Dairy, Livestock & Field Crops
Team
By Jerry
Bertoldo
Baytril 100® (enrofloxacin) Injectable Solution has
received FDA approval for the treatment of Bovine Respiratory Disease
(BRD) in dairy replacement heifers less than 20 months of age. Use of
enrofloxacin in older heifers may cause milk residues. Baytril® and
other flouroquinolone products have been allowed for young beef animals
for several years, but they’re still prohibited in veal production.
These days, antibiotics are seldom approved for additional uses in food
animals due to concerns about producing resistant bacteria. The medical
community and many consumers share this concern. So it’s somewhat
a surprise that Baytril 100®, a member of the flouroquinolone family,
received this recent approval in dairy heifers. Flouroquinolones are an
important weapon against bacterial infection in human medicine, and doctors
did not want to risk loosing the impact of this class of antibiotics.
Sensitivity patterns from both animal and human cultures, as well as DNA
tracing technologies, didn’t bear out these fears.
Baytril® joins Draxxin, Micotil and Nuflor as antibiotics labeled for BRD in dairy heifers. Therapeutic dosing may be daily for three to five days or as a single dose at triple the daily volume.
Unlike most other approved drugs for use in dairy animals, Baytril® carries an additional warning: “The use of this product for any condition or disease not on the label is a violation of federal law.” In other words, the customary extra-label use doesn’t apply to this drug. Baytril 100® is still prohibited in lactating dairy cows and should not be found in the area on a dairy reserved for lactating animals. It will continue to be a prescription drug used only by or on the order of a licensed veterinarian.
Taking aim at BRD
As bacteriocidal antibiotics, flouroquinolones kill rather than inhibit
growth. They penetrate tissues extremely well and begin working within
minutes. They demonstrate high efficacy against mycoplasma, one of the
BRD complex pathogens. Incidentally, mycoplasma isn’t listed on
the label.
In reality it isn’t practical to determine the exact cause of most respiratory problems. Often more than one pathogen is at work. Draxxin is the only product labeled for respiratory infections caused by mycoplasma. This unusual bacteria lack a cell wall, the structure most antibiotics work on to destroy or inhibit the organism.
Resistance after a few months of successful antibiotic use is a characteristic of mycoplasma. Nagging transition-calf (post-weaned) coughing and ear droop in young calves can be classic signs of a mycoplasma problem. The two are often closely linked.
Respiratory disease is responsible for about one-fourth of dairy heifers deaths, well below the two-thirds attributed to diarrheal diseases. That doesn’t mean there isn’t an economic impact: It lies in the long-term effects rather than up-front loss and treatment costs. Pneumonia, much more than scours, affects height and weight gains.
Calves treated for respiratory disease before 90 days of age have 2.5 times greater risk of death before calving than healthy herd mates. “Cured” heifers may have time-bomb lung abscesses that burst during calving or other physically exerting events. This can often result in sudden death or severe pneumonia symptoms.
Consult with your
attending veterinarian on the suitability of Baytril® or any of the
other approved antibiotics in managing your heifer replacement programs’
respiratory health. Keep this in mind: Management in a bottle, no matter
how potent and convenient, can’t replace proper ventilation, nutrition
and vaccinations.
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