Type traits (Australian Breeding Values – ABVs)
Australian Breeding Values are available for more than 20 type traits which are assessed by breed association classifiers. ABVs for type traits are expressed against the breed average which is set at 100. A bull’s type ABVs are based on his daughters’ classifications, including both registered and non-registered daughters.
Composite type traits
Dairy farmers are often more interested in a group of traits which combine to affect a cow’s functional performance in the herd.
An ABV based on a combination of traits is referred to as a ‘composite’ trait.
DataGene publishes ABVs for four composite type traits: mammary system, feet & legs, dairy strength and rump.
The Overall Type ABV is a combination of all traits, so is also technically a composite. At this stage, the only composites published for Jerseys are mammary system and overall type.
There are some variations in the composites provided to each breed as a result of differences in classification systems.
Overall type
The Overall Type ABV is a reflection of a cow’s overall classification score which is based on 23 linear traits as assessed by breed associations. An animal’s Overall Type ABV refers to its ability to produce daughters with higher classification scores. Cows with a higher Overall Type ABV are often more structurally sound; which contributes to longer herd life. This is why overall type is included in all three indices – BPI, HWI and Sustainability Index.
To improve overall type in your herd choose animals with an Overall Type ABV of greater than 100.
Dairy strength
The Dairy Strength ABV is a composite trait, incorporating dairy strength classification score,
- Stature
- Angularity
- Muzzle width
- Chest width
- Body length
- Body depth
Rump
The Rump ABV is calculated from rump classification score,
- Rump length
- Pin set
- Pin width
- Loin strength
Feet & legs
Sturdy and sound feet and legs are important for Australian dairy cows in grazing systems. The Feet & Leg ABV is calculated from feet & legs classification score,
- Rear Heel depth
- Foot angle
- Rear set
- Rear leg rear view
- Bone quality
Mammary system
The Mammary System ABV is a composite ABV calculated using a number of individual udder trait ABVs.
Individual traits are
- Udder texture
- Udder depth
- Fore attachment
- Rear attachment – height
- Rear attachment – width
- Centre ligament
- Teat placement – front
- Teat placement – rear
Cows with good udders last longer in the herd and are easier to milk. This is why mammary system is included in all three indices – BPI, HWI and Sustainability Index.
To improve mammary system choose animals with a Mammary System ABV of greater than 100.
