Across-flock analysis: Comparison of sheep across different flocks.
AGBU: Animal Genetics and Breeding Unit. AGBU run the Sheep Genetics analysis and routine evaluations and are responsible for the research and development of the Sheep Genetics evaluations.
Age stage: Age stages refer to when a trait is recorded and reported. Most ASBVs are reported with an age stage at the beginning that refers to the age that trait is targeting (see table below).
|
Age name |
Abbreviations (Upper case) |
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 |
AI: Artificial insemination.
ASBV: Australian Sheep Breeding Values (ASBVs) are the best prediction of an animal’s merit for a particular trait. They are an indication of how an animal’s progeny will perform and are comparable across flocks.
BLUP: Best linear unbiased prediction. The statistical method used to estimate breeding values such as ASBVs.
Breed code: A two digit code, generally a number but can be letters that identifies the breed of sheep. See PDF list of codes in the related information to the right.
Breeder: A person who participates in the Sheep Genetics genetic evaluation. In relation to data being submitted to Sheep Genetics, a ‘breeder’ is the person, organisation or business that is the registered owner of the data.
Breeding objective: Describes future production goals. When identifying a breeding objective consider current flocks’ performance, target market, profit drivers and the environment.
C site: 45mm 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.
Cross-breed analysis: Comparison of sheep across different breeds within a breed group. For example, multiple breeds are analysed in the Terminal and Maternal LAMBPLAN analyses.
Dam: A female sheep with progeny.
Data manager: A person, organisation or business who provides a service required by a breeder to prepare and submit the breeder’s data. See the Service providers page for a list of data managers.
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: A female sheep.
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 performance of a sheep trait within a flock. FBVs are not comparable between flocks.
Genetic advisor: A person, organisation or business who provides a service required by a breeder to advise on genetic aspects of a breeding program. See the Service providers page for a list of genetic advisors.
Genetic correlation: The genetic relationships that exist between traits. It describes the general direction a trait moves in when another trait is increased or decreased.
Genetic linkage: When two or more flocks share common genes.
Genetic parameters: The heritabilities, genetic and phenotypic correlations, variance and adjustment factors used in the 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.
Management group: A management group is used to group sheep accurately for the Sheep Genetics analysis. Sheep run under the same conditions up to a given measurement can be included in the same management group.
Heritability: The average proportion of the differences between sheep (after adjusting for known non-genetic influences) that can be passed on to their progeny.
ID: Sheep identification system 16-digit identification number.
MateSel: Computer software used to optimise genetic gain and inbreeding. MateSel is available to Sheep Genetics members after a training session.
Merino Superior Sires (MSS): Publications and activities from Australian Merino Sire Evaluation Association (AMSEA).
OVIS: The name of the best linear unbiased prediction (BLUP) software used to calculate ASBVs.
Phenotype: The actual performance for a trait 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 test.
Ram (or male progeny): An entire male.
Scored traits: Those characteristics of a sheep that are evaluated subjectively – by hand and/or eye – relative to a set of standards. For more information on scored traits, please refer to the Visual Scores Guide.
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.
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: Indexes take a range of important production traits and combine them into one number. They are a useful way to rank animals quickly and easily.
Selection response: The effect of selection on the merit of progeny, 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.
Sire: An entire male sheep that has progeny.
Tier: A section of the ewes within a flock 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.
