How to select a ram using estimated breeding values

Estimated breeding values (EBVs) are a vital tool in deciding which rams will add the most value to your breeding flock, says independent sheep consultant Catherine Nakielny.

She says traits such as growth and maternal ability cannot be accurately determined visually, particularly as maternal traits are only expressed by the ram’s daughters.

“Growth rate, fat levels, maternal ability and prolificacy all need the independent evaluation provided by EBVs to determine the genetic merit of an individual.”

But she reiterates EBVs are not the only thing to take into account.

“Ram production techniques, flock health and fitness to work all need to be taken into account regardless of what any numbers say.

See also: Find out what Neil Perkins looks for when buying a ram

“Rams need to be sound on their feet, have good mobility and have reproductive organs with no lumps and bumps in the wrong place.

“EBVs are of no use in identifying these animals. This can only be done by talking to the breeder and through physical examination of the ram.”

Step-by-step guide to obtaining the right genetics for your flock

1. Set breeding objectives

“The first thing a producer must do is determine which attributes they wish to enhance within the flock, remembering whether lambs are solely destined for slaughter or whether female replacements are to be kept,” says AHDB beef and lamb breeding specialist Sam Boon, who says this will influence the weighting of different traits.

“A critical look at the physical performance of the flock will identify weaknesses in the flock and it is probably these areas that are important to focus on,” he adds.

2. Breed

“Take into account the breed you are working with. Less attention needs to be taken when selecting for prolificacy where a ram is being used on a highly prolific breed of ewe,” warns Mr Boon.

For example, he says the focus placed on choosing a ram with the right fat depth EBVs will be influenced by whether the breed being selected has a tendency to produce finish early in life or not. Genetically fatter rams can be used in leaner breeds.

3. System

What EBVs you select will also depend on the type of system you are running, says Mr Boon.

“Different systems require slightly different genetics. In an early lambing system, high growth rates are vital to ensure lambs hit peak prices. On grass-based systems, rams with positive fat depth EBVs have the potential to produce lambs that are easier and potentially faster to finish.

“Store lamb producers can focus less on growth rate and simply select a ram with a balance of EBVs for growth and carcass traits. However, most systems require lambs with the genetic potential to grow well – even if these genes are not always needed to be fully expressed.”

4. EBVs to enhance performance

The next step is to find out which EBVs are required to enhance this performance.

“So to improve lamb growth rates, breeders have an eight-week weight and a scan-weight EBV; for milk production there is the maternal ability EBV and for prolificacy there are litter size EBVs.

See also: EBVs – what do they mean? [PDF]

To get a comparison of how good your prospective ram’s EBVs are you need to get a breed benchmark, which shows what the average, top 25% and top 10% of figures are like.

But Mr Boon warns these figures cannot be compared between breeds.

5. Optimise – not maximise

For some traits bigger is best – but not all. Instead producers should select the “optimum” EBVs for their flock, advises Mr Boon.

“Selecting rams on the basis of their fat depth EBVs is a good example where an optimum is required – as in most systems the very leanest and very fattest probably aren’t going to produce the ideal level of finish on a 21kg carcass. However, by studying the weights and grades of their lambs producers can identify roughly where they should be pitching their focus for this trait.”

6. Finding information

“EBVs are now widely published in sale catalogues and charts/display cards will be provided by performance-recording members.

“However, in recent years the information for most Signet-recorded breeds has been made available onnline, so anyone with a smartphone can use it to check a rams breeding potential.

“Information produced on charts provides a quick visual representation of a ram’s performance.”

7. What should I ask?

When talking to breeders about their involvement in recording, the buyer should ask how long they have recorded, how many lambs they ultrasound scan each year and what genetic progress they have achieved over time, advises Mr Boon.

“Most breeders will quickly show you the page in their reports showing genetic change over time. Ask about the rams they buy – do they use recorded rams themselves?

“Knowing a ram is sired by a Signet-recorded or highly progeny-tested sire should give the buyer greater confidence in the EBV predictions on display.”

For terminal sire producers the availability of computed tomography (CT) is particularly important as this will help to identify elite breeding lines with greater confidence.

8. What should I pay?

Mr Boon says that it is not about what you should pay, but rather what you can invest.

We know that high EBV rams are capable of producing progeny worth £3-£4 a head more than average animals – so investment in the right genetics is money well spent.