Navigation

 

GLOSSARY OF TERMS

 

Across-breed:

Comparison of sheep across different breeds within a breed group.

Across-flock:

Comparison of sheep across different flocks within a breed group.

AGBU:

Animal Genetics and Breeding Unit.

AI:

Artificial insemination.

ASBV:

Australian Sheep Breeding Value - the genetic performance (breeding value) reported by LAMBPLAN and MERINOSELECT that describes the across-flock, or across-breed (as applicable) performance of a sheep for a trait.

Australian sheep identification system:

This system provides a unique sheep identification (ID) for each sheep across all flocks

 

Base traits:

a. When a Management Group is evaluated for live weight the Base Trait is: Weaning (live) weight or an older age live weight.

b. When a Management Group is evaluated for carcase traits the Base Trait is: Fat and eye muscle depth at early post weaning or an older age.

c. When a Management Group is evaluated for Worm egg count the Base Trait is: Worm egg count at weaning or an older age.

d. When a Management Group is evaluated for greasy fleece weight the Base Trait is: Greasy fleece weight at post weaning or older age.

e. When a Management Group is evaluated for fibre diameter the Base Trait is: Fibre diameter at post weaning or an older age.

BLUP:

Best linear unbiased prediction. The statistical method used to calculate estimated breeding values such as ASBVs and FBVs.

Body weight (WT):

See Live weight

Brand name:

Sheep Genetics reports sheep under two brand names and their associated logos. The Merino breed group is reported under the MERINOSELECT brand name and logo. All other breeds at this stage are reported under the LAMBPLAN brand name and logo.

Breeder:

A person who participates in Sheep Genetics quality assurance procedures and genetic evaluation. In relation to data being submitted to Sheep Genetics a ‘breeder’ is the person, organisation or business that is the legal owner of the data.

Breed group:

The breeds of sheep that are combined in an analysis and report.

Breeding objective:

The goals of the breeding program – a combination of the traits to be selected for and the desired direction.

Breeding value:

A breeding value describes a sheep’s genetic performance expressed in terms of the expected genetic performance of its offspring. The breeding value is calculated by a BLUP analysis that can include information on the sheep’s own performance and/or its relative’s performance. A breeding value is used in this manual as a general term to describe either an ASBV or an FBV.

 

Clean fleece weight (CFW):

Greasy fl eece weight multiplied by the yield of the fleece sample.

Crimp frequency:

Measured crimps per inch at the mid-side along a standard length of the staple using a crimp gauge or as measured by an accredited fl eece measurement

laboratory.

CTSE:

Central Test Sire Evaluation.

C site:

45 mm from the centre of the spine at the 12th/13th rib, where eye muscle and fat depth is measured by an accredited muscle and fat ultra-sound scanner.

 

Dam:

A female sheep with progeny data analysed in a particular Sheep Genetics analysis.

Data Manager:

A person, organisation or business (not defined as a breeder) who provides a service required by a breeder to prepare and submit the breeder’s data to Sheep Genetics in a way that meets QA procedures.

Dataset:

Data provided to Sheep Genetics for sheep in one or more Management Groups.

 

Ear tag:

An attachment to the ear of a sheep which, with the assistance of inscriptions on the tag and/or the tag’s colour and/or an electronic signal, enable a sheep to be

identifi ed within a Management Group and, in some cases, between flocks and breeds. Ear tag information is readable and/or interrogated electronically. At present, ear tags are the major method used to identify sheep but other devices are also being used, such as electronic implants or rumen capsules. In

this manual the term ‘ear tag’ covers these alternative identification methods.

Environment:

All non-genetic influences that affect a sheep’s performance.

ET:

Embryo transfer

Eye muscle depth (EMD):

The depth of eye muscle (Longissimus dorsi) measured at the ‘C’ site.

Ewe (or female progeny):

A female sheep that does not have progeny in a particular Sheep Genetics analysis.

 

Faecal egg count (FEC):

See Worm egg count (WEC)

Fat depth (FAT):

The depth of subcutaneous fat measured at the ‘C’ site.

FBV:

Flock Breeding Value. The genetic performance (breeding value) reported by Sheep Genetics that describes the within flock performance of a sheep for a trait. FBVs can, but do not necessarily allow comparison of sheep across Management Groups within the flock.

Fibre diameter (FD):

Average fibre diameter of a representative sample of wool from a sheep.

Fibre diameter coefficient of variation (CV):

The standard deviation (SD) of fibre diameter (the distribution of fi bre diameter) divided by the mean (average) fibre diameter and expressed as a percentage.

Flock:

All the sheep described by a particular breed and flock section of an ID (Flock Code).

