EBV procedures

Methods used for breeding value estimation

Since May 2005, breeding values (EBV) for milk, fat, protein and somatic cell score have been jointly estimated using a so-called Multiple Trait Random Regression Test Day Model. Milk samples from all lactations are included in the evaluation. The model takes into account the cows’ individual lactation pattern, thus also providing an EBV for persistency for both cows and sires. Since July 2007 breeding values for somatic cell scores have been published for cows as well (previously only for sires).

Breeding values for conformation traits (linear description and classification) as well as for milking speed (based on scores given by farmers as part of the linear description) are estimated using a BLUP-animal model. Conformation traits are evaluated in groups (frame, rump, feet & legs, udder, teats including milking speed and final scores) (multiple trait model). The evaluation includes data from all lactations.

For estimation of breeding values for longevity a so-called survival analysis is performed, which allows for the inclusion of data on still living sires’ daughters. As far as the breeding values for female fertility are concerned, five individual EBVs, i.e. sons’ non return rate, sons’ interval from calving to first service, waiting period, cows’ non return rate and cows’ interval from calving to first service are combined into a fertility index (EBV fertility). The sons’ traits are weighted 1/12 each, cows’ non return rate and interval from calving to first service 1/4 each and the waiting period 1/3. Due to the low heritability, these breeding values are being published for bulls only.

The breeding values for calving ease (calf survival and calving ease) are estimated using a multiple trait sire model. Since 2006, besides the direct calving ease (calf’s influence) also breeding values for the cow’s influence (maternal calving ease) have been estimated.

Interpretation of breeding values for milk, fat and protein

Since May 2005 Braunvieh Schweiz has been using the following genetic base definition within the framework of breeding value estimation: the average breeding value of all cows aged 6 to 8 years equals to zero. This so-called rolling base is reviewed every year in April and is valid for one year. The current genetic base (BV16) was obtained by considering Brown cows born between 2008 and 2010. As the rolling base is always up-to-date, it is now easier to interpret EBVs than in the past, since no reference values have to be taken into account any longer. Within a population, breeding values therefore allow to compare the genetic potential of an animal with adult cows directly. To this purpose, the table “Interpretation of breeding values” can provide useful information. The specified EBV ranges are to be considered as rough indications that, thanks to the rolling base, can remain unchanged over several years.

Functional traits

With the introduction of the rolling genetic base in May 2005, the expression of breeding values for functional traits – somatic cell score, persistency, longevity, female fertility, calving ease and milk flow – was adjusted too. As a standard, the breeding values of these traits are published on a 100 base and with a genetic standard deviation equal to 12. Also traits for which deep phenotypic values are desirable (somatic cell score, waiting period) are expressed in a way that always allows to aim for high breeding values. This simplifies interpretation significantly: two thirds of all EBVs for these traits are between 90 and 110 index points. Breeding values over 110 are rated as good, those over 120 as very good. Breeding values over 130 or below 70 are rare.

Interpretation of breeding values for conformation traits

Since 1997 all first lactation cows on farms involved in the national progeny test program have been linearly described and classified. Estimated breeding values for conformation traits are published as indices, where the average EBV of cows aged six to eight years equals to hundred and twelve units of the index corresponds to one genetic standard deviation for each trait. To interpret the bar charts on BrunaNet, please note that not for all conformation traits high positive values are most desirable.

Interpretation of OB breeding values

The breeding values of Original Braunvieh cattle are expressed on a separate genetic base (OB16). In order for OB breeding values to be compared with breeding values on a BV base, it is necessary to apply the base constants specified in the table “Interpretation of breeding values” (OB breeding values = BV breeding values + OB constant).

Interpretation of breeding values

Evaluation
(% of all EBVs)
satisfactory
(c. 68 %)
good
(c. 14 %)
very good
(c. 2 %)
OB
constant
Milk kg  -400 to +400  +401 to +800 > +800 +514
Fat kg -17 to +17 +18 to +35 > +35 +26
Fat % -0.15 to +0.15 +0.16 to +0.30 > 0.30 +0.08
Protein kg -12 to +12 +13 to +25 > 25 +17
Protein % -0.10 to +0.10 +0.11 to +0.20 > 0.20 -0.01
Milk value 90 to 110 111 to 120 > 120 +13
Persistency
90 to 110 111 to 120 > 120 -3
Somatic cell score 90 to 110 111 to 120 > 120 -8
Conformation -1 to +1 +1 to +2 > +2  
Longevity 90 to 110 111 to 120 > 120 -10
Milking speed 90 to 110 111 to 120 > 120 -7
Fertility index
90 to 110 111 to 120 > 120 -12
Calving ease, direct 90 to 110 111 to 120 > 120 +23
Calving ease, maternal 90 to 110 111 to 120 > 120 +6
Calf survival, direct 90 to 110 111 to 120 > 120 -7
Calf survival, maternal 90 to 110 111 to 120 > 120 +1
TMI 90 to 110 111 to 120 > 120
Fitness value 90 to 110 111 to 120 > 120 -5
TMI grazing 90 to 110 111 to 120 > 120  

Contact:

Forquestions please contact
Qualitas AG
Chamerstrasse 56
6300 Zug
Tel. 041 / 768 92 92
info@qualitasag.ch

Braunvieh