The efficacy of different disinfectants used in mastitic control programs against economic bacteria -

Abstract

Mastitis is the inflammation of the udder, known as one of the most common economic diseases in dairy cattle throughout the world, resulting in reduced milk production and extra treatment costs. The first aim of this research is to compare the identities of the bacteria and their frequencies, the total bacterial and coliform counts, and the CMT scores involved in subclinical mastitis in three dairy farms of Lebanon in Fall and Spring seasons. The second aim of this research is to assess the in vitro susceptibility of the isolated bacteria to two commercial iodine-based teat dip disinfectants differing in glycerol levels, and the efficacy of these disinfectants against udder surface bacteria. The third aim is to determine the different CMT scores in milk with recovered Streptococcus spp. versus Staphylococcus spp. organisms. The identified bacterial genera from milk samples of thirty six teats on the three farms were more frequent in Fall versus Spring, including the following respective frequency means: Streptococcus spp (2 vs. 0), Staphylococcus spp (4.67 vs. 4.0), Pasteurella spp (1.67 vs. 0), Bacillus spp (2.3 vs. 0), Diplococcus spp (3 vs. 0), and Moraxella bovis (2.3 vs. 2.0). The mean of the means of frequencies of these bacteria in Fall and Spring was: 2.66 vs. 1.0, which were not significantly different (p0.05). Each category of the CMT scores of 0, 1, 2, and 3 of the milk on the three farms didn’t differ significantly between the collection in Fall versus Spring seasons (p0.05). In addition, the total bacterial and coliform counts didn’t also differ significantly between the two seasons (p0.05), resulting in counts that are not acceptable for the human consumption, according to Codex Alimentarius Standards. The in vitro mean inhibition zone diameter of Streptococcus spp by DP75 was significantly more than that of the Staphylococcus spp and Bacillus spp (p0.05). The other identified microorganisms had a similar mean inhibition zone diameter to Streptococcus spp, Staphylococcus s