Topics:
Genetics

Breeding FE tolerance into your flock

Have you considered breeding FE tolerance into your commercial flock? B+LNZ Genetics Sheep Genetics Specialist Sarah Powdrell talks you through where to start.
Tuesday, 3 November 2020

Breeding for FE tolerance has 40% heritability. Buying FE-tolerant rams will make a great difference in only a few years, but you have to be consistent in only bringing tolerant rams into your flock.

FE tolerance does not affect other traits, so you can continue to look for higher growth rates or heavier fleece weights (for example) while pursuing your FE programme.

1. Finding FE breeders

nProve can help you find breeders who are recording FE tolerance and are also connected. Connectedness is needed to validly compare the breeding values (BVs) and indexes for animals in different flocks.

Go to nprove.nz. Use the sliders and buttons to set your search criteria:

  • Select FE as a trait you want to focus on by moving the slider for FE (under Health Traits). This will give you a list of breeders benchmarked for FE tolerance.
  • Select breed type or location to further refine your search results.

Note: Some breeders in the list may have no value for FE. This means they are measuring FE but aren’t connected so can’t be compared fairly against other flocks.

2. Contacting breeders that look like a match for your operation

There are several indicators of merit and success to consider when choosing a breeder:

  • Genetic Trend Graphs
  • Trait Leader lists
  • RamGuard Flock Status Rating
  • FE Gold Breeders

Read more about these tools in our Breeding for Facial Eczema – Information to ask your breeder factsheet (PDF, 2.75MB)

When you are satisfied you have identified the best breeder for your operation – taking into account your overall basket of traits – then it’s time to select the ram(s).

3. Choosing a ram

Facial Eczema may be a high priority for your system, but it is important to remember it is only part of the genetic package you are purchasing. It may be helpful to look at the rams’ NZMW+X index. This index includes the core traits of the NZ Maternal Worth index (growth, reproduction, survival, wool and adult size) as well as facial eczema.

The DPX and NZMW+X indexes are specific to FE and tell you the dollar advantage a ram will deliver to your flock. The higher the figure, the more tolerant an animal.

Understanding what a good value is in terms of NZMW+X or DPX  values is important if you want to make an informed purchase. Familiarise yourself with the NZGE percentile band tables which show the range in values.

These can be found on the sil.co.nz website (under Tools > NZGE > Percentile Bands Tables).

RamGuard testing is very expensive so be prepared to pay more for FE tolerant rams.

4. Stick with that breeder

Having found a breeder that’s right for you, stick with them for as long as possible. This is critical, if you are serious about introducing FE tolerance into your commercial flock.

Remember, more than 80% of the flock’s genetics are contributed by the ram. If you buy rams or other susceptible stock from untested flocks, you could lose all the hard-won gains from breeding or buying FE tolerant rams.

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