Push to ramp up scan data for heifers

Genetic technology experts say an increase in the volume of live animal ultrasound data collected by seedstock producers could go a long way to delivering more accuracy in estimated breeding values (EBVs).

Gains could be particularly strong in traits such as eye muscle area (EMA), rib fat depth, rump fat depth and intramuscular fat (IMF).

Technical officer with Southern Beef Technologies Services (SBTS) Catriona Millen said it was not just the associated cost that was holding producers back on collecting ultrasound scanning records for heifers but the fact the benefits of doing so were not well understood.

SBTS, along with its counterpart in the north Tropical Beef Technology Services (TBTS), is the advisor on genetic technologies, set up to help maximise the understanding of, and use of, the likes of Breedplan, selection indexes and DNA based science.

Thirteen breed societies have partnered with the service in the south and six in the north.

Ms Millen said information on heifer scanning was a topic requested widely by stakeholders.

There were two major advantages to scanning heifers, she said.

“Firstly, heifers mature earlier than bulls,” she said.

“Therefore, when scanned at the same age, heifers tend to exhibit greater variations in rib and rump fat depth and marbling.

“It is this variation that Breedplan EBVs are calculated on,” Ms Millen said.

“Secondly, seedstock producers will often just scan a subset of their bulls, such as their sale bulls.

“That can result in a limited representation of the herd.

“A larger proportion of heifers are generally retained, with much less culling for carcase traits, therefore the heifers are likely to represent a better cross section of the rib and rump fat depths and marbling in a herd.”

While the number of animals with ultrasound scanning data has increased in recent years, the gap between the number of males and females scanned in each calving drop has not changed.

Female numbers are consistently lower.

“That’s not to say there are not seedstock producers scanning heifers,” Ms Millen said.

“But in general, more males than females are scanned – in the 2013 calving drop, across all SBTS and TBTS stakeholder breed societies, 9.7pc more males had ultrasound scan data recorded than females. ”

SBTS and TBTS recommends that where costs inhibit the scanning of all young animals in a herd, heifers be given preference.

Technical officers also point out pregnant heifers can be ultrasound scanned for carcase traits.

Things to consider include Breedplan analyses scanning data from animals that are between 300 and 800 days old and animals should be scanned when they are in as good a condition as possible.

Southern NSW seedstock producers Ian and Diana Locke, Wirruna Poll Herefords at Holbrook, scan both bulls and heifers.

All bulls not culled, which generally equates to around 65 per cent of male progeny, are scanned.

“With 95pc of heifers joined, it’s a much greater representation of the group,” Mr Locke said.

In the Wirruna system, heifers at scanning are always fatter and so provide a greater variation in the traits, particular IMF (intramuscular fat) and rump and rib fat.

“That means you get much better genetic information,” Mr Locke said.

“That then goes back into the lines to give far more accurate predictions.

“In a seedstock operation, in the end we are getting paid for the genetics we produce.

“So if we can better describe them, and then, secondly, show our commercial beef producing clients that our genetics are superior to what is available elsewhere, we will command a premium.”

The Lockes have been scanning since the early 1990s and for marbling since 1998.

“All that time we have done heifers and I’ve always been taught the heifers can be more important than bulls, because of the value of the genetic information,” Mr Locke said.

“A lot of seedstock producers see Breedplan as a marketing tool and only scan to market bulls - they are not seeing the huge value of it as a breeding tool.”