Protostrongylus stilesi, the parenchymal lungworm, has been attributed an important role in the widespread respiratory diseases of the Rocky Mountain bighorn sheep (Ovis canadensis canadensis). This study was conducted to delineate some of the immunologic and non-specific interactions between parasite and host. A procedure was developed for- the immunochemical quantitation of the ovine immunoglobulins IgG(1), IgG(2) and IgM and for the semi-quantitative analysis of IgA. This technique obviated, the preparation of highly specific antisera required for single radial immunodiffusion. The lungworm did not appear to be a significant part of the total antigenic environment of infected animals since no relationship between immunoglobulin levels and parasite activity was detected. Genetic influences were suggested in the levels of IgG(2) which remained at a relatively constant level characteristic of individual animals. The seromucoids were evaluated as correlates of the inflammatory reaction to parasitism. These proteins were useful in detecting changes in parasite activity and bacterial infection. Gastrointestinal disorders associated with severe scouring were accompanied by the disappearance of circulating orosomucoid (α-1 acid glycoprotein). The loss of this low molecular weight protein appeared to be related to vascular leakage. Lungworm infections induced the appearance of homocytotropic antibodies which could be detected in vitro by their ability to sensitize peripheral polymorphonuclear leucocytes for adherence to the larval cuticle. The elution of this antibody from sensitized cells and the inhibition of the adherence reaction with specific antiserum suggested that the reaction was mediated at least partly by IgG(1). The adherence reaction was used to assay homocytotropic activity of serum from infected animals (washed-cell test). This test was correlated with the ability of sera to sensitize skin for anaphylaxis. The effective hypersensitive response, accounting for both sensitizing and blocking activity, was determined by exposing normal cells to larvae in a medium containing serum (decomplemented-serum test). The results of this test paralleled inflammatory changes in parasitized animals, monitored by the levels of serum orosomucoid. Using this method, levels of homocytotropic and blocking antibodies were measured throughout the annual parasite cycle. Preliminary observations indicated that immunogenic inflammation, associated with the "spring rise" and "self cure," resulted from a shift in a dynamic balance between competing antibodies rather than a proportionate increase in homocytotropic activity. The response of peripheral lymphocytes to the presence of larvae or larval extracts was cursorily examined. Although ovine lymphocytes did not respond well enough in culture to draw definitive conclusions, the presence of larval extracts appeared to have a detrimental effect on cell survival and transformation. Even in the presence of EDTA, minute amounts of antibody sensitized lymphocytes for adherence to the larval cuticle. Sera from a wide variety of sources had an inhibitory effect on this reaction. Treatment of larvae with neuraminidase and high concentrations of NaCl engendered improved adherence. This suggested that Protostrongylus had adopted mechanisms similar to the trophoblast or the neoplastic cell which allegedly evade immunologic recognition with a strongly anionic coat. These aspects are discussed in terms of the possible role of Protostrongylus in respiratory diseases of the bighorn sheep, and the exploitation of molecular mechanisms in the control of parasitic diseases. / Land and Food Systems, Faculty of / Graduate

Two experiments determined the effects of flaxseed supplementation on reproductive parameters in sheep. In experiment one, 240 multiparous Rambouillet ewes were assigned to one of two treatments: basal ration alone or basal ration with a Flaxlic® Sheep Tub offered over 35 days. Serum was collected weekly for progesterone (P4). Flaxseed supplementation did not improve progesterone concentration or reproductive parameters (P ≥ 0.26). In experiment two, 120 Rambouillet ram lambs were assigned to one of two treatments: basal ration alone or basal ration with a Flaxlic® Sheep Tub offered over 112 days. Scrotal circumference measurements, serum for testosterone, and semen were collected on day 84 and 112. Day effects were found for select semen measurements, testosterone, weight, and scrotal circumference (P ≤ 0.05). There was no effect of treatment on testosterone concentration (P = 0.99) or any semen quality characteristics (P ≥ 0.33). Overall, tub supplementation did not alter reproductive ability.

