This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

The African Crowned Eagle, Stephanoaetus coronatus, is a large raptor with a particularly long breeding cycle, even considering its size (Newton 1979). The incubation period is 49–51 days, the nestling period is 104–115 days and the length of the post-fledging period is contentious and varies considerably within its distribution in Africa (Steyn 1982). In some regions where the bird breeds biennially, this period is up to 350 days (Brown and Amadon 1989, Shultz 2002), whereas in other regions the post-fledging period is shorter as pairs bred annually, even for nine years in succession (Vernon 1984). The reason for this discrepancy has been ascribed to environmental quality and seasonal variability, and differences in the main prey base, densities and mortalities between populations (Newton 1979, Jarvis et al. 1980, Steyn 1982, Vernon 1984, Boshoff et al. 1994, Shultz 2002). Furthermore, it is unclear if the fledglings disperse from the nesting area of their own free will or are evicted by the parents (Brown 1966, Oatley 1970).

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Canada has a long history of investing in agricultural research, with public funds playing a dominant role for most crops up until recently. With the advent of biotechnology in the 1980s, the research industry underwent significant transformations. Crops more amenable to the application of DNA modification techniques (e.g., canola) gained considerable attention by the private sector and experienced an influx of private R&D investment and proliferation of intellectual property rights (IPRs). IPRs have changed the nature of knowledge from being non-excludable to being excludable, thus affecting the nature of research benefits and research incentives. The advantages and disadvantages of a stronger IPR system in Canadian agriculture are currently hotly debated in policy circles. <p> This thesis develops a theoretical model that describes the incentives for innovation and the distribution of benefits from research when such innovations are protected by Plant Breeders' Rights (PBRs) versus patents. Specifically, the research industry is modeled as a monopolistic seed company undertaking research, developing a new variety and selling it to heterogeneous farmers. The difference between PBRs and patents is embodied in the farmers' decision that incorporates the possibility of seed saving envisioned by PBRs, but not by patents. The simulation results show that under certain conditions PBRs can be as effective as patents in encouraging R&D activity, and that the share of farmers in total benefits is generally smaller under patents than under PBRs. The benefits under patenting regime, however, are not necessarily smaller in absolute terms. <P>This dissertation also develops a game theoretic model to study the impact of IPRs on the sharing of research inputs. The results reveal that when two private firms compete in a differentiated product market, they will have an incentive to protect their technologies and maintain exclusive rights. Therefore, sharing within private industry may be a challenge. As IPRs proliferate, however, a lack of incentive to share/cross-license may not be confined to private industry. IPRs may also impact the propensity of public researchers to protect or share their technologies. <P>To address the issue of sharing and assess the efficiency of the current IP protection system in the Canadian plant breeding industry, interviews with wheat and canola breeders were conducted. The responses suggest that, in general, patents have become more prevalent in both industries over the last decade, which has, in turn, reduced germplasm and information flows and increased secrecy. There is also evidence that patents undermine R&D efforts in some potentially promising areas of research and make freedom to operate in the breeding industry a concern.

