Showing papers by "University of Zimbabwe published in 1995"
TL;DR: As a result of bioassay–guided fractionation, betulinic acid, a pentacyclic triterpene, was identified as a melanoma–specific cytotoxic agent and antitumour activity was mediated by the induction of apoptosis.
Abstract: As a result of bioassay-guided fractionation, betulinic acid, a pentacyclic triterpene, was identified as a melanoma-specific cytotoxic agent. In follow-up studies conducted with athymic mice carrying human melanomas, tumour growth was completely inhibited without toxicity. As judged by a variety of cellular responses, antitumour activity was mediated by the induction of apoptosis. Betulinic acid is inexpensive and available in abundant supply from common natural sources, notably the bark of white birch trees. The compound is currently undergoing preclinical development for the treatment or prevention of malignant melanoma.
829 citations
TL;DR: In this paper, the authors tested the contact hypothesis of the own-race bias in face recognition using a cross-cultural design and found that although on the whole subjects recognized own race faces more accurately and more confidently than they recognized other-race faces, the own race bias was significantly smaller among the high-contact subjects than it was among the low-contac...
Abstract: Although previous studies have demonstrated that faces of one's own race are recognized more accurately than are faces of other races, the theoretical basis of this effect is not clearly understood at present. The experiment reported in this paper tested the contact hypothesis of the own-race bias in face recognition using a cross-cultural design. Four groups of subjects were tested for their recognition of distinctive and typical own-race and other-race faces: (1) black Africans who had a high degree of contact with white faces, (2) black Africans who had little or no contact with white faces, (3) white Africans who had a high degree of contact with black faces, and (4) white Britons who had little contact with black faces. The results showed that although on the whole subjects recognized own-race faces more accurately and more confidently than they recognized other-race faces, the own-race bias in face recognition was significantly smaller among the high-contact subjects than it was among the low-contac...
313 citations
152 citations
TL;DR: On the basis of the plasma cortisol levels, chemical capture was less stressful than physical restraint, whereas animals that had suffered trauma or which died after they were captured had higher than normal cortisol levels.
Abstract: Plasma cortisol concentrations were determined by radioimmunoassay in 712 individual animals of 18 wildlife species after either physical or chemical restraint, tranquillisation or trauma, in order to define baseline values and to assess the possibility of using cortisol as an indicator of stress. The cortisol levels appeared to rise after capture in all the species examined except the Cape buffalo. On the basis of the plasma cortisol levels, chemical capture was less stressful than physical restraint. Animals which were tranquillised had lower than 'normal' cortisol levels, whereas animals that had suffered trauma or which died after they were captured had higher than normal cortisol levels.
129 citations
TL;DR: A logistic regression model was used to assess clinical, radiographic, and arterial blood gas predictors of PCP and tuberculosis and found that in resource-limited countries, a regionally appropriate management algorithm is required.
109 citations
TL;DR: Patients from a subgroup with a spiritual model of illness were less likely to conform to etic criteria of 'caseness' and they may represent a unique category of psychological distress in Zimbabwe.
Abstract: In order to describe the explanatory models and the etic and emic phenomena of common mental disorder in Harare, Zimbabwe, 110 subjects were selected by general nurses in three clinics and by four traditional healers from their current clients. The subjects were interviewed using the Explanatory Model Interview and the Revised Clinical Interview Schedule. Mental disorder most commonly presented with somatic symptoms, but few patients denied that their mind or soul was the source of illness. Spiritual factors were frequently cited as causes of mental illness. Subjects who were selected by traditional healer, reported a greater duration of illness and were more likely to provide a spiritual explanation for their illness. The majority of subjects were classified as 'cases' by the etic criteria of the CISR. Most patients, however, showed a mixture of psychiatric symptoms that did not fall clearly into a single diagnostic group. Patients from a subgroup with a spiritual model of illness were less likely to conform to etic criteria of 'caseness' and they may represent a unique category of psychological distress in Zimbabwe. A wide variety of emic phenomena were elicited that have been incorporated in an indigenous measure of non-psychotic mental disorder. Kufungisisa, or thinking too much, seemed to be the Shona term closest to the Euro-American concept of neurotic illness.
