Highveld Of Zimbabwe Research Articles

Impacts of wetland loss and fragmentation on the hydrology of Zimbabwe's highveld

Abstract Wetland loss and fragmentation are among the greatest threats to water resources in developed and developing countries. While several studies on wetland fragmentation have been done, a few have looked at impacts of wetland fragmentation on hydrology, with none having been done on Zimbabwe's highveld headwater catchments. There is a critical need to investigate the influence of wetlands on flow regimes of highveld headwater catchments, to understand the hydrological role that wetlands play in sustaining water resources. Endowed with dambos, marshes and riverine wetlands, Zimbabwe's highveld play a significant role in sustaining Zimbabwe's water resources, with major river systems originating from the highveld plateau, having wetlands as their source regions. Hydrologic impacts of wetland fragmentation on flow regimes of highveld headwater catchments i.e., Upper Manyame (Manyame catchment), Nyagui (Mazowe catchment) and Macheke (Save catchment) were analyzed for the period from 1984–2021. Analysis of landcover and wetland change as well as streamflow characteristics was done for 1984, 1994, 2004, 2014 and 2021 periods. Simulation of streamflow under wetland fragmentation was done using the topographically driven rainfall-runoff model (TOPMODEL), which was set up, calibrated and validated for the most sensitive parameters, which include scaling parameter (m), transmissivity (To) and root zone available water capacity (SRmax). Results from landuse/cover analysis for the period between 1984 and 2021 showed a decrease in wetland area, followed by an increase in built up area and bare land for the same period, owing to expansion of urban areas and cultivation into wetland areas. Hydrological simulation by TOPMODEL and flow duration curve analysis show that wetland fragmentation has resulted in increased peak flows, while low flows have declined for the three catchments. The findings of this research would be helpful in understanding the hydrological functions of highveld wetlands, providing the reference for protection and sustainable utilization of wetland resources in the highveld catchments.

Using Livelihood Profiles for Assessing Context in ICT4D Resarch: A Case Study of Zimbabwe's Highveld Prime Communal

AbstractThe importance of context specific ICT4D innovation has been highlighted in Information Systems research by the short‐comings of a‐contextual innovation. This has often been accepted without due understanding of how to develop context specific interventions. There is therefore a need for a framework that elucidates ICT4D contextualisation and guides the development of context specific interventions. This should be useful to practitioners that are constantly advised to develop context specific artefacts without any clarity of how to do so. Using evidence from Zimbabwe this paper proposes the use of livelihood profiles for identifying the livelihood issues that matter in a particular locality and Sen's Capability Approach for assessing the opportunity freedoms to exploit the local livelihoods. This is presented as a systematic way of establishing the context under which ICT4D interventions will be deployed. The study uses focus groups under an interpretivist paradigm to investigate contextual issues in Zimbabwe Highveld Prime Communal livelihood zone. The study found a politically polarised contextual setting characterised by poor agricultural finance, ineffective crop and livestock markets, unrewarding labour markets against a good agricultural climate that is affected by cyclical droughts. As a result the study posits that ICT4D innovations for the zone must be designed to operate under these realities and limitations.

A survey of ectoparasites, cestodes and management of free-range indigenous chickens in rural Zimbabwe

A survey of ectoparasites, cestodes and husbandry aspects of indigenous free-range chickens was carried out in selected districts from the highveld and lowveld of rural Zimbabwe. The survey recorded infection with 4 species from the order Phthiraptera (lice), 1 species from the order Siphonaptera (fleas), 6 species from the order Acarina (ticks and mites) and 9 species of cestodes. Among the ectoparasites, the most prevalent was Menacanthus stramineus (87.7%) followed by Echidinophaga gallinacea (71.9%). Chickens in the Mazowe district had the highest number of ectoparasites species (10 of 11) followed by Goromonzi district (9 of 11) both these districts are situated in the highveld of Zimbabwe. The most prevalent cestode species was Raillietina tetragona (84.4%), followed by Raillietina echinobothrida (32.2%). Chickens in the Goromonzi district had the highest number of cestode species (7 of 9), followed by Mazowe district (one subgenus and 5 of 9). In all the districts sampled the main purpose of keeping free-range chickens was for meat for the household, with few households using the birds as a source of income. The majority of households kept their birds extensively with barely any appropriate housing, and supplementary feeding was only occasionally practised.

