Making informed classing, selection and joining decisions
MLA & AWI July 19, 2024
After identifying the profit drivers and the type of sheep which fit the purpose and defining 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 effectively assessing the sheep and this can be aided by protocols that 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 the genetic investment.
Classing, selection and joining decisions to improve profitability
Classing, selection and joining are really about:
- classing existing sheep based on an assessment of their fitness for purpose as defined by the breeding objective
- identifying and selecting rams and ewes based on an assessment of their merit for the traits that suit the overall breeding objective
- joining these animals strategically to ensure their progeny express desirable traits and contribute towards the overall breeding objective.
Source: AWI ClassiFly
Remember, the traits selected and the breeding objective should be clearly linked to the 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:
- the performance of sheep and their progeny
- capacity of sheep to deal with challenging situations
- overall productivity and profitability
- classing and selection decisions through:
- greater numbers to select from through higher weaning rates
- 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:
- providing optimal nutrition throughout the year
- implementing an appropriate vaccination and drenching program and using worm egg count (WEC) testing to guide drenching decisions
- controlling predators
- providing adequate protection from weather extremes.
Fundamental to good health and welfare is matching feed demand to feed supply. This provides the basis for producing a product that conforms to market specifications, achieving a desirable price and optimising profitability.
Feed demand fluctuates throughout the reproductive cycle and pregnancy scanning is a key tool producers can use to help you manage the changing nutritional demands of pregnancy and lactation.
Scanning allows producers to manage mobs based on their nutritional requirements and body condition score.
A recent economic study calculated the average increase in farm profit as a result of scanning for multiples to be on average $5.55 per ewe scanned, based on long-term (2004 –2020) wool and meat prices. For more information see MMFS Module 10 Wean More Lambs.
Scanning is only part of the story; it is what producers do with the information that matters most. After the pregnancy status of ewes is known and they are drafted accordingly, producers can better manage paddock and feed allocation.
Scanning can also help producers target traits or management strategies to improve reproductive performance. For example, if the scanning percentage is low then nutrition in the lead-up to joining or ASBVs for conception or litter size may be of interest. If the scanning percentage is high, but weaning rate lower than expected, litter size or conception is probably not a priority as this doesn’t seem to be the issue, rather the producer may focus on rearing ability or weaning rate while optimising management post scanning.
Another example of where health and welfare is of high importance is lamb marking. Lamb marking should be carried out in clean yards close to the paddock being grazed and completed early in the day so ewes and lambs can successfully mother up.
Hygienic practices, including using clean equipment and regularly disinfecting equipment throughout marking, use of anaesthesia and analgesia, and vaccination, are all important.
Lamb marking is also a key time to look at the ewes. Carrying out wet and drying at lamb marking allows for dry ewes and those who have lambed and lost to be removed and returned to a maintenance ration, prioritising the best available feed for ewes raising lambs.
Condition score ewes with lambs at foot at lamb marking to ensure they’re receiving optimal 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 ewes and lambs reduces the number of ‘management culls’ at classing, as all lambs have been given the best chance of expressing their genetic potential.
Classing, selection and joining decisions
Accurate classing, selection and joining decisions rely upon reliable assessment of the sheep using both visual and measured assessment tools. Visual assessment, or raw data, is the assessment of how an individual sheep looks and performs.
This requires effective protocols, including 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.
It is important to combine the tools within the protocol to deliver the best outcome for the breeding objective. Over reliance on either visual or genetic tools can delay improvement or lead to an undesirable outcome. Functional or structural traits are also important. Avoid limiting the focus to production traits. Expand the focus to include physical characteristics, such as sound feet and legs, which allow sheep to realise their reproductive potential.
Visual assessment relies on assessing how each trait is phenotypically expressed in an animal, including what they look like and how they perform.
A number of traits can be assessed when classing for lifetime productivity and profitability as well as for breeding better progeny.
Visual assessment supports progress when:
- the trait is easily assessed (because it can be easily seen)
- the trait is highly heritable
- 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 considering 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 resulting classing and selection decisions.
When there are a few visual, highly heritable traits that are not antagonistic to each other in a breeding objective (such as fibre diameter coefficient of variation and staple length), visual assessment and the use of raw data can result in rapid genetic progress.
When including 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.
Ensure there is alignment between visual and objective measurements. Best practice is to use a combination of both visual and objective assessment.
Setting thresholds or using 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 expensive, so compromises are usually required.
Some rams that will improve a desired trait can have a negative effect on other traits of importance identified in a 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 the breeding objective. This can then be included in the selection plan, allowing the focus on to remain on the most important traits without compromising other areas. Consider these thresholds and trait emphasis when assessing rams to purchase.
Consistency is also important. The more similar the rams purchased, the more consistent the progeny will be. Even lines of surplus young ewes can attract premiums. Try to avoid outliers or rams demonstrating extreme traits.
