- ItemAn overview of disease-free buffalo breeding projects with reference to the different systems used in South Africa(MDPI - Multidisciplinary Digital Publishing Institute, 2012-11) Laubscher, Liesel; Hoffman, LouwrensThis paper describes the successful national program initiated by the South African government to produce disease-free African buffalo so as to ensure the sustainability of this species due to threats from diseases. Buffalo are known carriers of foot-and-mouth disease, bovine tuberculosis, Corridor disease and brucellosis. A long-term program involving multiphase testing and a breeding scheme for buffalo is described where, after 10 years, a sustainable number of buffalo herds are now available that are free of these four diseases. A large portion of the success was attributable to the use of dairy cows as foster parents with the five-stage quarantine process proving highly effective in maintaining the “disease-free” status of both the calves and the foster cows. The projects proved the successfulness of breeding with African buffalo in a commercial system that was unique to African buffalo and maintained the “wildness” of the animals so that they could effectively be released back into the wild with minimal, if any, behavioral problems.
- ItemThe contribution of wildlife to sustainable natural resource utilization in Namibia : a review(MDPI - Multidisciplinary Digital Publishing Institute, 2010-11) Van Schalkwyk, Diana, L.; McMillin, Kenneth, W.; Witthuhn, R. Corli; Hoffman, Louw C.Namibia is the driest country in sub-Saharan Africa, but well known for its richness in species and sustainable natural resource utilization. The Namibian farming sector consists mainly of extensive farming systems. Cattle production contributes 54% of the livestock sector’s production output, followed by sheep and goats (25%), hides and skins (9%), and other forms of agricultural production (12%). Namibia’s freehold farmers have obtained ownership rights over land and livestock since the early 1900s; commercial rights over wildlife and plants were given to freehold farmers in 1967 and to communal farmers in 1996. Natural resource-based production systems then overtook agricultural production systems and exceeded it by a factor of at least two. The shift from practicing conservation to sustainable utilization of natural resources contributed to the rapid growth of wildlife utilization. The wildlife industry in Namibia is currently the only animal production system that is expanding. There are in total at least two million head of different wildlife species. The broader impact of the utilization of wildlife on the economy is estimated to be around N$ 1.3 billion. Tourism, live sales and trophy hunting, cannot sustain further growth. Wildlife farming could offer better opportunities for ensuring long-term sustainability. As the game meat trade in Namibia is not formalized, harvesting wildlife to satisfy the demand for game meat in export markets is still in its infancy. Sustainable harvesting of wildlife for meat production, however, has the potential to increase earnings to the beneficiaries in the wildlife sector.
- ItemNear-isogenic lines of Triticum aestivum with distinct modes of resistance exhibit dissimilar transcriptional regulation during Diuraphis noxia feeding(The Company of Biologists Ltd, 2014-10) Botha, Anna-Maria; Van Eck, Leon; Burger, N. Francois V.; Swanevelder, Zacharias H.Russian wheat aphid (Diuraphis noxia, Kurdjumov) feeding on susceptible Triticum aestivum L. leads to leaf rolling, chlorosis and plant death – symptoms not present in resistant lines. Although the effects of several D. noxia (Dn) resistance genes are known, none have been isolated or characterized. Wheat varieties expressing different Dn genes exhibit distinct modes of D. noxia resistance, such as antibiosis (Dn1), tolerance (Dn2), and antixenosis (Dn5). However, the mechanism whereby feeding aphids are perceived, and how subsequent transcriptional responses are partitioned into resistance categories, remains unclear. Here we report on downstream events in near-isogenic wheat lines containing different Dn genes after D. noxia biotype SA1 feeding. Transcripts involved in stress, signal transduction, photosynthesis, metabolism and gene regulation were differentially regulated during D. noxia feeding. Expression analyses using RTqPCR and RNA hybridization, as well as enzyme activity profiling, provide evidence that the timing and intensity of pathways induced are critical in the development of particular modes of resistance. Pathways involved include the generation of kinase signalling cascades that lead to a sustained oxidative burst, and a hypersensitive response that is active during antibiosis. Tolerance is a passive resistance mechanism that acts through repair or de novo synthesis of photosystem proteins. Results further suggest that ethylene-mediated pathways are possibly involved in generating volatile compounds and cell wall fortification during the antixenosic response.
- ItemThe morphology of the nasal region of Amphibia and its bearing on the phylogeny of the group(Stellenbosch : Stellenbosch University, 1970-12) Jurgens, J. D.; du Toit, C. A.; Stellenbosch University. Faculty of Science. Department of Botany & Zoology.ENGLISH ABSTRACT: An attempt has been made to reconcile the anatomical features of the snout region of the three living orders of the amphibia with one another. It is concluded that the three orders are closely related to one another and that the apparent differences which they do show, are the result of differences in the degree of adaptation to terrestrial life. On balance the evidence indicate that the living amphibia are a monophyletic group.
- ItemCarcass and meat quality characteristics of three halothane genotypes in pigs(Stellenbosch : Stellenbosch University, 1995) Fisher, Peter; Mellett, F. D.; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science.ENGLISH ABSTRACT: The object of this study was to determine the effect of the halothane gene in pigs on certain production, carcass, meat and processed meat characteristics. Fifty nine (gilts = 25, castrates = 34) Landrace x Large white pigs of three halothane genotypes (NN = 31, Nn = 17, nn = 11) were raised under commercial conditions from 27 kg to 86 kg live weight. Variables measured during this period were days to slaughter and ADG. Upon reaching slaughter weight (86 kg) the pigs were transported to a commercial abattoir and slaughtered and classified according to factory procedures. Variables measured at the classification point were pH1, carcass length, warm carcass weight, fat thickness, meat depth and percentage predicted lean yield. After a 24 h cooling period the carcases were weighed, pH24 measured, cut to factory specifications and samples of the loin removed to determine drip loss. Certain portions (left hand side ham and back) of the carcass were removed, deboned and frozen for further processing. The backs and hams were defrosted after all the pigs were slaughtered. The backs were used to manufacture back bacon according to commercial procedures followed in the factory. This consists of brine injection, immersion in brine for 24 h, smoking and tempering or cooling. Weights of the individual samples (n = 59) were recorded before and after each of the processes mentioned. The deboned hams were grouped according to genotype and minced using a 20 mm mincerplate. Spices, preservatives and ice water were added to the minced meat and tumbled for 30 min to enhance the water binding potential of the meat. The ham mixture of each genotype was canned (20 cans/genotype), weighed and sterilized. After a cooling period the hams were removed from the cans, residual water drained off and the weight of each sample determined.