breeders Group. The group welcomes like-minded breeders to join them. The chairman is Humphrey Mills who can be contacted on telephone number: or humphreymills@btinternet.com Romney sheep initiative Signet is working with members of the Romney Sheep Society and commercial Romney breeders to increase the number of performance recorded Romney flocks in the country. Four new flocks have already joined the scheme. In the future these flocks will work together to develop a breeding group. Any Romney breeders interested in performance recording should contact Lucy Webb-Wilson, Signet Breeding Consultant by lucy.webb-wilson@eblex.ahdb.org.uk New Poll Dorset recorded ram sale The Centurion Poll Dorset Group recently held their second performance recorded ram sales at Sedgemoor market. Signet provided support to the event, which saw a good clearance rate for such an early sale. The group also chose the Centurion Ram of the year from Jim Dufosee s Blackhill flock (shown above). Why record a maternal breed? Romney Case Study, Hugh and Pauline Skinner, Aragon Flock Signet is working with several breeders to promote the importance of performance recording within maternal breeds. from around 18kgs up to around 21kgs. Single lambs are now averaging around 24kgs. By only retaining those ewes with good Maternal Ability EBVs, the milkiness of the ewes on the farm has increased. This has allowed the increase in prolificacy to be managed more easily, as the ewes are capable of supporting multiple lambs. Hugh Skinner and his wife Pauline have been farming Romney sheep in Kent for more than 30 years. Together they have built a prolific Romney flock that is successful commercially and in the show ring. They began performance recording in 1986 and have progressively selected for commercially important traits. Originally the focus was on flock prolificacy. Through selecting rams and breeding ewes with high EBVs for litter sizes, the average size for the flock has increased and stabilised at around 2.1 lambs per ewe. The percentage of singles being born on the farm has also decreased from 30% to around 15%. Targeting growth and milk After prolificacy the on-farm focus moved to improving the genetics within the flock for growth and milk. The average adjusted eight week weight for a twin lamb has increased The next focus for the Aragon flock is improving worm resistance. Sheep, which are genetically more resistant to round worms, are being identified through the use of faecal egg count (FEC) analysis. The data from individual dung samples is entered into the BLUP model to produce an EBV for worm resistance. The Skinners are a perfect example of what can be achieved through performance recording. They are motivated and driven to improve their flock and utilising EBVs is a key part of this.

8 Using EBVs and Accuracy Values Sale catalogues Estimated Breeding Values are now being displayed in sale catalogues for many different breeds. This allows buyers to easily take into account an animal s genetic merit alongside its visual appearance at a sale. The catalogue entries show the EBV and Accuracy Values below the animal s pedigree information. There is usually a Breed Benchmark within the catalogue. EBV and Accuracy Values are displayed on the right of the graph SOUTH WEST RAM SALE 25 TH ANNUAL RAM SALE 13 BREEDS SHEEP Organised by the NATIONAL SHEEP ASSOCIATION (South West Ram Sale Committee) at EXETER LIVESTOCK CENTRE on WEDNESDAY 14 TH AUGUST 2013 At 10.30am Subject to DEFRA Regulations OFFICIAL SOCIETY BREED SALES ALL RAMS INSPECTED Official Catalogue Exeter Livestock Centre, Matford Park Road, Exeter, Devon, EX2 8FD E: livestock@kivells.com T: W: Estimated Breeding Values Estimated Breeding Values provide an assessment of the breeding potential of an animal for a specific trait. They are expressed in the same units as the recorded trait, eg kg for Eight Week Weight EBV. They relate to a common baseline set when the breed started recording. Accuracy Values Accuracy Values are produced for each EBV. They are expressed as a percentage and indicate the amount of data used to calculate the EBV. The higher the Accuracy Value, the lower the chance of the EBV changing over time as new data becomes available. Sale charts Estimated Breeding Values are often presented on charts when rams are being marketed at sales, making it easy for potential customers to assess their genetic strengths and weaknesses: Bars that lie to the right of the central line indicate the EBV/Index is above the breed average, ie superior. The further the line is to the right, the better Bars to the left of the central line indicate the EBV/Index is below the breed average High Litter Size EBV = more prolific ewes High Maternal Ability EBV = ewes with more milk High Eight Week Weight EBV = high early growth rate High Scan Weight EBV = high growth rate High Muscle Depth EBV = better conformation Negative Fat Depth EBV = leaner lambs Positive Fat Depth EBV = fatter lambs N.B. from 2014 onwards positive fat depths will be displayed on the right-hand sides of sale charts The Index gives an indication of the overall ranking according to the breed objectives Further information on interpreting sale cards can be found in Ram Buyer s Guides produced by Signet for individual breeds.

