Addis Ababa University Libraries Electronic Thesis and Dissertations: AAU-ETD! >
College of Veterinary Medicine and Agriculture >
Thesis - Tropical Veterinary Epidemiology >

Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/658

Advisors: Dr. Abebe Wossene
Keywords: Ectoparasites
Skin defects
Skin Quality
Copyright: 2004
Date Added: 21-Apr-2008
Abstract: The objectives of this study were to determine the prevalence of ectoparasites on sheep and goats, assess the effect of major ectoparasites on the quality of skin processed in the tanneries and identify the type and magnitude of defects that cause down grading and rejection in pickled sheep and wet blue goat pelts. The study was carried out through questionnaire survey, clinical examination and analysis of pickled and wet blue skin defects in Kombolcha and Dessei tanneries. Out of 752 sheep and 752 goats examined 50.5% of sheep and 56.4% of goats were found infested with one or more ectoparasites. The major ectoparasites identified on sheep were D. ovis (38.5%), M. ovinus (12.5%), tick infestations (3.4%) and Linognathus spp. (2.4%). The major ectoparasites recorded on goats were Linognathus spp. (28.3%), ticks (22.2%), sarcoptic mange (6.1%) and Ctenocephalides spp (8.1%). In sheep, there was significant difference (p<0.001) in prevalence of M. ovinus and D. ovis, between lowland and highland and midland and highland. There was also significant difference in prevalence of Linognathus spp. between midland and lowland (p<0.01) and tick infestations between lowland and midland (p<0.01), and between lowland and highland (p<0.001) but no significant difference (P>0.05) was detected in prevalence of sarcoptic mange and Ctenocephalides spp. In goats, the risk of sarcoptic mange infestation in lowland (Odds ratio (OR) =4.6, p<0.001) and midland (OR=5.0, p<0.05) was 4.6 times and 5.0 times, respectively higher than the highlands. There was also significant difference in prevalence of Linognathus spp between lowland and highland (p<0.01) and Ctenocephalides spp. infestations between midland and highland (p<0.001) and between midland and lowland (p<0.001) agro climate, the risk being higher in midland. Both in sheep and goats no significant difference (p>0.05) was recorded in prevalence of all ectoparasites except D. ovis infestation by age. D. ovis was found to affect more significantly (p<0.05) the adults (42.2%) than the young (29.9%) sheep. Analysis of body condition showed no significant variation (p>0.05) to ectoparasite infestation in sheep. However, poor body condition goats were 4.3 times at risk from sarcoptic mange (OR=4.3, p<0.001), Linognathus spp. (OR=2.1, p<0.001) and tick (OR=1.6, p<0.05) infestation than good body condition goats. The prevalence of M. ovinus was significantly higher in wooly sheep (41.2%) than wooly sheared (0.8%) and hairy (0%) indicating the importance of wool size for the parasite abundance. The prevalence of ‘ekek’ at pickled stage on each group of 20 pickled sheep pelts infested with D. ovis and M. ovinus and each group of 20 pickled goat pelts x infested with sarcoptic mange and Linognathus spp. were 100% and 95% and 100% and nil respectively. However, the prevalence on apparently free control groups 20 sheep and 20 goat pelts were 15% and nil respectively. There was a strong association (p<0.001) between ‘ekek’ and infestation of sheep with M. ovinus and D. ovis and infestation of goats with sarcoptic mange. Besides this, the severity of infestation of sheep with D. ovis and M. ovinus and goats with sarcoptic mange were found to correlate significantly (p<0.05) with severity of ‘ekek’ defect. Study on 1000 pickled sheep pelts and 1000 wet blue goat pelts indicated ‘ekek’ was the predominant defect both in pickled sheep (70.8%) and wet blue goat pelts (42.3%) followed by scratch, scars and technical defects. There was significant difference (OR=3.3, p<0.0001) in proportion of ‘ekek’ between pickled sheep and wet blue goat pelts. Moreover, a strong association (p<0.001) was observed between ‘ekek’ and scratch, and ‘ekek’ and scars both on pickled sheep and wet blue goat pelts. The economic loses due to drop in quality of exported skin in Kombolcha and Dessie tanneries because of ‘ekek’ was estimated to be 1.6 million for pickled sheep and 0.6 million for wet blue goat pelts per year. Favorable climates, poor level of management, poor awareness of farmers and poor animal health extension services are believed to have contributed for widespread occurrences of ectoparasites. The increasing threat of ectoparasites to small ruminant production and the tanning industry necessitate urgent control intervention.
Description: A thesis submitted to Faculty of Veterinary Medicine, Addis Ababa University in partial fulfillment of the requirement for the Degree of Master of Science in Tropical Veterinary Epidemiology
URI: http://hdl.handle.net/123456789/658
Appears in:Thesis - Tropical Veterinary Epidemiology

Files in This Item:

File Description SizeFormat

Items in the AAUL Digital Library are protected by copyright, with all rights reserved, unless otherwise indicated.


  Last updated: May 2010. Copyright © Addis Ababa University Libraries - Feedback