Flock code:

see Group.

Flock group:

see Group.

 

Genetic Advisor:

A person, organisation or business (not defined as a breeder) who provides a service required by a breeder to advise them on genetic aspects of their breeding

program.

Genetic correlation:

The genetic relationships that exist between traits.

Genetic group:

see Group.

Genetic linkage:

When two or more flocks share common genes.

Genetic parameters:

The complement of heritabilities, genetic and phenotypic correlations, variance and adjustment factors used in an Sheep Genetics analysis.

Generation interval:

The time interval between generations, defined as the average age of parents when their progeny are born.

Genotype:

A combination of the genes of a sheep.

GR site:

110 mm from the centre of the spine at the last long rib.

Greasy fleece weight (GFW):

The weight of greasy wool shorn from the sheep before skirting. As long as all sheep at the fleece weighing of a Management Group are treated the same the belly wool can be either included or excluded.

Group:

Group records are required to adequately describe contemporary and genetic grouping of sheep records in the Sheep Genetics analysis. The group types that need to be submitted to Sheep Genetics are as follows:

Flock Code

The combined breed and flock sections (the first six digits) of the 16-digit Australian sheep identification

Flock Group

A flock group has one or more flock codes that are considered by the breeder to have a comparable genetic group. A flock group will generally only have one flock

code but in a small percentage of situations will be more than one. A flock group can have one or more site codes. A flock code can only exist within a single flock group. A flock group that contains a single flock code is not required to submit a flock group because in this case the flock group will default to the flock code. If more than one flock code is present in a flock group the group needs to be assigned a code (FG1, FG2, etc)

Site code

Site codes are relevant when a flock group is evaluated at different ‘sites’. Sites are locations that are geographically remote from each other. Sites are independent of flock codes and flock groups and therefore two or more breeders can share a site code. A flock group that is only evaluated at one site is not required to submit a site code because in this case the site code will default to the flock group. However, if a flock group is evaluated at more than one site a site code is required. A general name such as the property name can be used as the site code however it is preferable to use the property identification code (PIC) of the property that is most relevant to the site.

Genetic group

Genetic groups are segments of a flock code (or tiers within a flock code) that, for the traits submitted, are considered to be of significantly different genetic standard. The vast majority of flock groups will contain a single genetic group. All sheep can be assigned a genetic group however, where full pedigree exists the assigned genetic group is not used in the Sheep Genetics analysis. A genetic group is not applied across flock groups or across flock codes within a flock group. If more than one genetic group is present in a flock group then each genetic group is assigned a code (GG1, GG2, etc). If only one genetic group is present no code should be submitted.

Genetic groups should only be assigned when there are significant genetic differences within a single flock code or tiers within a flock code. For example, genetic groups would be applied when separate fine and superfine lines are bred within a particular flock code. Genetic group codes will be used only for analysis

and will not be publicly reported in a way that identifies a breeder or individual sheep.

Management Group

When a breeder submits data to Sheep Genetics the sheep need to be separated into a group known as a ‘Management Group’. A Management Group is used to group sheep accurately for an Sheep Genetics analysis. In addition, the name of the Management Group is used to describe the sheep being submitted and reported.

A Management Group is a group of sheep with all the following characteristics:

a. Born under similar management conditions at one site.

b. Born over a period that is no longer than 42 days.

c. Male or female progeny from one Breed Group.

Breeders may submit data that contains both male and female progeny if they have been managed together up to the time when the records were taken. Male and female progeny are often managed together in the period when birth records and weaning records are taken. Some breeders require additional Management Group

records to ensure sheep are correctly grouped in the analysis. Additional Management Group records (see ‘Group’) are required to be submitted when,

a. a Management Group contains more than one flock code (first six digits of the 16-digit ID).

b. a Management Group contains more than one tier or section of a flock that are considered to be different genetic groups.

c. a flock code is evaluated at more than one site code.

Management Subgroup

If sheep in a Management Group cannot continue to be managed the same way, then two or more Management Subgroups need to be established and recorded to

ensure the analysis is correctly carried out. Each Management Subgroup needs to be recorded within the Management Group by identifying them 1, 2, etc in a

Subgroup field. Subgroup records need to be submitted the first time after traits have been evaluated following the establishment for the Subgroups. These codes are only applied by Sheep Genetics within a Management Group

 

Heritability:

The average proportion of the difference between sheep (after adjusting for known non-genetic influences) that can be passed on to their progeny.

 

ID:

Australian sheep identification system 16-digit identification number

 

Live weight (WT):

The weight of a live sheep in Kilograms.

 

Management Group:

see Group.

