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Start thinking about dry cow therapy

Dairy Pipeline: June 1997

by Tom Bailey
Dairy Production
Virginia-Maryland Regional College of Vet Medicine
Virginia Tech

It is time again to start thinking about dry cow therapy. Over the next few months, many herds in Virginia will be drying-off a large percentage of cows. As a reminder, every quarter of every cow should be dry treated with an effective, approved, long acting antibiotic. The two most critical times for new infections to occur are (1) at dry-off, and (2) around calving. A lot of producers are still only dry treating the quarters that had mastitis in the previous lactation, leaving the uninfected quarters subject to new mastitis infections. Although this topic has been discussed thoroughly in the past, a recent herd visit has underscored its importance. This herd was dry treating every quarter of every cow. However, new infections at freshening with an environmental Strept organism were occurring. The dry cow therapy used in this herd is typically very effective against these environmental Strepts and may work very well in your herd. However, this particular product had been used for the past 15 years with no periodic change to a different dry cow therapy. These environmental Strepts had become resistant to the antibiotic and was no longer effective. This makes three very important points. First, culture mastitis cows and periodically check antibiotic sensitivities to the mastitis causing organism. Resistance can develop. Second, occasionally switch dry cow and lactating cow therapy based on antibiotic sensitivities to avoid mastitis organisms becoming resistant to antibiotics. Third, the answer is usually simple. Periodically reviewing your mastitis control program with your veterinarian can help with cultures and appropriate selection of therapy.

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