Set thresholds for any key traits used when classing or selecting sheep — visual or measured. For example, if we are seeking to reduce breech wrinkle, but not lose fleece weight, we might adopt the current fleece weight as the threshold below which we 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.
Combining all assessment information
Bringing the visual and objective assessment information together in a balanced way to deliver the 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 being assessed, how they are being assessed and the weighting assigned to those traits.
Make a checklist of what will be visually assessed in 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, assess neck wrinkle as an indicator of breech wrinkle. When undertaking visual assessment:
- 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. Avoid comparing each animal to others in the mob, rather compare them to the diagrams and score descriptions in the guide. If we just focus on the mob and assess on that basis, we can compound a problem or class out sheep that are actually 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, look at the animal carefully. Make sure you can clearly see the areas on the sheep you are scoring and they are not crowded. This is a chance to absorb all the information visual assessment can provide including ‘doing ability’, spring of rib, length of body, bone, etc. A classing box is ideal so you can assess the sheep individually. If this is not possible, avoid packing the race too tightly so the sheep can stand freely.
- Go through the usual assessment for conformation, soundness, wool quality and the 4Ts (teeth, toes, tackle, testicles).
Sheep can be assessed as a standalone activity, for example to establish a flock’s susceptibility to flystrike, or as part of the classing process, or even when mobs are brought into the yards for other reasons. Identifying when and how sheep are assessed in a written protocol can help capture all the assessment opportunities.
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. It may not always be practical to optimise all of these but finding a reasonable compromise may be the best way forward.
An annual management calendar can help schedule events.
The reason assessment may happen separately to classing is because we may not know something about the sheep when we assess them that we want to take into consideration when we class them. For example, their reproductive performance may not be known when we are assessing them for wrinkle off shears.
Breeding value assessment
Genetic assessment using decision support tools can happen progressively although it is important to remember that ASBVs are updated regularly. This means a ram’s ASBVs for important traits may change over time. Access and utilise the most recent data via Sheep Genetics when making selection decisions.
Consider thresholds and weightings to ensure the assessment is according to the traits of interest. 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 we are seeking to achieve. There may be additional traits or traits within the index that require particular attention.
Understand the genetic position and base the targets on improving the current position.
Performance assessment
Conduct a performance assessment 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.
Classing sheep in light of a breeding objective
Classing sheep in light of a breeding objective requires consideration of the sheep based on the traits being assessed. Where possible, class sheep from the same age and management group to ensure the influence of other factors is limited.
Key points for classing:
- Look at the traits across the animal in the same way, starting at the head and working backwards to the tail and back legs.
- Look at all important traits in combination including horns, breech wrinkle, wool quality, wool length and density, feet, legs, backline, etc.
- Classing sheep involves constant compromise between a range of traits. It is an individual sheep decision.
- Consider how to group the sheep into ‘classes’ other than just ‘keep’ or ‘cull’. For example, we may class 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 we 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.
- Stop and check how classing proportions are going against planned culling percentage throughout.
- 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 the breeding objective comes in to guide the classing process.
Selecting sheep to match the breeding objective
Most breeders buy in rams on a regular basis and in some situations, particularly terminal enterprises, ewes are also purchased. Both rams and ewes can be selected to introduce into a flock but most of the decisions relate to the annual purchase of rams.
When buying sheep, the purchasing decision is often more one of selecting rather than classing, but selecting should match the breeding objective, the thresholds set for important traits and the environment in which the sheep will run.
Buying in rams
Ram source
When choosing a ram source, it’s important the breeding objective of the source enterprise aligns with the breeding objective of the purchasing enterprise as genetic progress will track the source over time. This does not require complete alignment, but a high degree of alignment in areas which affect the business’ profit drivers is desirable.
Key considerations when sourcing rams include:
- understanding the emphasis the ram source places on the key traits interest and how they are progressing in these areas
- understanding how the sheep will perform in the intended environment. There is a risk the source genetics will perform differently in a new environment to the source location, especially if the operating environments differ significantly
- gaining access to the data the ram source uses in their decision making. This can include raw data, like visual scores and measured performance data, or ASBVs. Understand their approach to assessing and classing for traits of high importance and visually assess rams on offer for these traits, particularly where there may be a different approach to key traits.
A positive relationship between buyer and seller is important, particularly in relation to pricing, payment terms, transparency, openness to appreciating individual business needs and communicating and sharing information that will help producers progress towards their breeding objective.
Preparing for a ram sale
It is crucial to understand the current genetic position to ensure the rams sourced will progress the breeding objective.
The next step is to establish the number of animals required. This can be achieved by sorting the existing rams, culling any that have broken down and fail a health check, as well as any that no longer suit the 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 required is likely to vary from year to year, depending on:
- the outcome of classing decisions
- the total number of ewes joined
- joining percentages
- the number of ewes and rams culled
- the number of existing sheep that will be used again.
