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MMFS Manual

Chapter 9.5 Informed classing, selection and joining decisions are critical

Background information

Once you have identified your profit drivers and the type of sheep which fit your purpose and defined this in a breeding objective, it’s time to implement classing, selection and joining practices to achieve the desired outcome. Making good decisions relies upon effective assessment of the sheep and this can be aided by protocols which ensure an impartial and consistent approach. Animal health, welfare and management throughout the breeding cycle and well considered joining practices help optimise the return on your genetic investment.

At a glance

  • Classing sheep helps ensure those in your flock are fit for purpose and complement your breeding objective.
  • Choosing the right sheep when purchasing or selecting rams and ewes is important.
  • Joining tactics can help maximise the return on your investment in genetics.

Classing, selection and joining decisions improve profitability

Classing, selection and joining are really about:

  • classing your existing sheep based on an assessment of their fit for your purpose as defined by your breeding objective;
  • identifying and selecting rams and ewes based on an assessment of their merit for the traits that suit your overall breeding objective; and
  • joining these animals strategically to ensure their progeny express desirable traits and contribute towards the overall breeding objective.

Source: AWI ClassiFly

Remember, the traits you have selected and your breeding objective should be clearly linked to your profit drivers.

Good decision making is underpinned by good sheep health, welfare and management

Breeding is underpinned by good sheep health, welfare and management which improves:

  1. the performance of your sheep and their progeny;
  2. their capacity to deal with challenging situations;
  3. your overall productivity and profitability; and
  4. your classing and selection decisions, through:
    1. greater numbers to select from through higher weaning rates; and
    2. better expression of some traits (variation) so they are easier to find across the mob.

Good sheep health, welfare and management results in more sheep being able to express their genetic potential and fewer being culled for management reasons.

Good sheep health and welfare means:

  1. Providing optimal nutrition throughout the year;
  2. Implementing an appropriate vaccination and drenching program and using worm egg count (WEC) testing to guide drenching decisions;
  3. Control of predators; and
  4. Providing adequate protection from weather extremes.

Fundamental to good health and welfare is matching feed demand to feed supply (chapter 8.3 in MMFS Module 8 Turn Pasture into Product and chapter 11.1 in MMFS Module 11 Healthy and Contented Sheep). This provides the basis for producing a product which conforms to market specifications, achieving a desirable price and optimising profitability.

Feed demand fluctuates in a breeding program and one tool in particular which can help you manage the nutritional demands of reproduction is pregnancy scanning.

Scanning for multiples will give you the option to separate ewes into mobs based on their nutritional requirements and then to manage them accordingly in consideration of body condition scoring.

A recent economic study calculated the average increase in farm profit as a result of scanning to be on average $5.55 per ewe scanned, based on long term (2004 to 2020) wool and meat prices while the return on investment for scanning for multiples has been calculated to be 400%. For more information see Tool 10.8 in MMFS Module 10 Wean More Lambs.

Scanning is only part of the story; it’s what you do with the information that matters most. Once you understand the pregnancy status of your ewes and have drafted them accordingly, you can better manage paddock and feed allocation.

Scanning can also help you target traits or management strategies to improve reproductive performance. For example, if your scanning percentage is low then nutrition in the lead up to joining or ASBVs for conception or litter size may be of interest to you. If your scanning percentage is high but weaning rate lower than expected, you probably won’t prioritise litter size or conception as this doesn’t seem to be the issue, rather you may focus on ewe rearing ability or weaning rate while ensuring management issues post scanning are optimised.

Another example of health and welfare being of high importance is at lamb marking. Carry out lamb marking in clean yards close to the paddock being grazed and ensure the operation is completed early in the day so ewes and lambs can successfully mother up.

Hygienic practices, including using clean gear and regularly disinfecting it throughout marking, use of anaesthesia and analgesia, and vaccination, are all important.

Lamb marking is also a key time to take a look at your ewes. Carrying out wet and drying at lamb marking will allow you to remove the dry ewes and those who have lambed and lost, prioritising the best available feed for ewes raising lambs.

