Estimated Breeding Values (EBVs)

What are Estimated Breeding Values (EBVs)?

Estimated Breeding Values or EBVs are science-based, industry-tested measurements of heritable traits that can be tracked and measured. EBVs are proven to improve on-farm productivity and enhance breeding decisions.

For those familiar with Expected Progeny Differences (EPDs) used in cattle, EBVs are very similar. EPDs denote the breeding value of an individual animal’s progeny whereas EBVs denote the value of the individual animal. More simply, EBVs equal EPDs times two.

Why Use EBVs?

Many economically important traits cannot be determined by visual appraisal alone. Using EBVs is the proven method of accurately predicting if an animal will pass on important traits such as growth rate, reproductive proficiency, carcass quality, wool quality, and parasite resistance.

How I should I use EBVs?

EBVs begin with on-farm production data but then convert it to actionable genetic information. Performance data is adjusted for variables that are not related to genetics, such as flock management techniques. And, EBVs are calculated on the performance of the individual animal, related animals in the same flock, and related animals in other flocks.

NSIP has grouped certain EBV traits together in order to create indexes that are particularly useful tools for selecting breeding stock that are suited to a particular situation. For example, the Western Range Index places emphasis on both lamb and wool production and is designed to improve profitability for flocks raised on grasslands in the western U.S.

Sheep producers may find it most valuable to balance a number of traits. For example, birth weight, weaning weight, post weaning weight and yearling weight are growth traits that are positively correlated. However, balancing for a moderate birth weight and a low yearling weight are ideal for lambing ease and feed efficiency. Because they are positively correlated, the only way to balance these four traits is by using EBVs.

Case Study – Using EBVs in a Commercial Flock – The Leading Edge Project

Want to Learn More About EBVs?

Estimated Breeding Values Explained

NSIP EBV Descriptions – Updated- 16 Dec 2018 – Dr. David Notter and Dr. Ron Lewis
Nuts and Bolts of EBVs
New Traits for NSIP Polypay Genetic Evaluations by Dave Notter 2011
New Traits for NSIP Western Range Breed Genetic Evaluations by Dave Nottter 2011

Production Indexes Explained
Maternal Wool Breeds Index by Dave Notter 2014
Maternal Wool Index Factsheet-2014
Maternal $ INDEX INFO 2010

Data Collection Standard Operating Procedures
Data Collection Schedule: What data to collect and when
Data Collection Age Categories
Fecal Egg Count Collection Methods
Recording Orphan and Foster Lambs – Updated Dec 2020

NSIP Genotyping Guidelines
Overview of GEBVs

Technical Notes
Adjustment Factors in NSIP by David Notter and Daniel Brown March 2015

Value and Use of EBVs
NSIP Ram Buying Guide
What is an EBV worth?
10 Steps to Become an Effective NSIP Breeder

National Sheep Improvement Program
PO Box 1258 | Ames, IA 50014 | Phone: 515-708-8850 |