Production traits

Time to read: ca 2 min

Production traits for which breeding values are calculated are milk, meat, milking speed and leakage.

Production index (27% of TMI)

The emphasis on the traits in this index is made so that a slight positive development is expected for dry matter content in milk.

The production index includes several yield traits.

Traits Relative weight (%)
Kg milk -16.0
Kg fat 47.0
Kg protein 37.0
Protein (%) Not included
Fat (%) Not included


Information about milk production is obtained from the Norwegian Dairy Herd Recording system. The amount of milk is registered once a month, and every other month the content of protein, fat and somatic cell count in the milk is registered. Both the amount of milk and the content of milk are important for the economy of production.

The breeding value calculations include data from 1st to 3rd lactation back to 1979.

Milking speed (2% of TMI)

Milking speed has an important economic impact on herd profitability
and its importance has increased in herds with automatic milking
systems, which have become widespread in Norway.

Milking speed is scored by farmers on first lactation heifers. They use
a scale of 1 to 3, where 1-Fast, 2-average and 3-slow.

Leakage (0.5% of TMI)

Leakage is registered by farmers as "none", "hint" or "obvious".

Beef index (males) (9.3% of TMI)

The slaughter traits are registered at the slaughterhouses and transferred on an individual basis to the Norwegian Dairy Herd Recording System.

Traits included in the beef index are:

  • Slaughter weight
  • Carcass muscling
  • Fat grading

Only information from bulls are used. The bulls must be between 40 and 121 weeks old at slaughter and the slaughter weight must be between 50 and 500 kg.

These requirements are set to avoid the use of incorrect registrations in the calculations. Data are collected from and including bulls slaughtered back to 1988. It is taken into account that the classification system for slaughter class and fat group in 1996 was changed to the EUROP-system.


Norwegian Dairy Herd Recording System

The Norwegian Dairy Herd Recording System is run by the national dairy co-operative owned by Norwegian dairy farmers, TINE. It is certified by ICARs Certificate of Quality (International Committee for Animal Recording).

Data is collected from almost all dairy farmers in Norway, and from a whole range of sources.

Read more about the Norwegian Dairy Herd Recording System here