Cattle diseases in dairy herds in Tanzania: Farmers’ view and laboratory confirmation

Cattle diseases remain a major constraint to increasing dairy productivity in Tanzania,
by killing or keeping them sick and under-producing. Recent studies report overall
mortality between 12 and 14 % in smallholder dairy cattle across different regions of
Tanzania. Many of these diseases can also be transmitted to people, causing illness
and/or even death. Existing information on the diseases affecting dairy cattle in Tanzania
and their relative importance is limited and relies either on passive reporting by
poorly resourced veterinary services or on localised surveys focused on a specific well
known diseases. The causes of cattle diseases remain often unknown and differential
diagnosis is not conducted leading to mistreatment or ineffective treatment. Addressing
this concerns a survey was conducted among cattle farmers in two regions in Tanzania
using participatory techniques to collect information on disease importance supported
by laboratory investigations on commonly expected cattle pathogens but also
those seldom looked for but known to be important in other regions. For this purpose
blood samples were collected from cattle (n=402) reported by farmers to be sick and
subjected to a range of tests (ELISA) including tick borne diseases, selected zoonoses
(brucellosis, Q Fever), infectious bovine rhinotracheitis, bovine viral diarrhea (BVR)
and bovine respiratory syncytial virus (BRSV) among other pathogens. Biological
sampling was aligned with data collection on farm and diseases management. Results
indicate that diseases are common for the region. Among those most prominent were
East Cost fever and Anaplasmosis (32 % each). Also important zoonoses were found
(e.g. Brucellosis, 11 %). High numbers of positive tested sera were also reported
for pathogens commonly not tested for (e.g. IBRV). Preliminary results suggest discrepancies
between laboratory results (tested positive sera) and farmer’s perceptions
on specific diseases. While for East Cost Fever farmer’s perception on disease importance
confirmed laboratory results (37 % versus 32 %) we found a discrepancy
for brucellosis (1 % versus 11 %), a neglected zoonoses with the potential of causing
chronic, long lasting diseases in humans. Implications of farming management practices
on the presence/absence of certain pathogens are currently developed and part
of ongoing dissemination efforts.