Select Sires Develops First-Of-Its-Kind Genetic Tool To Combat Mastitis


Mastitis is the most common clinical disease reported in dairy cows and cited as the No. 3 reason for culling in commercial dairy herds. A case of clinical mastitis in the first 30 days of lactation can result in an economic loss of $4441. This cost includes treatment expenses and the subsequent effects on milk loss, premature culling, replacement loss and future reproductive challenges. To combat mastitis, Select Sires has introduced Mastitis ResistantPROTM, a new genetic tool to boost mastitis resistance in the next generation.

Mastitis ResistantPRO is the latest designation to be added to Select Sires’ toolbox and will appear on qualifying sires following the April 2021 sire summaries. A new icon will identify sires that excel in multiple indicators of mastitis resistance, including CDCB Mastitis Resistance, CDCB Somatic Cell Score (SCS) and Zoetis Mastitis Resistance genomic evaluations. Both Holstein and Jersey sires will be eligible for this designation.

Avoiding costly mastitis cases saves money
Select Sires professionals across the nation have analyzed the economic impact of mastitis resistance traits in dairy herds. Genetic audits of CDCB Mastitis Resistance and CDCB SCS revealed significant savings for higher genetic merit animals, translating to more profit for farmers. The farmer-owned cooperative and farmer-led sire committees recognize the immense value of mastitis resistance traits to secure greater profit margins.

On-farm benefits extend to consumer approval
Industry reports show the incidence rate for mastitis is 24.8 percent and most cows with a mastitis event are treated with antibiotics. Improving genetic merit for mastitis resistance will reduce the use of antimicrobials, which translates to both on-farm savings and consumer approval.

Holstein sires that carry the Mastitis ResistantPRO designation will reduce mastitis cases by 2.3 percent. In a 1,000-cow herd, the savings are greater than $10,000 per year. In addition to the cost savings gained from less treatments, taking genetic strides to reduce mastitis events improves udder health, increases milk quality and strengthens consumer trust.

To learn more about Select Sires’ new Mastitis ResistantPRO designation and view a list of qualifying sires, visit