liMouSin - Harrison & Hetherington

10A User’s Guide to Estimated Breeding Values BER PEDIGREEHERDContents1. Estimated Breeding Values (EBVs)2. How are EBVs Calculated?3. Breeding Indexes4. Accuracy5. EBV Indexes6. 200 Day Milk7. How to Use EBVs and Indexes8. Understanding Sale Cards and Catalogues9. EBVs and Pedigrees Just a Click Away10. Further Information1. Estimated Breeding ValuesMany factors influence the appearance and performance of a bull, so selecting ‘by eye’ alone can be misleading.The only accurate way of assessing the genetic potential of an animal (i.e. what it can pass on to its calves) is byusing Estimated Breeding Values (EBV’s) and Indexes. These are produced by Signet using a system known asBLUP (Best Linear Unbiased Predictor) and are calculated from animals’ individual performance records as wellas those of all their known relatives, where the effects of the environment (feeding, management, disease,climate etc) are sifted out to leave an estimate of the genetic value for each trait, as follows…Birth Weight (kg)EBV What Does the EBV Indicate? Look for…Calving Ease (%)Maternal CalvingEase (%)Gestation Length (days)200 Day Milk (kg)200 Day Weight (kg)400 Day Weight (kg)Muscle Depth (mm)Fat Depth (mm)Age at 1 st Calving (%)Genetic potential for calf weight atbirthEase with which a bull’s progeny willbe bornEase with which a bull’s daughterswill calveGenetic potential for gestation lengthThe maternal component of 200 daygrowth (i.e. the contribution that themilking and maternal abilities of abull’s daughters make towards theircalves’ growth at 200 days of age)Genetic potential for growth frombirth to 200 days of ageGenetic potential for growth frombirth to 400 days of ageGenetic potential for muscularity andpotential to increase lean meat yieldGenetic potential for leaner carcasesGenetic potential for early sexualmaturityHigh negative EBVs if you want lowcalf birth weightsHigh positive EBVs if you want lessassisted calvingsHigh positive EBVs if you want lessassisted calvingsHigh negative EBVs if you wantshort gestation lengthsHigh positive EBVs if you wantdaughters to wean heavier calvesHigh positive EBVs if you want highgrowth rates to weaningHigh positive EBVs if you want highgrowth rates to finishingHigh positive EBVs if you wantgood calf conformationHigh negative EBVs if you want toproduce leaner carcases or takecalves to heavier weights withoutpenalty for fatnessHigh negative EBVs for a greaterproportion of heifers that hold to 1 stservice