103 citations
TL;DR: It is inferred that the association between HIV-positive status and arterial aneurysms or fibroproliferative aortic occlusion are causally related and that the principles of vascular surgery can be successfully applied to their treatment.
Abstract: The ever-spreading incidence of infection with the human immunodeficiency virus (HIV) has introduced a spectrum of unusual, subtle, and often life-threatening lesions that can affect almost every organ and tissue in the body. With the introduction of laboratory serologic evidence of HIV infection, the spectrum of indicator diseases has extended beyond the classic opportunistic infections and Kaposi sarcoma. An analysis of 28 patients in Zimbabwe with focal areas of vascular disease treated during a 4-year period (1989–1993) defined 16 patients ranging in age from 12 to 46 years appropriate for special scrutiny as they evinced none of the usual causes of vascular disease. Twelve of the patients were HIV-positive; in two patients the serologic status was unknown; and two patients were HIV-negative at the time of their presentation. There were special clinical features in this group of patients selected for study: (1) They were young with a mean age of 31 years; (2) they were all indigenous Africans with no evidence of atherosclerosis; and there was (3) rapid development of focal necrotizing vasculitis with aneurysm formation and rupture or (4) slow, progressive development of granulomatous vasculitis. The sites of cardiovascular involvement included the left ventricle; aortic arch; thoracic, thoracoabdominal, and abdominal aorta; and iliac, femoral, gluteal, popliteal, and subclavian arteries. It is inferred that the association between HIV-positive status and arterial aneurysms or fibroproliferative aortic occlusion are causally related and that the principles of vascular surgery can be successfully applied to their treatment.
93 citations
TL;DR: The authors reviewed the situation in Harare, Zimbabwe as the contextual setting for an on-going investigation of these two important considerations, placing the present policy responses in their appropriate historical and economic framework, and assessing the research issues which need to be addressed.
90 citations
TL;DR: A reverse sense shear zone forms the boundary of the Northern Marginal Zone with the Zimbabwe craton as mentioned in this paper, and the southern boundary is the Triangle Shear Zone, which is proven as a continuous structure along a much greater strike length than previously documented.
Abstract: The Northern Marginal Zone of the Limpopo Belt in southern Africa comprises a Plutonic Assemblage of granitoids including a distinctive suite of porphyroclastic granites. and a much less abundant Supracrustal Assemblage of metabasites and iron formations. These rocks are at granulite facies above a normal thickness of continental crust. Most of the Plutonic Assemblage are intrusive rocks that crystallized from dry melts from 2800 to 2600 Ma, with a relatively simple thermal history. They may have been derived from partial melting of a mafic source. Some supracrustal rocks have experienced two thermal events at granulite facies.
A reverse-sense shear zone forms the boundary of the Northern Marginal Zone with the Zimbabwe craton. The southern boundary is the Triangle shear zone, which is proven as a continuous structure along a much greater strike length than previously documented. A widespread sub-vertical foliation in the Northern Marginal Zone and the reverse shear zone formed during progressive NNW-SSE shortening. Crustal thickening occurred both magmatically and tectonically in the late Archaean, and was accompanied by synchronous uplift. Protracted magmatism provides a mechanism to incorporate supracrustal rocks into the lower crust, and can explain the occurrence of more than a single thermal event.
90 citations
TL;DR: The Focus Group Discussions (FGD) described in this paper are the first step of a study aiming to develop an 'emic' case-finding instrument and enabled us to develop screening criteria for mental illness to be used by traditional healers and primary care nurses in the next stage of the study.
