Trait measurement

Trait measurement

Traits evaluated by Sheep Genetics

The list of traits is growing over time, as more industry data is collected, and new traits are developed.

You do not have to record every trait. Consider your breeding objective, and record those traits that are important to you as directly as possible.

When to measure traits

When you submit a record, you provide the relevant age stage that reflects the age of the animals when they are recorded.

Age name	Abbreviations	Average age of the management group	Age range
Birth	B	0	0
Weaning	W	100	40-149 days
Post weaning	P	225	150-299 days
Yearling	Y	365	300-449 days
Hogget	H	540	450-659 days
Adult	A	700	660 days or older

 

Where the age of animals within a group falls across the cutoff between age stages, choose the age stage based on the average age of the group.

The evaluation does not split groups where the age range overlaps two age stages, given the whole group is allocated the same age stage for the measurement.

For example, you are recording a body weight on animals that have been managed together, and whose age at the time of recording ranges between 250 and 310 days. Based on the age stage table above, these animals could fit in either the post weaning or yearling age stage. However, the average age of the group is 270 days, therefore the body weights on these animals is allocated as postweaning (PWT).

When submitting trait data, include

• The trait code and age stage
• Trait measurement
• Management group
• Measurement date - making sure that, where possible, animals that are in the same management group are measured on the same day

 

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Live weight (WT)

How to collect? Using on-farm scales, or scales provided by a carcase scanner.

Recorded at:  

• Birth (B)
• Weaning (W)
• Post-weaning (P)
• Yearling (Y)
• Hogget (H)
• Adult (pre-joining)

Units:

• Birth weight is measured to nearest 0.1kg
• Other weights are measured to nearest 0.5 kg.

Sheep Genetics QA protocols Before weighing, check scales are accurate using a known weight Ensure animals are empty by taking them off feed and water at least four hours before weighing, so that gut fill is not a significant component Measure the whole management group on the same day (because contemporary groups are split on the date they are measured) Birth weight must be recorded within 24 hours of birth on live and dead lambs (where whole body is available) Record adult ewe weights in the 30 days prior to joining. Recording pre-joining means that body weight is not affected by reproductive status. It is also easier to submit this pre-joining data in the mating module of the software so that it is exported with the relevant lamb drop (rather than exporting multiple year drops after weighing mixed age ewes)

 

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Eye muscle depth (EMD) & fat depth (FAT)

How to collect? An accredited scanner. A list can be found on the Service Provider page. 

Recorded at:

• Weaning (W)
• Post-weaning (P)
• Yearling (Y)
• Hogget (H)

Animals should not be recorded for EMD and FAT after being joined (or beyond the hogget age stage) as the physiological processes associated with reproduction impact the expression of this trait.

Units: EMD and FAT are measured to at least the nearest 0.5mm

Sheep Genetics QA protocols Must be measured by an Sheep Genetics accredited scanner Animals must be over 30kg liveweight. Group must have an average of at least 1.5mm of fat over the C-site. The fatter the animals are, the more expression of the trait and, therefore, more variation. Liveweight must be recorded on the same day Scan animals at a similar age to when your commercial clients market lambs

 

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Greasy fleece weight (GFW)

How to collect? On-farm

Recorded a:  

• Post-weaning (P)
• Yearling (Y)
• Hogget (H)
• Adult (A)

Animals must be between 7 months and 6 years of age.

Units: Fleece weight is measured to nearest 0.1kg

Sheep Genetics QA protocols Animals must have at least 6 months wool growth Before weighing, check scales are accurate using a known weight Fleece weighing is usually done in the shed during shearing and before skirting. Try and include the belly wool. If you do not include the bellies, be consistent and ensure you do not include them for all animals. If shearing a management group over multiple days, submit this data with a single date of measurement. This is to avoid the group being split based on different dates of measurement, as fleece weight data is not impacted by being overnight in the yards. If an accurate birth date or birth type is not known, you can shear animals early in life (tip shearing to even up all the animals) to help account for any impact of age, birth type and maternal effects.

 

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Clean fleece weight (CFW) and yield (YLD)

How to collect? Clean fleece weight (CFW) measurements are derived from a greasy fleece weight (GFW) measurement and a yield (YLD) measurement: CFW = GFW x YLD

You can either:

• Calculate the CFW yourself and submit all three trait measurements (CFW, GFW and YLD) to the evaluation.