Assess the rams on offer and create a shortlist of rams before sale day that aligns to the breeding objective. This approach can improve purchasing success, assist with keeping to budget and minimise the number of rams that require physical inspection on the day.
Use information to create a shortlist from a variety of sources, including:
- ram breeders, usually as sale catalogues
- the Sheep Genetics database
- sale catalogues published on the Sheep Genetics website
- RAMSELECT.
When creating a shortlist, have more rams than needed as some may be may not come up to scratch after visual assessment, or exceed the budget. Having a few extra rams that may not be at the top of the list but are still acceptable also helps avoid bidding on or purchasing a ram that is not fit for purpose. Remember, the influence of a ram is significant and lasts for many years, so care is required.
When creating a shortlist, consider talking to the ram breeder to gain more information about the individual rams. Environmental factors also influence the outcome so consider the ram breeder’s environment and management in relation to that of the destination.
If there are not enough rams to meet thresholds, tweak the combination of traits and the emphasis placed on them and consider how they might fit into different joining strategies.
Establish a budget for ram purchases before the sale by considering:
- the number of rams required
- placing a value on the genetics being sourced
- available funds.
Finally, it’s important to establish what to visually assess on the day.
This will include the traits related to what the breeding objective and whether the ram is fit to join (so checking the standard 4Ts – teeth, toes, tackle, testicles) and overall conformation, wool quality, etc.
A checklist for each ram on sale day can ensure each ram is assessed consistently and thoroughly, without being rushed.
All of this information can be brought together in a plan which includes:
- the goals in terms of traits of interest
- strengths and weaknesses of the current ram team
- the number of rams needed
- a shortlist of rams that, based on their data, would contribute well to the current flock
- a list of what you to visually assess on the shortlisted animals on sale day, such as structure
- a budget to spend at the sale.
On sale day
On the day, evaluate the shortlist based on the checklist for visual assessment.
It’s likely some of the shortlisted rams can be eliminated if they are not suitable physically or are too expensive. This is why having more rams on the 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 the purchasing process and plan. If possible, run through the shortlist with an advisor before the sale and when preparing the shortlist and then visually assess the shortlisted rams on sale day with an advisor to ensure their fit for 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
Producers looking at making a dramatic change, may not be able to achieve this using their current ram source and may be motivated to look elsewhere. An example may be the transition from a mulesed to a non-mulesed enterprise.
In such a situation, it is worth asking:
- What other ram sources are available?
- Does the alternative ram source have a similar breeding objective to the business in question?
- Do they have similar environmental conditions? If not, it is likely their sheep will perform well in the environment? Is there any way to verify this?
- Are rams available in sufficient numbers and in the right price range from an alternative supplier? Set realistic performance and welfare targets.
- What service is provided and at what price?
If there is no viable alternative to the existing ram source, the breeding objectives may require further consideration and moderation. Working with the 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 the ram source to target particular genetic and visual trait expression and selecting ewes on the same basis can bring rapid changes, but these changes are likely to extend beyond the target traits.
Changing ram supplier can lead to a different type of sheep and it may take many years to achieve consistency.
An option is to trial rams from a new source against rams from the existing source. In this case, keep the progeny identifiable so the transition can be extended or abandoned, based on performance. Trial on a small scale before making wholesale changes. Monitor and review.
Breeding rams
Some producers choose to breed some or all 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 rams, producers need to ensure they continue to make progress given it is unlikely new genetics are being brought into the flock at the same rate as sourcing rams externally. One way to do this is to use decision support tools. For example, genomic testing could be used to identify genetically superior rams.
Inbreeding needs to be carefully managed through a well-considered joining plan when breeding your rams. If experience or confidence is lacking, engage an advisor regarding joining decisions.
Joining sheep strategically to achieve the 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 the breeding objective. There are different joining tactics available to increase the rate of progress towards a 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
- single sire joining to establish pedigree and more specific results may be worth considering if breeding rams
- 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 the best rams. Keep in mind, however, the other joining combinations will still contribute to the next cohort meaning the overall average may not change. This is more effective in flocks with a high lambing percentage (in excess of 100% lambs weaned to ewes joined).
- corrective joining, where like and unlike are joined to exploit where the average of the next drop will be. For example, if ewes are classed into a group that performs poorly for an important trait, joining them to a ram that performs well for that trait is an option.
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 any given enterprise requires due consideration as they all have significant ramifications.
Joining period
A tight joining period supports ewe management during pregnancy, lambing and lactation as a more 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. Targeting nutrition based on reproduction status throughout, pregnancy scanning and managing different lambing groups in appropriate paddock sizes are the keys to weaning more lambs. Remember the more lambs on the ground to select from, the more selection pressure can applied at classing.
Other factors that contribute to joining and reproductive success include nutritional diseases or deficiencies, as well as environmental issues. An example of a nutritional issue are 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
- using 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
- large joining paddocks where rams and ewes become separated.