Breeding Terms

Term Meaning Description
AHDB Agriculture and Horticulture Development Board Agriculture and Horticulture development board. Responsible for calculating UK genetic evaluations.
Allele A variant of a specific gene A variant of a particular gene, which can result in a change in function of the gene.
Bull Selector Online bull mating tool Online tool to choose potential mating sires from the list of currently available AI bulls.
BV  Breeding Value A mathematical measure of the value of the animal’s genetics. Also known as genetic merit and equivalent to twice the PTA value.
Chromosome A piece of DNA Structure containing DNA found in all cells. Cattle have 30 pairs of Chromosomes.
ClassAct  Data interrogation tool Online tool for review and analysis of classification scores.
Classification Type Classification Assessment of cattle conformation, also known as Type Classification.
Classifiers NBDC employees who "classify" animals according to conformation criteria A team of professional people specialising in the assessment of both dairy and beef cattle conformation traits according to a series of carefully defined, internationally agreed criteria. 
Conformation The physical external appearance of an animal The shape or structure of an animal.
Daughter Proven Daughter Proven Bull A bull with daughter information used in calculating his genetic merit.  Originally applied to bulls who had only daughter information used in their evaluation. This later grew to include ancestors and siblings and can now include a bull who has both his own direct genomic test results included, supplemented by daughter results.
DCE Direct Calving Ease Direct Calving Ease. The effect of the sire or dam on the characteristics of the calf, when considering ease of calving.
DNA Deoxyribo Nucleic Acid - a protein based complex molecule found in the nucleus of living cells carrying the organism's genetic instructions A molecule that carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms. Constructed from four proteins,  cytosine (C), guanine (G), adenine (A), or thymine (T), plus a monosaccharide sugar called deoxyribose and a phosphate group.
Reference DNA Reference Reference for the genotype used to pedigree register the bull. 
Dominant Dominant Gene Causes the trait to be expressed when either one or two copies of the allele are present. An example is polled in cattle. 
Eartag An ear tag is used for identification National identification number.
EBV Estimated Breeding Value Estimated Breeding Value (see Breeding Value).
Environment The surroundings and management of a farmed animal, as opposed to its genetic code For farmed animals this describes the effect of for example, feeding, disease and housing.
ET Embryo Transfer A process by which viable embryos can be taken from one animal, the "donor" (usually of high or exceptional genetic merit) and implanted in the womb of another animal, the "recipient" to be developed as a pregnancy and progressed through to birth. The ET process may or may not involve fertilisation of the embryo outside the animal (known as "in vitro" fertilisation). ET is most often carried out under veterinary supervision by non-surgical procedures which do not harm either the donor or recipient in any way. But enables the genetics of a high merit animal (usually a female) to be transferred to a greater number of offspring than would be possible by more traditional reproduction, by not requiring the donor to carry each embryo to a full term pregnancy. Removal of the embryo(s) early in the reproductive cycle enable the donor animal to produce further ova and offspring more frequently. Donor females are often also given hormonal treatments to create multiple ova (eggs) to be generated simultaneously, so further increasing the number of recipient pregnancies that can be achieved from the embryos produced by the donor. The suffix "ET" applied to an animal's name is used to denote the animal was born by embryo transfer.
ETN Enucleated Transfer An animal which is the result of an enucleated transfer (Cloned Animal).
Fertility Haplotypes Groups of similar genes affecting Fertility Groups of genes inherited together which appear to have a recessive inheritance. I.E. Two copies and the embryo dies is not viable.
FI Fertility Index Selection index for fertility traits.
Flushing The process by which ova/eggs or fertilised embryos are removed from a donor female See "ET"
Gene A section of genetic material or DNA of a living creature or organism which affects a particular aspect or characteristic of the organism's phenotypic traits, its morphology or metabolism A chunk of DNA on a Chromosome which codes (i.e. Is the 'instructions') for an Amino Acid (the building blocks of Proteins). Often used when referring to parts of a gene rather than the gene itself, genes often have several variants (Alleles),  each with a slightly different DNA sequence.
Genetic Literally "of the genes" Generic term for the effect/influence of DNA.
Genetic Base Genetic Base Year The group of animals against which PTA values are compared. The genetic base will usually represent breed average and have a PTA value of zero.
Genetic Evaluation The process of mathematically predicting an animal's genetic merit The statistical process which uses pedigree, milk recording, classification and genomic information to calculate genetic merit values for animals.
Genetic Merit A statistical measure of the breeding worth of an animal A mathematical measure of an animal's genetics. Otherwise known as breeding value and equivalent to twice the PTA value.
Genetic Trait Genetic traits other than Type and Production A code indicating the genotype of an animal for a particular genetic condition; including certain genetic defects as well as coat colour and polled status.
Genomic Of the whole genome; considering the effect or value of all Chromosomal DNA An animal with genotype information included in its genetic evaluation.