Abstract: The Focus Group Discussions (FGD) described in this paper are the first step of a study aiming to develop an 'emic' case-finding instrument. In keeping with the realities of primary care in Zimbabwe, nine FGD were held with 76 care providers including 30 village community workers, 22 traditional and faith healers (collectively referred to as traditional healers in this paper), 15 relatives of patients and 9 community psychiatric nurses. In addition to the general facets of concepts of mental illness, three 'etic' case vignettes were also presented. A change in behaviour or ability to care for oneself emerged as the central definition of mental illness. Both the head and the heart were regarded as playing an important role in the mediation of emotions. The types of mental illness described were intimately related to beliefs about spiritual causation. Angered ancestral spirits, evil spirits and witchcraft were seen as potent causes of mental illness. Families not only bore the burden of caring for the patient and all financial expenses involved, but were also ostracized and isolated. Both biomedical and traditional healers could help mentally ill persons by resolving different issues relating to the same illness episode. All case vignettes were recognized by the care providers in their communities though many felt that the descriptions did not reflect 'illnesses' but social problems and that accordingly, the treatment for these was social, rather than medical. The data enabled us to develop screening criteria for mental illness to be used by traditional healers and primary care nurses in the next stage of the study in which patients selected by these care providers on the grounds of suspicion of suffering from mental illness will be interviewed to elicit their explanatory models of illness and phenomenology.
88 citations
TL;DR: The G→A mutation has been shown to predict the incidence more than 60% of poor metabolizers among white subjects and Japanese subjects, and in the current investigation it is obtained a similar relationship in the black population.
Abstract: The S-mephenytoin hydroxylase has recently been identified as cytochrome P450 2C19 (CYP2C19). This enzyme metabolizes mephenytoin, diazepam, omeprazole, and citalopram and has been shown to be polymorphically distributed. One clinical implication of CYP2C19-dependent drug metabolism for persons who reside in tropical regions is in the use of the antimalarial drug chloroguanide hydrochloride, which is apparently biotransformed to its active metabolite by this isozyme. In this investigation we studied mephenytoin metabolism in 103 black Zimbabwean Shona subjects. Four were identified as poor metabolizers (4%). This prevalence is comparable to that in white subjects (2% to 5%) but lower than the 15% to 20% incidence of poor metabolizers among Oriental subjects. Of the subjects phenotyped, 84 were genotyped for the G-->A mutation in exon 5 of CYP2C19, which creates a cryptic splice site, causing the production of a nonfunctional protein. Three of the four poor metabolizers were homozygous for this mutation, whereas the fourth one was heterozygous. The G-->A mutation has been shown to predict the incidence more than 60% of poor metabolizers among white subjects and Japanese subjects, and in the current investigation we also obtained a similar relationship in the black population.
TL;DR: This chapter presents the nonconventional methods for the modification of starch and suggests that the effect of irradiation on starch gels is generally monitored by the changes in viscosity, reducing power, and reaction with iodine.
Abstract: Publisher Summary This chapter presents the nonconventional methods for the modification of starch. Starch is the most readily available and abundant pure carbohydrate. Native starch forms a complex matrix and water plays an important role in its construction. It is widely accepted that water fills capillaries of the matrix as well as participates in the strengthening of the amylose helices in the granule. The observation indicates that water cooperates with high pressure in causing deterioration of the starch matrix. Simultaneously, the ascending portions of the compressibility curves show that the resistance of the starch matrix toward compression decreases as the volume of added water increases. It is observed that solid starch changes its electrical conductivity on compression. At constant temperature and humidity, there is a positive correlation between the tamping of starch layers in cylinders, containers, and silos and their electrical conductivity. For the irradiation of amylose, it has been shown that the solvent may stabilize the irradiated matrix. As with starch, monosaccharides and oligosaccharides exhibit peculiar behavior in their formation of free radicals on irradiation. It is suggested that the effect of irradiation on starch gels is generally monitored by the changes in viscosity, reducing power, and reaction with iodine.
TL;DR: In a preliminary study on the nutritional value of seven multipurpose trees (MPTs), currently showing potential use in agroforestry systems in Zimbabwe, crude protein values ranged from 189 gkg −1 DM in Flemingia macrophylla to 292 g kg −1DM in Acacia angustissima.
TL;DR: In this paper, the decomposition of 15 litter types from four miombo woodland species, two tree species, Brachystegia spiciformis and Julbernardia globiflora, a grass species, Dactylotaenium aegyptium, and a sedge, Bulbostylis megastachys, was determined on the assumption that different plant components could be used as predictors for C and N mineralization.
