Accurate and diverse genetic indexes
Dairy cattle breeds indexes

French genetic evaluation of dairy cattle breeds offer 30 main indexes on specific criteria and varied: production index (milk yield, fat and protein contents,...), functional index (longevity, fertility, ...) index morphology (udder, feet and legs, ...) and index of synthesis.

This enables a breeder to make the best-informed choice based on the combination of traits that best fits their performance targets and priorities.

The Institut de l’Elevage is the official authorized publisher of the French genetic merit indexes for cattle, sheep and goat breeds.

 The yield indexes

• MP: quantity of proteins (in kg), 5% less than the quantity of nitrogenous solids widely used in international publications;
• MG: quantity of fats (in kg);
• LAIT: quantity of milk produced (in kg);
• TP: pure protein content (in g/kg), 5% less than the crude protein yield widely used in international publications;
• TB: butterfat or fat content (en g/kg) ;

These core indexes are rounded off with an economic composite index:

• INEL (INdex Economique Laitier – or economic dairy yield index): composite of the core indexes that have direct economic impact for the livestock farmers (quantity of proteins and fats; protein and butterfat content). It is defined in exactly the same way for all breeds, via the formula: INEL = 0.98 (MP + 0.2 MG + TP + 0.5 TB).

 Functional-trait indexes (breedability traits)

The functional indexes, which if improved can decrease production costs and increase labour productivity, cover four trait classes:

Udder health:

• MACL (clinical mastitis) translates mastitis resistance and is calculated based on clinical mastitis case records.
• CEL (cell count) indirectly translates mastitis resistance and is calculated based on analysis of the number of somatic cells counted in the milk (results that, in France, have been available since 1990 and exhaustively reported since 1994).

Fertility:

• FER (cow fertility) translates the post-partum fertility of bull daughters (this index does not describe the fertilization rates of the bull semen), and FERG (heifer fertility);
• IVIA1 (calving interval to first insemination): The set of indexes calculated for these fertility traits is completed by the interval between calving and first artificial insemination, which translates how quickly the cow is expected to return to post-partum heat.

Functional longevity

• LGF translates the likelihood that a bull’s daughters will have a long milk-producing career independently of milk production output, the aim being to cut down the number of unwanted reforms (animals reformed for any reason other than due to their productivity level).

Birthings and calvings, with:

• NAI (birthing ease) and VEL (calving ease), which translate the calf birthing conditions (direct effect) and the calving ease of a bull’s daughters (direct and maternal effect), in order to avoid matings on heifers at risk of difficult births;
• VIN (birthing vigour) and VIV (calving vigour) which evaluate bull calf stillbirth rates (direct effect) and bull daughter stillbirth rates at calving (direct and maternal effect) within the first 48 hrs post-birth.

 Morphology indexes

Morphological trait evaluations are based on examining each individual animal with a breed-specific cow scorecard that can feature up to 30 baseline indicators which are either physically gauged or scored along a linear scale of 1 to 9.

All-round indexes are calculated for the general morphological features. They are all-round composites of baseline indicators produced according to the selection objectives targeted for each breed.

The main composite indexes are:

• MO (Morphology) and MA (Udder)
• CO (Body) and ME or AP (Legs or Body-set)

Then, depending on breed, follow TY (Type), FT or FO (Format), MU or VB (Muscling or Carcass value), BA (Pelvis), and so on.

 The Upra all-round index (ISU)

In addition to the productivity traits (milk, MG, MP, TB, TP) used to optimize income, dairy profitability also hinges on keeping costs down (veterinary bills, breeding and reproduction costs, cows reformed for any reasons other than productivity,…).

Developed for breeders looking for an all-round profitability index solution, the ISU is a comprehensive and specially-adapted index that combines production-trait indexes (INEL) and functional-trait indexes (somatic cell count, fertility and longevity) with the all-round morphology traits composite index. The weightings applied to these different criteria-sets are adjusted specifically to each breed according to the selection objectives defined.

An illustrative example is the ISU for the Holstein breed, which is weighted 50% on production traits (INEL), 12.5% on somatic cell count, 12.5% on fertility and 12.5% on functional longevity, and the final 12.5% on morphology.