Genotype The genetic code of the animal for a particular gene or genes  Identity of nucleotide base code (A, T, G or C) in DNA. E.g. 50K Genomic test will identify the code at 50,000 DNA sites (SNP's) in the Genome.
Genotype File   The genetic code in digital format using either SNP or Microsatellite DNA markers.
GMACE Genomic MACE A genetic evaluation calculated by Interbull, sometimes referred to as genomic MACE. See also MACE.
Haplotype DNA Haplotype A section of DNA containing a number of alleles which are usually inherited together.
HBN Herd Book Number 12 alpha-numeric characters (excluding the UK Breed Code) comprising the reference identifier of an animal in a Breed Society Herd Book. 
HCD  Haplotype Cholesterol Deficiency  Haplotype Cholesterol Deficiency, a genetic defect causing a reduction of cholesterol production in young calves.
HD High Density (genotype) Genomic test which typically genotypes over 50k SNP's
Health Trait   A trait affecting animal health, such as Mastitis.
Heritability How much of a particular trait can be expected to be passed from one generation to the next, on average A mathematical estimate of the proportion of a measured trait which is due to the animal's genetic makeup.
Heterozygous   An animal carrying one copy of an allele.
Homozygous   An animal carrying two copies of an allele.
ICAR  International Committee for Animal Recording The international voluntary body that sets standards and guidelines for a range of activities including milk recording, animal identification, data transfers, conformation ("Type") assessment and genetic evaluation for a range of farmed animal species. With the objective that results gathered and used in those countries should remain comparable internationally. Over 32 countries involved worldwide. see www.icar.org/
IGM International Genomic MACE (see GMACE) UK labelling of Interbull GMACE evaluation results for Type (used from December 2014).
Imputation Genotype Imputation Process by which low density genotypes have genetic information added to genotypes from parental genotypes, prior to genomic evaluation.
Inbreeding Mating related animals Likelihood of an animal inheriting two copies of an allele from the same ancestor (which appears more than once in its pedigree), expressed as a % probability.
Inbreeding Coefficient   A mathematical measure of inbreeding. The probability of an animal inheriting two copies the same allele from the same ancestor in its pedigree.
Insemination The process of transferring sperm/semen from a male into the reproductive tract of a female Can be "Natural" as during the mating of a male and female. Or "Artificial", whereby semen produced by a male is diluted and packed into small plastic straws, enabling easy transportation and storage* before being inserted into the female by a human operator using  specialised equipment. Straws can be frozen in liquid nitrogen which enables their contents to remain viable over extremely long periods and easily transported worldwide. The techniques for AI were first developed in the UK during the 1950's by veterinary scientists working for the Milk Marketing Board in collaboration with other private organisations involved in the cattle breeding industry.
ITB Interbull. The International genetic evaluations centre for bovines. International body overseeing and calculating genomic evaluations using data from up to 30+ countries worldwide (actual number of countries whose data is used varies from trait to trait. Interbull is a wholly owned sub-organisation of ICAR.
L&F Legs and Feet A composite type trait derived from the key individual linear assessment conformation traits describing the morphology of the animal's feet and legs, combined into a single score.
LD Genotype Low Density Genotype Basic genomic test which typically genotypes (reads) a lower number of SNP than HD tests (typical 30k or less).
LIFT Linear Inspection for Type traits Scheme to progeny test UK bulls for type merit conducted by Holstein UK, Genus and Cogent.
Linear Linear Type Trait Linear Type Trait expressed on a 1-9 scale. Can also refer to the genetic version of a type trait.
LP Lactation Period The portion of an individual lactation from Calving up to and including the 305th day. See "Natural Lactation".
LS Lifespan Index Lifespan of the cow expressed in lactations.
MACE Multiple Across Country Evaluation, calculated by Interbull Comparison method that enables translation of a foreign genetic evaluation into a set of UK results.  Most commonly used in respect of Type evaluations.
MAM Mammary composite index A composite type trait derived from the key individual linear assessment conformation traits describing the morphology of the animal's udder, combined into a single score.
MCE Maternal Calving Ease The effect of the sire or dam on the characteristics of the mother, when considering ease of calving.
Monogenic   A trait that is influenced by variations in a single gene. Coat colour is an example.
Natural Natural Lactation The full length of a lactation up until the animal is dried off. Usually longer than 305 days.
Normal distribution   The shape of a graph showing the distribution of most complex genetic traits, e.g. milk production or stature. Also known as a bell curve.
Pedigree An animal's ancestry The documented ancestry of an animal. Usually applied to that ancestry recorded in a Breed Society's Herd Book.
Pedigree Index Index calculated for animals which do not receive a AHDB genetic evaluation, using an average of ancestor evaluations A substitute for a genetic evaluation, usually applied to newborn and younger animals.  Calculated from the relatives of the animal only. Used until the animal can gain a more reliable evaluation its own right. (No daughter or genomic information is included). Pedigree Index values are normally only calculated for the main overall composite traits. Individual Type Traits being omitted.
