Block Calving Breeding Indexes - £SCI and £ACI

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To help you breed the right cow to fit your system AHDB Dairy recommend the following four step plan when selecting bulls for your breeding programme:

1)            First select bulls with a higher £SCI or £ACI value than your best cow

2)            Then select fitness traits to maintain your strengths and address herd weaknesses (Fertility, Lifespan etc)

3)            Match type to suit your herd

4)            Selected calving ease for maiden heifers

About the Spring Calving Index (£SCI)

The £SCI was introduced in August 2014. It provides UK farmers operating a spring block calving system, making extensive use of grass and targeting production of around 6,000 kgs/yr, with an across-breed evaluation to highlight bulls suitable for their system. The index has been calculated on its own base and for a specific farming system; so comparison of bulls on the £PLI or £ACI list is not possible.

The index has been developed to provide an initial screen tool to ensure bulls used on farm meet specific criteria. It is then recommended specific emphasis is placed on the management traits that require attention on individual farms*. The main updates introduced in 2018 are shown below.

Relative weighting of traits within £SCI

SCI chart

 

 

 

 















The £SCI:
- Promotes milk quality rather than volume
- Has a strong emphasis on fertility
- Selects for reduced maintenance costs
- Improves udder and leg health
- Places a strong emphasis on longevity
- Promotes easier calving
- Protects functional type - Feet & Legs and Udders

For more information at FAQ’s on the £SCI download the factsheet here.

 

About the Autumn Calving Index (£ACI)

The £ACI is a new genetic index introduced in August 2018. It provides UK farmers operating an autumn block calving system, with a higher requirement for winter feeding and targeting production of around 7,500 kgs/yr, with an across-breed evaluation to highlight bulls suitable for their system. The index has been calculated on its own base and for a specific farming system; so comparison of bulls on the £PLI or £SCI list is not possible.

As with the £SCI, the index has been developed to provide an initial screen tool to ensure bulls used on farm meet specific criteria. It is then recommended specific emphasis is placed on the management traits that require attention on individual farms*. The main features of the new index are shown below.

Relative weighting of traits within £ACI

 

ACI chart

 The £ACI:

- Promotes milk quality with more weight on volume than the £SCI
- Places strong emphasis on fertility
- Selects for reduced maintenance costs
- Improves udder and leg health
- Places a strong emphasis on longevity
- Promotes easier calving
- Protects functional type - Feet & Legs and Udders

For more information at FAQ’s on the £ACI download the factsheet here.

*Farmers can identify the strengths and weaknesses of their herd by viewing their Herd Genetic Report (HGR). To register for your farm HGR please contact the evaluation team at breeding.evaluations@ahdb.org.uk providing your trading name, farm postcode and NMR/CIS or UDF milk recording number