New data aids breeding for mastitis resistance

By Dairy News

AUSTRALIAN DAIRY farmers can now breed specifically for Mastitis Resistance, a trait which delivers animal welfare and economic benefits.

The Mastitis Resistance Australian Breeding Value is one of eight new or updated health and type traits released by DataGene which include:

  • Calving Ease (updated)
  • Gestation Length (new)
  • Mastitis Resistance (new)
  • Overall Type (updated)
  • Dairy Strength (new)
  • Feet and Legs (new)
  • Rump (new)
  • Mammary System (updated).

The three new or updated health ABVs complement on-farm management practices.

Farmers will now have more Holstein bulls to choose from if they want their cows and heifers to calve easier.

Thanks to the inclusion of genomics in the updated Calving Ease ABV, most Holstein bulls have a Calving Ease ABV, including — for the first time — young genomic sires.

To breed for improved calving ease, select bulls with a Calving Ease ABV of at least 103.

The new Gestation Length ABV gives farmers a breeding tool to manage late calving cows and help tighten calving patterns.

The ABV identifies bulls and cows whose calves are born earlier than their expected due date. Cows that calve earlier are in-milk for more days before re-joining and have longer to recover post-calving.

To breed for a shorter gestation, look for bulls and cows with a Gestation Length ABV of less than zero.

Farmers milking all breeds of dairy can now select to directly improve the mastitis resistance of their next generation. Even young genomic animals now have a Mastitis Resistance ABV.

Previously the Cell Count ABV used an indirect selection criterion for mastitis resistance, but this new ABV draws on three sets of information to directly target mastitis. These include: 305-day somatic cell count, udder depth and clinical mastitis records.

The Cell Count ABV continues to be published as it is a useful tool to breed cows that contribute to a lower bulk milk cell count.

To breed replacements with improved mastitis resistance, select animals with a Mastitis Resistance ABV of greater than 100.

The updated Overall Type ABV has been introduced to help breeders identify animals with higher classification scores.

This change has been reflected in DataGene’s latest bull and cow rankings as Overall Type and Mammary system are included in the three indices: Balanced Performance Index, Health Weighted Index and Type Weighted Index.

The new type traits complete the set of composite traits and this means farmers have an overview of an animal’s strengths for rump, feet and legs as well as dairy strength.

The new and updated type breeding values are published for Holsteins, Red Breeds Guernseys and Ayrshires. Type ABVs are unchanged for Jersey.

The new ABVs are the result of DairyBio research, drawing upon records supplied by Ginfo herds. DairyBio is a joint initiative between Agriculture Victoria, Dairy Australia and the Gardiner Dairy Foundation.