Well-known mastitis researchers Steve Nickerson, PhD, from the University of Georgia, and Bill Owens, PhD, from the Louisiana State University Agricultural Center, advocate treating prepartum heifers with dry-cow therapy if greater than 5% of animals in the herd are freshening with Staph. aureus mastitis.
Individual therapy also is important for heifers known to be infected. They suggest routine visual and manual examination of the developing udder, mammary fluid and teat skin to identify swollen quarters and abnormal secretions (clots and flakes). Heifers with teat scabs and abrasions also are likely to be infected and should be treated.
While producers may worry that stripping the teats of pre-fresh heifers will destroy the protective keratin plug in the teat canal, Nickerson and Owens say the practice is safe as long as (1) teat ends are properly sanitized; (2) samples are taken aseptically; and (3) teats are dipped with a barrier product after sample collection.
The researchers also offer the following practical tips for treating heifers intramammarily:
- Treat heifers at a time that is convenient for the dairy, such as at the time of artificial insemination, during pregnancy diagnosis or when moved to the close-up pen.
- Administer treatment no less than 45 days prior to expected calving to prevent violative antibiotic residues.
- Restrain heifers in a squeeze chute equipped with a head gate.
- Scrub teat ends with cotton balls soaked in 70% alcohol or with the alcohol pads packaged with mastitis tubes.
- While administering therapy, use the partial insertion method to avoid damaging the interior teat tissue and introducing new bacteria.
- Dip each teat after treatment with a barrier product.
- Conduct residue testing before mixing milk from treated animals with herd milk (the potential for residues is especially likely in animals that freshen early).
They also note that treatment of bred heifers may constitute extra-label drug use and should be carried out under the supervision of the herd veterinarian and within the context of a valid veterinary-client-patient relationship.
Source: Nickerson, SC; Owens, WE. Mastitis Detection, Prevention and Control in Dairy Replacement Heifers. DairExnet, December 2010.
To learn more, visit the Dairy Calf & Heifer Association