Are too many heifers on your farm showing up with mastitis early in that first lactation? You may want to examine your prevention strategies. A review paper that examined the effectiveness of various precalving treatments in heifers was published earlier this summer. Here are the key take-a-ways:

• When the infection is caused by contagious bacteria (e.g., Streptococcus agalactiae, Staphylococcus aureus), antibiotics, teat sealants, and vaccines can improve udder health outcomes.
• Particularly if you are considering using antimicrobial treatments, culture quarter milk so you know who the enemy is. We want to minimize the development of antibiotic resistance.
• When environmental pathogens (e.g., Escherichia coli, non-agalactiae streptococci) are the problem, teat sealants and combination therapies are effective at reducing mastitis risk.
• When coagulase-negative staphs (CNS) are infecting heifer udders, antibiotics, teat-sealants, and combination therapies offer the most help.
• When employing any of these treatment options, be sure they are delivered by a well-trained person.
• On farms with effective fly control and that minimize stress for late-gestation heifers, there may be little benefit from preventative medical treatment.

The paper: Naqvi, Nobrega, Ronksley, & Barkema. June 2018. Effectiveness of precalving treatment on postcalving udder health in nulliparous dairy heifers: A systematic review and meta-analysis. Journal of Dairy Science 101:4707-4728.

Another good resource is the National Mastitis Council’s Heifer Mastitis Prevention and Control Plan.