Abstract
Morbidity and mortality of calves are considered to be the main barrier in the development of expected number of dairy industry in Bangladesh. Shahjadpur, Sirajgonj and Muktagacha, Mymensingh are two major dairy intensive regions in Bangladesh. The risk factors and etiological agents associated with calf morbidity and mortality have not been well studied in these areas. The present study was carried out to identify the risk factors and etiological agents associated with calf morbidity and mortality and development of mitigation plan to promote animal health in the selected areas of Bangladesh from Oct 2011 to Oct 2014 under large and small holder dairy farms in rural conditions. In this study, a Mobile Veterinary Clinic (MVC) was also established and implemented to ensure veterinary services at farmers door step. Calves up to 1 year were included in the study. A total of 486 farmers were selected and interviewed following the questionnaire and data from filled questionnaires were analyzed by Chi-square test and logistic regression to identify risk factors. Health cards were distributed to the selected farmers for recording the health status of cattle. Diseases were confirmed by clinical and laboratory methods. A total of 870 fecal samples were examined for the detection of internal parasite. Enteropathogens were detected by rapid diagnostic kit, ELISA and PCR techniques. Five risk factors (area, herd size, breed, age and nutritional status) were found to be associated with morbidity and mortality of calves. Before implementation of MVC services, the overall mortality at herd level was 11.5% which was 8.2% and 14.7% in Muktagacha and Shahjadpur respectively. The overall morbidity was 48.5% which was higher in Shahjadpur (57.9%) than Muktagacha (33.8%). Prevalence of diseases were higher in female (62.25%) than in male (37.75%) calves. Prevalence of diseases was highest in summer (17.7%) followed by winter (16%) and rainy (15.9%) seasons. The highest prevalence of diseases was in systemic states (19.7%) followed by digestive disorders (19.3%), infectious diseases (2.81%) and skin condition (2.22%). Among 43 different types of clinical disorders, the highest prevalence was found for diarrhea (10.5%) followed by malnutrition (9.9%), parasitic gastroenteritis (PGE) (4.56%), pica (3.68%), fever (3.45%) and dysentery (2.97%). The highest prevalence of disease was found in calves upto 1 month (31.86%) followed by 27.7% (6-12 months), 22.79% (>1-3 months) and 17.65% (>3-6 months). In Muktagacha, the highest prevalence was found with PGE (5.67%) followed by fever (4.76%), diarrhea (4.35%), dysentery (2.73%), anorexia (2.13%), FMD (2.02%). In Shahjadpur, the highest prevalence was found with malnutrition (15.3%), followed by diarrhea (14.4%), pica (5.14%), PGE (3.84%), dysentery (3.13%), fever (2.6%) and others. The overall prevalence of helminth infection in calves was 43.91% which was 72% in Muktagacha and 43.39% in Shahjadpur. Three trematodes (19.31% Paramphistomum spp., 3.1% Fasciola spp., 2.29% Schistosoma spp.), one cestode (3.21% Moniezia spp.,), nine nematodes (11.84% stomach worms (Haemonchus spp. and Strongyles spp.), 5.86% Strongyloides spp., 4.94% Trichuris spp., 1.15% Ascaris spp., 0.69% Bunostomum spp., 0.46% Capilaria spp., 0.46% Oesophagostomum spp., 0.11% Dictyocaulus spp.) and four protozoa (57.63% Balantidium coli, 28.18% Cryptosporidium spp., 20.34% Giardia spp. and 5.17% Eimeria spp.) were found to be responsible for PGE in calves. In addition, 9.09% rotavirus, 43.64% Clostridium perfringens, 0.91% Escherichia coli, were also identified from fecal samples of diarrheic calves. Seroprevalence of bovine viral diarrhea (BVD) was 35.85% and 16.13% at herd and individual level respectively. This is the first report on investigation of risk factor associated with BVD occurrence in Bangladesh. It can be concluded that 5 risk factors, 13 helminths, 3 viruses, 2 bacteria and 4 protozoa were found to be responsible for calf morbidity and mortality in the study areas. As the morbidity and mortality of calves are higher in larger herds, better management practices should be given to the calves in larger herds. Calves at high risk like poor physical condition, cross breed, up to one month, more than one to three months and more than six to 12 months should also be given special care to reduce the morbidity and mortality. Deworming and vaccination against rotavirus and BVDV associated diarrhea can be initiated as a preventive measure. Balantidiasis, clostridial enteritis, cryptosporidiosis, corona viral enteritis should be considered for the differential diagnosis of calf diarrhea. Due to MVC at farmers door step, the overall herd level mortality was significantly reduced from 11.5 to 2.9% which were 8.2 to 2.3% in Muktagacha and 14.7 to 3.6% in Shahjadpur. All of these achievements were possible due to experimentally established MVC and its efficient use which played an important role to provide veterinary services at farmers' door step that reduced morbidity, mortality and improve animal health and productivity by rapid disease diagnosis and treatment, routine de-worming and vaccination. Therefore, it can be recommended to adopt or replicate MVC in other parts of the country.