Genetic Information & Services

Genetic Evaluations in Canada

The calculation and publication of all dairy cattle genetic evaluations in Canada is the responsibility of Canadian Dairy Network (CDN). This non-profit national organization is governed by an 8-member board of directors, the majority being dairy producers. Member organizations include all breed associations, milk recording agencies and artificial insemination centres across Canada as well as Dairy Farmers of Canada.

Genetic Evaluations are provided by CDN for seven dairy breeds (Holstein, Ayrshire, Jersey, Brown Swiss, Canadienne, Guernsey, and Milking Shorthorn). All animals receive a genetic evaluation for a complete series of traits in production, conformation, and Functionality.

All genetic evaluation calculations in Canada use a methodology called the "animal Model”, which refers to the goal of estimating each animal’s genetic merit.  The genetic evaluation of each animal is based on contributions from four possible sources: parents, performance, progeny and DNA (genotype).

When an animal has no performance, no progeny or no DNA, we therefore rely on the average of his parent to evaluate its genetic potential and calculate its genetic merit or Parent Average.  An animal’s Parent Average continually evolves as the sire, dam and/or older ancestors in the pedigree add performance data on themselves as well as on existing and new progeny.

The major contributing source of information for estimating an animal’s genetic merit is the performance of their progeny.  It is then an "ultimate test” to know how good an animal is in transmitting its genetic potential. 

For cows, their performance (classification and production records) also counts but at a lower extent. For animals that are genomically tested, the DNA contribution is ADDED to the information available; it does not replace any source of information. When information is added, reliability of the genetic evaluation usually increases.

Reliability of Genetic Evaluations

The degree of certainty in calculating an Estimated Breeding Value (EBV) is measured by "reliability”. It is defined as squared correlation between the true and estimated breeding values of a trait. The level of reliability is a function of heritability as well as the amount of the information available on the trait.

Information from each animal’s DNA profile as an additional source of data has significantly changed the landscape of genetic improvement programs and strategies contributing to genetic evaluations. Effective August 2009, official genetic evaluations in Canada for the Holstein breed include genomic information in combination with traditional pedigree and progeny performance data. The largest gains in accuracy of genetic evaluations are realized for young bulls and heifers, which traditionally would only have a Parent Average. The table below shows the average gain in LPI Reliability (April 2013) for various sub-groups of animals in the Canadian Holstein population.

Genetic Evaluations

Lifetime Profit Index (LPI)

Canada has been selecting for a balanced breeding and the national index of selection reflects the relative profitability that can be expected during the lifetime of future daughters. Each breed has a different emphasis for each trait but it always include three main sections known as Production, Durability and Health & Fertility.

Interpretation of Genetic Evaluations

The main objective of genetic evaluations is to select the superior males and females of each breed to be parents of the next generation. They are identified and compared to a base reference group, which is considered the breed average. The next table will help you to interpret the different traits evaluated, their scale and the units they are expressed.