Abstract: The decomposability of 15 litter types from four miombo woodland species, two tree species, Brachystegia spiciformis and Julbernardia globiflora, a grass species, Dactylotaenium aegyptium, and a sedge, Bulbostylis megastachys, was determined on the assumption that different plant components could be used as predictors for C and N mineralization. The chemical composition of the litter, in terms of lignin, polyphenol, cellulose and total C and N contents was determined. The C and N mineralization patterns of the litter were also investigated during 75 days of aerobic laboratory incubation with soil and correlated with the initial composition. The litter materials contained between 40–51% organic C and total N contents of 13 of the 15 litter types were low, ranging from 0.47% for D. aegyptium leaf to 1.29% for lichens + bark fragments found associated with B. spiciformis stem. The lignin contents ranged from 0.03% in lichens + bark fragments to 16.5% in twig litter from B. spiciformis. Polyphenol contents ranged from 0 to 6%, with the highest values being found in twigs and pods. Cumulative C mineralization data were fitted to first-order kinetics estimating the decomposition parameters. Seed litter from B. spiciformis evolved more CO2, 68.8% of initial C, than all the other litter materials tested. It was found that identical plant parts from the two tree species showed a similar rate of C mineralization, which was as follows: seed > lichens + bark fragments > tree leaflet litter > rachis litter > twig litter. Cellulose, which has received less attention in the literature, was found to influence both C and N mineralization patterns among other natural biopolymers (P < 0.001) but the content of ash-free available C, which was calculated as the difference between total C and lignin C + polyphenol C + cellulose C on an ash-free basis, had the highest R2 value (0.910) for C mineralization and total N had the highest R2 value (0.881) for N mineralization. Net N mineralization during 75 days was only apparent in 6 of the 15 litter samples, with results ranging from 0.2% of initial N in lichens + bark fragments from J. globiflora to 46% of initial N in B. spiciformis seed. The remaining samples immobilized N during the 75 days. Net N mineralization-immobilization was better correlated with the lignin C-to-N ratio (R2 = 0.695; P < 0.001) and the (lignin + polyphenol) C-to-N ratio (R2 = 0.688; P < 0.001) than the lignin-to-N ratio (R2 = 0.656; P < 0.001) or lignin + polyphenol-to-N ratio (R2 = 0.613; P < 0.001). Total N concentrations, C-to-N ratios and cellulose-to-N ratios appeared to be good predictors of N mineralization rates of the N-poor woodland (P < 0.001). The major part of miombo litter may not be a source for mineral N during the first 2–3 months after addition but the fractionation of litter into different C fractions gave a good indicator of potential C mineralization.
TL;DR: The Umlali Thrust Zone has been mapped between the granite-greenstone rocks of the Zimbabwe craton and the granulite-facies rocks of Limpopo Belt as mentioned in this paper.
Abstract: The Umlali Thrust Zone has been mapped between the granite–greenstone rocks of the Zimbabwe craton and the granulite-facies rocks of the Limpopo Belt. A tectonic break had not been previously recognized in the southwest because of the intrusion of syn- to post-kinematic porphyritic granites. These intrusions locally obliterate evidence for the tectonic break, although in some localities the associated mylonites are preserved as xenoliths within the intrusive porphyritic granite bodies. The porphyritic granite bodies were emplaced during and after the main regional fabric forming event. A U–Pb zircon age of 2627 ± 7 Ma obtained from a late-kinematic microgranite is interpreted to be the minimum time of thrusting. A whole-rock Rb–Sr age of 2583 ± 52 Ma obtained from plutonic rocks and retrogressed zones within the North Marginal Zone falls within error of the zircon age, suggesting widespread magmatic and hydrothermal activity coeval with the thrusting.
01 Jan 1995-Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering
TL;DR: The levels of Ni, Zn, Fe, Co, Cr, Pb, Cu and Cd were determined in water hyacinth and water samples collected from Mukuvisi and Manyame rivers in Zimbabwe.
