Includes bibliographical references (leaves 274-316) / xxii, 333 leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines several aspects of male reproduction in the sheep, and how these are related to fertility in the female when semen is introduced by natural mating or artificial insemination. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1991

Three experiments were conducted (1) to develop and characterize polyclonal antibodies against ovine adipocyte plasma membranes (APM), (2) to evaluate the effect of administering the developed antibodies to lambs on lamb growth and carcass characteristics, and (3) to investigate the possibility of using the developed antibodies to identify antigenic components on ovine APM that are tissue, species and possibly site specific. In Experiment 1, the developed antibodies showed a high rate of reactivity to APM and cross reacted with plasma membranes (PM) from liver, kidney, heart and erythrocytes. Adsorption of antisera with either liver PM or erythrocyte PM for 6 h resulted in a significant reduction in antisera cross-reactivity to liver or erythrocyte PM, respectively, with little effect on its specific reactivity to APM or cross-reactivity with PM of the other tissues tested. The antisera also reacted in different affinities to APM from sheep, pig and rat. The antisera also showed differential binding to APM isolated from different anatomical locations. In Experiment 2, five wether lambs were assigned to either a control or treatment group to study the effect of passive immunization with the antisera immunoglobulin (ASig) on lamb growth and carcass characteristics. Treatment with ASig resulted in a significant (P<.OS) reduction of 45% in wet perirenal fat weight, and of 1.8 and 0.8% in subcutaneous and perirenal lipid content, respectively. ASig immunization also significantly (P<.O5) reduced blood plasma non-esterified fatty acid without adversely affecting blood plasma triglycerides or packed cell volumes (hematocrit). Animals immunized with ASig also showed a significant (P<.OS) reduction in average weight daily weight gain, but this effect was not associated with any adverse effect on efficiency of carcass production. Moreover, passive immunization tended to improve protein accretion and efficiency of nitrogen utilization. In Experiment 3, the developed antisera immunoglobulins recognized three unique ovine APM components, in comparison with plazma membranes from liver, kidney, heart or RBC, with molecular weights of 70, 106 and 110 KD, and showed to react more intensely with APM antigenic components that are in common with PM of the tissues tested. Antisera immunoglobulins recognized just two (44, 46 KD) antigenic components on porcine APM that are shared with those of ovine APM but did not react with any component on APM of either rat or chicken. / Graduation date: 1990

Spring-born ram lambs were used to examine: (1) sexual maturational changes in LH, FSH and prolactin (PRL) secretion, testicular gonadotropin receptors, and testicular size and function; (2) predictability of yearling ram reproductive function from juvenile testicular size and reproductive hormone measurements. Despite continuous increases in testis size, serum LH-profile characteristics became greatest between 2 and 4 months and declined thereafter. However, LH-peak frequency increased by about 2-fold between 6 and 7 months; this was associated with marked increases in testosterone (T) secretion and spermatogenic function. Mean FSH and PRL levels were maximum at 2 months and 3 to 5 months, respectively, and decreased thereafter. Increases in steroidogenic and spermatogenic function were due partly to increases in testicular content of LH and FSH receptors. Yearling ram testis size and spermatogenic function were predictable from testis size at 5 to 6 months, neonatal (50 days) secretion of LH and T, and pubertal (150 days) secretion of T. However, combinations of testicular size and reproductive hormone measurements provided greater predictive power.

Four studies were conducted to investigate some factors affecting milk fatty acid composition of dairy ewes. The first study was performed to determine the influence of freezing temperatures and storage time on ovine milk composition and cheese making. The other three experiments were conducted to examine the effects of dietary added fats with different profiles of fatty acids from canola, sunflower and flaxseeds on animal performance, nutrient utilization, milk yield and cheese making. The main emphasis was on fatty acid composition, particularly CLA and Omega-3 fatty acids, in milk and cheese. Results showed that: (1) feeding up to 8% of canola, sunflower and flaxseed had no adverse effects on dry matter intake and total tract digestibilities of dry matter, neutral detergent fiber, acid detergent fiber and crude protein, while the digestibilities of fatty acids and gross energy were increased with oilseed supplementation; (2) feeding flaxseed to lactating ewes up to 260g/ewe/d increased milk yield by up to 8.4%, and fat content by up to 14.3% without adversely affecting other milk components or cheese yield and composition; (3) Oilseed supplementation increased milk concentrations of long-chain and unsaturated fatty acids in the expenses of short-chain, medium-chain and saturated fatty acids. The concentrations of CLA and Omega-3 fatty acids were also increased by oilseed supplementation; (4) the manipulated fatty acids profiles can be reflected in cheese; (5) good quality cheese can be produced from ovine milk frozen at -15°C and -25°C for up to 6 months without influencing cheese content of fat and protein and fatty acid composition. / In conclusion, ovine milk with nutritionally healthy characteristics can be produced by feeding ewes diets with oilseeds, and freezing storage of milk for up to 6 months at -15°C or -25°C does not significantly affects milk composition including fatty acid composition. The characteristics of milk can be reflected in cheese.

No description available.

Includes bibliographical references (leaves 290-309) / 310 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates aspects of the intake and utilization of barley grain and grain legume supplements by sheep fed low quality pasture hay and when grazing mature summer pastures. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1987

Thesis (Ph. D.)--University of Adelaide, Dept. of Animal Sciences, 1993. / Includes bibliographical references (leaves 281-316).

Thesis (M.Ag.Sc.) - Dept. of Animal Physiology, University of Adelaide, 1982. / Typescript (photocopy).

Thesis (Ph. D.)--University of Adelaide, Dept. of Agronomy, 1965. / Typescript.

Thesis (B.Ag.Sc.(Hons.))--University of Adelaide, Dept. of Animal Science, 2002. / Bibliography: leaves 63-73.