Holstein Canada

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

Sub-Group for Holstein Breed Average LPI Relability (%)
Traditional Genomics Gain DGV Weight
50K Young Bulls and Heifers (Born 2010-2012) 38 70 32 65%
LD (3K or 6K) Heifers (Born 2011-2013 34 67 33 66%
LD Young Cows in 1stor 2nd Lactation 50 69 19 58%
LD Foreign Cows with MACE in Canada 42 69 27 62%
1st Crop Proven Sires in Canada 85 90 5 51%
Foreign Sires with MACE in Canada 69 83 14 55%

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.

Trait Interpretation
Lifetime Profit
Index (LPI)
Expected relative lifetime profit of future progeny based on their genetic potential for production, durability and health & fertility.

Units and Scale- Holsteins:
Units: Points relative to breed average: ( 1800)
Scale: 0 to 3500 pts
Milk, Fat, and
Protein Yields
Expressed as Estimated Breeding Values (EBVs). Expected yield of milk, fat and protein during a 305-day lactation in a herd of average management

Units and Scale- Holsteins:
Units: Kilograms
Scale: Milk: ± 2550 kg
Fat: ± 95 kg
Protein: ± 80 kg

More Information:
Calculated under the Canadian Test Day Model. Each cow 24-hr yields on each monthly test are used.
Fat and Protein
Percentage
Deviations
Expected deviations from breed average for the % of fat and protein during a 305-day lactation in a herd of average management.

Units and Scale- Holsteins:
Units: %
Scale: Holstein: Fat: ±0.80
Protein: ±0.50
Conformation
Traits
Expected relative superiority of first lactation daughters for each type trait.

Units and Scale- Holsteins:
Average: 0
Range: -15 to +15

More Information:
Official classifications are used. All classifications and reclassifications within 1st lactation are included to calculate those indexes.
Somatic
Cell Score
Expected SCS of daughters during the first 3 lactations. Lower SCC reflect more resistance to mastitis.

Units and Scale- Holsteins:
Average: 3.0
Range: 2.50 (desirable)
to 3.5 (undesirable)

More Information:
SCS is the only trait in Canada for which the lowest value is considered desirable.
Lactation
Persistency
Expressed as a % of daughters’ expected daily milk yield at 280 days in milk compared to day 60.

Units and Scale- Holsteins:
Average: 100
Range: 85-115

More Information:
Bulls with an above average proof have daughters with a flatter lactation curve compared to bulls with daughters that have lower average in daily milk yields after peak lactation.
Herd Life Number of additional lactations that daughters are expected to last due to reduced involuntary culling compared to the average bull, independent of daughter production levels.

More Information:
Include a combination of true survival information (known later in life) and a prediction of expected longevity (indirect herd life).
Milking Speed % of first lactation daughters evaluated as "Average” or "Fast”.

Milking
Temperament
Expected % of first lactation daughters evaluated as "average”, "Calm” or "Very Calm”.

More Information:
Each cow is evaluated during first 6 months of lactation by herd owner as being "Very Slow”, "Slow”, "Average”, "Fast” or "Very Fast”.
Calving Ability Helps to identify sires that increase the likelihood that their progeny are born easily and alive.

More Information:
Includes : Calving Ease at 1st and later calvings, Calf survival at 1st and later calvings – for direct progeny of the sires.
Daughter
Calving Ability
Aims to reduce calving problems and increase the rate of calf survival.

More Information:
Includes : Calving Ease at 1st and later calvings, Calf survival at 1st and later calvings – when daughters of these bulls calve.
Daughter
Fertility
Measurement of the expected fertility of a bull’s daughters evaluated across all lactations.

More Information:
Include 4 traits: Age at 1st insemination of virgin heifers, the 56-day non-return rate for virgin heifers, interval between calving and 1st insemination for cows and the 56-day non-return rate for cows.
Body
Condition
Score
Allows for selection to raise the average BCS at first calving and when they are in peak production.

Units and Scale- Holsteins:
Average: 100
Range: 85-115

More Information:
This selection goal is expected to improve fertility, reduce the incidence of disease, and lead to a longer productive life.