Manual 1 – Choosing bulls to breed for better returns - Eblex

Growth rateHigh growth rates can enhanceweight of cattle sold, productionefficiency and timing of salesSelecting bulls with high 200 and 400Day Growth Rate EBVs ensures heaviercalves at weaning and slaughter.Cattle with high growth rates make more efficient use offeed. Therefore, feed costs per kilogram of liveweight gainare reduced, as is time to slaughter.Cattle with high growth potential are easier to400 daysmatch and manage for periods of high market returns.200 daysBull A:higher rate growth450kg350kgBull B:slower rate growthWhich EBVs are important?200 Day Growth EBV (kg)An indication of breeding potential for growthto 200 days of age.ExampleBull with EBV of +20kg is estimated to producecalves 10kg heavier at 200 days than a bullwith an EBV of 0.400 Day Growth EBV (kg)An indication of breeding potential for growthto 400 days of age.ExampleBull with EBV of +48kg is estimated to producecalves 24kg heavier at 400 days than a bullwith an EBV of 0.RememberThe potential for high growth rates is only realised under goodmanagement – adequate feed and high herd health status.BewareSelecting for high growth rate alone can increase birthweights, leading to calving problems (page 8) – and increasecow mature size, which on some systems might reduce herdefficiency (page 12).Do not select on growth rate EBVs alone.6

Maternal performance – early fertilityIt is common UK practice to calve heifersat 2, 2.5 and 3 years old. Calving at ayounger age under appropriatemanagement, will increase the numberof calves raised during a cow’s lifetimewith consequent financial benefits.Heifers must be reproductively active to calve at 2 years.The key factors influencing puberty are body conditionscore and liveweight, as well as age. To ensure highconception rates, heifers should reach 2/3 of adultweight before mating.Breed can influence age of puberty, with native breedstending to reach puberty earlier than continental ones.Within every breed there is variation that can beexploited using EBVs.Which EBVs are important?Producers can select bulls using the age at first calving EBV. There is also some relationship betweenbull’s scrotal circumference and the age at which his female progeny will reach puberty.Age at First Calving EBVIdentifies female breeding lines that arereproductively active and capable of conceptionat an early age.ExampleA bull with an EBV of -0.10 will produce 5% morefemales likely to have a first calf at an early age(if mated) than a bull with an EBV of 0.Scrotal Circumference EBV (cm)Increasing scrotal circumference in malesenhances reproductive performance in maleand female progeny.ExampleA bull with an EBV of +4 cm will produce sonswith scrotal circumferences 2cm greater thana bull with an EBV of 0 cm and daughters arelikely to reach puberty earlier.• Use careful management when calving heifers at 2 years.• Pay particular attention to:– pre-mating and pre-calving nutrition– selection of easy calving bulls.9

Maternal performance – milk productionOptimising a cow’s milk production gives new born calves a good startand provides adequate nutrition up to weaning.Assessing breeding potentialfor milk productionProducers breeding replacements can select beefsires to improve the herd’s milking ability using the200 Day Milk EBV.Pedigree producers can also score udder and teatconformation, with EBVs which will become availablein the future (below).sonsdaughtersInfluence ofgrowth genesInfluence ofgrowth genesInfluence ofmilk genes1 2 3Udder score 1 – A tight udder, with the base above the hockUdder score 2 – Normal udder, with the base level with the hockUdder score 3 – Udder hanging below the hocks of the cowWhich EBVs are important?Producers can enhance the milking ability of cows retained within the herd by selecting bulls withsuperior 200 Day Milk EBVs.200 Day Milk EBV (kg)Identifies female breeding lines that will producemore milk and so wean heavier calves.ExampleA bull with an EBV of +8kg will produce femaleprogeny whose calves are 4kg heavier at200 days than a bull with an EBV of 0.Teat Score EBV & Udder Score EBV – (Signet)Could enable breeders to breed beef cattlewith superior udder conformation.ExampleAvailable in the future.• Purchase sires with superior 200 Day Milk EBVs to breed femalereplacements with increased milk production.• Do not select on this trait when breeding replacementsout of dairy cows.11

