Evaluation of the Compatibility between Different Teat Sealants and Intramammary Antimicrobials in Selective Dry Cow Treatment Protocols

The dry period is a crucial time in the lactation cycle, it is the period of highest susceptibility to new infection and the optimum time to cure existing intramammary infection. In selective dry-cow antimicrobial therapy, we have two different ways of intervening in the management treatments of dry period: in the first case there are dairy cows diagnosed healthy, that will be treated only with the teat sealant, in the second, dairy cows with pathogenic mastitis or high cell counts that will receive the intramammary treatment together with the sealant. One of the main prerogative of an intramammary sealant is to ensure that it remains in the teat throughout the dry period. To guarantee this, it is necessary that the sealant is characterized by good rheological properties, especially when it is administered with an antimastitis ointment. The aim of the present study was to compare the rheological behavior of several intramammary sealant suspensions present on the Italian market. To evaluate the rheological behavior of the intramammary suspensions used during the dry period, rheological comparison methods have been developed. The parameters assessed during the rheological study are Viscosity, 3 Interval Thixotropy Test (3ITT) and the viscoelastic nature of materials: Amplitude Sweep. In addition, to evaluate the sealant performance of intramammary sealants, was performed a compatibility in-vitro test, comparing the behavior of the products alone and in contact with two intramammary antibiotic suspensions (Fatroximin and Mastout, both manufactured by Fatro S.p.A. and used during the dry period). The results obtained highlighted that, when a sealant has good viscosity and good thixotropic behavior, is more probable that it remains in the teat, carrying out its sealing action and preventing the entry of pathogens.