Impact of teat canal closure on the metagenomics profile of bacterial communities and its effect on udder health

Abstract

In recent years, with the advancement of molecular techniques, there has been a growing search for communities of commensal microorganisms, due to the fact that many of these populations have the capacity to prevent or favor many diseases. Thus, no consensus was found about the sterility of the mammary gland. some authors have assumed that the mammary gland has its own microbiota, while others argued that it is sterile. Regarding that, the objective of the present project is: 1) to define the best technique to collect material for the microbioma analysis; 2) to evaluate the relationship between the integrity of the teat canal and the microbiota of the mammary gland of heifers, and its effect on the mammary gland health during the postpartum period; and 3) to investigate the existence of commensal microorganisms in nulliparous animals. For these reasons, this study will be divided into three phases. in phase 1, we will be use three forms of milk collection in multiparous animals, to define the best method of milk collection for the metagenomics analysis, as: the collection of milk through the use of a cannula, the collection with the use of an intracanula cannula, and vacuum collection system directly from the udder. Then, the microbiological and metagenomics analyses of the milk samples will be performed. For the second phase of this work, the opening of the teat canal during the prepartum period (21 days before parturition) in dairy heifers will be evaluated by visual inspection and ultrasonographic examination. Then, milk secretion will be collected for microbiological and metagenomics analyses. Furthermore, postpartum colostrum and milk samples will be collected at four moments (M1: at the day of parturition; M2: seven; M3: 15; and M4: 30 days postpartum) for microbiological analysis and somatic cell count. Therefore, in the third phase, the existence of microbial populations in nulliparous animals will be investigated through mammary biopsy and metagenomics analysis. (AU)