Maternal performance – cow efficiencySelecting to improve growth rate will lead to increased mature cow size in most herds. Where feed is plentiful andfeed costs low this may not be a bad thing. However, where feed supply is limited, using a smaller cow requiringlower feed requirements can be advantageous. Smaller-framed animals are more likely to retain a higher bodycondition score under harsh conditions. This greatly enhances overall fertility.Breeding smaller cowsAdvantages✓ Lower feed costs✓ Higher stocking rates✓ More fertile underharsh conditions✓ Easier to outwinter/cheaper to houseDisadvantages✗✗✗Lower cull cow valueLighter weight calvesPotential for morecalving problems✓ Potential to reachpuberty earlierProducers can select breeding stock with superior EBVs for early (200 day) growth rate, but low mature size.The growth curve of these animals is unconventional and they are referred to as “curve benders”.Producers can also enhance herd efficiency by extending cow longevity. This can be achieved throughwithin breed selection using EBVs or crossbreeding to exploit hybrid vigour.Which EBVs are important?A Mature Size EBV will enable producers to modify mature cow size. Longevity EBVs are availableto extend cows’ reproductive life within the herd.Mature Size EBVEstimates size at maturity.ExampleA bull with Mature size EBV of -50kg willproduce female replacements 25kg lighterat maturity than a bull with an EBV of 0.Longevity – (Signet)Estimates how long cows will bereproductively active in the herd.ExampleA bull with a Longevity EBV of +1.0 year willproduce female replacements that live 0.5years longer in the herd than females siredby a bull with an EBV of 0.• In herds that breed female replacements, increased calf growth rateleads to increased cow mature size. This can be controlled usingMature Size EBVs.• Optimum cow size for the herd depends on available resources,particularly feed.12

Breeding indexesEBVs enable stock to be selected for specific traits. However, theycan be combined into indexes to meet specific breeding objectives.Each trait is weighted according to its relative economic value to providea single figure on which selection decisions can be based.IndexesCalving ValueAim: Reduce cost of difficult calvingsEBVs• Gestation Length• Calving Ease• Birth Weight• 200 Day GrowthBeef Value/Terminal Sire IndexAim: Increase carcase values• 400 Day Growth• Muscle Score• Muscle Depth / Area• Fat Depth• Age at First CalvingMaternal ValueAim: Identify superior genetics toproduce female replacementsMaintenance ValueAim: Reduce cow maintenance costs• Maternal Calving Ease• Scrotal Circumference• Calving Interval• 200 Day Milk• Longevity• Mature SizeMaternal Production ValueAim: Identify superior genetics to producequality female replacements withbeef carcase characteristics• Calving Value• Beef Value• Maternal Value• Maintenance ValueThose EBVs shown in blue are only available for Signet recorded herds. “Maternal Production Value”,designed to assist producers breeding a self replacing suckler herd.Breedplan has developed beef indices for individual breeds, with weightings customised to breedcharacteristics. A maternal index is under development for some breeds and a suckler replacementindex is available for others. Breed societies can provide further information.• Use indexes as an overall guide.• Consider EBVs for particular breeding objectives.13

Interpreting EBVs when buyinga recorded bullEBV data for two Limousin BullsBuyers can use EBVs to assess a bull’s strengths andweaknesses. Only then can they decide whether it hasthe right breeding attributes for their herd. Compare andcontrast the EBVs for these two Limousin bulls.Bull A: Winterhill RobertSire: Winterhill BobDam: Bradwell MaryAnalysis date Calving 200 Day 200 Day 400 Day Muscle Fat Depth BeefValue Milk (kg) Growth (kg) Growth (kg) Depth(mm) (mm) ValueE B V LM1C +4 +28 +42 +4.1 -0.1 LM27Accuracy % 57 42 72 69 69 62 63100 200 300 400 500 Scannedday wt. day wt. day wt. day wt. day wt.118 253 378 556 710 YESBull B: Huntingdon FredSire: Oakham IanDam: Oldbrook ClareAnalysis date Calving 200 Day 200 Day 400 Day Muscle Fat Depth BeefValue Milk (kg) Growth (kg) Growth (kg) Depth(mm) (mm) ValueE B V LM6C -5 +30 +52 +2.0 +0.3 LM25Accuracy % 59 43 73 68 66 60 64100 200 300 400 500 Scannedday wt. day wt. day wt. day wt. day wt.126 256 385 568 744 YESAccuracyBelow 50% 50–74%preliminarymedium75–90% Over 90%medium/highhighAt sales EBVs are often presented in a graphic form.The higher the level of accuracy,the less likelihood of radical changeto an EBV.14

Breed benchmark exampleThe Breed benchmark indicates the distribution of EBVs across the breed. The benchmark can beused to identify an animal’s ranking within the breed.Trait Bottom Breed Top1% 10% 25% average 25% 10% 1%Calving Value LM-4C LM-1C LM0C LM1C LM2C LM3C LM5C200 Day Milk (kg) -7 -3 -2 0 1 3 6200 Day Growth (kg) -8 0 5 12 18 24 37400 Day Growth (kg) -13 0 10 21 31 41 63Muscle Depth (mm) -1.4 -0.1 0.5 1.3 2.1 3.0 4.7Fat Depth (mm) 0.4 0.1 0 -0.1 -0.2 -0.3 -0.5Beef Value LM0 LM6 LM11 LM16 LM20 LM25 LM34By comparing each bull’s EBVs against the breed’s EBV benchmark:• Each bull has been fully weight recorded and scanned with satisfactory accuracy figures (for a young animal).• Both bulls have above average EBVs for growth and carcase traits and would make suitable bullsfor use as terminal sires, but in several important ways their characteristics differ:Bull A: Winterhill Robert• has high Muscle Depth EBVs• has a 200 Day Milk EBV in the Top 10%of the breedBull B: Huntingdon Fred• has the highest EBVs for Growth Rate• has a Calving Value in the Top 1% of the breedBull A would be ideal for beef production where cattle are sold for slaughter and carcase qualitytakes a high priority. The high 200 Day Milk EBV would also make it a suitable sire for herds where femalereplacements are being retained for breeding.Bull B would be suitable for mating to heifers because of its high Calving Value.It could also be used in herds where the top priority is to improve growth rate.• Take your time• Consider your breeding objectives• Select bulls with the right EBVs for your needs15

