The RZorganic is a new breeding value in Holsteins that is specifically designed to fit the needs of organic and extensive farms. It will be issued for the first time on the breeding value data sheets with the August 2023 breeding value estimate. It is available for all genomically tested (typed) female Holsteins and bulls with German breeding values. Since no health breeding values are exchanged via Interbull, the new breeding value cannot be estimated for bulls with pure Interbull breeding values.
Idea and composition
In organic dairy farming, there are two aspects that are at least as important as the performance component. On the one hand, the animals should be and should remain healthy and, on the other hand, the longevity of the animals is an essential component of the sustainable management of a farm. These two characteristics are therefore incorporated in the new breeding value with a high weight of 21% (RZhealth) and 38% (RZN). In total, 2/3 of the breeding value is focused on functionality. In addition to the aforementioned traits, this also includes body condition (BCS) with 5% and calving traits of the dam with 3%. The BCS is used to ensure that the cows have more body reserves and are therefore more resistant.
Due to the higher weighting of the performance component in RZ€ and RZG, many of the organic farms find it a challenge to feed Holstein cows exclusively with regional, organically certified feed. As a rule, Holsteins already have an excellent performance capacity, so that in the RZorganic, milk yield is weighted less strongly at 27%, even though it is also of great economic importance here. The breeding value includes protein and fat in a ratio of 2:1. Generally, the dairy purchase price reflects the fat and protein content of the milk.
A new feature in German breeding is probably the negative consideration of the milk quantity with 6%. This component is intended to reduce the energy-free milk quantity and the lactose content in the milk via the correlation of these traits to the milk quantity. This means that pure milk quantity sires are specifically penalized here. The overall breeding progress is thus significantly slowed down in milk quantity, but is still slightly positive due to the consideration of fat and protein quantity.
What can the RZorganic achieve?
The RZorganic definitely has its strengths in the area of health and useful life.
Source (https://richtigzuechten.de/common/home-gb.html)