High lamb prices and low supply mean many producers are keen to build flock numbers, but how best to do it?

Sheep CRC postgraduate student Cesar Rosales Nieto is looking at whether joining Merino ewes earlier, at 8-10 months rather than the traditional 18 months, may provide the solution.

Mr Rosales Nieto’s research is aimed at developing guidelines to achieve consistent and cost-effective reproductive performance from Merino ewes joined at 8-10 months.

“My research is important because it addresses an aspect of the production system that has the potential to improve efficiency for sheep producers,” he said.

“Breeding ewe lambs at 8-10 months of age has a number of potential advantages.”

His research project commenced in 2009, and is funded by the WA’s Department of Agriculture and Food (DAFWA), Meat and Livestock Australia (MLA) and the Cooperative Research Centre for Sheep Industry Innovation (Sheep CRC), and also involves Murdoch University and the University of WA.

Operating as part of the Federal Department of Innovation Industry Science and Research’s CRC program, the Sheep CRC is a collaboration of industry, government and the commercial sector. It is working to increase productivity and profitability of the industry through adoption of new technologies in both the meat and wool supply chains.

Mr Rosales Nieto began his research trajectory in Mexico, his country of birth. With a Bachelor degree (honours first class) from the University of San Luis Potosi (Faculty of Plant and Animal Science), he studied the relationship between reproduction and nutrition in Creole goats for his honours project.

He worked at Mexico’s National Institute of Forestry, Agricultural and Livestock Research (INIFAP) as a researcher until 2004 when he went to Texas A&M-Kingsville to undertake a masters degree in animal science. He was accepted for his PHD in 2009.

“Basically my research interests are in reproduction and nutrition of small ruminants,” he said.

“Since I started working here in Australia my interests have expanded to different areas such as genetics and this combination fits perfectly with the Australian industry.”

In 2011, the Australian flock fell to 1950s’ levels due to poor wool prices, adverse weather conditions, high grain prices and high labour requirements. The level of sheep supply is now a major issue in Western Australia as it is not possible to meet the current requirements of processors and live exporters without a further fall in sheep numbers.

“The sheep industry needs to improve the reproductive efficiency of the ewe flock to meet current and future demands for slaughter lambs, live sheep and lambs for export,” he said.

“The majority of lambs still come from Merino dams while there has been a shift toward more specialist meat breeds.

“Previous research has shown that it is possible to mate Merino ewe lambs at 8-10 months of age but the results are highly variable. It is therefore important to develop management guidelines to improve the likelihood of success.

“In order to develop these guidelines and to properly define the economic impact of the strategy we need to identify critical ages, liveweights and condition scores required for reproductive success.

“Our research shows that under the right management conditions fertility rates above 75 per cent can be achieved,” he said.

To achieve these high fertility rates Merino ewe lambs need to be more than 45 kilograms at the start of joining as well as gaining more than 100 grams per day during the joining period.

“This requires good nutritional management as well as the right genetics for good growth rate.

“Lambing a year earlier, through joining at 8-10 months of age, can increase the lifetime reproductive performance of a ewe by around 20 per cent.”

Mr Rosales Nieto said while the additional feeding costs needed to be set against improved lifetime reproductive performance, the overall benefits appear to outweigh the additional management inputs.