Conjunctival Mucous Membrane Colour As An Indicator For The Targeted Selective Treatment Of Haemonchosis And Of The General Health Status Of Peri-Urban Smallholder Goats In Southern Malawi

The world's growing population is becoming increasingly centred around large cities, affording opportunities for peri-urban food production. Goats are well-suited to conversion of resources that are available in pen-urban settings into meat and occasionally milk. Haemonchus contortus has been described as "the nemesis of small ruminant production systems in tropical and subtropical regions"; hence control of haemonchosis through planned animal health management affords a pragmatic first step in improving the production efficiency of periurban goats. This study of pen-urban goat production investigated the potential value of targeted selective treatment of haemonchosis. 452 pen-urban goat keepers in southern Malawi were visited during three seasonal periods with relevance to the epidemiology of haemonchosis. 622, 599 and 455 individually identified goats were clinically examined during the dry season, the rainy season, and shortly after the end of the rainy season, respectively. Data were recorded for sex, age, weight, conjunctival mucous membrane colour score (FAMA-CHA(C)), body condition score (BCS) and faecal worm egg count (FEC); and where possible for pregnancy and lactation status. Animals with pale ocular mucous membranes were treated with 10 mg/kg albendazole, then reexamined 14 days later. Animals with pink mucous membranes, but FECs >= 250 eggs per gram were also reexamined and treated 14 days later. The results show high variability in growth rates deduced from the ages and bodyweights of each of 999 goats at the time of their enrolment. FAMACHAO scores alone were a poor index for the targeted selective treatment of haemonchosis, because they failed to identify too many animals that would have required treatment at different times of year and using different FAMACHAO and FEC cut-offs. Combining the indices of FAMACHAO scores >= 4, body condition scores >= 2, and age >= 18 months was more reliable in identifying those animals requiring treatment when different epidemiologically-relevant FEC thresholds for different seasons were taken into account. Inclusion of late pregnancy or early lactation status would have resulted in very few animals requiring treatment being missed. The use of conjunctival mucous membrane colour scoring in this way provided a valuable insight of the general health status of the pen-urban goats, to create opportunities for planned animal health management to improve productivity. The efficacy of albendazole treatment was poor, putatively due to drug resistance, or poor drug bioavailability in goats. In summary, our study shows opportunities for better production efficiency in pen-urban goats, and demonstrates the value of simple clinical diagnostic indices as decision support tools in planned animal health management.