Ewes with lambs at foot should also be condition scored at lamb marking to ensure they’re receiving adequate nutrition during peak lactation (the most nutritionally demanding time of the ewe’s year), and supplementary fed if required.

Taking steps to actively manage the health and welfare of your ewes and lambs will reduce the number of ‘management culls’ at classing, as all lambs will have been given the best chance of expressing their genetic potential.

Make accurate classing, selection and joining decisions

Making good classing, selection and joining decisions relies upon good assessment of the sheep using both visual and measured assessment. Visual assessments or raw data is the assessment of how an individual sheep looks and performs.

This requires effective protocols which should include tight lambing, identifying multiples and maiden progeny, maintaining as few management groups as possible for the relevant mob, optimising the timing of assessments, a good husbandry and animal health program and maintaining best practice commercial condition scores.

Combining the tools within the protocol to deliver the best outcome for your breeding objective is important. Over reliance on either visual or genetic tools can delay improvement or lead to an undesirable outcome. Functional or structural traits are also important, your focus should not be limited to production traits. This should include physical characteristics which allow the sheep to realise their reproductive potential such as feet and legs.

Visual assessment relies on assessing how each trait is phenotypically expressed in an animal including what they look like and how they perform.

You can visually assess a number of traits when classing for lifetime productivity and profitability as well as for breeding better progeny.

Visual assessment can help you make good progress when:

  1. The trait is easily assessed (because it can be easily seen);
  2. The trait is highly heritable; and
  3. There is variation for that trait within the flock when managed under the same conditions.

Objective assessment relies on assessing animals using actual measurements and consideration of other information known about the animal. The better the quality of the data and the more of it that is used to evaluate differences in traits, the greater the accuracy of your classing and selection decisions.

When you have a few visual, highly heritable traits that are not antagonistic to each other in your breeding objective (such as fibre diameter coefficient of variation and staple length), visual assessment and the use of raw data can result in good genetic progress.

As you include traits that are not easily assessed or measured visually, such as eye muscle depth, objective measurement and the use of breeding values improves selection accuracy.

There should be good alignment between visual and objective measurements. Best practice is to use a combination of both visual and objective assessment.

Set thresholds or use weightings to aid decision making

Sheep rarely perform exceptionally well for all desirable trait areas and those that do are rare or likely to be very expensive, so compromises are usually required.

Some rams that will improve a trait you are focusing on may have a negative effect on other traits of importance identified in your breeding objective.

One way to overcome this and avoid negative effects is to rank traits of importance and set minimum thresholds for other traits in your breeding objective. This can then be included in your selection plan. That way you can focus on your most important traits and make sure you don’t go backwards in other areas.

Consider these thresholds and trait emphasis when assessing rams that you will potentially purchase. Consistency is also important. The more similar the rams you purchase are, the more consistent the progeny will be. Even lines of surplus young ewes can attract premiums. It’s generally advisable to avoid outliers or rams demonstrating extreme traits.

Thresholds can be set for any trait you’re using in the classing or selection of your sheep, visual or measured. Any traits you are unwilling to compromise on should have thresholds set. For example, you may be seeking to reduce breech wrinkle but not lose fleece weight. In this example, you may adopt your current fleece weight as the threshold blow which you are not prepared to go.

An alternative approach is to apply weightings whereby some traits will contribute more to a selection decision than others. This may not be as decisive as thresholds but can still ensure the traits of importance dominate decision making while less important traits have less influence.

Combine all assessment information

Bringing the visual and objective assessment information together in a balanced way to deliver your breeding objective is the next step.

Visual assessment

Visual sheep assessment is best undertaken following clear protocols to ensure important traits are not overlooked and the difference between individual animals for important traits is due to genetic differences rather than the environment. The assessment protocol should spell out the traits you are assessing, how you will assess them and the weighting you are assigning to those traits.