Submit GFW and YLD to the evaluation, which will then calculate CFW for you.

Sheep Genetics QA protocols Refer to the GFW protocols above When measuring yield to inform clean fleece weight, ensure the yield measurement relates to the same shearing event that the greasy fleece weight was recorded.

 

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Wool quality traits

Traits include:

• Fibre diameter (FD) – measured in microns
• Coefficient of variation of FD (FDCV) – measured in %
• Staple length (SL) – measured in mm
• Curvature (CUR) – measured in degrees
• Staple strength (SS) – measured in newtons per kilotex

Recorded at:  

• Post-weaning (P)
• Yearling (Y)
• Hogget (H)
• Adult (A)

Animals must be between 7 months and 6 years of age.

Sheep Genetics QA protocols Animals must have at least 5 months wool growth Sample the fleece from either: The mid-side: over third last rib, halfway between mid-line of the back and mid-line of the belly The pinbone – over the pinbone Must use the same methodology (sample site) for all animals in the group. If testing a management group over multiple days, submit this data with a single date of measurement. This is to avoid the group being split based on different dates of measurement, as fleece data is not impacted by being overnight in the yards.

 

Further recommendations

• The fleece sample area should be about 100mm x 100mm
• If you sample at shearing, find and mark the sampling site on the standing sheep before shearing (eg mark a spot on the animals so sampling is consistent between animals).
• If sampling at shearing, remove the sample on the board during or after shearing, or during skirting on the wool table.
• If sampling prior to shearing, shear the wool off the sample area as close and consistently to the skin as possible. If you want to measure staple length, staple strength or crimp frequency do not make second cuts.

Measuring staple length (SL) on-farm:

• Use a straight but relaxed staple from the mid-side. Measure SL in mm using a ruler (a 15cm steel ruler is recommended), and
• Measure three staples selected at random but equally distant from each other on the outer edge of an imaginary 100mm diameter circle around the mid-side. Submit the average of the three measurements to Sheep Genetics
• It is best to evaluate SL on sheep that have already been shorn at least once.

 

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Worm Egg Count (WEC)

If you need help or advice around WEC testing, the ParaBoss website provides a consolidated list of testing laboratories and their contact details.

Recorded at:  

• Weaning
• Early-postweaning
• Post-weaning
• Yearling
• Hogget

Sheep Genetics QA protocols The average count for the group (when individual samples are collected) must be over 300 eggs per gram (EPG) Submit the total count of strongyle eggs (this includes Trichostrongylus, Ostertagia, Haemonchus and other minor species), unadjusted for faecal consistency Management groups for WEC must reflect previous drenching protocols, particularly if selective drenching of a portion of the group has occurred

 

Recommendations

• Take bulk samples of the mob to see if the worm burden is high enough prior to individual sampling.
• If you have Haemonchus (Barber’s Pole) then the average count should be 500–1000 epg.
• If you measure WEC during weaning age, try and sample lambs at least six weeks after weaning, to reduce any influence of the dam’s immunity.
• You can also submit an individual species count for Nematodirus separately if available. Sheep Genetics do not use this yet but could include it in the future.
• Some labs adjust WEC for faecal consistency (FC). WEC must be submitted unadjusted however faecal consistency may be submitted separately (as FC).
• Do not submit WEC samples animals that have been treated with internal parasite vaccinations (such as BarberVax) for genetic evaluation, as the influence of these treatments changes the trait definition of Worm Egg Count

 

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Reproduction

Traits

Component reproduction is comprised of three different traits (or components) that cover the entire reproduction cycle these are:

• Conception (CON)

Did the ewe conceive?

Sires with higher CON will produce daughters which have a higher conception rate. This trait is reported as adult and yearling. Yearling age is for ewe joined as ewe lambs.

• Litter Size (LS)

How many lambs were born?

Sires with higher LS will produce daughters that give birth to more lambs., This trait is reported as adult and yearling.

• Ewe Rearing Ability (ERA)

How successfully did the ewe rear her litter?

Sires with higher ERA will produce daughter which rear more of their litter. This trait is reported as adult and yearling.

The three component traits are then combined into a trait called Weaning Rate (WR).