9 Assessing rams on paper have a go! 1 Take a look at the sales charts for these two Charollais rams and decide which one would improve lamb growth within the flock RAM A RAM B 2 Which of these two Texel rams would improve the growth rate or muscling within a flock? I RAM M BREEDER A STONELEIGH ABF 10 SIGNET TOP UK ABF (1) Born: 18/02/2013 Sire: OVERHILL ELITE (2) by FORSETWOOD HERCULES Dam: XYZ07069 (2) by RIVER ROCKSTAR ABC04210(E) EBVs: Litter Size 8 Wk Wgt Maternal Scan Wgt Musc Dpth Fat Dpth CT Gigot Musc Index kgs -0.40kgs 11.16kgs 1.11mm 0.25mm 4.79mm 271 Accuracy 41% 72% 35% 72% 64% 66% 60% 72% Y RAM R BREEDER B BETTER RETURNS LOL 11 BREEDING ULTIMATE UK LOL (1) Born: 05/02/2013 Sire: BREEDING KING HIJ (E) by SUPREME CHAMPION Dam: PQR (2) by WOOLSHED WINNER RST08501(1) EBVs: Litter Size 8 Wk Wgt Maternal Scan Wgt Musc Dpth Fat Dpth CT Gigot Musc Index kgs -0.51kgs 9.77kgs 2.47mm -0.39mm 5.07mm 307 Accuracy 48% 73% 39% 77% 70% 79% 74% 75% Answers on the back page

10 Interpreting Sale cards Sale cards are used to display EBVs for commercially important traits. Two types of Sale card are used: Three Trait used by terminal sire breeds Seven Trait used by maternal and hill breeds Photo courtesy of CA MacG SIG When looking at Sale cards, producers should refer to the Breed Benchmark to work out where the EBV sits within the breed. Higher EBVs tend to mean greater levels of performance. Breed Benchmarks can be found on the Signet website For traits like Litter Size and Fat Depth, buyers should consider the optimum EBV for their system rather than the maximum. EBVs and Breeding Indexes Signet produces a range of EBVs for each breed it works with. These demonstrate the genetic merit of an animal for a specific trait. Signet also produces Breeding Indexes to aid the simultaneous selection of sheep for a combination of traits to meet a given breeding objective. EBVs are weighted within the index according to their economic importance. Examples of Breeding Indexes include: Terminal Sire Index combining growth and carcase traits to select superior terminal sires Maternal Index focuses on early lamb growth rate, maternal ability and prolificacy. These indexes are useful for self-replacing flocks Hill Index enhances the overall productivity of hill ewes. Several traits are improved simultaneously to influence the number of lambs successfully reared.

11 Finding EBVs online Estimated Breeding Values for performance recorded animals can be accessed online through the Signet website: All the reports for each breed are published in the Latest reports section. One report that may be of particular interest to buyers is the High Five Ram Lamb list. This report lists the top five ram lambs for each performance recording breeder, allowing buyers to identify the superior lambs in a particular flock. Clicking on the EBV search button takes visitors directly to the BASCO search website where the figures for a particular animal can be found by using the quick search funtion. Select the breed of interest and then enter the name, flock book number or ear tag number of the desired animal. Within the individual animal record, buyers can look at the individual EBVs in numerical and graphical form and view a five-generation pedigree. Online training BRP has recently launched an online training package to help producers increase their knowledge of EBVs when buying a Signet Recorded Ram. The package covers a range of topics including: The importance of breeding Assessing breeding potential Interpretation of EBVs Sale cards Sale charts Sale catalogues The value of genetics The importance of ram longevity It includes interactive exercises on the interpretation of EBVs, allowing users to test their knowledge. The package can be accessed from the Technical Information section of the Signet website:

12 Ram buying strategies Producers tend to purchase recorded rams either through the auction or directly from the breeder at their farm. Fit for purpose rams Purchasing a ram of good genetic merit is very important. However, the ram s ability to perform in the field after the sale is just as crucial. This is why it is vital that ram buyers purchase a ram that is fit for purpose. On-farm sales Lower biosecurity risk Purchases can be made at any time More time to discuss requirements with the breeder The rest of the flock can be viewed at the same time Auctions Wider selection of rams to choose from Competitive bidding process Published genetic merit information on show, eg sale charts or catalogue entries This term can mean a variety of things, from structural soundness to fertility, all elements that can influence how well the ram will work throughout his lifetime. Data from ram performance trials suggests around 20% of rams are culled prematurely. A third are lost through infertility. BRP has produced a Fit for Purpose Rams booklet to help breeders ensure breeding stock are fit and ready to work when they reach the customer s farm. View at In either situation, when buying a recorded ram it is vital to: Speak to the vendors about the information offered Take a breed benchmark to see how the animal s EBVs compare to the rest of the breed Check the most recent EBVs for an animal are being displayed Verify if the ram has been ultrasound scanned or not Assessing rams on paper have a go! Answers: 1) Ram A 2) Ram B For more information contact: EBLEX BRP Agriculture and Horticulture Development Board Stoneleigh Park, Kenilworth Warwickshire CV8 2TL Tel: brp@eblex.ahdb.org.uk Agriculture and Horticulture Development Board All rights reserved. EBLEX is a division of the Agriculture and Horticulture Development Board.