Big data adds precision to breeding for mastitis resistance
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 (ABV) is one of eight new or updated health and type traits released by DataGene on 14 April.
1. Calving Ease (updated)
2. Gestation Length (new)
3. Mastitis Resistance (new)
4. Overall Type (updated)
5. Dairy Strength (new)
6. Feet and Legs (new)
7. Rump (new)
8. Mammary System (updated)
The three new or updated health ABVs compliment 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. Every 1 ABV is about 1 day shorter gestation.
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 was 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, according to DataGene’s Michelle Axford.
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 (BPI), Health Weighted Index (HWI) and Type Weighted Index (TWI).
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 Jerseys.
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. We also thank farmers and software providers who supply data used in genetic evaluations.
Tim Humphris, Nirranda South, Western Victoria dairy farmer milking 400 including Aussie Reds and three-way crosses (Aussie Red, Jersey and Holstein).
“I certainly consider Cell Count when I look at selecting my bulls, but the Mastitis Resistance ABV will give me more confidence,” he said. “To me it’s more important to reduce clinical cases of mastitis than have a cow with a lower cell count. We have an 80,000-100,000-cell count, so it isn’t really an issue. But I’d really like to reduce the cases of clinical mastitis.
The economic impact of a mastitis case is far greater than a cow with a slightly higher cell count.” Read more
Trevor Saunders and Anthea Day, dairy farmers at Shady Creek, Gippsland milking 950, predominantly Jerseys, across two farms.
“Mastitis resistance is a significant thing for us,” Trevor said. “We were using cell count as one of our key selection criteria, but we will change that to Mastitis Resistance because it brings in more aspects, other than just cell count.
For example, the Mastitis Resistance ABV includes a record for clinical cases of mastitis, this makes it a significantly more rounded ABV.” Read more
Patrick Glass and family, NE Victoria, milk about 550 cows in a seasonal calving system.
“For us in a seasonal calving situation, using shorter gestation length sires means cows inseminated in the last three weeks of artificial insemination have a better chance of getting in calf to AI next year.
It’s because they will have another five-to-10 days between calving and joining and this is a great animal welfare outcome.” Read more
DataGene is an initiative of Dairy Australia and the herd improvement industry.
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