Breeding indexes and traits

Breeding indexes and traits can help you making the right breeding decisions which are an important part of long-term profitability since changes are passed from one generation to the next. These pages look at breeding indexes, explain how they are calculated and how they can be used during breeding decisions.

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Breeding briefs

Breeding indexes and traits

High-quality cows with good genetics are at the heart of profitable dairy farming. Without this, there’s a limit to your herd’s performance, no matter how good your management is.

This isn’t just about genetics for milk production. It’s also about health, welfare, management and type traits, which all contribute to your profitability. All of these can be improved through breeding.

Poor breeding decisions can mean the difference between profit and loss, and even between the survival and failure of your business. Yet the time, cost and effort needed to make good breeding decisions is much the same as for bad ones. 

Remember, breeding decisions are cumulative – the effects build up over generations, meaning that improvements can be introduced over just a few years through the breeding choices you make. 

Here, we cover aspects of breeding indexes and traits, including:

  • The theory behind genetic improvement and how it helps you to make better breeding decisions
  • Predicted transmitting ability (PTAs) of production, health and welfare, calf survival, management and type
  • Genetic progress in the UK
  • Genetic defects

Follow the links below to find out more about breeding indexes and traits.

Genetic indexes: the theory

An introduction to the basics of genetic indexes and PTAs, why they are needed and how they’re calculated.

Find out more about genetic indexes

Production PTAs

You can use production PTAs to allow selection to produce cows that best suit the available milking contract. Find out about production PTAs for milk, fat, protein and persistency.

Learn about production PTAs

Health, welfare and fertility PTAs

There are several PTAs that concern health, welfare and fertility, including important aspects such as SCC and mastitis. Find out more about them and how they’re calculated.

Find out about health, welfare and fitness PTAs

Calving PTAs

These PTAs cover calf survival and related aspects, such as direct and maternal calving ease and gestation length.

Learn about calf survival PTAs

Management PTAs

Temperament, ease of milking, calving ease and maintenance traits can make a difference to the smooth running and management of your farm.

Find out about management PTAs

Conformation PTAs

Conformation traits can affect cows’ suitability for sustained milk production. Find out about the different groups of conformation traits and how they’re calculated.

Discover the different groups of type PTAs

Genetic indexes for selection

Our three economic breeding indexes – £PLI, £SCI and £ACI – help you make quick decisions about choosing bulls most suited to your calving system. Find out more about the three UK indexes and the types of herds they’re suited to.

Find out more about selection indexes

What genetic progress has been made?

Genetic selection has resulted in impressive gains in milk yield, along with improvements in other traits for UK dairy farmers, in the last few decades.

Learn about the progress made in dairy herd genetics

Genetic defects

Find out about the common genetic defects affecting dairy breeding in the UK.

Find out about common genetic defects

Dairy herd genetic reports

This report help you see the breeding potential of your milking cows and youngstock through their genetic index, trait and inbreeding values.

Discover more about the herd genetic reports