Abstract: The levels of Ni, Zn, Fe, Co, Cr, Pb, Cu and Cd were determined in water hyacinth and water samples collected from Mukuvisi and Manyame rivers in Zimbabwe. Metal concentrations in the plants were much higher than in the water, and bioconcentration factors of 1 to 4 orders of magnitude were obtained depending on the element. In addition the levels of most elements studied were significantly higher in the roots than the tops of the plants.
TL;DR: The prevalence of rickettsia-like organisms in ticks from Zimbabwe was determined using the hemolymph test and the agent of African tick-bite fever was shown to be present in A. hebraeum and Haemaphysalis leachi.
Abstract: The prevalence of rickettsia-like organisms in ticks from Zimbabwe was determined using the hemolymph test. Amblyomma hebraeum had the highest prevalence of rickettsia-like organisms. Other species with rickettsia-like organisms included Amblyomma sparsum, Amblyomma variegatum, Hyalomma marginatum rufipes, Ripicephalus simus, Haemaphysalis leachi, Amblyomma rhinocerotis, and Hyalomma truncatum. Ticks with no demonstrable rickettsia-like organisms infection were Boophilus decoloratus, Haemaphysalis spinulosa, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, and Rhipicephalus sanguineus. Polymerase chain reaction followed by restriction fragment-length polymorphism analysis on samples of hemolymph-positive ticks showed the agent of African tick-bite fever to be present in A. hebraeum, Rickettsia conorii to be present in Rhipicephalus simus and Haemaphysalis leachi, and a spotted fever group rickettsia similar to that in Hyalomma marginatum marginatum ticks from Morocco and Portugal to be present in Hyalomma marginatum rufipes.
TL;DR: Faecal specimens were obtained from 202 adults and 106 children in Harare, Zimbabwe and E. bieneusi was the most prevalent parasite identified, particularly in patients with diarrhoea of over 4 weeks duration, amongst patients with proven or suspected HIV infection.
Abstract: Infection with the nucrosporidian parasite Enterocytozoon bieneusi may be a major cause of prolonged diarrhoea in individuals also infected with human immunodeficiency virus (HIV). The parasite has been reported from Europe, Australia and the Americas, with a prevalence of 7–29%. Faecal specimens were obtained from 202 adults and 106 children in Harare, Zimbabwe, all of whom were in hospital and had diarrhoea. HIV serology was available for 119 adults: 106 were HIV seropositive. There were clinical grounds for suspecting HIV infection in 23 of the remaining patients. E. bieneusi was identified in specimens from 13 129 patients (10%) for whom HIV infection was indicated by serology and/or clinical signs, 1 60 patients (2%) of uncertain HIV status, and 0 13 seronegative patients. 18 106 children were HIV seropositive and 12 were not; HIV serology was not available for the remainder, but 19 were strongly suspected of being infected with HIV on clinical criteria. E. bieneusi was not detected in samples from any child. As is common in Zimbabwe, the prevalence of other parasites in faecal specimens was low and, amongst patients with proven or suspected HIV infection, E. bieneusi was the most prevalent parasite identified, particularly in patients with diarrhoea of over 4 weeks duration.
TL;DR: The analysis of the assessed somatic symptoms showed that various aches and pains in different parts of the body represented cross-culturally the most frequent symptoms for which there was no medical explanation.
Abstract: The World Health Organization has recently launched an international study of somatoform disorders in different cultures. Five centres representing distinct cultures participated in phase I of the project, the main objective of which was to test the cross-cultural applicability and reliability of instruments for the assessment of somatoform disorders. The analysis of the assessed somatic symptoms showed that various aches and pains in different parts of the body represented cross-culturally the most frequent symptoms for which there was no medical explanation. Such symptoms may indicate the presence of an underlying mental disorder but can also represent a means for culture-specific expression of psychosocial distress. This bears particular significance for health professionals in primary and general medical care, who are most likely to encounter patients presenting with multiple, persistent and medically unexplained somatic symptoms.
TL;DR: In this article, the authors classified planar fabrics in small dextral shear zones in the Zimbabwe Archaean craton into porphyroclastic, megacrystic and banded types, depending mainly on the values of the angles between S- and C- or C′-surfaces.