WR describes the genetic difference between animals for the number of lambs weaned per ewe joined. It is expressed as number of lambs and a useful way for commercial producers to use reproduction in their selection decisions.

Additional traits that can be recorded relating to reproduction include:

• Maternal Behaviour Score (MBS)

How far the ewe moves from the birth site when her lambs are being tagged.

• Pre-joining weight (AWT) and condition score (CS)

Both the prejoin weight and the prejoin condition score need to be taken at the same time and submitted in the mating module within 30 days prior to joining (within 30 days of the rams going in with the ewes). The weight will contribute to Adult weight ASBV for the ewe.

• Lambing Ease

 Ease of which lambs are born, where a more positive ASBV indicated a better lambing ease. It is a traits scored against the lamb, therefore multiple receive separate scores. A Lambing Ease scoring guide is available.

Recording Reproduction data

Overall requirements (flock level)

• At least 70% of the lambs in a drop must have dam pedigree

Reproduction is a trait of the dam, so complete pedigree recording ensures we are capturing the full variation of the joining cohort.

• Consistency between birth types (BT) of lambs supplied and the count of lambs in the drop

Compare the BT of each lamb, and the total number of lambs in the drop. This validate the consistency of recording through the lambing. For example, does the total number of lambs and DAB animals match the birth types included in the drop?

Event recording (at a contemporary group level)

Joining
Data to be recorded	Why we need it	How to record it
ID of the ram the ewe is joined to	To identify if a sire fails (and there for avoid penalising the ewes he was joined to).	List the 16-digit ID of the ram joined to in your software.  NOTE: If joining as syndicate (and using DNA parentage) leave the ram in the mating module as the syndicate but update the pedigree of the progeny to the individual sire.
Ram in and out date	Check dates for relevance, ensuring that it is the joining event you are recording listed and the there are not future dates within the submission.	List the date rams are put in and pulled out in your software. NOTE: Try and be as accurate as possible (to the day) and record any back up joining as well under the appropriate sections in your software.
Ewe Joining weight and Ewe joining condition score	Contributes to the AWT and CS ASBVs.	Measure within the 30 days before the rams goes in. Ensure to include a date of measurement.
Management group of the ewes	Groups are checked for relevance and usefulness to the reproduction analysis e.g. are there dry ewes in the joining group showing variation	List the management group of the ewes prior to joining in your software.
Conception method of the ewe	Ensure fair comparison of the ewe’s reproductive performance.	Need to include against each ewe and also notify the use of chemical intervention (such as oestrus induing products). ET ewes are not used in the reproduction evaluation.

 

Pregnancy
Data to be recorded	Why we need it	How to record it
Pregnancy scan result	Informs the CON and (if not doing lambing rounds) LS ASBV	Record against each ewe and submit in your software, this allows us to identifies dry ewes (either as a preg scan 0 or a DRY tag) for analysis. NOTE: Ensure that you are scanning for multiple, wet/dry results are only used for conception and will not contribute to the other reproduction traits.
Pregnancy scan date	Checks the accuracy of the scan	Record against each ewe and submit in your software. NOTE: Scan results a minimum 70 days and maximum of 110 days from ram in date are sued within the analysis.
Foetal age (optional)	Can provide more accurate lamb DOB when not tagging at birth (e.g. early, mid and late)	Submit within your software
Scanner name (optional)	Looking to use this information in the future to help inform work around accuracy of pregnancy scanning.	Submit within your software

 

Lambing (if tagging at birth and doing daily lambing rounds)
Data to be recorded	Why we need it	How to record it
Environmental effects (fixed effects)	Helps inform the analysis of environmental differences between animals that may impact on performance	Include data such as Accurate date of birth, birth type, sex and sire or dam ID in your software. Additionally include any dead at birth (DAB) animals at this time.
Birth Weight	Contributes to the BWT ASBV.	A trait measured against the lamb (if there are multiples they each get a measurement) within 24hrs of its birth. Measured in kg and submitted in your software.
Lambing Ease	Contributes to the LE_DIR and LE_DTR ASBVs.	Scored from 1 to 5 based on the scoring guide. NOTE: this is a trait measured against the lamb (is there are multiples they each get a measurement) when a lambing event is witnessed or in obvious events (swollen heads, yellowy colour) soon there after.
Maternal Behaviour Score	Contribute to the MBS ASBV	Scored from 1 to 5 based on the scoring guide. NOTE: this is a trait measured against the ewe (if there are multiples only once score the for dam) when recording other information (i.e. BWT) at how attentive and close by the ewe stays to her progeny.

