RZG for the first time with breeding values for health

A number of changes affect this year’s April breeding value evaluation.

New calculation of the German total index RZG

For the first time since 2008, the calculation of the RZG was changed. The weighting of the production index (RZM) was reduced from 45% to 36%, whereby the pure production sires lose their top positions in the German RZG list. In return, the breeding value „RZ health” has been newly integrated into the RZG, with an own weighting of 18%. Together with other fitness and management traits, the weighting for health increases in total from 40% to 49%. The weighting of the conformation skills remains constant at 15% in total, but with changed weightings for udder, feet & legs and body.

weighting former RZG new RZG former RZG new RZG

45 %

36 %


45 %

36 %

RZhealth 0 % 18 % health 40 % 49 %
RZN 20 % 18 %
RZR 10 % 7 %
RZcalves fitness 0 % 3 %
RZKm 3 % 1,5 %
RZKd 0 % 1,5 %

7 %

0 %

index – udder 7,5 % 6,75 % conformation 15 % 15 %
index – feet & leg 7,5 % 5,25 %
index – body 0 % 3 %

Index “RZ health” now with larger variation

The significant increase in variation of the breeding index “RZ health” and an moderate increase in variation of the total conformation index RZE leads also to an slightly increase in variation of the total index RZG. Since the already daughter proven bulls couldn’t be selected for health due to the previously missing breeding values, these bulls are at a disadvantage compared to the actual genomic bulls. For a top production bulls like the OHG sire SINUS (the German number 1 for RZG in December 2020), the effects mentioned (including the yearly base adjustment) add up to a loss of 10 RZG points (RZG 145 to RZG 155). In just four years at the latest, the daughter proven bulls should no longer present this disadvantage, so that the difference between the best genomic and best daughter proven bulls will becomes smaller again.

The larger variation of the breeding values is accompanied by higher reliability of the breeding values, whereby the positive breeding values increase further and the negative values decrease further. Therefore it is basically more difficult to find faultless daughter proven bulls. Due to the significant variation increase of the breeding index “RZ health”, the true weighting of the health traits, especially in the top of the genomic bulls, may be even higher than the mentioned weight of 18%.

The winners of these changes are good health bulls with great fitness and management traits and also tremendous values for udder, feet & legs and body – resulting in bulls which present the Osnabrueck breeding goal in an excellent way.

Base adjustment

In order to correct the breeding values for the high yearly breeding progress in Germany and especially in the Osnabrueck area, the following significant base adjustments were made this April:

RZG -6,1 RZM -3,0 RZE -3,4 RZhealth -4,3 RZN -1,8 RZS -1,3

GENIUS, MIRCO and GARY-RED are the biggest winners

It is extremely enjoyable that the current main OHG insemination sires are the winners of this April evaluation due to their outstanding health values (OHG was Germany’s pioneer for health tests with the so called “GKuh program” (https://www.gkuh.de/Texte/background_project1.html) that was started already in 2009) and due to their outstanding conformation values. Despite of the mentioned significant base adjustment of 6.1 RZG points, they were even able to increase their own RZG against the trend.

Sire gRZG gRZE gRZhealth
Samuel P 160 +2 126 +2 123 +8
Mirco 159 +3 136 +6 121 +8
Calvin 159 +0 123 +1 124 +8
Genius 155 +3 145 +6 127 +8
Roman 151 +1 146 +6 125 +8
Rosco 150 +0 123 +3 124 +9
Gigant 147 +0 150 +6 129 +10
Sound PP RDC 147 +0 130 +3 118 +5
Essex RDC 145 +0 133 +3 124 +6
Rolls 144 +1 130 +2 121 +7
Gary-Red 157 +3 136 +2 134 +9
Sky-Red PP 152 +0 131 +3 120 +5

Despite of the new RZG formula with less emphasis on production performance SAMUEL P with gRZM 149 ranks now as 2nd highest of all German polled Pp bulls for total index.

With NTM 34 in Scandinavia, PF 145 in Poland and ISU 197 in France, the outcross bull MIRCO ranks also very high internationally.

The complete CALVIN has been able to consolidate his top position further on despite of the base adjustment and his production power with gRZM 152 (!). CALVIN ranks also very high, for example in the Netherlands with NVI 323.

GENIUS is currently the most popular sire in the OHG area. With his strong breeding values ​​especially for many “problem traits” and his latest significant proof increase, his popularity will continue for sure.

GIGANT, with gRZE 150 (!) the number 1 for conformation in Germany, will remain a sought-after bull for every auction marketer and show enthusiast (udder 143, feet and legs 130).

For Red Holstein, GARY-RED is the German number 1 sire for overall health, especially with his high proof results for hoof health (120), Mortellaro resistance (116) and his significant reduction of mastitis (119) and reproduction disorders (116).

Due to the positive development of his breeding values, the homozygous polled and extremely complete components sire SKY-RED PP will continue to enjoy great popularity – both nationally and internationally.

For the total offer of Osnabrueck Holstein bulls, which you can sort for several selection traits, please click here.

If you are interested in special bulls and quantities we will send you our price offer immediately. For questions, please contact us – best by E-Mail.