NZ lambs

Better feed efficiency through genetics

The provision of feed is a major cost in New Zealand sheep production. As such, any reduction in feed costs, while maintaining productivity, would be of significant economic benefit to farmers.

“One way of achieving that,” AbacusBio consultant Jason Archer says, “is through genetic improvement.”

Jason has been working with colleagues Tim Byrne and Luke Proctor on a project that looks at assessing the value of genetic improvement in improving feed efficiency – for the NZ sheep industry.

“While most genetic improvement programmes in NZ emphasise selection to improve outputs such as growth rate, fertility, and carcass traits, there is also a need to consider avenues for reducing inputs,” Jason says.

Recent research shows that there is considerable variation among animals in terms of feed intake based on size and growth rate.

“This difference in intake is generally termed ‘residual feed intake (RFI)’, also known as the measure of net feed efficiency,” Jason adds.

The team looked at various models for selecting for RFI, using selection index theory, and evaluated their economic returns for the entire NZ sheep industry.

The analysis shows that the total economic benefits arising from 10 years of selection on currently recorded traits and RFI using genomics is calculated as $1,032 million (with RFI contributing $39 million).

This was based on using both direct and indirect (via greenhouse gas production) measurements of RFI in industry progeny test flocks to calibrate the genomic prediction for RFI.

“Selection for lower RFI could lead to a reduction in feed intake of animals, with no compromise in growth performance, although the challenge in achieving that is by no means simple,” Tim remarks.

The next step is to further investigate the incorporation of RFI as a trait into NZ sheep breeding programmes.

This project is contracted by Beef + Lamb New Zealand Genetics, and co-funded by the Pastoral Greenhouse Gas Research Consortium.