Canada has a long history of investing in agricultural research, with public funds playing a dominant role for most crops up until recently. With the advent of biotechnology in the 1980s, the research industry underwent significant transformations. Crops more amenable to the application of DNA modification techniques (e.g., canola) gained considerable attention by the private sector and experienced an influx of private R&D investment and proliferation of intellectual property rights (IPRs). IPRs have changed the nature of knowledge from being non-excludable to being excludable, thus affecting the nature of research benefits and research incentives. The advantages and disadvantages of a stronger IPR system in Canadian agriculture are currently hotly debated in policy circles. <p> This thesis develops a theoretical model that describes the incentives for innovation and the distribution of benefits from research when such innovations are protected by Plant Breeders' Rights (PBRs) versus patents. Specifically, the research industry is modeled as a monopolistic seed company undertaking research, developing a new variety and selling it to heterogeneous farmers. The difference between PBRs and patents is embodied in the farmers' decision that incorporates the possibility of seed saving envisioned by PBRs, but not by patents. The simulation results show that under certain conditions PBRs can be as effective as patents in encouraging R&D activity, and that the share of farmers in total benefits is generally smaller under patents than under PBRs. The benefits under patenting regime, however, are not necessarily smaller in absolute terms. <P>This dissertation also develops a game theoretic model to study the impact of IPRs on the sharing of research inputs. The results reveal that when two private firms compete in a differentiated product market, they will have an incentive to protect their technologies and maintain exclusive rights. Therefore, sharing within private industry may be a challenge. As IPRs proliferate, however, a lack of incentive to share/cross-license may not be confined to private industry. IPRs may also impact the propensity of public researchers to protect or share their technologies. <P>To address the issue of sharing and assess the efficiency of the current IP protection system in the Canadian plant breeding industry, interviews with wheat and canola breeders were conducted. The responses suggest that, in general, patents have become more prevalent in both industries over the last decade, which has, in turn, reduced germplasm and information flows and increased secrecy. There is also evidence that patents undermine R&D efforts in some potentially promising areas of research and make freedom to operate in the breeding industry a concern.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Respiratory disease complex is a major cause of mortality and economic losses in the commercial broiler industry. In 1991 a previously unidentified bacterium associated with respiratory disease and cranial cellulitis was isolated from broilers in the then Transvaal Province (van Beek, van Empel, van den Bosch, Storm, Bongers, du Preez, 1994. ). In 1994 the organism was named Ornithobacterium rhinotracheale (Vandamme, Segers, Vancanneyt, van Hove, Mutters, Hommez, Dewhirst, Paster, Kersters, Falsen, Devriese, Bisgaard, Hinz, Mannheim, 1994.). Since then Ornithobacterium rhinotracheale has been isolated worldwide from chickens and turkeys showing respiratory signs and has become well established as contributing to the respiratory disease complex in both species (van Empel, Hafez, 1999). In South Africa respiratory disease and Ornithobacterium rhinotracheale in particular is routinely controlled by the inclusion of antibiotics such as Oxtetracycline into the feed of broilers during rearing. Concerns about antibiotic residues in poultry meat for human consumption as well as evidence that suggests that Ornithobacterium rhinotracheale readily develops resistance to antibiotics (Devriese, Hommez, Vandamme, Kersters, Haesebrouck, 1995), make this strategy unsustainable. It was with a view to reducing producers’ dependence on long term prophylactic antibiotic therapy that this study to determine the safety and efficacy of an OR bacterin vaccine was carried out. Injection of the bacterin into broilers was deemed impractical on a commercial scale, so it was applied to broiler breeder parent stock in order that they could protect their progeny through vertically transmitted immunity developed as a result of vaccination. Breeder flocks were vaccinated intramuscularly at nine and 18 weeks with a monovalent bacterin based on OR serotype A with oil adjuvant. Vaccine safety was evaluated by palpation of vaccination sites and clinical observation of breeders for two weeks after vaccination. The serological response of breeders to vaccination was monitored using an ELISA test for Ornithobacterium rhinotracheale optimised for use under South African conditions. Vaccine efficacy was determined by monitoring of broiler progeny of vaccinated breeders raised under commercial conditions as well as through controlled challenge studies with Ornithobacterium rhinotracheale under laboratory conditions. In order to determine the financial consequences of using the test vaccine, a partial farm budget was drawn up from available broiler data and possible outcomes were modelled using a stochastic model. The vaccine proved to be safe for use in commercial broiler breeders and vaccinated birds developed a good humoral response to vaccination. As a result of cross-contamination of isolators with Ornithobacterium rhinotracheale the results of the challenge studies were inconclusive. No evidence of protection of broiler progeny of vaccinated breeder flocks could be detected through the challenge trials. In the absence of in-feed medication, broilers hatched from vaccinated breeders did, however, performed better under commercial conditions than those hatched from unvaccinated breeder flocks. The partial farm budget showed that broilers raised from OR vaccinated breeder flocks were more profitable than the negative control flocks. The quantitative risk analysis showed that the probability of making a relative profit from broilers as a result of OR vaccination of parent stock was 74%, from the use of in-feed medication in broilers from unvaccinated parents was 70% and from a combination of the interventions was 99%. It can be concluded that the last of these options was most profitable. / Dissertation (MSc (Veterinary Sciences))--University of Pretoria, 2003. / Veterinary Tropical Diseases / unrestricted

Several Breeders within the Bonsmara cattle breeders’ association have been selecting for polledness otherwise known as the trait for the genetic absence of horns. There are less costs associated with polled animals, as they require less management input than horned animals. International stud breeders are willing to pay a premium for Bonsmara stud animals certified as homozygous polled, and Bonsmara breeders therefore requested a study for the identification of polled status, using DNA markers. Several microsatellite markers were tested in a linkage analysis on a number of Bonsmara families originating from three polled herds. All of the markers tested in the final Twopoint linkage analysis showed significant linkage with the polled trait. This indicates that the current model proposed for the gene action of polledness is applicable to the Bonsmara breed. Furthermore, by using the Transmission disequilibrium test (TDT), an allele of one of these microsatellites was found to be strongly associated with the polled trait. Due to an inherent lack of phase-known, three-generation families, tracing this allele through the test pedigrees to determine polled status was not possible. These results indicate that phase-known family data must be available so that microsatellite markers linked to the Polled trait can be traced visually to differentiate homozygote polled animals from heterozygote polled animals. Microsatellite markers are a tool that can add additional information in the conclusive determination of Polled status, but cannot as yet be used in isolation to test for polledness in the South African Bonsmara breed. Copyright / Dissertation (MSc)--University of Pretoria, 2005. / Animal and Wildlife Sciences / unrestricted

