Document Detail

Performance of hair sheep composite breeds: resistance of lambs to Haemonchus contortus.
MedLine Citation:
PMID:  14974560     Owner:  NLM     Status:  MEDLINE    
This study was designed to evaluate breed differences in resistance to Haemonchus contortus in lambs. A total of 181 ewe lambs representing crossbred Dorsets (DO) and Dorpers (DP; out of 1/2-Dorset, 1/4-Rambouillet, 1/4-Finnsheep ewes) and straight-bred Katahdins (KT) were evaluated over 3 yr. An additional 144 DO, DP, KT, and Barbados Blackbelly x St. Croix (HH) wethers were evaluated over 2 yr. Lambs were weaned at 60 to 90 d of age. After deworming at about 4 mo of age, ewe lambs received approximately 10,000 infective larvae and were evaluated for parasite resistance in drylot, whereas wethers were evaluated on pasture under conditions of natural infection. Each sex was analyzed separately. Egg counts per gram of feces (FEC), log-transformed FEC (LFEC), packed cell volumes (%), and body weights (kg) measured at 3, 4, 5, and 6 wk after deworming and reinfection were analyzed. Breed influenced all traits (P < 0.05) except BW in ewe lambs and PCV in wethers. Year and week influenced (P < 0.05) all traits. At most times, DP had the highest FEC, DO had the lowest PCV, and KT and HH had lower FEC and higher PCV than either DO or DP. Clearly, Dorper sheep were not more resistant to parasites than DO, but they were able to cope with infection better by maintaining similar or higher (P < 0.05) PCV and similar BW. Katahdin and HH were more resistant, with lower FEC (P < 0.05) than DO or DP. Breed differences were more apparent when infection levels were higher; DO and DP were less affected when infection levels were low and when animals were on a better plane of nutrition. Caribbean hair sheep originated in hot, humid regions of West Africa. They and the derivative Katahdin breed seem relatively resistant to parasitism. The Dorper, in contrast, was developed in more arid regions and exhibited little parasite resistance.
H B Vanimisetti; S P Greiner; A M Zajac; D R Notter
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of animal science     Volume:  82     ISSN:  0021-8812     ISO Abbreviation:  J. Anim. Sci.     Publication Date:  2004 Feb 
Date Detail:
Created Date:  2004-02-20     Completed Date:  2004-08-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8003002     Medline TA:  J Anim Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  595-604     Citation Subset:  IM    
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
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MeSH Terms
Crosses, Genetic
Disease Susceptibility / veterinary*
Haemonchiasis / genetics,  immunology,  parasitology,  veterinary*
Haemonchus / pathogenicity,  physiology
Intestinal Diseases, Parasitic / genetics,  immunology,  parasitology,  veterinary*
Parasite Egg Count / veterinary
Sheep / genetics*
Sheep Diseases / genetics,  immunology*,  parasitology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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