Persistency Persistency of lactation Milk yield at day 280 of lactation as a percentage of yield at day 60.
Phenotype A physical characteristic, observable or measurable in the "real world". E.g. Milk yield or conformation; Genotype + Environment = Phenotype.
PI(1) Pedigree Index An estimate of a young animal's genetic potential before it has any production or genomic information of its own. The Pedigree Index is based on the average of the parents' genetic merit, but in the absence of parent information, indexes from further back in the pedigree are used. Pedigree Indexes can be calculated for almost any trait or other derived index ranging from the basic PTA to the more complex economic indexes or even type indexes. The effective use of a pedigree index enables breeding decisions to be made at an early age and can therefore reduce heifer rearing costs. A Pedigree Index is less reliable than either a genomic test result of the animal's own genetic code or a full evaluation of its own production or progeny information, such as the "proof" it would normally obtain later in life. The PI should therefore be used with the appropriate caution. The reliability of Pedigree Indexes generally ranges from about 20 to 40%.
PI(2) Production Index A measure of a cow's individual, single lactation production of milk solids  compared to the production of herdmates and contemporaries at a particular point in time.  Calculated at the end of each Lactation Period and assessed against the herd average weight of Fat & protein over the previous 12-months (called the "Herd Base"). An animal would therefore normally expect to get a different Production Index for each lactation during its lifetime.  Each Production Index takes the animal's own production, adjusted for age, month of calving and lactation number to bring its production closer to a heifer equivalent, then expressed as a percentage of the Herd base at that time. Hence the Production Index  can vary widely from lactation to lactation, as also can the Herd Base. A Production Index should not be confused with any genetic index as there is no genetic element in its calculation. 
PLI Profitable Lifetime Index, overall UK index provided by AHDB UK selection index combining key genetic traits and represented as a £ value. From August 2014 this is a total lifetime value. The £PLI value represents the additional profit a high £PLI animal is expected to return over its lifetime compared to an average bull of £0 animal.  In the case of a bull, this is additional profit from each of the bull's milking daughters.
Polled An animal genetically without horns Polled = no horns, single gene. Polled gene is dominant.
Proof The collected range of genetic evaluation results for an animal across all traits Refers to a bull's genetic merit being based on his daughter information, stemming from the era when the only method to measure a bull's genetic merit was to "prove" his genetic characteristics by the production and conformation of his daughters. This is a misnomer however as at best any genetic index it is only a 'good' statistical estimate, not actual definite 'proof' of genetic merit.
Proven   See daughter proven.
PTA Predicted Transmitting Ability, half of the breeding value A statistical estimate of the genetic merit an animal will, on average, pass on to its progeny (defined as half of the animals own EBV).
PTAT Predicted Transmitting Ability for Type An overall composite index of key type traits weighted according to importance in breeding a functional animal. In the UK we use the Type Merit figure as the overall PTAT.
Quantitative traits   Genetic traits influenced by many genes with an effect that can be measured. Also referred to as complex traits.
Recessive Recessive Allele The allele is only expressed when two copies of the gene are present.
REL Reliability The higher the reliability, the less likely the genetic evaluation will change over time, as more information is added.
SCC Somatic Cell Count The most commonly used measure of white blood cells in milk. 
SCI Spring Calving Index Selection index aimed at spring calving herds.
SD Standard Deviation. A statistical measure of the variability among a set of data Type trait PTA's are expressed as standard deviations (from the mean of the population). I.E. A bull with 2 points of type has a PTA 2 SD better than breed average and is in the top 2.5% of the population (3 points = top 0.15%)...see also STA.
Selection Index A genetic index such as PLI or Type Merit Overall breeding index for an animal which weights the genetic merit of key traits according to their economic value in commercial dairy production.
SNP Single Nucleotide Polymorhism, a single unit of DNA that can vary Genetic marker which is genotyped in current genomic tests, informs as to genotype of DNA in the physical vicinity on a Chromosome. Often referred to in conjunction with Haplotypes. As such a Haplotype will typically have one SNP within it. 
STA Standardised PTA Standardised PTA, published for genetic type traits. The type PTA transformed into a standard deviation units.
TM Type Merit PTA for Type. Derived from a weighted combination of several of the animals and/or offspring's conformation or "Type" traits. Does not include Production, Health or Fitness traits.
TPI Total Performance Index Main selection index for Holsteins in the USA. Broadly similar in usage if not calculation, to the UK's PLI.
Trait Physical Trait A characteristic of the animal. Usually refers to a quantitative trait.
WebMate Online cow mating tool A free to use Breeding Toolbox application that optimises the possible bulls available to recommend matings  for each of a herd's eligible cows. The only such application covering the "whole of market" in the UK. This has been succinctly described as "Computer dating for cows"!
Young Genomic Bull Young bulls that have genomic information (but no daughter information) included in their genetic evaluations A bull whose genetic evaluation results are based solely on his genomic sample results, with no daughter information included in the evaluation. Usually applied to younger males who do not yet have daughters whose results can be measured.