Your Rams

On average, how many years
do you use your rams?


Enter the tailing percentage for
your farm on the line below


Generally, how many ewes will each
of your rams mate per year?


Over their lifetime, how many times
will your ewes lamb?


What percentage of ewes do you
replace each year?

Terminal Sires

Typically, what percentage of ewes do you
mate to a terminal sire each year?


On average, what percentage of your lambs
survive until tailing each year? This factor represents the expected survival of lambs born to tailing/docking time. On average, research suggests this is 84% in NZ flocks. Only alter this if you believe your survival is significantly better or worse than this prediction.

Marginal Value of
Ram A compared to Ram B

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Farm Settings

Save Settings

You have made changes to one or more of your settings. Would you like to save your changes and continue?

Ram4Ram Help

These calculators allow you to determine the relative value of two rams based on their NZMW or NZTW index.

  • The Maternal calculator should be used when you are breeding both terminal and replacement stock.
  • The Terminal calculator should be used if you are only breeding terminal stock.
  • The questions we asked you when you first opened this calculator are important for calibrating the results specifically to your farm. You can adjust these values in the settings section of this app.

    To use the calculators you will need the index of two rams. These calculators are not intended to tell you the value of a ram. Instead, they compare the relative value of one ram to another. For instance, if Ram A has a NZMW index of 1600, and Ram B has a NZMW of 1000, the calculator may determine that Ram A is worth $900 more than Ram B to you. If Ram B is priced at least $900 less than Ram A, it will provide the best value, despite its lower index.