From the NMC Newsletter "Udder Topics", June, 1999

The efficacy of an Escherichia coli J5 bacterin for reducing the incidence of intramammary infections and clinical signs of mastitis was tested in first lactation heifers. Ten primigravid heifers were immunized with an E. coli J5 bacterin. Four heifers received a placebo. The bacterin and placebo were injected subcutaneously approximately 60 days prior to calving, 28 days later, and within 48 hours after calving.

Vaccinated and placebo-injected heifers were challenged by intramammary infusion of E. coli in one mammary gland between 23 and 37 days after calving. All challenged quarters were diagnosed with an intramammary infection within 6 hours after bacteria were infused. The severity and duration of local signs of clinical mastitis were reduced in vaccinated heifers compared with placebo-injected heifers. Systemic signs of clinical mastitis were limited and did not differ between treatment groups. Bacteria counts in milk from challenged quarters were lower in vaccinated heifers than in control heifers at 12, 15, and 48 hours after challenge. Serum immunoglobulin G titers against whole-cell E. coli J5 antigen at calving were higher in vaccinated heifers than they were in controls. Vaccinated heifers had higher immunoglobulin G titers than did controls in mammary secretions at calving and immediately prior to challenge.

Immunizing primigravid heifers with an E. coli J5 bacterin during the last trimester of gestation and at calving reduced the severity and duration of clinical signs following intramammary challenge with E. coli.

Source: Journal of Dairy Science, Vol. 82, pg. 939 (1999)