 

Weaning
Data to be recorded	Why we need it	How to record it
Rear type	Helps with adjustments made for fixed effect, contributes to calculation of ASBVs including early in life traits and reproduction.	Adjust RT to reflect the survival of lambs, i.e. 2 were born but only 1 made it to weaning.

 

Using DAB tags and pedigree to estimate rear type

You can infer ewes which lambed and lost lambs by matching pregnancy scan to pedigree (e.g. DNA parentage). For ewes in which the pregnancy scan does not match the number of alive lambs through pedigree, the gaps need to be filled with Dead at Birth (DAB) Lambs.

results). To use this method you must:

• have full pedigree on the whole drop cohort (not getting pedigree selectively)
• pregnancy scan for multiples
• get pedigree as early as possible (marking is preferred over weaning)
• be confident in the reliability of pregnancy scan data.

When submitting a DAB lamb to Sheep Genetics making sure that the information of the DAB lamb links up with the correct dam and alive lamb is important. Below is an example of how to submit a set of twins (pregnancy scan of 2) where one is an alive lamb and the other a DAB

Animal ID	Sex	BT	RT	DOB	Sire	Dam
609999-2024-240001	2	2	1	01/01/2024	609999-2021-210001	609999-2022-220001
609999-2024-DAB001	1	2	0	01/01/2024	609999-2021-210001	609999-2022-220001

 

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Visual traits

There are a number of visual traits which can be scored and submitted to Sheep Genetics.

Visual Sheep Score Guide

The Visual Sheep Scores Guide provides scoring protocol for a suite of visual traits, including conformation, wool quality characteristics, pigmentation, breech and body wrinkle and cover. The guide provides a set of illustrative standards and simple instructions on how and when to visually score animals.

Most traits in this guide can be scored to the nearest 0.5 and scores range from 1 to 5.

Shedding Score Guidelines

Work is underway to develop shedding ASBVs in the future. Breeders may collect and submit shedding score data to contribute to the evaluation. You can refer to the Visual Shedding Score Guideline for details. 

Sheep Genetics QA protocols If measuring a management group over multiple days, submit this data with a single date of measurement. This is to avoid the group being split based on different dates of measurement, where this visual data is not impacted by being overnight in the yards.

 

Helpful hints:

• Several visual traits are recorded at marking and are therefore submitted with an M to indicate the age stage. For example, breech cover measurements captured at marking are submitted as marking breech cover (MBCOV).
• Pay careful attach to the trait code included in the scoring protocol, and ensure you use the same code when entering the data into your software.

Reporting visual traits

Although visual traits are recorded with the relevant age stage, the resulting ASBVs tend to be reported as either early (E) which encompasses the early in life age stages or late (L). Early (E) reflects early in life expression of the trait (birth through to postweaning), and late (L) reflects later in life expression of the trait (yearling through to adult).  

Not all traits which are recorded on-farm have a reported ASBV, however this list is regularly growing as more data is recorded.

Submit visual traits that are in your breeding objective, so when there is enough data they can be included in the evaluation and reported as ASBVs.

The traits which currently have MERINOSELECT ASBVs include:

• early breech wrinkle (EBWR)
• early breech cover (EBCOV)
• late dag (LDAG)
• late wool colour (LCOL)
• late fleece rot (LFROT)
• late fleece character (LCHAR)

The traits which currently have DOHNE ASBVs include:

• early breech wrinkle (EBWR)
• early breech cover (EBCOV)
• late dag (LDAG)

The traits which currently have Maternal ASBVs include:

• late dag (LDAG)

 

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Footrot (FR)

How to collect? By an accredited scorer

Recorded: When animals are between 6 months and 2 years of age

Units:

All four feet are scored on a six-point scale (from 0 to 5)

Sheep Genetics QA protocol Only data collected in New Zealand currently informs the FR ASBV Challenge thresholds must be met where: 10% of animals have at least one foot that is score 3 (underrun) or greater 50% of animals have at least one foot that is score 2 (affected) or greater Must be at least 40 animals of the same sex and age in the challenge group