A review of some characteristics, socio-economic aspects and utilization of Zulu sheep: implications for conservation
Zulu sheep are Nguni sheep of Zululand and are adapted to the harsh conditions of KwaZulu-Natal. They are used by rural farmers for economic purposes. Their numbers are declining, indicating a potential extinction threat. Knowledge of their phenotypic and genotypic characteristics is essential for conservation planning. In this review, there is a focus on the utilization, socio-economic aspects, phenotypic and genotypic characteristics as well as a proposed breeding programme. A survey has shown that rural farmers in the areas of northern KwaZulu-Natal prefer to keep this breed for its adaptability, resistance to diseases and meat quality. Zulu sheep are small-framed multi-coloured animals. Mature males weigh up to 38 kg and females up to 32 kg. Based on four morphological traits and live weight, phenotypic diversity between three populations was estimated at 48%. A genetic diversity between these three populations was estimated at 22%. Live weight of Zulu sheep can be estimated using the heart girth and wither height measurements. Scrotum circumference of young rams (up to 22 months old) is reliable for estimating the live weight. Animals that were characterized in the studies were grazed extensively and no supplements were provided. There is therefore a potential of weight increase if these animals are reared in a semi-extensive environment. An open nucleus breeding scheme is thus recommended for a sustainable use and conservation of this breed. For more conclusive results, larger numbers of phenotypic and genetic characteristics, in larger numbers of Zulu sheep populations, should be investigated.
Phenotypic characterization of Zulu sheep: implications for conservation and improvement
Dissertation submitted in fulfilment of the requirements for the Degree of Master of Science in Agriculture (Animal Science) in the Department of Agriculture, Faculty of Science and Agriculture at the University of Zululand, South Africa, 2012.
Changes in the kidney and blood following hypoxic hypoxia in rats
Summary1.Rats were rendered hypoxic by maintaining them within silicone rubber membrane covered enclosures. In experiment one the inspired oxygen concentration was progressively reduced from 21 per cent to 7 per cent over a period of 13 days. In the second experiment the inspired oxygen was maintained at nine per cent for seven days.2.The reticulocyte counts, haematocrit values and haemoglobin concentration of blood samples from control and hypoxic rats were measured. These results showed a significant increase in all three parameters in both experiments compared with the values from control rats.3.The renin content of the kidneys of the rats was bioassayed by its hypertensive effect in bilaterally nephrectomised rats. There was no significant difference in renal renin content of the hypoxic rats of experiment one or two when compared with their controls.
 These results do not support the concept that the juxtaglomerular cell granule is a source of erythropoietin or its precursors in rats.