The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers. / Since discovering a Chemical Hybridizing Agent (CHA) for cotton in 1978, we have perfected the technique of utilizing this breeding tool as well as determining the potential of hybrids in a breeding program.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers. / Cotton breeding stocks were evaluated for resistance to pink bollworm. Resistance is being transferred into improved agronomic stocks.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

Choice of shearing time is one of the major management decisions for a wool-producing Merino flock and affects many aspects of wool production and sheep health. Previous studies have investigated the effect of shearing on only a few of these factors at a time, so that there is little objective information at the flock level for making rational decisions on shearing time. This is particularly the case for flocks that lamb in spring, the preferred time in south-eastern Australia. / A trial was conducted in a self-replacing, fine wool Merino flock in western Victoria, from January 1999 to May 2004, comparing ewes shorn annually in December, March or May. Within each of these shearing times, progeny were shorn in one of two different patterns, aligning them with their adult shearing group by 15–27 months of age. / Time of shearing did not consistently improve the staple strength of wool. December-shorn ewes produced significantly lighter and finer fleeces (average 19.1 μm, 3.0 kg clean weight), whereas fleeces from March-shorn ewes were heavier and coarser (19.4 μm, 3.1 kg). Fleeces from ewes shorn in May were of similar weight to fleeces from March-shorn ewes (3.1 kg), but they were of significantly broader diameter (19.7 μm). In young sheep, beneficial changes in some wool characteristics for each shearing group were offset by undesirable changes in others. / Shearing ewes in March or May, and weaners in March, May or June, significantly increased the risk of post-shearing mortality about three- and four-fold, respectively, compared to unshorn sheep. Substantial, highly significant associations in young sheep between post-weaning mortality, bodyweight and growth rate were also quantified using various survival analysis techniques. For example, the lightest 20% of weaners at weaning contributed 31% of all deaths in the year following weaning, and increasing average growth rate over summer and autumn from 250 to 500 g/month reduced the risk of death by 74%. These results could be used to develop supplementary feeding systems that efficiently reduce weaner mortality, which is a significant animal welfare issue in many Australian Merino flocks. / Mortality effects were incorporated into estimates of the total value of wool produced by the different shearing times between birth and culling at 6¼ years of age. Using median historical (1991–2006) wool prices, shearing ewes in March and their progeny first in June, or October (weaner)-December (ewe) shearing produced the greatest total value of wool ($111/head). March (weaners)-March (ewes) shearing had a wool value of $107/head and December (weaners)-December (adults) shearing $103/head. May-shorn ewes produced the smallest value of wool, irrespective of whether their progeny were first shorn in May or July ($93–96/head). / No shearing time consistently improved all animal health measures. May-shorn ewes had significantly more fleece rot in late autumn than the other shearing groups (odds ratio 2.5) and were up to 0.4 condition score lighter during winter, although they had a lower cost of dag (average $0.64/head) and significantly less breech strike risk in spring, compared to December-shorn ewes (odds ratio 0.18). December-shorn ewes had the greatest cost of dag ($1.50/head). March-shorn ewes had an intermediate cost of dag ($1.03/head) but significantly less breech strike than May-shorn ewes (odds ratio 0.38).Overall, December and March shearing were shown to be appropriate alternatives for a self-replacing Merino flock in south-eastern Australia, whereas May was an undesirable shearing time.

Thesis (Ph.D.) -- Memorial University of Newfoundland. / Typescript. Restricted until January 1992. Bibliography: leaves 180-195. Also available online.

