Impact of management interventions on helminth levels, and body and blood measurements in working donkeys in South Africa

The aim of the study was to determine the effect of alternative management interventions on levels of nematodes and the condition of working donkeys in South Africa. Twenty-four adult donkeys (Equus asinus) within an area of 200 km radius were randomly allocated to eight paddocks. Two replicates each of three management interventions together with a control group were tested in a 16-month study. The interventions included monthly removal of feces from paddocks where the donkeys grazed, a pre-winter moxidectin treatment, and a combination of a pre-winter moxidectin treatment and monthly fecal removal. The influence of the different interventions on the nematode fecal egg counts, animal live weights, body condition scores and general blood chemistry were compared. In addition, herbage samples were collected from the pastures in each paddock to determine the number of third-stage larvae (L-3) per kg dry matter. At the end of the study worm recoveries and counts were performed on eight of the animals following euthanasia. The cyathostomes represented the largest portion of the helminth species composition in both the fecal egg counts and larval cultures. Monthly fecal removal alone did not significantly reduce the L-3 on pasture and consideration of more frequent removal is discussed. Pre-winter moxidectin treatment resulted in a 100% reduction in fecal egg counts, an average egg reappearance period of 42-55 days, a reduced average egg count for up to 8 months, and reduced total helminth burdens in all the treated donkeys. It also resulted in improved live weights, hemoglobin concentration, packed cell volumes and to some extent body condition score of the donkeys. (C) 2002 Elsevier Science B.V. All rights reserved.