TL;DR: In a review of 282 black patients seen at Harare Central Hospital, Zimbabwe, the relative incidence of various tumour types and the age and sex distribution were similar to those reported in other series.
TL;DR: To examine how often atypical features occur in HIV-positive compared with HIV-negative persons and how these findings correspond to sputum-smear findings, detailed demographic, clinical, and chest radiographic features of tuberculosis were assessed.
Abstract: In the developing world, the diagnosis of tuberculosis is dependent on clinical and radiologic features as culture facilities are not readily available. It has been reported that tuberculosis in HIV-positive persons can present with atypical clinical and radiographic features. The object of this study was to examine how often atypical features occur in HIV-positive compared with HIV-negative persons and how these findings correspond to sputum-smear findings. Detailed demographic, clinical, and chest radiographic features of tuberculosis were assessed in 202 HIV-positive adults and 220 HIV-negative patients admitted consecutively. Using univariate analysis, several of these features were found to be significantly associated with being HIV-positive, but after multiple regression analysis only, age group (15 to 42 yr), a negative tuberculin response, intrathoracic lymphadenopathy, and lack of cavitation but not sputum-smear status remained significant.
TL;DR: Most of the factors that account for malnutrition in children in Zimbabwe are preventable, and the nutritional status of a child is determined by a variety of factors that are biological, social, cultural, and economic in nature.
Abstract: Using data from the Zimbabwe Demographic and Health Survey (1988), this study investigates the factors that determine the nutritional status of children under five years of age. Several sociocultural, economic, and demographic variables were selected for the study. These independent variables were regressed against three proxy measures of malnutrition: height-for-age, weight-for-age, and weight-for-height. The results show that the nutritional status of a child is determined by a variety of factors that are biological, social, cultural, and economic in nature, namely, birth status, birth weight, diarrhoeal status, duration of breastfeeding, and residence. The study concludes that most of the factors that account for malnutrition in children in Zimbabwe are preventable.
TL;DR: The behavioural-analytic study investigated the use of different types of herbs/substances used by 75 HIV positive and 76 negative sexually active females and the perceived effects of these agents and the role of Wankie and similar substances in transmitting HIV cross-infection.
Abstract: Heterosexual intercourse accounts for 80% of HIV transmission in sub-Saharan Africa. Factors facilitating cross-infection may include sexual practices such as the vaginal use of herbs/substances to dry, contract and heat the vagina for enhancement of sexual pleasure. The behavioural-analytic study investigated the use of different types of herbs/substances used by 75 HIV positive and 76 negative sexually active females and the perceived effects of these agents. Individual in-depth interviews were conducted. 99% of all subjects admitted using herbs/substances mainly to contract (94%), dry (58%) and heat (28%) the vagina. There was no significant difference in the pattern of use of herbs and reasons given for using the agents by HIV positive and negative women. 69% of HIV negative and 80% of positive subjects had used a mean of 4 difference types of herbs and/or substances during the last 5 years. 39% negative and 25% positive subjects had experienced intra-vaginal pain and lower abdominal pains during and after sexual intercourse, laceration of the vagina and excessive vaginal secretions after using herbs. These effects were attributed to Wankie (herb or substance) in 70% of the complaints. 14 HIV positive subjects compared with 7 in the negative group had used Wankie. The role of Wankie and similar substances in transmitting HIV cross-infection requires further investigations. From the point of view of AIDS prevention, expectations of a dry and contracted vagina in sexual intercourse may reduce acceptability and use of female and male condoms.
TL;DR: The results imply that oxamniquine, primaquine and chloroquine could be substrates of cytochrome P4502 D6 or that they are potent non-substrate inhibitors of the enzyme similar to quinidine, which could lead to interference with in vivo population-phenotyping procedures in the tropical regions where treatment with the drugs is common.
Abstract: The interaction of antiparasitic drugs with the polymorphic cytochrome P450 2D6 was studied in human liver microsomes.
