Breeding to increase the value of both dairy replacements and dairy-beef crossed
Why is this research important?
Breeding contributes cumulative and permanent gains, and can also concurrently improve antagonistically correlated traits, such as milk yield and fertility or milk yield and beef merit. Therefore, breeding is an obvious low cost and sustainable solution to improving the productivity of both dairy replacements and dairy-beef crossed calves.
What the research tells us
Currently, there are two breeding indexes and two management indexes available for use within the dairy herd, some of which have only recently been developed and deployed.
Breeding for dairy replacements
The Economic Breeding Index (EBI) is a well-established index for identifying genetically elite animals, including dairy herd replacements, to use as the parents of the next generation. The Cow Own Worth (COW) index is used to identify dairy females that are likely to contribute the most to the profitability of the herd over the remainder of their lifetime by combining information from multiple sources including milk recording, inseminations, pregnancy diagnosis, calving date and genotyping. The COW index updates as additional herd information becomes available and re-ranks dairy females based on their expected profit potential.
Breeding for dairy-beef crossed calves
The Dairy-Beef Index (DBI) is used to select beef bulls to use on dairy females. This index should be used in tandem with the recently launched dairy-beef sire advice, which recommends the mating of beef bulls to dairy females. After the resulting dairy-beef crossbred calf is genotyped, it will receive a commercial beef value (CBV), which was launched nationwide in 2024. The CBV is strongly correlated with the beef sub-index of the DBI for the bull that was used to generate the calf. To maximise the chances of achieving dairy-beef crossed calves with a four or five star CBV, most dairy herds should use beef bulls with a beef sub-index of at least €80, increasing to €86 in crossbred herds.
Outputs
Integrated selection tools, where the data populating these tools originates from a single source (the ICBF database), will help to facilitate breeding of dairy replacements and dairy-beef crossed calves with greater value. For example, in dairy-beef breeding, where the beef bull is selected using the DBI and then mated with the most appropriate dairy females in the herd that are identified with the aid of the dairy-beef sire advice tool, dairy-beef calves with greater CBV can be generated. Calves with greater CBV have better saleability and economic value. Integration is equally important when breeding dairy replacements, hence the EBI and COW indexes are strongly correlated with one another. Breeding replacement heifers from animals with the greatest EBI and culling low COW index dairy females, it is possible to shift the performance of the dairy herd in a favourable direction.
More information
Contacts
Maeve Williams (maeve.williams@teagasc.ie)
Donagh Berry (donagh.berry@teagasc.ie)