To make the most of visual scoring, the Visual Sheep Scores Guide has outlined the following protocols to be followed when scoring your flock:

  • Sheep should be scored within management groups (sheep that have been run together with the same management applied to them). Sheep running in different mobs may express traits differently and cannot be directly compared. Ideally management groups should be as large as possible. Care should be taken when comparing small management groups as the group may be biased.
  • If birth type and rear type are known, sheep should be separated into these groups prior to scoring as these factors may influence the visual appearance of sheep. This is particularly important at young ages.
  • Sheep should be presented for scoring in good commercial condition. Sheep that are affected by drought or have been under-managed may not have expressed their genetic potential.
  • Scorers should be appropriately trained and have experience in the traits they are assessing.
  • Where possible, the same scorer should be used between years to minimise variables across years and to allow the best comparison between drops.
  • Most traits are best scored in a classer’s box; however, some traits (such as those relating to feet and leg structure) may be best scored as the sheep walks away from the scorer. Situations where sheep are tightly packed into a race should be avoided for classing.

Make a checklist of what you will visually assess in your ewes and when selecting rams. Remember related traits as well, for example if no visual scores or ASBVs for breech wrinkle are available and rams have been mulesed, you assess neck wrinkle as an indicator of breech wrinkle. When undertaking visual assessment, it is recommended that you:

  • Have a well-defined assessment protocol for assessing each sheep and follow these each time to ensure accuracy and consistency.
  • Assess sheep relative to the diagrams in the Visual Sheep Scores Guide using the written description of each score in the guide to help. It’s important to remember that you are not comparing each animal to others in the mob, rather you’re comparing them to the diagrams and score descriptions in the guide. Were you just to focus on the mob and assess on that basis, you may compound a problem or class out good sheep which are performing well above the average in an elite flock.
  • Where possible, assess sheep that are from the same age and management group to ensure the influence of these non-genetic factors is limited. If at a ram sale, ask if all the rams on display have been managed in the same management group.
  • When visually assessing sheep, you need to look at the animal carefully. Make sure you can clearly see the areas on the sheep that you are scoring and that they are not crowded. This is a chance for you to absorb all the information that visual assessment can provide including “doing ability”, spring of rib, length of body, bone, etc. A classing box is ideal so the sheep can be assessed individually. If this is not possible, avoid packing the race too tightly so the sheep are able to stand freely.
  • Go through the usual assessment for conformation, soundness, wool quality and the 4Ts (teeth, toes, tackle, testicles).

You may assess your sheep as a standalone activity, for example if you are establishing your flock’s susceptibility to flystrike, or it may occur as part of your classing process, or even when you bring mobs into the yards for other reasons. Identifying when and how you will assess sheep in a written protocol can help ensure you don’t miss an assessment opportunity.

Some traits are best assessed at different times to others, for example off shears or with a certain wool length.

Use the Visual Sheep Scores Guide to determine the best time to assess the traits of interest.

Be aware that early life environmental effects (such as birth and rear type) will impact the expression of a trait as the animal grows; however, the impact lessens as they age.

For practical purposes, consider the timings recommended in the Visual Sheep Scores Guide and weigh these against when early life effects may have passed. You may not be able to practically optimise all of these but finding a reasonable compromise may be the best way forward.

An annual management calendar can help you schedule events.

The reason assessment may happen separately to classing is because you may not know something about the sheep when you’re assessing them that you want to take into consideration when you class them. For example, their reproductive performance may not be known when you’re assessing them for wrinkle off shears.

Breeding value assessment

Genetic assessment using the decision support tools discussed in Chapter 9.3 can happen progressively although it is important to remember that ASBVs are updated regularly. This means that a ram’s ASBVs for traits that are important to you may change over time and the most recent data should be accessed via Sheep Genetics and utilised when making selection decisions.

Consider thresholds and weightings to ensure your assessment is according to the traits you are prioritising. Indexes can be a useful tool but it is important to understand how traits are weighted within an index and ensure this is consistent with what you are seeking to achieve. There may be additional traits or traits within the index that require particular attention.