Fifteen abomasally cannulated, growing wether lambs were used in two metabolism studies to evaluate the utilization of RNA and DNA. Wethers were blocked by weight and breeding and randomly assigned within block to one of five treatments with the restriction that no animal receive the same treatment in both trials. All animals were fed 350 g, twice daily, of a basal ration supplying 7.1 g nitrogen. In addition, the lambs received twice daily infusions of either soy protein, RNA, DNA, or a 1:1 combination of RNA and DNA or a sham infusion. Tris buffer was used as the solvent for RNA and DNA, the carrier for soy protein and the sham infusion. Infusions, except for the sham, were calculated to be isonitrogenous supplying 2.5 g nitrogen per day. Following a 10-day preliminary period, all urine and feces were collected during a 10-day collection period. Jugular blood was obtained at 6 and 12 hr post feeding on the last day of each trial. Crude protein digestibility was significantly elevated for the nucleic acid infusions over that for the sham. The RNA value, though not different from DNA or the combination, was comparable to that for the soy. Calculated by difference, the absorption values of RNA, DNA, and the combination of RNA and DNA were 97, 77, and 72%, respectively. Nitrogen retention, expressed in g/day, tended to be higher for the nucleic acids than for the sham. The combination of RNA and DNA was not different from the soy treatment which had the highest (P< .05) nitrogen retention. Urinary urea, allantoin, and ammonia levels were elevated (P <.05) for the nucleic acid treatments over the sham. Urinary creatinine and “other” nitrogen (nitrogen unaccounted for) were not affected by treatment. Blood urea.nitrogen tended to be higher for the combination of RNA and DNA than the sham, while RNA, DNA, and the soy treatments were higher (P <.05) than the sham. Serum protein concentrations were unaffected by treatment. The amino acid concentrations either tended to be higher or were higher for the nucleic acids, especially the RNA and combination of RNA and DNA, than for the sham. Concentrations for the nucleic acid treatments compared well with those for the soy treatment and in some cases were higher than the soy. From these data, the following conclusions were made: 1) nucleic acids are well digested and absorbed; 2) retention and utilization of nitrogen from nucleic acids appears to be minimal; 3) the majority of the absorbed nucleic acids are excreted as urea and allantoin; and 4) essential and non-·essential plasma free amino acids are increased by exogenous nucleic acids. The effect may be influenced by urea recycling to the rumen as the result of nucleic acid degradation. Urea recycling would stimulate microbial growth with consequent increases in microbial amino acid synthesis. Amino acids associated with the urea cycle were noted to be affected. / Master of Science

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Digitized by Kansas State University Libraries

Call number: LD2668 .T4 1965 M943 / Master of Science

Thesis (MScAgric) -- Stellenbosch University, 1993. / ENGLISH ABSTRACT: A model of interdependents that makes provision for the particular needs of dorper sheep farming and is based on the relationship between the main groups of behaviour determined variables, was constructed. This model served as a basis for an interview schedule whereby personal interviews were held with 130 randomly drawn dorper farmers in the summer rainfall area of the Dorperland. Various independent and mediatory variables were examined and in certain cases it was quantified. Thus certain relationships between the needs, aspirations and endeavours of the respondents and their particular personal and environmental factors were determined. The determination of the independent and mediatory variables provide the extension officer with important background information whereby the application/non-application of certain practices as well as the efficiency of practice application are put into perspective. In this respect the findings of this survey serve as an important reference point by which specified extension actions could be evaluated in the future. The effectiveness of practice application is determined on the basis of 5- and 10-point scales as well as a description of what is actually done. In doing this the existence of certain definite differences between the perceptions of the respondent~ concerning the efficiency of praxis application and the assessment of the interviewers, baled on • description of what is actually done, was found. Practice accepta1Ce, • manifested in efficiency is measured on the basis of particular effectivity stMcWds. Thus relationships between the efficiency standards and certain personal, socioeconomical, socia-psychological and biological-technical variables wet"d determined. / AFRIKAANSE OPSOMMING: 'n Model van interafhanklikes wat voorsiening maak vir die eiesoortige behoeftes van dorperskaapboerdery en gebaseer is op die verwantskap tussen die hoofgroepe van gedragsbepalende veranderlikes, is gekonstrueer. Hierdie model het as basis gedien vir 'n onderhoudskedule aan die hand waarvan persoonlike onderhoude met 130 ewekansig gelote dorperboere in die somerreenvalgebied van Dorperland gevoer is. Verskeie onafhanklike en bemiddelende veranderlikes is ondersoek en in sekere gevalle is dit gekwantifiseer. Sodoende is verwantskappe tussen die behoeftes, aspirasies en strewes van die respondente en bepaaIde persoonlike- en omgewingsfaktore van sodanige respondente bepaal. Die bepaling van die onafhanklike- en bemiddelende veranderlikes bied die voorligter belangrike agtergrondinligting op grond waarvan die toepassing/nie-toepassing van bepaalde praktyke asook die doeltreffendheid van praktyktoepassing in perspektief geplaas word. Die mate waartoe sekere praktyke wat met dorperskaapboerdery verband hou toegepas word. is ook bepaal. In hierdie verband dien die bevindinge van hierdie ondersoek as belangrike verwysingspunte aan die hand waarvan bepaalde voorIigtingsaksies in die toekoms geevalueer kan word. Die doeltreffendheid van praktyktoepassing is aan die hand van 5- en 10puntskale. asook 'n omskrywing van wat werklik gedoen word, bepaaI. Sodoende is die bestaan van sekere duidelike verskille tussen die persepsies van die respondente wat betref die doeltreffendheid van praktyktoepassing en die aansIag van opnemers, gebaseer op 'n beskrywing van wat werklik gedoen word, bevind. Praktykaanvaarding, saos dit manifesteer in doeltreffendheid. is aan die hand van bepaalde doeltreffendheidsmaatstawwe gemeet. Sodoende is verwantskappe tussen die doeltreffendheidsmaatstawwe en sekere persoonlike, sosio-ekonomiese, sosio-psigologiese en biologies-tegniese bepaal.

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