The Australian Dairy Herd Improvement Scheme (ADHIS) has officially launched three new breeding indices, new breeding values for feed saved and residual survival, updated type expression and made other refinements to the Australian Breeding Values (ABV).
New breeding indices
The April ABV release heralds some major changes, including the introduction of Balanced Performance Index (BPI) that focuses on maximising net profit through production, fertility and type; replaces the current Australian Profit Ranking (APR).
The other two new indices include Type Weighted Index (TWI) that focuses on improving overall type, mammary system, udder depth and fore udder attachment; and Health Weighted Index (HWI) that has the strongest focus on fertility, cell count, feed saved and survival.
Feed Saved ABV
A Feed Saved ABV has also made its debut. It will be published in the Good Bulls Guide and is also incorporated in all three of the new breeding, so farmers who make bull selections using one of the indices will be including feed saved in their breeding decisions.
Daniel Abernethy from ADHIS said the Feed Saved ABV allowed farmers to breed dairy cows that produced the same amount of milk from less feed, due to lower maintenance requirements.
The Feed Saved ABV allows farmers to identify bulls that can save at least 100kg of dry feed matter per cow, per year.
Mr Abernethy said the Feed Saved ABV was the first practical use of genomic tests to measure a trait that can’t be routinely measured on farm.
“Visually, you can’t spot a highly feed efficient cow, but with the help of genomics and research collaborations, farmers can now breed for it,” Mr Abernethy said.
The development of this new ABV was a collaborative effort involving researchers from across the globe. The Australian team included the Dairy Futures CRC, ADHIS, AgriBio and the Victorian Department of Economic Development, Jobs, Transport and Resources with funding from Dairy Australia and the Gardiner Foundation.
Residual Survival ABV
A Residual Survival ABV has also been added and is also included in all three of the new breeding indices.
This new ABV includes all the reasons why cows last in the herd that aren’t related to production, fertility, cell count or other traits that have their own economic values in the indices. Residual Survival has replaced Survival in the indices to ensure a component of survival isn’t unfairly double counted. To breed for longer lasting cows, continue to use the Survival (Longevity) ABV as it is the most complete trait for all the characteristics that improve longevity in cows.
Also in the April ABV release, the expression of Type ABVs and the definition of ‘average’ has changed to be more consistent with the way breeding values are expressed in other countries.
Type ABVs are now ‘standardised’ to make it easier to see if an animal is average, a bit above average or extreme for a trait. One standard deviation will be set to 5. For example, a bull with an ABV of 105 is 1 standard deviation above average. A higher ABV is not necessarily better. For example an ABV of 112 for stature indicates an extremely large stature but not everyone wants bigger cows. In this case, an ABV around 100 may be more preferable.
The standardised expression of type ABVs does not affect the ranking of sires.