TL;DR: A novel substrate specificity is an adaptation by the seed lipase to the triacylglycerols of the seed oil that contain up to 80% vernolic acid, which shows pronounced selectivity for the native triacyLglycerol, trivernolin.
TL;DR: A review of 206 pleomorphic adenomas seen over a 10-year period was carried out and found the tumor was common in the 3rd, 4th, and 5th decades with 39.8% of the tumors occurring in the parotid gland.
Abstract: A review of 206 pleomorphic adenomas seen over a 10-year period was carried out. Fifty-eight percent of the tumors were in females. The tumor was common in the 3rd, 4th, and 5th decades with 39.8% of the tumors occurring in the parotid gland.
TL;DR: In this article, an experiment was carried out to evaluate dairy performance and rumen fermentation from a forage-based diet supplemented with Lucaena leococephala (leucaena) and maize bran.
Abstract: An experiment was carried out to evaluate dairy performance and rumen fermentation from a forage-based diet supplemented with Lucaena leococephala (leucaena) and maize bran. Bos indicus (Ayrshire/Brown Swiss) х Bos taurus (Sahiwal) cattle were offered Pennisetum purpureum (napier grass) ad libitum either unsupplemented (N) or supplemented on a dry-matter (DM) basis with 1 kg (LL) or 2 kg leucaena (LH) or 2 kg leucaena together with 1 kg DM maize bran (LHM). Food intake, milk yield, diet apparent digestibility and nitrogen balance were measured using eight cows (mean live weight 384 (s.d. 41) kg in two 4х4 Latin squares. Rumen fermentation was measured using four rumen fistulated steers (mean live weight 352 (s.d. 12) kg in a 4 х 4 Latin square. Performance was recorded during the last 7 days of each 21-day experimental period. Supplementation increased food intake (6·3, 7·6, 7·9 and 8·7 kg DM per day; P < 0·01; s.e.d. 0·24) and milk yield (5·1, 5·4, 5·5 and 6·5 kg/day; P < 0·01; s.e.d. 0·28) for N, LL, LH and LHM respectively. Supplemented diets tended to be more digestible compared with napier grass as the sole food (organic matter apparent digestibility coefficients 0·54, 0·55, 0·57 and 0·57; s.e.d. 0·020; N, LL, LH and LHM, respectively) and N balance increased progressively with supplementation.Supplementation progressively increased rumen ammonia-nitrogen concentrations in steers and the rate of rumen degradation of napier grass increased when leucaena (diets LL and LH) was offered. The results suggest that supplementation of napier grass with leucaena increased DM intake owing to increased ammonia concentrations and rates of napier degradation in the rumen. Supplementation of the forage diet with 1 kg DM maize bran did not significantly reduce the rumen degradation of napier grass and increased the molar proportions of propionate which may have increased the efficiency of utilization of metabolizable energy and therefore milk production.
TL;DR: It appeared that a feeding duration of 5 h per day was adequate for maintenance but insufficient for optimum production of indigenous goats in Zimbabwe.
Abstract: The feeding behaviour of indigenous goats grazing on natural vegetation in a semi-arid region of Zimbabwe was studied over five seasons covering a period of one year (March 1989 to March 1990). The goats were randomly allocated to two groups, A and B, which grazed for 8 h (08.00-16.00 h) and 5 h (11.00-16.00 h) daily, respectively. These grazing times were based on the current practices of smallholder farmers. The botanical and chemical composition of the diet was determined by analysing samples collected from oesophageal fistulated goats. Daily feed intake was estimated by the total faecal collection method. Feed selection varied markedly with season and was similar in both groups. From January to March (wet season) grass formed 55-70% of the forage consumed, while from May to early November (dry period) browse, herbs and fruits formed 77-91% of the diet. Dietary crude protein levels ranged from 128 to 157 g/kg over the seasons. Neutral detergent fibre content ranged from 590 to 790 g/kg, and was highest in wet months and lowest in dry months. Feed intake ranged from 33 to 60 g/kg BW 0.75 or 16-28 g/kg of body weight. It appeared that a feeding duration of 5 h per day was adequate for maintenance but insufficient for optimum production