Hunt for sheep gene

The newly established Centre for High-throughput Agricultural Genetic Analysis (CHAGA) has launched its research program with an attempt to develop a method to identify sheep with a natural resistance to parasitic worms.

Australian animal production industries spend around $100 million a year on chemicals to treat livestock for worms. Labour costs and damage to livestock add a further $120 million, said Centre Director, Professor Keith Gregg.

In recent years the chemical treatments have become less effective because the parasites can develop immunity. In Australia, resistance to the chemicals is widespread and increasing.

Where chemicals are used to combat pests, the pests most able to cope with the chemicals are the ones that survive and produce the next generation of pests.

An estimated 85 per cent of farms in Australia have resistance problems with milky drenches and 65 per cent have resistance to clear drenches. Over 60 per cent of properties have resistance to both types. The most effective chemical, Ivermectin is still effective in most areas, but resistance is now appearing.

CHAGA research scientist Dr Kylie Munyard is working to develop a genetic screening process, so breeders can identify animals with the best natural resistance and use them to breed their future stock.

It makes excellent sense to use nature’s own methods to keep livestock from being damaged by parasites, by selecting the breeding stock that are least affected by the parasites, said Program Manager, Dr David Groth.

The feature that helps sheep to resist worm problems is their own body immunity.

Our challenge is to find a reliable and affordable way for sheep breeders to identify the sheep with the best immune systems for this purpose.