Make sure you understand your genetic position as explained in Chapter 9.4 Your targets should be based on your current position.

Performance assessment

Performance assessment should be conducted using the most up-to-date information available. This may include weaning percentages as a gauge for reproductive performance, wool test results or carcase data.

Class sheep in light of your breeding objective

This requires consideration of the sheep as a whole, based on the traits you have assessed.

Where possible, class sheep that are from the same age and management group to ensure the influence of other factors is limited. This should apply to both the annual classing of maiden ewes and the classing of older age groups to identify animals which may not be consistent with your breeding objective because your objective has changed, or the sheep have matured to diverge from your breeding objective.

Key points for classing:

  1. Look at the traits across the animal in the same way, starting at the head and working backwards to the tail and back legs.
  2. Look at all important traits in combination including horns, breech wrinkle, wool quality, wool length and density, feet, legs, backline, etc.
  3. Classing sheep involves constant compromise between a range of traits. It is an individual sheep decision.
  4. Consider how you will group the sheep into ‘classes’ other than just 'keep’ or ‘cull’. For example, you may class your sheep into different groups based on their scores for visual traits that don’t make them a cull (such as ‘ones’, ‘twos’ or ‘threes’) or sheep that you may crossbreed. For example, ewes that are conformationally sound but have broader wool with harsh handle may be classed out into a line to be joined for meat production or marketed separately.
  5. Stop and check how classing proportions are going against planned culling percentage throughout.
  6. Make sure you are able to assess the sheep fairly. Don’t force them into a race or pen where they are cramped or too loose and traits cannot be assessed.

The emphasis on traits and what is chosen for and against varies between flocks. This is where your breeding objective comes in to guide whoever is classing.

Select sheep to match your breeding objective

Most breeders buy in rams on a regular basis and in some situations, particularly terminal enterprises, ewes are also purchased as well. Both rams and ewes can be selected to introduce into a flock but most of the decisions you make relate to the annual purchase of rams.

When buying sheep, the purchasing decision is often more one of selecting rather than classing, but you should always check to ensure they match your breeding objective and the thresholds you have set for your important traits and that they will thrive in your environment.

Buy in rams

Ram source

When choosing a ram source, it’s important that the breeding objective of the ram source aligns with your breeding objective as your genetic progress will track theirs over time. This does not require complete alignment as it is your farm and your decision but there should be a high degree of alignment in areas which affect your profit drivers.

When sourcing rams:

  1. Talk to your ram source and classer or advisor to understand the emphasis the ram source places on the key traits that are of most importance to you and how they are progressing in these areas.
  2. Make sure you have a good understanding of how the sheep will perform in your environment compared to your ram source’s environment, as it reduces your risk. An independent classer can help provide an insight into this. There is a risk that their genetics will perform differently at your place to what is visually assessed at the source’s location, especially if they are from a different operating environment.
  3. See what kind of data you can access from the ram source and what they use in their decision making. This may include raw data like visual scores and measured performance data, or ASBVs. Understand their approach to assessing and classing for traits of high importance for you and visually assess rams on offer for these traits, particularly where there may be a different approach to key traits.

Importantly, make sure you are comfortable with the relationship you have with the ram source, including their pricing, payment terms, transparency, openness to appreciate your business needs and communicate and share information with you and help you progress towards your breeding objective.

Preparing for a ram sale

First and foremost, understand your genetic position so you can ensure the rams you are looking at will move you forward.

Then establish the number of animals you require. You should begin by sorting your existing rams, culling any that have broken down and fail a health check, as well as any that no longer suit your breeding objective. This may include older rams or those which are now demonstrating undesirable traits which weren’t apparent in earlier years. The number of rams you require is likely to vary from year to year, depending on:

  1. The outcome of your classing decisions
  2. The total number of ewes joined
  3. Joining percentages
  4. Number of ewes and rams culled
  5. Number of existing sheep that will be used again.

