Reproduction

2013 CPT ewe progeny

In this video, NZM’s Production Science Manager, Dr. Mark Ferguson, provides an update on the scanning results from the 2013 CPT ewe progeny, who have been mated naturally as two-tooths.  The scanning data shows how the sires of those ewes have impacted on the reproductive performance of their daughters.

How are liveweight, condition score, the breeding value for genetic fat, and scanning percentage related?

The liveweight and condition score of each progeny group at joining gives us an indication of the likelihood of conception.  Further, we know that condition score is important for both ewe and lamb survival.  

These two graphs show the correlation between ewe condition score and liveweight, as well as the correlation between ewe condition score and the estimated breeding value for genetic fat.  Each dot represents a different sire.

These graphs show that there was almost a full condition score difference between the progeny groups, which is directly related to the genes these ewes inherited from their sires.


How do the breeding values for muscling and fat relate to the actual condition score of my ewes?

Both muscling and fat are positively correlated with condition score (see graph).  The higher the amount of genetic muscle and fat a sheep has, the better condition they will be in when run under the same grazing conditions as a sheep with less genetic muscle and fat. This results in better reproductive outcomes and generally better welfare.


How well does the number of lambs weaned (NLW) breeding predict reproductive performance?

The next graph shows the correlation between the number of lambs weaned (NLW) breeding value for the ewes’ sires and the ewes’ actual scanning percentage.  It demonstrates the power of breeding values and their ability to predict future performance of a ram’s progeny.


Can the breeding value for genetic fat predict reproductive performance?

This graph shows the correlation between the genetic fat breeding value and scanning percentage.  While the correlation is not as strong as some of the other results, there is a positive correlation between the genetic fat breeding values of the ewes’ sires and the ewes’ actual scanning percentage.  This demonstrates that the genetic fat breeding value can be used to improve reproduction (for instance when the NLW breeding value is not available).