Selection of a ram source or stud

Page last updated: Wednesday, 3 October 2018 - 4:15pm

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Wool growers can achieve their breeding objectives by retaining superior breeding stock and by choosing superior rams. It can be difficult for growers to choose superior rams because there are few estimates of the actual production differences between ram producers. The direction of performance or genetic gain in the stud will be determined by their breeding objective, while the rate of progress will be determined by the efficiency of the breeding program. The best ram source is one that balances high performance now with a breeding program that will deliver long term genetic gain.

When you buy a ram, you are purchasing its genes and it is important to separate out the genetic component of its expressed performance. Breeding values (which are estimated within the stud) or Australian Sheep Breeding Values (ASBVs) are used to describe the genetic potential independent of the rearing conditions and how the ram is presented for sale.

The selection of stud or ram source is equally important as selecting the best ram for your flock. The direction of gain in the stud will be determined by their breeding objective, while the rate of progress will be determined by the efficiency of the breeding program.

To evaluate the rate of gain that will be achieved by choosing rams from a stud, you will need to know the breeding objective of the stud and obtain proof of their progress. Any stud that participates in the Sheep Genetics performance testing scheme will be provided with the genetic trends of the different traits the stud wants to improve. This tells a lot about the stud’s commitment to genetic progress. Without this information any claims of genetic progress will be difficult to prove.

Why is selecting the right stud important?

Genetic progress in the flock is entirely set by the breeding program of the ram source:

  • If you are a long term client of a ram breeder, the genetic response in your flock will be dictated by the genetic responses being made in the ram breeding flock.  This applies to all traits.
  • The genetic trend in the commercial flock will follow that of the ram breeding flock. There is a time lag for improvement to pass from the stud through to their client’s level of production.
  • If a source has no clear breeding direction and their level of production for a trait is inconsistent, their client response will follow the same path.
  • Similarly, if a ram source is making no genetic gain then neither is their client.

How to compare studs?

Depending on what information is available this may be accurate or simply a guess.  Some sources of useful information include:

  • Lambplan
  • MerinoSelect
  • progeny tests
  • wether trials
  • on-farm trials
  • performance of the studs’ own commercial flock
  • performance of the stud’s clients' flocks run under similar conditions to yours.

How to determine a stud's likely progress?

When trying to determine a stud’s likely progress consider the following:

  • How are rams selected for use in the stud? What is their breeding objective and how do they measure them?
  • What is the selection differential for rams used in the stud? Selection differential is the difference between the performance of the selected rams and the group from which they were selected.

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