Dry cow therapy: effects of method of drug administration on occurrence of intramammary infection.

Two methods of administering a dry cow infusion product were evaluated: 1) full insertion of infusion cannula into the teat cistern, and 2) partial insertion of infusion cannula into the teat canal. Eighty-six Jersey cows were treated at dry off; two quarters of each cow were infused using method 1, and two quarters were infused using method 2. The new quarter infection rate for method 1 with major intramammary pathogens was 9.9% (17 infections/172 quarters); that for method 2 was 4.1% (7 infections/171 quarters). Treatment efficacies against major pathogens for methods 1 and 2, were 57.9% (11 cures/19 quarters) and 85.7% (12 cures/14 quarters), respectively.