Farmer Focus: DNA results help to select best ram lambs

I can now refocus my efforts on the sheep with harvest over and leave Jo to start breaking ground down with the disc cultivators.

As briefly mentioned in my previous article, we have collected DNA samples from our 500 recorded stock ewes. To date, we have paired up dams/sires/lambs. 

We have eight-week and weaning weight data from that group, which we will be submitting to Sheep Improvement Ltd (SiL) to come up with an initial score for each of the lambs. 

See also: DNA test snares Welsh sheep thief

Once SiL has identified the 100 best ram lambs, we will put their DNA through a complete breakdown and identify what gene sets each ram lamb has.

Currently, we can identify 24 different traits from growth rates through to parasite resistance and foot-rot resistance. The DNA tests will reveal the best 70 ram lambs that are also carrying the Myomax gene (as this is the first year it will only be a single copy). 

Those 70 ram lambs will all be put across the 2,000 commercial ewe flock to improve carcass confirmation while retaining the usual Romney attributes. 

We have weight and carcass data going back four years, so over time, as the Myomax gene takes root within the flock, we should start seeing some statistically significant results. 

In the meantime, we will record and mate all the single-carrying ewe lambs to an imported double-carrying Myomax NZ Romney. So, next year (with a bit of luck), we should at least have some reasonable double-carrying Myomax Romney ram lambs.

This will improve the flock’s average carcass grade at a quicker rate than using animals with a single copy.

The key will be to drive the genetic progress of the flock while still trying to select for the Myomax gene.

Single-trait selection is always tricky, as other aspects of the sheep invariably suffer. The only real solution would be to increase recording numbers and have a greater population for more selection.

But with the prices of the genetics tests, I can’t really see Jo agreeing to that.  Especially after reading some of the doom and gloom predictions on sheepmeat prices for next year.


See Rob and Jo Hodgkins’ biography