No Difference in Dry Cow Therapy

This article is in conjuntion with the article "In Command of a Crisis" in the February 2014 issue of Dairy Today.

A non-inferiority trial, similar in methodology to the Cornell University study, found no differences in dry cow treatments.

This study, conducted by the University of Minnesota, the University of Wisconsin, Iowa State and the University of California, set the non-inferiority threshold at 10%. That meant a product would have to be 10% better than the other products in the study to be judged better.

Nearly 1,100 cows from six commercial herds in California, Iowa, Minnesota and Wisconsin were used in the trial. Products compared were Quartermaster, Spectramast DC and Tomorrow.

"Non-inferiority analysis showed no effect of treatment risk for cure between dry-off and calving," says Sandra Godden, a University of Minnesota veterinarian involved in the research. "Secondary analysis also showed no difference for risk of new intramammary infection between dry off and calving, and no difference for risk of a clinical mastitis event between calving and 100 DIM."

The authors note, however, that the herds involved in the trial were much larger than the national average and had higher milk quality. These well-managed herds averaged more than 27,000 lb. of milk per cow with somatic cell counts averaging 242,000 cells per ml. In addition, all the herds used Orbeseal and a commercial coliform mastitis vaccine at dryoff.

Because there was no difference in dry treatment efficacy, the researchers concluded: "Dairy producers could ... base their [dry cow product] selection decision among the three products on other characteristics such as meat and milk withholding times, targeted dry period length and cost."

And because of antibiotic resistance concerns in humans, veterinarians might consider recommending older, first generation antimicrobials such as Quartermaster and Tomorrow as a first choice when recommending a dry cow therapy product, say the authors.