Whole-farm profit and the optimum maternal liveweight profile of Merino ewe flocks lambing in winter and spring are influenced by the effects of ewe nutrition on the progeny’s survival and lifetime wool production

J. M. Young, A. N. Thompson, M. Curnow and C. M. Oldham - Animal Production Science, CSIRO Publishing

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

Incredibly interesting paper that models so many different variables across different regions. Definitely read through this entire paper if the summary here intrigued you.

What is the problem?

This paper opens by acknowledging that the profitability of sheep production systems in southern Australia is at its optimum when stocking rate = adequate nutrition for breeding ewes = utilization of pasture. However, achieving the balance is difficult as the quantity and quality of pasture changes so much between season, and between years.

This research worked to develop optimum live weight profiles for spring-lambing Merino ewes in different environments. To do this, valuing the trade-off between extra production and cost of feed must be analyzed.

What did the research involve?

Three regions of southern Australia with spring-lambing Merino ewes were trialed:

  • Vic: south-west, 8-month growing season, winter rainfall (>550mm), mixed with annual and perennial ryegrasses and sub clover, total pasture production of 7-8T DM/Ha
  • WA: great southern, winter rainfall (400-550mm), 6-month growing season, the mix of annual grasses and sub clover, TPP of 6-8T DM/Ha.
  • NSW: southern, 6-month growing season, winter rainfall (>450-600mm), mixed with annual grasses, phalaris and sub clover, total pasture production of 6-8T DM/Ha

Fifteen live weight profiles were analyzed for each region. The research looked at the different cost profile of altering grain feeding, stocking rate, the timing of grazing, allocation of feed between animals.

What were the key findings?

The research found that whole-farm profitability is sensitive to the livestock of Merino ewe flocks and that there is a live weight profile that maximises whole-farm profit.

The variation between the most and least profitable ewe was:

  • Southwest Victoria: $14.30/ewe
  • Great Southern WA: $8.70/ewe
  • Southern NSW: $9.70/ewe

Changes in profit were due to the difference in cost of feeding to achieve the live weight profile and its production influence on the ewe and the lamb.

The optimum livestock profile for all three regions was similar and insensitive to:

  • Commodity price changes
  • Pasture productivity
  • Management

The optimum ewe profile was:

  • Join at 90% of standard reference weight for its genotype
  • Lose small amount of weight and regain to joining weight by lambing. The cost of missing this target by 1kg was between $1.45 – $1.60/ewe

Final comment

The study found that there was an opportunity to increase whole farm profit by up to 15% by managing ewes to achieve the optimum live weight profile.

2011 - Australia - J. M. Young, A. N. Thompson, M. Curnow and C. M. Oldham - Animal Production Science, CSIRO Publishing
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