Aussie sheep trials carried out

DIETARY additives showing potential to improve the viability of newborn animals when supplied in utero are undergoing the first comprehensive trials in sheep in Australia.

The Meat & Livestock Australia (MLA) project aims to identify compounds with the biggest potential to boost a lamb’s ability to survive and thrive in late pregnancy and the days immediately after birth.

Previous MLA research has recognised poor lamb survival pre-weaning is a major source of reproductive inefficiency in the national sheep flock and this new investment will help producers fine-tune their nutrition and management tactics.

MLA sheep R&D programme manager Richard Apps says the project is particularly targeted at finding dietary supplement options for twin-bearing ewes in the second half of gestation, but would also apply to ewes carrying a single fetus.

“Survival rates for twin and singleton lambs across Australia’s sheep flock average about 70 per cent and 90 per cent respectively and this has not changed in many years,” Apps says. “For the national Merino flock, the average is lower at about 50 per cent and 75 per cent respectively.

“Improving these rates is integral to increasing on-farm productivity and the competitiveness of sheep production and meeting an expected global rise in demand for red meat in coming years.”

The project is led by the South Australian Research and Development Institute (SARDI) and the University of Adelaide.

Phase one started this year with a team of sheep reproductive biology experts testing a range of the most promising dietary and biomedical compounds for increasing energy stores in fetal lambs and/or reducing the risks of damage from any oxygen deprivation during the birth process.

SARDI research scientists Dave Kleemann says it’s the first time the products have been tested on sheep in such a comprehensive way.

“We will be feeding a range of compounds to ewes in late pregnancy initially, and tracking physiological responses that suggest enhancement of survival and weaning rates of lambs,” Kleemann says.

The most promising products will then be tested in field trials across SARDI’s research stations in South Australia and then, if successful, in commercial paddocks with four farming systems groups in South Australia and two in Western Australia.

University of Adelaide Senior Lecturer in Reproductive Physiology William van Wettere says the key objective is to find compounds targeting improved lamb energy stores at birth.

“This could reduce the incidence of stillbirths, enhance lamb thermo-regulation to help them survive cold and windy conditions outside the uterus, increase early vigor and growth and – ultimately – lift survival rates,” van Wettere says.

“There may also be compounds that increase ewe colostrum production, which could boost lamb weights and improve their ability to survive the first few days after birth.”

Kleemann says if supplements are feasible, he anticipates lamb survival rates could increase by about 10 per cent on average – and more for Merino flocks – which means an extra 10 lambs for every 100 joined.

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