Dz. Moyo et al., THE EPIDEMIOLOGY OF GASTROINTESTINAL NEMATODE INFECTIONS IN COMMUNAL CATTLE AND COMMERCIAL BEEF-CATTLE ON THE HIGHVELD OF ZIMBABWE, Veterinary parasitology, 67(1-2), 1996, pp. 105-120
An epidemiological study of gastrointestinal nematode infections of ca
ttle was conducted on the highveld of Zimbabwe from June 1993 to May 1
995. The study was carried out in two communal areas, two conventional
beef farms and two commercial beef farms with irrigated pastures. On
all farms/areas, faecal egg counts were low (< 500 eggs per g faeces)
during the dry season, During the rainy season faecal egg counts were
highest in communal areas and lowest in conventional beef farms. Those
of irrigated farms had intermediate values. During the dry season pas
ture larval counts were low in irrigated pastures and conventional bee
f farms and virtually zero in communal areas. They increased and peake
d during the rainy season, coinciding with the egg count peaks. Worm b
urdens of necropsied cattle indicated that 100% of the animals were in
fected with nematodes, The important species were Cooperia pectinata,
C, punctata, Haemonchus placei, Trichostrongylus axei and Oesophagosto
mum radiatum in all farms/areas and Ostertagia osterragi in a beef far
m with irrigated pastures, Haemonchus survived the dry season as inhib
ited early fourth stage larvae whereas Cooperia and Trichostrongylus s
urvived as adults.