Microbial pathogens associated with calf diarrhea in dairy farms in and around Addis Ababa, Ethiopia
No Thumbnail Available
Date
2007-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A longitudinal prospective observational study on calf diarrhea and mortality in dairy farms in
and around Addis Ababa was conducted from October, 2006 to May, 2007 with the objectives of
describing incidence of calf diarrhea and mortality and identification of potential pathogens
associated with calf diarrhea. A total of 254 calves; 37 from four large dairy farms and a random
sample of 217 calves from market oriented smallholder and medium-sized dairy farms were
included in the study. Each calf was individually identified and regularly monitored for clinical
health problems up to the age of six months. Information on different management aspects were
collected by personal observation during the regular visit to farms and from questionnaire survey
conducted during the study period. Fecal samples were also aseptically collected from diarrheic
calves for laboratory examination to detect entropathogens involved. Rotavirus, Coronavirus,
Escherichia coli K99 and Cryptosporidium parvum were detected using antigen ELISA.
Salmonella were isolated and identified following ISO 6579 (2002) and Quinn et al. (1994).
Antimicrobial susceptibility test for Salmonella isolates was also done following NCCLS (1997)
guidelines. The overall incidences of calf diarrhea and crude mortality found in this study were
33.6% and 11.6%, respectively. Other disease conditions that were diagnosed in calves included
navel ill, joint ill, pneumonia, septicemia, congenital loss of vision and other miscellaneous cases.
The incidence of calf diarrhea was apparently higher in medium-sized and large dairy farms than
smallholder dairy farms while the incidence of calf mortality was higher in smallholder and large
dairy farms. Based on laboratory examination, Rotavirus, Coronavirus, E. coli K99,
Cryptosporidium parvum and Salmonella were detected from diarrheic calves at rate of 1/36
(2.8%), 3/36 (8.3%), 8/36 (22.2%), 23/36 (63.9%) and 6/36 (16.7%), respectively. The serotypes
of Salmonella identified were Salmonella Typhimurium (4/6), S. Dublin (1/6) and S.
Mishmarhaemek (1/6). Of the serotypes tested for resistance to a panel of 13 antimicrobial agents
all isolates of Salmonella Typhimurium showed intermediate resistance to one or more drugs.
Salmonella Dublin was intermediate in resistance to tetracycline, kanamycin and nalidixic acid.
All serotypes tested were resistant to erythromycin. In conclusion, the incidence of calf diarrhea
and mortality found in this study were high and could affect dairy production through substantial
economic losses mainly due to morbidity, cost of treatment, mortality and future productivity. All
potential pathogens were detected in diarrheic calves. Some of these pathogens such as
VIII
Cryptosporidium and Salmonella are zoonotic and hence can serve as source of infection to
humans. Control and management of calf diarrhea should focus on reducing exposure to the
infectious agents and optimizing the calves’ resistance to them.
Description
Keywords
Coronavirus, Rotavirus, E. coli K99, Cryptosporidium parvum, Salmonella