Settle on a ram source or sources that suit your enterprise. Assess the rams on offer and create a shortlist of rams prior to sale day that aligns to what you’re trying to achieve. This can improve your purchasing success, assist with keeping to budget and minimise the number of rams you have to physically inspect on the day, helping you focus your attention.

You can use information to create your shortlist from a variety of sources, including:

  • ram breeders, usually as sale catalogues;
  • the Sheep Genetics database available via the website;
  • sale catalogues published on the Sheep Genetics website; and
  • RAMSELECT.

When you’re creating your shortlist, make sure you have more rams than you need as you may strike some out when you get to the sale based on your visual assessment, or you may not be successful in your bidding. Having a few extra rams that may not be at the top of your list but are still acceptable will also help you avoid the situation where you end up bidding on or purchasing a ram which really does not suit your purposes. Remember, the influence of a ram is significant and lasts for many years, so care is required.

When creating your shortlist, consider talking to the ram breeder to gain more information about the individual rams. Don’t forget environmental factors also influence the outcome so consider the ram breeder’s environment and management, and if it aligns to yours.

If you are in a situation where there are not enough rams that meet your thresholds, you may need to:

  • tweak the combination of traits and the emphasis you are placing on them; and
  • consider how they might fit into different joining strategies.

It is also best to establish a budget for ram purchases prior to the sale. This should be created with consideration of:

  • the number of rams required;
  • value you put on the genetics you are sourcing; and
  • what you can afford.

Finally, it’s important to establish what you will visually assess on the day.

This will include the traits related to what you want to focus on as well as whether they’re fit to join (so checking the standard 4Ts – teeth, toes, tackle, testicles) and overall conformation, wool quality, etc.

It may be helpful to prepare a checklist of what you want to assess for each ram on sale day to ensure you look at each ram consistently and thoroughly, without being rushed.

You can choose to bring all of this information together in a plan which includes:

  • what you want to achieve and traits of interest;
  • strengths and weaknesses of your current ram team;
  • how many new rams you need;
  • a shortlist of rams that, based on their data, would contribute well to your flock;
  • a list of what you will visually assess on the shortlisted animals on sale day such as structure; and
  • a budget to spend at the sale.
On sale day

On the day, evaluate your shortlist based on the checklist you created for visual assessment.

It’s likely you will eliminate some of your shortlisted rams if they are not suitable physically or too expensive. This is why having more rams on your shortlist than required is essential.

Third party advisors, such as classers, can be helpful on sale day, as long as they have a clear understanding of your purchasing process and plan. If possible, run through your shortlist with your advisor before the sale and in preparation of your shortlist and then visually assess your shortlisted rams on sale day with your advisor to ensure their fit for your purpose.

Remember, pre-sale day preparation of rams will influence what they look like on sale day. This is why the combination of visual and objective assessment is important.

Changing ram source

If you are looking at making a dramatic change, you may not be able to achieve this using your current ram source and may be motivated to look elsewhere. An example may be if you are considering a transition from mulesed to non-mulesed.

In such a situation, ask yourself:

  1. What other ram sources are available?
  2. Does the alternative ram source have a similar breeding objective to your own?
  3. Do they have similar environmental conditions to you? If not, do you think their sheep will perform well in your environment? Is there any way you can verify this?
  4. Are those rams available in sufficient numbers and in your price range from an alternative supplier? You need to set realistic performance and welfare targets.
  5. What service do you get and at what price?

If your investigations reveal that there really is no viable alternative to your existing ram source, reconsider and moderate your goals. Working with your existing supplier may provide slower initial gains but deliver the best long-term option.

While a different ram source might increase progress for traits of particular interest, for example, breech traits such as wrinkle and cover, there may be unfortunate impacts on other traits such as fibre diameter, fleece weight, fleece rot, body weight, etc.

Changing your ram source to target particular genetic and visual trait expression and selecting ewes on the same basis can bring very rapid changes but these changes are likely to extend beyond the traits you are targeting. How important is it to you to maintain your current sheep type? How important is it to you and your market to have an even line of sheep?

