Epidemiology and control of worm infections in cattle on traditional, small-scale and large-scale dairy farms in Iringa district, Tanzania
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Date
2004
Authors
Journal Title
Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
This study aimed to determine worm control practices, anthelmintic usage and the
epidemiology of gastrointestinal (GI) nematodes and flukes (Fasciola and
amphistomes) in cattle on traditional, large-scale and small-scale dairy farms in
Iringa District, Tanzania. A combination of qualitative data collection methods was
used to obtain information on worm control practices and anthelmintic usage on the
cattle farms. Strategic treatments, efficacy trials, an abattoir survey based on
examination of GI tracts, cross sectional and longitudinal studies based on monthly
coprological examination of cohorts for nematode and fluke eggs, worm counts in
tracer calves and pasture larval counts were used to obtain quantitative data on
helminth infections. Results indicated that worm control was based entirely on
routine use of anthelmintics in 87.7%, 1 00% and 97.8% of traditional, large-scale
and small scale-dairy farms respectively. Dairy farmers (55.5%) treated at least four
times a year while traditional farmers (45.8%) treated twice a year. The treatment
period on most farms depended on availability of money and not on the
epidemiology of parasites. Absence of policy on worm control, lack of quality
assurance of anthelmintics, inadequate extension workers and low education among
farmers contributed significantly to irrational worm control and anthelmintic usage.
The type of management especially the grazing practice had significant influence on
the prevalence and intensity of GI nematodes and flukes. The prevalence of GI
nematodes in traditional, large-scale and small-scale dairy cattle was 67%, 44.4%
and 37% respectively. Worm burdens in tracers were mainly composed of Cooperia
spp (51.6%), Oesophagostoinum radlatum (35.7%) and Haemonchus placet (10.2%).
Faecal egg counts (EEC) and tracer worm counts were generally low and peaked only in calves and weaners. Pasture larval counts, FEC and tracer worm counts
peaked toward the end of the rainy season (May). The overall prevalence of
Fasciola gigantica in traditional, large-scale and small-scale dairy cattle was
63.8%, 46.2% and 28.4% respectively. The prevalence of amphistomes was 81.9%,
55.5% and 41.1% in traditional, large-scale and small-scale dairy cattle respectively.
Adult animals had the highest prevalence of both Fasciola and amphistomes. The
prevalence of flukes was high in all age groups on traditional cattle, only in adults
arid yearlings in large-scale dairy cattle and low in all age groups in small-scale dairy
cattle. The proportion of animals excreting fluke eggs in faeces was highest at the
end of the dry season (November) and the early part of the rainy season.
Triclabendazole (Fasinex®), nitroxynil (Trodax®) and ivermectin-clorsulon (Ivomec-
Super®) were highly effective against Fasciola', a reduced efficacy of levamisole-
oxyclozanide formulations was suspected. Strategic treatment with triclabendazole at
the end of the rainy/early dry season significantly reduced the proportion of animals
excreting Fasciola eggs while albendazole treatment maintained low nematode FEC
until the next rainy season. It was concluded that helminths infection in the district
has a seasonal pattern and farmers could save substantial amounts of money through
strategic treatment programmes. Strategic treatments at the end of the rainy/early dry
season
(May/June)
and
at
the
end
of
the
dry/early
rainy
season
(November/December) are recommended for sustainable and cost-effective helminth
control in the district. An additional treatment against GI nematodes in the middle of
the rainy season (February/March) is recommended especially in calves and weaners.
Treatment against GI nematodes and flukes in all age groups in small-scale dairy
cattle might not be necessary if animals will be given pasture from clean areas.
Description
Thesis
Keywords
Worm infections, Dairy farms, Iringa district, Tanzania