Gastrointestinal nematodes in indigenous Zebu cattle under pastoral and nomadic management systems in the lower plain of the southern highlands of Tanzania.

This study aimed to determine the prevalence and intensity of gastrointestinal nematode infections in indigenous Zebu cattle in the lower plain (lowland zone) of the southern highlands of Tanzania. Gastrointestinal tracts were randomly purchased at the Iringa regional abattoir and at Kihesa and Ipogolo slaughter slabs in different seasons of the year. The contents of the abomasum, small intestine and large intestine were processed separately to recover the worms. The results indicated that 140 out of 144 (97.2%) of the examined animals were infected. The mean (+/-SE) total worm burden was 1284 +/- 183 (range 10-12,600) worms per animal and most infected animals contained more than one nematode species. The nematode species present, their prevalence and mean burden were as follows: Haemonchus placei, 84.7%, 316; H. similis, 5.6%, 1; Oesophagostomum radiatum, 79.2%, 66; Cooperia pectinata, 55.6%, 713; C. punctata, 44.4%, 157; Bunostomum phlebotomum, 5.6%, 5; Trichuris globulosa, 5.6%, 2; and Trichostrongylus colubriformis, 1.4%, 24. The burdens were mainly composed of Cooperia pectinata (55.5%), Haemonchus placei (24.6%), Cooperia punctata (12.3%) and Oesophagostomum radiatum (5.1%). The highest burdens occurred at the end of the rainy/early dry season, while the lowest burdens were found at the end of the dry/early rainy season. There was no difference in the burdens between male and female animals. Immature cattle (< 3 years) had significantly higher worm burdens than mature cattle (p < 0.01). A poor grade for a live animal was associated with higher worm burdens only in immature cattle and then especially during the dry season (r = 0.456, p < 0.001). Anthelmintic treatments in the late rainy/early dry season and early rainy season are recommended in order to prevent outbreaks of helminthosis during the dry season and to reduce carryover of infection into the next rainy season. An additional wet season treatment is advisable in immature cattle, but may not be needed for mature cattle owing to the availability of plenty of mature, good quality pasture.