News Archive

Love is in the air at the University of Western Australia (UWA) and it is the good
‘old-fashioned’ kind that hasn’t been chemically induced and, best of all, it will keep the hormones away from the dinner table.

And it isn’t in the student body, but in the sheep at the UWA Faculty of Natural and Agricultural Sciences School of Animal Biology.

Associate lecturer Dr Penny Hawken is exploring the possibility of controlling sheep reproductive cycles using pheromones (the smell of a ram) instead of hormone treatments, which will help increase the 382,000 tonnes of lamb and 244,000 tonnes of mutton Australia produces, which equates to seven per cent of the world’s supply.

“We’re exploring clean, green and ethical ways of stimulating ewe reproductive cycles, while reducing the amount of artificial hormones which can ultimately end up on consumers’ dinner plates,” Dr Hawken said.

“An added bonus is that growers’ hip pockets will benefit from not having to buy and administer expensive hormone treatments.”

The smell of rams was so potent that ewes could be stimulated to ovulate simply by being put in a shed where rams had been for a day or two ‘stinking it out’.

“It’s well established that exposing ewes to a ram causes an almost instantaneous increase in concentrations of luteinising hormone, the hormone that drives ovulation.

“This hormonal response means this technique can be used to help break traditional sheep seasonal breeding patterns and switch ewe reproductive activity back on, allowing her to fall pregnant outside the natural breeding season,” she said.

“The technique is better than hormonal treatments, from an animal welfare perspective and costs almost nothing.”

Dr Hawken said the phenomenon known as ‘ram effect’ was used widely in Australia to breed ewes during the non-breeding season.

Her project focused on understanding how it worked at the level of the brain and discovering why it worked well in merinos, but not in meat breeds.

She hoped that by understanding the mechanism behind the ‘ram effect’, it could be improved as a management tool.

“It produces valuable out of season lambs, while increasing a ewe’s lifetime productivity, which would benefit wool and lamb growers.

“Growers can change lambing times to suit fattening lambs and selling them
off-season when prices are higher.

“A bonus of the ram-induced ovulation is that pregnancies are synchronised, giving the grower control over the timing of mating and lambing, allowing for better and more economic management of labour and resources,” she said.

“Historically, this type of reproductive control has only been possible with intravaginal sponges or controlled internal drug-releasing device, which are costly and impractical in large sheep flocks.”

Dr Hawken noted the ‘ram effect’ offered growers a non-chemical, non-invasive method of controlling reproduction cycles that didn’t impinge on animal welfare.

However, to ensure the ‘ram effect’ worked effectively, Dr Hawken recommended growers select rams with the highest possible libido.

“A high libido leads to more action, which equals more activation!”

Chair in Animal Science at UWA’s School of Animal Biology, Professor Graeme Martin, commended Dr Hawken’s work, noting that more predictable mating and lambing times allowed growers to combine natural oestrus synchronisation with nutritional strategies to improve ovulation rates, lamb survival and, ultimately, lamb production and profit.

Media references

Dr Penny Hawken , Telephone (+61 8) 6488 3588

Professor Graeme Martin , Telephone (+61 8) 6488 2518

Professor Kadambot Siddique , Telephone (+61 8) 6488 7012, Mobile 0411 155 396