- Selection for higher productivity can fail because
of environmental constraints.
- Breeders try to modify the environment - often at
a cost that absorbs the extra income earned with little or no result.
- Productivity increases achieved by improved nutrition
and management does not automatically lead to genetic improvement of
- However, an understanding of the relationship between
genetics and the environment can see improvements in the genetic efficiency
of the flock.
- It is imperative
that the breeder understands the relationship between production potential
and the flock’s level
of resistance to environmental stress.
- Instead of artificially modifying the environment
of a ram breeding flock, breeders should breed rams in an environment
similar to that in which they will ultimately get lambs.
- This process will lead to achieving the right balance
between selection for higher productivity and the resistance to stress.
- It is important to consider a number of factors
in order to obtain accurate flock management records.
- Group size
- Age of the group
- Wool length and shearing dates
- A uniform lambing season
- Random allocation of ewes at mating
- Duration of mating
- A common environment
- Adjustments for age of dam and birth status
- The management of multiple births