Gastrointestinal nematodes in traditional cattle of Zambia : seasonality and relationship between faecal egg counts and worm burden

Abstract

Faecal egg counts, differential larval counts and post mortem total worm counts were done on seventy traditional cattle from Southern province of Zambia between February and September 1997 to establish the relationship between faecal egg counts and total worm burden and to determine the seasonality of gastrointestinal nematodes in the same traditional cattle. The animals were sampled at Turn Pike slaughter slab in Kafue district on a biweekly basis at an average of five animals per visit. During the same visits, at least 20 animals per visit were checked for gastrointestinal nematode eggs in the faeces.The highest faecal egg counts were recorded during the rainy months February to April and the lowest where in the cold dry month of July. The same was observed with total worm counts. The mean monthly temperatures were also found to be positively correlated to both the faecal egg counts and the total worm counts. Rainfall was however, only found to positively correlate with faecal egg counts and not with total worm counts. In all the eight months that the study was carried out, no inhibited larvae (hypobiotic larvae) were observed in all the animals sampled.The genera identified by either coprocultures or post mortem worm counts were Haemonchus spp., Cooperia spp., Oesophagostomum spp., Bunostomum spp. and Trichostrongylus spp. The prevalence of these worms in the gastrointestinal contents were Cooperia 73 percent, Haemonchus 22 percent, Oesophagostomum two percent and Bunostomum and Trichostrongylus each at one percent. All the animals examined were found to be infected with at least one genus of gastrointestinal nematodes and of these 84 percent were infected with Cooperia, 76 percent with Haemonchus, 74 percent with Oesophagostomum 14 percent with Bunostomum and another 14 with Trichostrongylus. The different genera were compared with the faecal egg counts to determine the relationship between the different genera and the faecal egg counts. A positive correlation was found between Haemonchus spp (r = 0.5785, p<0.05), Cooperia spp (r = 0.7469, p<0.05) and Oesophagostomum spp (r = 0.5987, p<0.05) and faecal egg counts. However no relationship was found between Bunostomum, Trichostrongylus and faecal egg counts. A positive correlation (r^ = 0.57, p< 0.05) was found between faecal egg counts and total worm counts.