In 2003 the Department of Health of South Africa embarked on a mandatory fortification programme of maize meal as part of the Integrated Nutrition Program (INP) to alleviate malnutrition. The aim of this study was two-fold: firstly, to determine the vitamin A content of South African fortified white maize meal as purchased and the maize porridge as traditionally prepared from it as consumed and secondly, to determine the relative efficacy of the daily consumption of maize meal in sustaining or improving vitamin A status. Maize meal samples for analysis were purchased from various supermarkets and small retail outlets. A High Performance Liquid Chromatograph-Diode Array Detector system with a Reverse Phase C-18 column and isocratic elution was used for separation and quantification of vitamin A. The highest mean vitamin A concentration measured in the maize meal was 261 μgRE/100g and the lowest mean vitamin A concentration was <19 μgRE/100g. Pertaining to the regulations the final minimum level of vitamin A in fortified maize meal must not be less than 187.7 μgRE/100g. The average retention of vitamin A in maize porridge as the difference in vitamin A concentration measured between raw maize meal and cooked porridge was calculated at 39.8%. One of the considerations in a fortification program is the availability of certain micronutrients in the fortified foods, with the focus in this project on vitamin A. An animal model, namely chickens, closely relating the metabolism of vitamin A in humans was used. Chickens are very susceptible to vitamin A deficiencies with similar symptoms. Growth and vitamin A status was evaluated by the weight, feed conversion and liver retinol stores of chickens on five different maize based diets over a six week period. No significant difference in vitamin A levels in the livers of birds on diets with fortified white maize meal, compared to the normal poultry diet consisting of yellow maize meal with added vitamin A was found. It can thus be concluded that the fortificant in the white maize meal is as bioavailable as the vitamin A in the premix used in poultry nutrition. The results of this study show that the vitamin A added as fortificant is absorbed and available to the body. Therefore, fortification of commonly eaten staple foods in the country can significantly improve the vitamin A intake of the population and will improve the overall micronutrient density of their diets. Fortification should be set at levels to include losses incurred through packaging and during transportation, shelf losses and preparation losses. It is also important that the vitamin A content of the product as purchased and consumed must be regularly monitored and regulated by government. Valid and reliable evaluation data are needed to evaluate a program’s success, and to make timeous adjustments for optimal efficiency. / Thesis (PhD)--University of Pretoria, 2011. / Animal and Wildlife Sciences / unrestricted

Lysine deficiency is a major nutritional problem faced by poor people living in the arid and semi-arid tropics who depend on sorghum as their staple food. This is because of poor lysine content and digestibility of sorghum proteins, which aggravates when sorghum is cooked in food. To address this nutritional problem, compositing with locally available lysine-rich legumes has been proposed. Therefore, this study investigated the effects of compositing with the African grain legume, cowpea, on the protein and functional quality of important traditional African sorghum foods. Two sorghum cultivars, a red, tannin (NS 5511) and a white tan plant, non-tannin (Orbit) composited with cowpea at 70:30 ratio, were used to prepare three traditional sorghum foods, ugali (unfermented thick porridge), uji (fermented thin porridge) and injera (fermented flatbread). The protein quality of the traditional sorghum foods was determined by measuring their protein contents, lysine and reactive lysine contents, and in vitro protein digestibility. The functional properties of the foods were studied using instrumental texture analysis. Other sensory properties of ugali were determined using a trained sensory panel. Compositing with cowpea increased the protein contents of the foods by up to 35% and 57% for NS 5511 and Orbit foods, respectively. Lysine contents of the food proteins increased by 67% to 139%. Reactive lysine content increased by 10% to 75%. Protein digestibility of the foods increased by 13% to 62%. There was approximately three- and two-fold increase in protein digestibility corrected amino score (PDCAAS) of NS 5511 and Orbit foods, respectively, due to addition of cowpea. However, Orbit-plus-cowpea foods still had better protein quality than NS 5511-plus-cowpea foods, primarily because of the tannins in the latter which bind the proteins thereby lowering their digestibility. Compositing reduced paste peak viscosity (PV) and cool paste viscosity (CPV) of uji porridge by 6% to 23%, and 6% to 12%, respectively, probably as a result of decreasing porridge starch content. Principal component analysis (PCA) showed that compositing contributed 38% of the variation in 17 sensory attributes of ugali. Compositing imparted cowpea flavour to ugali. Most of the variation in sensory properties (59%) of ugali was due to the quality characteristics of the sorghum cultivars. Compositing increased the stiffness of NS 5511 injera by up to 25%, while it reduced the stiffness of Orbit injera by up to 12%. These differences in stiffness suggested a weakening effect of weaker H-bonding between tannins and other food polymers such as proteins instead of stronger covalent bonds like those involved in proteins-protein interactions. Compositing important traditional sorghum foods with cowpea has potential for helping to solve lysine deficiency faced by sorghum consumers in the semi-arid tropics. However, it introduces cowpea flavour which may need to be eliminated, in foods intended for consumers not accustomed to cowpea flavour. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Food Science / unrestricted