Wednesday, 28 March 2007

Increasing feed intake and synchronising merino ewes’ ovulation could stimulate a 20 per cent increase in twin lambings and lift the 380,000 tonnes of lamb produced annually across Australia.

With WA’s sheep flock at 25 million, the lowest in almost 70 years, reproductive research to assist farmers increase twin births will also boost incomes.

According to Professor Graeme Martin, Leader of Animal Production Systems at the Institute of Agriculture, The University of Western Australia (UWA), Uruguayan researcher Dr Carolina Vinoles Gil is one of the few sheep reproductive biologists in the world who can follow the development of egg carrying follicles in ewe ovaries by scanning.

“Although very challenging research, her experimental approach here at UWA to synchronise merino ewes’ follicular development has made it possible to see how nutrition affects ovulation rates,” Professor Martin said.

Dr Vinoles Gil said her project aimed to increase merino ewes’ reproductive performance, using clean, healthy, environmentally friendly techniques.

“Feeding ewes 500 grams of lupins a day for six days can increase ovulation rates by 30 per cent and the ability to produce twins by 20 per cent,” she said.

Therefore, if farmers invested $200 during a short supplementation period, their return could be $1000.

The study aimed to improve the effectiveness of combined lupin and synchronised ovulation on farms.

Trials at Arthur River and Kojonup resulted in 20 per cent more ewes ovulating just before mating and a 10-14 per cent increase in twin ovulations.

According to UWA Senior Research Fellow, Dr John Milton, lupins are the key to providing sheep with the energy to improve their reproduction, especially outside the usual breeding season.

“Lupins, fed in association with synchronisation methods, trigger increased twinning rates,” he said.

Dr Vinoles Gil’s research illustrated that fat ewes responded better to supplementation and had 54 per cent higher ovulation rates than lean ewes.

“This is opposite to the thinking of the past 30 years, when scientists believed lean animals responded better to lupin supplementation,” she said.

Currently, synthetic hormones are used to artificially induce and synchronise oestrus, but consumers are concerned about residuals in meat after the animal is slaughtered.

Dr Vinoles Gil said her Meat & Livestock Australia funded project supported ‘clean, green and ethical’ methods.

“The ultimate aim is to eliminate hormones altogether by using natural methods, including the ram effect, which fellow UWA researcher Dr Penny Hawken studies.”

The ‘ram effect’ occurred when sudden exposure to rams stimulated ewes to start ovulating and subsequently breeding earlier. Combining the ‘ram effect’ and lupins promoted the desired synchrony to increase lambing and weaning rates.

Dr Vinoles Gil’s research employed ethical solutions to improve twin survival, including scanning ewes from 45 to 80 days after mating, so that farmers could meet the nutritional needs of twin carrying ewes and also strengthen ewe-lamb bonds.

“Our long term aim is a 50 per cent increase in ovulation rate and 20 per cent less lamb mortality, leading to more lambs weaned and greater profits,” she said.

Media references

Dr Carolina Vinoles-Gil, 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

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