Management Subgroup:

see Group.

Merino Superior Sires (MSS):

Publications and activities conducted by Australian Merino Sire Evaluation Association (AMSEA).

Micron:

One millionth of a metre.

 

Nemesis:

Research and extension project carried out to establish an understanding of the genetics of sheep worm resistance. Nemesis guidelines were the basis for the worm egg count QA standards in this manual and the standards for the measurement of worm egg count. Also see worm egg count.

 

OVIS:

The name of the BLUP software used to calculate LAMBPLAN or MERINOSELECT breeding values (ASBVs and FBV).

 

Phenotype:

The observable performance for a given trait, as measured or scored for a sheep.

Progeny test:

A comparison between the progeny of a group of sires that were mated to randomly selected females. Pregnant females and progeny for all sire groups are run under

identical conditions for the period of the test.

 

Quality:

The ability of a product or service to satisfy its customers.

Quality assurance (QA):

What you need to demonstrate so a product or service will satisfy your customers.

Quality assurance system:

The organisational structure, processes and procedures necessary to ensure the QA intentions and direction are met and the quality of a product or service is assured.

 

Ram (or male progeny):

An entire male sheep that does not have progeny data analysed in a particular Sheep Genetics analysis.

 

Scored traits:

Those characteristics of a sheep that are evaluated subjectively – by hand and/or eye – relative to a set of standards.

Selection:

The choice of sheep to be used as parents.

Selection accuracy:

The correlation between true breeding value and estimated breeding value. Selection response is directly proportional to selection accuracy.

Selection criteria:

The traits used to evaluate sheep for a particular breeding objective.

Selection differential:

The difference between the average phenotypic or genetic merit of the selected parents and the average merit of the group from which they came.

Selection index:

A calculation that weights and combines the performance of a sheep for two or more traits to give an overall index value for that sheep. An index value can be used to assist selection for the breeding objective defined by the index. Sheep Genetics will produce index values by combining ASBVs and/or FBVs.

Selection response:

The effect of selection on the merit of progeny or later descendants, measured as a deviation of the merit expected if parents had been chosen at random, rather

than by selection on a trait or combination of traits.

Service provider:

Data manager, Scanner, WEC Labs or Genetic Advisor. Contact details can be found on the Service Provider menu item.

Shearing:

The removal of wool from a sheep by machines, blades or chemical defleecing. The latter can affect the calculation of age and wool growth due to difference in the wool growth being harvested.

Sire:

An entire male sheep that has progeny analysed in a particular analysis.

Site code:

see Group.

 

TGRM:

Total Genetic Resource Management. TGRM is computer software used to optimise genetic gain and inbreeding.

Tier:

A section of the ewes within a fl ock group that has been selected for mating and is considered to be of a different genetic standard compared to other sections of the flock group.

Trait:

A trait name, for example live weight, is often accompanied by a description of the age of evaluation of the trait. Reports list both the trait and the age to provide a clear definition of the information reported.

The abbreviation of an ‘age and trait’ is presented by adding the abbreviation for the ‘age’ in front of the ‘trait’ abbreviation. For example, hogget (live) weight is

recorded as ‘HWT’. 

Trait Age names, abbreviations

 

Age Name

Abbreviations

(Upper case)

Average age

of the group*

Approximate age in

weeks or months

Birth B birth to 24 hours
Weaning W 42 to 120 days 6 to 17 weeks
Early post weaning E 120 to 210 days 4 up to 7 months
Post weaning P 210 to 300 days 7 up to 10 months
Yearling Y 300 to 400 days 10 up to 13 months
Hogget H 400 to 540 days 13 up to 18 months
Adult A 540 days or older 18 months or older

* Management Group

 

Trait names and abbreviations

 

Trait Name

Abbreviation

(upper case)

Units

Submitted

Units

Reported

Live weight WT kg kg
Maternal weaning weight MWWT Not submitted kg
Eye muscle depth EMD mm mm
Fat depth FAT mm mm
Greasy fleece weight GFW kg %
Clean fleece weight CFW kg %
Fibre diameter FD um

um

Coefficient of variation of FD FDCV % %
Staple strength SS N/ktex N/ktex
Staple length SL mm mm
Worm egg count WEC % %
Number of lambs born NLB 0 to 4 %
Number of lambs weaned NLW 0 to 4 %
Scrotal circumference SC cm cm

 

Worm egg count (WEC):

A measurement of intestinal parasite load to evaluate worm resistance that is obtained by counting the number of parasite eggs per gram (epg) in a sheep faecal sample collected and measured to Nemesis standards.

 

Yield:

The proportion of a fleece sample remaining after relevant washing.