The epidemiology of ovine gastrointestinal helminthiasis on native pasture at Barnhart, Texas : a thesis /
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| Format: | Thesis Book |
| Language: | English |
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College Station, TX :
Texas A&M University,
1982.
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| Abstract: | ABSTRACT: An experiment was conducted at the Texas Range field station at Barnhart, to investigate the effects of different grazing systems on transmission of gastrointestinal nematodes of sheep. Groups of three 30-40 kg Rambouillet lambs raised in parasite-free condition were grazed with sheep and cattle during various periods of the year on switchback, Merrill 4-pasture, intensive and continuous grazing systems. The effects of these treatments on the transmission of free-living larvae from pastures to lambs were assessed by worm counts of lambs which grazed the paddocks. The results were analyzed by Duncan's multiple range test after logarithmic transformation. There was little effect of any treatment on numbers of Haemonchus contortus or Trichostrongylus axei, and except for the intensive system and Nematodirus spp. There was no significant difference between the worm counts of the various groups after exposure, it was concluded that, in general, any grazing system might be utilized without special recommendations. Because intensive system did not increase the chance of greater transmission, it would be advantageous for greater pasture utilization. Precipitation was the principal environmental factor influencing larvae transmission. Hematological and serological studies gave values within the normal range although there was a slight inverse correlation between worm counts and packed cell volume. |
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| Item Description: | Typescript (photocopy). "Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of Master of Science December 1982". "Major Subject: Veterinary Parasitology". Approved as to style and content by: Thomas M. Craig, Leon H. Russell, Gerald G. Wagner, Ian Tizard. Vita. |
| Physical Description: | viii, 85 leaves : illustrations ; 29 cm. |
| Bibliography: | Includes bibliographical references (leaves 62-71). |