BDGP was introduced in 2015 and created quite a stir in the suckling community. Some agreed with the figures - more didn’t.

While stars and genetic indices have been part and parcel of suckler farming in Ireland for many years now, BDGP focused the breeding plans for thousands of farmers across the country on stars.

It’s a requirement of the programme to have a genotyped four- or five-star terminal bull and also that 50% of the reference number of females are genotyped four or five-star on the replacement index by 31 October 2020.

If farmers fail to hit these targets, then penalties apply, so everyone is focused on hitting the targets.

Gripe

A gripe that many have had with the figures, particularly pedigree breeders, is the way figures change between each evaluation.

As data on genotyping, live weights, calving ease and carcase weight - among other things - are fed into the database, this changes a bull's figures.

You have to say that this is good for commercial farmers, as it means the most up-to-date information is included in the genetic evaluation of a bull, so if anything - for example difficult calvings - is taking place with a certain bull, this is fed in and the calving difficulty figure will rise.

It also works the other way and if cattle are grading very well of a certain bull, then his conformation figure will rise.

It’s difficult for a pedigree breeder to take a gamble inseminating a cow

On the other hand, it’s difficult for a pedigree breeder to take a gamble inseminating a cow on 1 February 2020 knowing that this calf will be for sale in spring 2022, a long way away.

There will likely be about 11 database updates during this time and a lot can change. That’s where reliability comes in and bulls with a high reliability figure generally won’t move too much.

Young bulls or new genetics can move more frequently and this deters some breeders from taking a chance on new blood. So do stars really move that much?

Results

To look at how much these stars move, Teagasc researcher Alan Twomey took a look at some figures in the ICBF database. He looked at heifers in BDGP herds that calved for the first time in 2017.

He then compared the cows' index value with the results to their first genomic evaluation in 2016. The results are detailed in Table 1 below.

The table shows that of the 20,931 five-star cows in the first genomic evaluation in 2016, 52% are still five-star, 24% are four-star, 14% are three-star, 7% are two-star and 3% are one-star.

It’s a similar story down the line for the rest of the categories, with less movement in the one-star category. This wouldn’t be described as huge movement and changes will always occur in the database, meaning more accurate figures for farmers.

BEEP

Alan also took a look at some data from the Beef Environmental and Efficiency Programme (BEEP). He found that as replacement index increases, cow liveweight decreases.

Along with this, higher-replacement index cows are weaning heavier calves. There is a thought out there that small cows will produce small calves, but Alan’s analysis demonstrated that for every 10kg that cow liveweight reduced, weaning weight reduced by 1kg.

So a 600kg cow would wean a calf 10kg lighter than a 700kg cow. Figures 1 and 2 show the relationship between the replacement index and dam weight and weaning weight.