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dpi note
Sheep genetics
Which stud to choose?

Dr Mary Rose, formerly of DPI.
Revised by Dr Roger Lewer and Nicole McLennan, DPI's Agency for Food and Fibre Sciences

Key points

  • Studs control the genetic improvement of their ram buying clients.
  • Select a stud with a well defined breeding objective that is compatible with your production objective.
  • Compare your stud (and its rams) with others by benchmarking and examine the long-term performance of its commercial flock and other clients' flocks.
  • Examine how the stud selects its rams - objective information, selection index, and are they using the top performers on measured information in their stud?

Role of studs in genetic improvement

The structure of the Merino industry in Australia is a hierarchy, either traditional or cooperative, see Diagram 1. In a traditional hierarchy there are a few large parent studs at the top with daughter and general studs on the next level, which buy rams from one or more of the parent studs. Commercial flocks are at the base of the pyramid and they buy rams from the studs above. All of the genetic material flows down the structure. There is very little upward migration of breeding sheep due to a registration barrier.

In a cooperative hierarchy controlled movement of both sexes is promoted, although most upward genetic transfers are females. As a result, cooperatives have a potential additional genetic gain of 10 to 20 per cent compared with a traditional hierarchy.

The structure of the Merino industry in Australia is either a traditional or cooperative hierarchy.

Diagram 1. Traditional and cooperative structures of the Australian Merino industry.

Because far fewer rams are required as replacements in stud flocks, their standard can be higher than that of ewes, most of which may be needed as replacements. This means that up to 100 per cent of genetic gain in studs may be due to ram selection; if rams are objectively selected and ewes are inefficiently selected and lambing percentages are low. Where lambing percentages are reasonable and ewe selection is efficient, ram selection may account for 80 to 90 per cent of genetic progress.

The important consequence of a hierarchical structure, genetically, is that the studs determine the rate and direction of genetic improvement in the commercial flocks that buy their rams. This means choosing a stud is the single most important sheep breeding decision a commercial sheep breeder makes. In choosing a stud you need to ask some important questions.

What is the stud's breeding objective and does it agree with my production objective?

For a studs breeding program to be successful it must be based on a clearly defined breeding objective, which must be followed consistently. A breeding objective simply states the desired level of improvement in the traits and the time frame over which the change is to be made. An example of a good breeding objective for a stud is: "Over the next 10 years, increase clean fleece weight by 0.5kg, decrease fibre diameter by one micron, increase staple strength by 5N/ktex while maintaining body weight."

When choosing a stud, it is important that the commercial breeder finds a stud with a breeding objective that is compatible with their own production objective. A production objective defines where the producer wants their flock to be in a defined period of time in terms of quantity, quality and value. The difference between a breeding objective and production objective is that a stud only uses breeding and selection to achieve the breeding objective while a commercial breeder can use a range of strategies eg selection, nutrition, marketing to achieve the production objective.

When a commercial breeder buys rams consistently from a stud, the genetic changes in their commercial flock will follow those in the stud. If the stud is reducing fibre diameter, the rate of reduction in the commercial flock will parallel that of the stud in both direction and magnitude. If you purchase rams from a stud that is not making progress or is going backwards - your flock will do the same. For more detail see the DPI Note Sheep genetics: which grade of ram to choose? .

Your production objective must be clearly defined before the search for a stud with a well defined and compatible breeding objective can begin.

If you are unsure of a particular stud's breeding objective - ask them. Any reputable stud will have no hesitation in outlining their breeding objective, but make sure it is defined in terms of measurable outcomes.

How does the stud compare with other studs?

If you can find a stud that is outstanding for the production traits you are interested in improving, it means you are starting from as far ahead as possible. Some of the sources of information you can use to assess different studs and rams include:

  • Wether trials - randomly selected teams of wethers from each participant are run together and their performance is measured. Check whether the stud or clients have been active in wether trials, and what results were achieved. 
  • Bloodline comparisons - wether trials where each bloodline is represented by several teams. Merino Bloodline Performance trials are a national series of linked wether trials. Teams representing a bloodline that participate in more than one wether trial form the links.
  • On farm trials - compare more than one stud by trial mating teams of rams to your ewes on farm.
  • Central Test Sire Evaluation - a national series of linked progeny tests to compare sires.
  • Merino Benchmark - provides estimated progeny values for both progeny tested and other rams in recorded flocks.
  • Merino Lambplan - across flock sire evaluation that relies on links formed by sires being used in more than one stud.
  • The long-term performance of the stud's commercial flock - examine at least five years of all fleece wool test certificates to reduce environmental effects.
  • Performance of client flocks run under similar conditions to your own.

How are rams selected for use in the stud?

Ask the stud how they select their worker rams, if and how they use measured and visual information, whether they use a selection index and what it contains? The higher the level of objective selection, the greater will be the gain in the objective traits. Visual selection should be used to remove those sheep that have some physical fault. If the stud uses a selection index (based on their breeding objective) to select rams it will optimise the rate of economic and genetic progress and will have flow on effects to commercial clients.

Ask to have a look at the list of rams from which the stud chose its sires, to ensure that the top performers were used based on objective information or the selection index value. If this occurs then the stud will be maximising its genetic progress, which will be passed onto their clients.

Other considerations

From a genetic point of view, Queensland bred rams are likely to be better in our northern environment than their New South Wales bred counterparts. The problem when importing animals from a different environment is that some genes important in your environment may not be switched on under the stud's conditions. During the ram selection process, the wrong rams may then be chosen to breed rams for the Queensland environment.

Locally bred rams are already adapted to the environment in which they have to perform and will be expressing appropriate genes. So when shopping around it is always a good idea to start with the closest studs. Only look further afield if the rams you want are not available locally. But don't expect Riverina rams to look like Queensland rams. These southern rams have been bred under far less challenging conditions than their Queensland contempories.

It is also important to have confidence in the stud's management and a good understanding and rapport with the stud master and classer. You must also be satisfied of being treated fairly and on an equal footing with the stud's other clients.

Having settled on a stud, keep in contact with them and preferably select replacement rams yourself. Stud field days, ram displays and local shows are all good opportunities to talk to stud representatives, as well as to compare what they have to offer with that of other ram suppliers.

If at any time you have cause for complaint (eg latest replacements not up to scratch; flock wool type not going the way that you want it to; unusual number of stags or black lambs at marking; etc.) let your stud know about it. But by the same token, if you are satisfied with how things are going, let them also know that you are satisfied.

Further information

For further information contact the DPI Customer Service Centre on 13 25 23 (Queensland residents) or (07) 3404 6999 (non-Queensland residents) between 8 am and 6 pm weekdays, or e-mail callweb@dpi.qld.gov.au.

This DPI Note is also published on the DPI's PrimeNotes CD-ROM.

Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.

File No: SW0074 . Date created: June 1994  . Reviewed: September 2003


 

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