Preliminary Study on the Effective Microbial Supplementation of Feed on the Infection of <i>Salmonella</i> in Two Lymph Nodes of Beef Cattle in Eastern Ethiopia

Abstract

A double-blinded randomized controlled field trial based on parallel group design was conducted from January, 2018 to July, 2018 in Chercher Oda-Bultum Farmers Union beef Farm. The present study was conducted to evaluate the roll of effective microbial supplementation to feed on the infection of Salmonella in the mesenteric and sub-iliac lymph nodes of beef cattle. In order to undertake the study, 130 beef cattle kept by the farm were used to establish a cohort. The study animals were randomly assigned to the treatment group ( n = 100) and control group ( n = 30). The feed of treatment group was mixed with EM at dose of 5× 10 10 cfu/day/head for 90, 100 and 115 days while that of the control group was mixed with molasses, which acts as placebo. Both the treatment and control were slaughtered and two lymph nodes were collected from each animal under strict sterile condition and processed for the isolation and identification of Salmonella using standard procedure. The occurrence of Salmonella was 70% (CI = 51% - 85%) in control group while it was 33% (CI = 24% - 43%) in treatment group. The difference in the proportion of Salmonella infection in the two group was significant ( x 2 = 13.01; p = 0.000). The relative risk of Salmonella isolation in the control was 2.12 (1.41 - 3.20) compared to treatment group. The absolute and relative risk reduction in the treatment were 37% (CI = 17% - 57%) and 53% (CI = 29% - 69%), respectively. This preliminary study indicated that effective microbial supplementation of beef cattle feed reduced the occurrences of Salmonella in the lymph node of beef cattle, thereby potentially minimizing the economic and public health impacts of Salmonella infection. Then, it was recommended to use EM as prevention and control option in Salmonella carriage in cattle.