Basic Sheep Terminology

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

Across-breed: Comparison of sheep across different breeds within a breed group.

Across-flock: Comparison of sheep across different flocks within a breed group.

AI: Artificial insemination.

B

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.

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.

Broken-mouth or broken-mouthed: A sheep which has lost or broken some of its incisor teeth, usually after the age of about six years.

C

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.

D

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

E

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 identified 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.

F

Faecal egg count (FEC) or 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.

Fat depth (FAT): The depth of subcutaneous fat measured at the ‘C’ site.

G

Genetic correlation: The genetic relationships that exist between traits.

Genetic linkage: When two or more flocks share common genes.

H

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

Hogget or hogg: A young sheep of either sex from about 9 to 18 months of age (until it cuts two teeth). Also the meat of a hogget.

I-J

ID: Australian sheep identification system 16-digit identification number

K-L

Lambing percentage: The number of lambs successfully reared in a flock compared with the number of ewes that have been mated – effectively a measure of the success of lambing and the number of multiple births. May vary from around 100% in a hardy mountain flock (where a ewe may not be able to rear more than one lamb safely), to 150% or more in a well-fed lowland flock (whose ewes can more easily support twins or even triplets).

Live weight (WT): The weight of a live sheep in Kilograms.

M-N-O-P

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.

Q

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.

R

Ram (or male progeny): An entire male sheep that does not have progeny data analysed in a particular Sheep Genetics analysis.

S

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

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

T

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’.

U-V-W

Weaner: A young animal that has been weaned from its mother, until it is about a year old.

Wether: A castrated male sheep.

X-Y-Z