Does genetic progress have to slow during the rebuilding phase?
Michael Wellington and Karissa de Belle, Bush AgriBusiness Pty Ltd. With the current lack of stock across the country, many herd or flock managers will not have the luxury of culling that they normally would. This raises the question of how genetic progress is affected by, and should be managed in, different seasonal conditions. We have heard from some producers and advisors that genetic progress will slow during commercial herd/flock rebuilds. However, we are not entirely convinced that this is necessarily the case. In the equation for genetic progress (see footnote 1), selection intensity (i) is affected by selection itself (how different are the new sires and breeders coming into the breeding herd from the current herd average?) and culling (how different is the herd average after culling, from the…