Selecting a bull forphysical soundnessWhile EBVs will help bull buyers select breedingstock for a range of economically important traits,a subjective assessment is still required to assessfertility, temperament and structural soundness.Fertility is one of the most important traits, becauseinfertile bulls are a major source of economic loss.Check scrotal tone and size, as testicle size has adirect influence on daily sperm production andhence mating load.For a bull to actively seek out cows for mating andmount them, it needs to be physically fit, possessgood locomotion and be free from pain or discomfort.More bulls are culled for problems with their hindlimbs than for any other structural condition,so check their feet and legs carefully.Bull health and fertility- before and after purchaseIt is often said, quite correctly, that the bull is half the herd. This suggeststhat he should be regarded as being as important as all the other stockput together. Yet in practice he is often lucky if he receives half the careand attention of the other stock.This leaflet offers advice on how to care for the healthand fertility of what is probably the most expensiveasset in your herd - the stock bull.For more guidance on bull careask for this leaflet free from EBLEX BeefBetter Returns ProgrammeAnd finally… look after your new bullLooking after a new bullHaving purchased a new bull it is important toget him settled in his new environment as quicklyas possible.Delivery• Ensure the bull is loaded quietly, placed on anon-slip surface within the cattle float and tiedcorrectly, to prevent problems in transit.Health status• Avoid unloading a new bull straight into theherd. Rest him in a quiet part of the yard,where he can be isolated and monitored forsigns of ill health.• As well as checking the sellers’ herd healthstatus prior to purchase, find out when thebull’s next set of vaccinations are due.Starting work• Let him see his new surroundings andother stock.Avoid keeping him in a confined space andensure the surface on which he is walking andwill be expected to work is not uneven,slippery or very soft.• Find out what your new bull has been fed priorto sale and use this knowledge to gently adjusthim onto his new diet, starting with somethingsimple like hay.The money spent on your new bullis a major investment in the herd.It is time well spent getting himsettled in and ensuring he is fitand healthy.16

ContactsName and addressContact no. email/webEBLEXwww.eblex.org.ukBetter Returns ProgrammeNetta de la Cour, Project Manager Tel: 0870 241 8829 nettad@eblex.org.ukHeather Stewart, Project Administrator Tel: 0870 241 8829 brp@eblex.org.ukGraphic House, Ferrars Road, Huntingdon PE29 3EERegional ManagersWestern Region: Clive Brown Tel: 0870 241 8528 cliveb@eblex.org.ukRosedale House, Askham Bryan College, York YO23 3FRNorth East Region: Steve Powdrill Tel: 0870 241 8528 stevep@eblex.org.ukRosedale House, Askham Bryan College, York YO23 3FREast Region: Michael Richardson Tel: 0870 242 1394 michaelr@eblex.org.ukGraphic House, Ferrars Road, Huntingdon PE29 3EESouth East Region: Nick Allen Tel: 0870 241 9012 nicka@eblex.org.ukGraphic House, Ferrars Road, Huntingdon PE29 3EESouth West Region: Peter Reynolds Tel: 0870 608 6610 peterr@eblex.org.ukOffice Suite A, Hamilton Road, Taunton, Somerset TA1 2YHSouth West Region: Phil Hadley Tel: 0870 608 6610 philh@eblex.org.ukOffice Suite A, Hamilton Road, Taunton, Somerset TA1 2YHLiz Ford, Regional Project ManagerRosedale House, Askham Bryan College, York YO23 3FR Tel: 0870 241 8528 lizf@eblex.org.ukMLC’s Signet Breeding ServicesPO Box 603 , Winterhill, Milton Keynes MK6 1EL Tel: 01908 844 210 www.signetfbc.co.uksignet@mlc.org.ukPedigree Cattle Services (Breedplan)Pedigree House, 6 King's Place, Perth, Scotland, PH2 8AD Tel. 01738 622478 www.breedplan.co.ukbarbara@breedplan.co.uk17

For more information contact:Beef Better Returns ProgrammeEBLEXGraphic HouseFerrars RoadHuntingdonPE29 3EEFunded bywww.defra.gov.ukTel: 0870 241 8829Fax: 0871 433 6205Email: brp@eblex.org.ukwww.eblex.org.uk© EBLEX 2007The tables and contents of thispublication may not be reproducedwithout the express permissionof EBLEX.R262457 July 07