Before they give their first drop of milk, some heifers already succumb to intramammary mastitis infections. How does this happen? Mastitis specialists Steve Nickerson, PhD, with the University of Georgia, and Bill Owens, PhD, at the Louisiana State University Agricultural Center, say the answer is not completely clear.

Most likely, heifer mastitis is caused by bacteria that enter the teat orifice from a variety of sources, including:
1. On the udder and teat skin, from which it may colonize the teat end and enter the teat orifice;
2. Harbored in the oral cavities of calves, which enter the teat orifice via suckling of penmates;
3. Present in heifers' environment, including the soil, manure and bedding materials; and
4. Spread by biting flies that congregate on teat ends.

The experts recommend a clean, dry housing environment (see DCHA's Gold Standards for housing guidelines); vigilant fly control; and housing calves in individual hutches to prevent cross-suckling. Regular visual examination of bred heifers also is suggested. Evidence of mastitis infections in heifers includes swollen quarters; abnormal secretions (clots and flakes); and teat-end scabs.

When intramammary infections do occur, Nickerson and Owens suggest that commercial, intramammary dry-cow therapy is the most effective, research-proven course of action. However, they caution that such treatment may constitute extra-label drug use, so should be performed only under the supervision of the herd veterinarian and within the context of a valid veterinarian/client/patient relationship.

To read more of Nickerson's and Owens' advice on heifer mastitis, click here.

Source: DCHA Editorial Committee member Maureen Hanson