NZMW & NZTW INDEXES

Choosing rams has been made easier by the introduction of two New Zealand indexes. Every ram sold by a performance recording breeder in the NZGE has a single “index” figure:
 

Dual purpose or maternal rams have a “Maternal Worth” figure (NZMW), based on Reproduction, Lamb Survival, Lamb Growth and Adult Size. 

Terminal rams have a “Terminal Worth” figure (NZTW), based on Lamb Survival, Lamb Growth and carcase Meat Yield.

 

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Maternal Worth (NZMW) or Terminal Worth (NZTW)?

If you’re breeding both terminal and replacement stock, then look at rams with a NZMW figure.
If you’re only breeding terminal stock, then look for rams with a high NZTW figure.

Health traits

If you want to target specific traits, like FE tolerance or resistance against internal parasites,
the indexes can do that.

If you want facial eczema tolerance, identify breeders who prioritise FE,
then ask them for: NZMW + X*

If you want resistance to internal parasites, identify breeders who prioritise this trait,
then ask them for: NZMW + FEC*

The higher the number, the better the ram.

* X = FE trait; FEC = internal parasite resistance trait

 

Test yourself

Here are four good rams:

Ram A – NZTW of 1200 
Ram B – NZTW of 1360 
Ram C – NZMW of 1640
Ram D – NZMW of 2210

Q1: You run a breeding/finishing sheep policy. Which ram would you choose?
Q2: You buy in old ewes and put them to a terminal sire. Which ram would you choose?

Answers: Q1 = D; Q2 = B

Hover mouse over answers to read

Here are another four good rams:

Ram W – NZTW of 1390
Ram X – NZTW of 1110 
Ram Y – NZMW of 2250
Ram Z – NZMW of 1530

Q1: You run a breeding/finishing sheep policy. Which ram would you choose?
Q2: You buy in old ewes and put them to a terminal sire. Which ram would you choose?

Answers: Q1 = Y; Q2 = W

Hover mouse over answers to read

Key message

This season, ask your ram breeder for:

NZMW figures if you breed your own replacements
NZTW figures if you need a terminal sire

The higher the number, the better the ram.

SHEEP GENETICS LEARNING MODULE

Good rams provide remarkable value over their lifetime. They are an investment. More than 80% of the flock’s genetics are contributed by the ram. That’s an exciting opportunity to improve your flock’s performance. Our online Sheep Genetics Module below can help you select the best genetics for your flock – and find breeders that match your genetic plan.

Sheep Genetics Learning Module: Making Good Decisions »

nProve: DISCOVER GENETICS FIT FOR YOUR PURPOSE

nProve is a free online tool that makes it easy for New Zealand farmers to find the best rams for their operation. Using a series of button­­­­­s and slider scales, farmers can customise what they are looking for in their ram team, then – with a simple click of a button – nProve generates a list of breeders who have rams that best fit the criteria defined by the farmer. Users do not need to register.
 
The tool is freely available at nprove.nz and includes helpful tips to get started.
 

RAM VALUE CALCULATOR

Our Ram Value Calculator - Ram4Ram - allows you to determine the relative value of two rams based on the NZMW and NZTW index. To use the calculator you will need the index number of two rams. Type the index numbers in for both rams and the calculator will compare the relative value of one ram to another.

Launch Ram Value Calculator »