The objectives of these experiments were to evaluate the effects of selenium (Se) and vitamin E (Vit.E) supplementation in maternal and progeny diets on the performance of breeder hens and the performance and meat quality characteristics of progeny. Inclusion of Se, as Se yeast, in the diets of developing broiler breeder pullets resulted in greater Se accumulation of Se (P<0.01) in liver, pancreas, and breast tissues than when Se yeast was not provided. Improving the overall Se status of breeder pullets in the early stages may help maintain adequate tissue Se concentrations during egg production. Maternal supplementation of Se yeast and Vit.E increased the liver and breast Se concentration (P<0.05) of newly hatched chicks compared to the chicks originating from hens not receiving dietary Se. At 7d of age, Se yeast supplementation in either the chick or maternal diet increased breast and liver Se concentrations (P<0.01). At 14d of age, breast and liver Se concentrations remained the highest for chicks supplemented with Se yeast (P<0.01), however there was no effect of maternal Se supplementation. Vitamin E supplementation in either the chick or maternal diets did not affect the liver Vit.E concentrations of chicks at 7 or 14d of age. Supplementing broiler diets with Se yeast and Vit.E improved the meat quality characteristics of raw and marinated breast fillets. The Se content of breast meat from broilers fed Se yeast was higher (P<0.01) than those from broilers that were not fed Se yeast. Antioxidant supplementation improved the drip loss (P<0.05) and oxidative stability (P<0.10) of raw breast fillets after 7d of refrigerated storage. Marination appeared to increase the susceptibility for lipid oxidation of the marinated breast fillets. Dietary supplementation of Se yeast and Vit.E reduced lipid oxidation (P<0.01) of marinated breast fillets after prolonged refrigerated storage, thus improving oxidative stability. Overall, dietary supplementation of Se yeast can increase the accumulation of Se in the tissues of broiler breeder hens and their subsequent progeny. Improvements in the avian antioxidant system may have beneficial effects on the performance of broiler breeder hens, broilers, and the meat quality characteristics of broiler breast fillets.

This set of experiments evaluated the physiological responses of intensively managed ostriches to L-carnitine. In experiment 1, 32 female and 16 male Zimbabwean Blue Neck and South African Black Neck breeders (n=48 of each sub-species; eight years old), were investigated in 16 breeder units of two females and one male (Trio), in a completely randomised design within four treatments and four replicates over an 8-month period during the breeding season. The same basal diet was fed supplemented with 0 (T0, control), 125 (T125), 250 (T250) or 600 (T600) mg/kg L-carnitine. T600 improved the egg production percentage, egg fertility percentage and the hatchability of set eggs for Black-Necks and Blue-Necks, respectively, and the hatchability of fertile eggs in Black Necks. L-carnitine did not affect egg shape index, defective eggs, egg weight, embryonic and post-hatch mortality. In experiment 2, 12 Black Neck males (5.5 years old) were allocated to three treatments (T0, T250 and T500) and four replicates. Semen samples were collected once a month over three months. L-carnitine had a significant effect on semen volume, sperm motility, live sperm percentage and sperm count, but had no significant effect on abnormal sperm percentage. In experiment 3, 32 day-old Black Neck ostrich chicks were allocated to treatments T0, T125, T250 and T600 with four replicates of two chicks. Chicks were vaccinated against inactive Newcastle Disease (ND) vaccine at day 30 as primary, and at day 51 as booster immunisation. ND antibody responses in the sera were monitored over three phases at 51, 70 and 80 days. Anti-NDV antibodies were detected using a modified chicken anti-NDV enzyme-like immunosorbent assay (ELISA). The treatments and the time periods and their interactions influenced ND antibody responses. T125 and T250 had the highest level of ND antibody response compare to the other groups. There were no differences in ND antibody response between T0 and T600 as well as T125 and T250. The highest ND antibody responses were recorded at day 70. Experiment 4 was designed the same as 3, to determine chicks’ growth responses over the 60-day period. Live weight and live weight gain values of T125 and T250 did not differ from those of T0. T600 had the lowest feed conversion ratio (FCR) during the total period. Feed intake (FI) was reduced in the T125 and T600 treatments compared to T0 and T250 over the total period. T125 gave the lowest FI and FCR responses over the total period, whereas there was no difference between T0 and T250. These results suggest that dietary T600 can have a beneficial effect on egg production, fertility and hatchability in the Black and Blue Neck breeders and T250 might improve sperm quality in males. In ostrich chicks T125 and T250 had positive effects on immune responses and T125 can improve the performance by decreasing the FCR. In contrast, the suppressive effect of a high inclusion level (T600) might indicate that ostrich chicks are sensitive to high inclusion levels that could cause adverse effects. / gm2013 / Animal and Wildlife Sciences / Thesis (PhD)--University of Pretoria, 2013. / Unrestricted