SNP chip

 

Breeding a better sheep

Between 1997 and 2009, thanks to greater lamb weights and CEO, Beef + Lamb New Zealand
more lambs per ewe being born, the weight of New Zealand lamb
produced per ewe rose by a spectacular 81%.

This gain was the result of an ongoing, concerted effort by many organisations including Ovita, a joint enterprise between AgResearch and Beef + Lamb New Zealand (formerly Meat & Wool NZ).

Even more spectacular is that the rate of genetic gain among the national flock may become faster still. One reason: a new technology called the Ovine SNP50 Beadchip.

Developed by researchers from AgResearch, Baylor UCSC, Australia’s CSIRO, Utah State University, the USDA, and biotech company Illumina, the SNP50 allows researchers to identify the small genetic differences that produce important traits in sheep including not only growth rate, but also fertility, parasite resistance, survival and more.

SNP chips do what traditional DNA methodology can’t: namely, test the genetic merit of an animal, opening up the potential to select on many genes across the whole genome.

That said, the first iteration of the ovine SNP chip (based on Ovita technology and released commercially by Pfizer Animal Genetics in 2010), was able to measure for just six traits across three sheep breeds. Later versions are more powerful still – having recently added meat yield traits, wool and facial eczema – and the future promises even more quantum leaps in ‘processing power’.

John McEwan heads the AgResearch team behind the new chip. Recipient of the 2010 Ross Clark Distinguished Biotechnologist of the Year Award, John says recent developments include a test that can identify potential sire rams at birth, and they are working on measures for longevity, adult live weight and lamb survival.

“You can currently record these,” he says, “but you can’t get accurate breeding values for an animal until many years after it has first bred.” In other words, the technology is causing a shift from a broad-stroke historical model (pick the animals that have performed well and breed from them) to a powerful, fine-tuned, predictive one.

The prospects are huge. The SNP chip is combining with other work, including the longrunning Beef + Lamb New Zealand funded Central Progeny Test, to the extent that John believes a doubling of the current rate of genetic gain is now on the cards.

That creates a new challenge. “The changes we scientists create are always disruptive. Sheep breeders range from instant adopters to those who feel very uncomfortable about using new methods. So one of our challenges is to take what we’ve learned and package it in a way that’s consistent with the methods breeders already use and that their commercial farmer clients also understand.”

“The Red Meat Industry sector strategy identifies improving productivity at
all stages of the supply/value chain, leveraging R&D and knowledge transfer
as critical elements of sustainable future profitability. Beef + Lamb New Zealand’s
collaboration with AgResearch through our joint enterprise, Ovita, continues to play a central role in delivering on these goals.”

Dr Scott Champion, CEO, Beef + Lamb New Zealand