Changing ram supplier can lead to a very different type of sheep and it may take many years to achieve consistency.

You could trial rams from a new source against rams from your existing source. Keep the progeny identifiable so that the transition can be extended or abandoned, based on performance. Try in your environment on a small scale before making wholesale changes. Monitor and review.

Breed your own rams

Some producers choose to breed some or all of their own rams. To be done effectively, a clear breeding and joining plan is required and it’s important to get help if this is an option.

When breeding your own rams, you need to ensure you are continuing to make progress given that you are likely not bringing in new genetics at the same rate you would have if sourcing rams externally. One way to do this is through the use of the decision support tools discussed in chapter 9.3. For example, genomic testing could be used to identify the genetically superior rams in your flock.

Inbreeding needs to be carefully managed through a well-considered joining plan when breeding your own rams. If you’re not experienced or confident in managing this, engage an advisor to assist you in keeping track of this and for advice regarding joining decisions.

Join sheep strategically to achieve your breeding objective

Joining protocols describe how the animals that have been classed and selected for the breeding program are combined to create the next generation of lambs that will contribute to your breeding objective.

There are different joining tactics that you can adopt to increase the rate of progress towards your breeding objective.

These include:

  • Joining ewes at a younger age (e.g. 7-10 months of age) to bring new genes into the flock quicker.
  • Cross breeding to realise hybrid vigour.
  • Split joining in which superior rams are used twice.
  • If breeding your own rams, single sire joining to establish pedigree and more specific results may be worth considering.
  • Elite joining where rams are selectively joined to ewes that are similar for specific attributes together (like with like). For example, joining the flock elite ewes with your best rams. Keep in mind, however, that the other joining combinations will still contribute to your next cohort meaning your overall average may not change. This is more effective if you have a very high lambing percentage.
  • Corrective joining where like and unlike are joined to exploit where the average of the next drop will be, for example if you classed ewes into a group that performs poorly for an important trait you may consider joining them to a ram that performs well for that trait.

These tactics need to be balanced with strategies to ensure enough lambs are produced and the genetic progress of the whole flock, not just small subsets of the flock.

Which of these tactics are appropriate to your enterprise requires due consideration as they all have significant ramifications for your enterprise. You should speak to an advisor about these different approaches.

Joining period

Implementing a tight joining period will aid the management of ewes during pregnancy, lambing and lactation as a greater number of females will be in the same reproductive phase at the same time.

This will also aid pregnancy scanning accuracy and with the management of different mobs of ewes according to their nutritional requirements.

Tighter joining periods also deliver a more even line of progeny, which will in turn deliver management advantages as they mature, including assisting at classing as there will be no need to adjust for age as may be required for an extended joining.

Industry research recommends joining for five weeks (35 days), which is two cycles (each cycle is 17 days).

Most ewes will conceive within five weeks so extending the joining period beyond this to gain a few extra lambs will probably not compensate for the additional management complications during pregnancy, lambing, lactation and beyond.

Reproduction rates can be improved by ensuring optimal condition score and management throughout the reproduction cycle. This should include targeting nutrition based on reproduction status throughout, pregnancy scanning and managing different lambing groups in appropriate paddock sizes. Remember the more lambs you have on the ground to select from, the more selection pressure you can apply at classing.

Other factors to consider that contribute to joining and reproductive success include nutritional diseases or deficiencies, as well as environmental issues.

An example of a nutritional issue can be seen in high endophyte perennial ryegrass pastures which may decrease conception rates by 20%.

Environmental issues include:

  • insufficient effective rams for the number of ewes in the breeding flock. The required rate will depend on paddock size but generally 1% plus one is recommended for mature ewes and at least 1.5% for maidens and 2% for ewe lambs;
  • use of too many rams, which encourages fighting and is wasteful;
  • mixed ages of rams in joining groups, or mixing rams shortly before or during joining, which can affect conception while social dominance is being established; and
  • large joining paddocks where rams and ewes become separated.

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