Seedling recruitment ofColophospermum mopaneon the Highveld of Zimbabwe

Synopsis Factors controlling seedling recruitment of Colophospermum mopane (Kirk ex. Benth) Kirk ex. J. Leonard were investigated on the high veld of Zimbabwe. Seed germination and seedling survival and growth were monitored under canopy and outside canopy microhabitats for a period of3 years. Seed germination in both microhabitats exceeded 70%. Although there was no significant difference in seed germination between the two microhabitats, seedling survival was significantly lower under canopies than outside canopies. More than 75% of newly emerged seedling losses were attributed to water stress, which suggests that abiotic factors (mainly rainfall) may account for most of the fluctuation in recruitment in this species. Open areas with bare ground or sparse grass cover were favourable sites for seedling recruitment. Seedlings appear to be shade-intolerant and require increased light intensities and temperature for growth. Seedlings grew slowly probably because they initially allocated more biomass to root...

<b>Original Papers</b> <i>Ostertagia ostertagi</i> infection in cattle on an irrigated farm on the highveld of Zimbabwe

<b>Original Papers</b> <i>Ostertagia ostertagi</i> infection in cattle on an irrigated farm on the highveld of Zimbabwe

The effect of treatment with a 1% injectable formulation of moxidectin during the rainy season and at the beginning of the dry season on gastrointestinal nematodes in cattle from communal areas in Zimbabwe.

The effect of 1% moxidectin/cydectin at 0.2 mg/kg live weight on gastrointestinal nematodes and on the growth of calves, weaners and cows was investigated in five communal areas on the highveld of Zimbabwe. Three field experiments were carried out between March 1996 and June 1997. In experiment 1, treatment was administered in all five areas at the end of the rainy season in March 1996, followed by a further treatment at the beginning of the dry season in May/June 1996. In experiment 2, the treatment was administered in three areas at the end of the rainy season in March 1997. In experiment 3, treatment was administcred in one area at the beginning of the dry season in April 1997. Large numbers of eggs were present in the faeces of calves and weaners at the start of experiments 1 and 2. Epg values were lower in cows and in all age categories in experiment 3. There was a statistically significant reduction in epg values in calves, weaners and cows following treatment with a reduction of 90-99% in all cases except in cows in experiment 3, where no meaningful assessment was possible owing to the low egg counts in both the treated and control cows. The dominating larval types in faecal cultures were Cooperia and Haemonchus. Trichostrongylus, Oesophagostomum and Bunostomum were also found. Following treatment, Haemonchus was suppressed far more than Cooperia. This may be related to a longer residual effect against abomasal parasites like Haemonchus in comparison to small intestinal worms like Cooperia. Anthelmintic treatment conferred significant weight gain advantages (p < 0.05) on treated calves. weaners and cows. The weight gains are discussed in relation to disease and nutrition.

Buffalo-associated Theileria parva: the risk to cattle of buffalo translocation into the Highveld of Zimbabwe.

There has been an increase in the introduction of game animals, including African buffaloes, into the Highveld of Zimbabwe to establish private game reserves on condition that they are confined in separate and secured paddocks. Owing to shortages of pastures cattle were grazed in buffalo-grazed paddocks resulting in outbreaks of buffalo-derived theileriosis. This paper reports the results of epidemiological observations carried out on two game reserves to assess the risk of buffalo translocation. The infection rate with Theileria parasites in ticks collected from buffalo-grazed pastures was high and produced fatal theileriosis in susceptible cattle. Similarly, adult R. appendiculatus ticks artificially fed as nymphs on the buffaloes produced fatal infections in susceptible cattle. Theileria parva (Boleni), the vaccine used to immunize cattle against theileriosis, and a buffalo-derived T. parva stabilate (BV-1) were inoculated in naïve buffaloes to study the Theileria carrier-state in these animals. The two buffaloes that had received the Boleni stabilate showed no clinical theileriosis reaction; however, the ticks derived from them produced a subclinical reaction in one susceptible calf. The buffalo which had received stabilate BV-1 developed fever, high schizont parasitosis for 10 days and 15% piroplasms parasitemia. R. appendiculatus ticks fed as nymphs on this buffalo produced fatal theileriosis reaction in a susceptible calf.

Evaluation of the MAP-1B ELISA for cowdriosis with field sera from livestock in Zimbabwe.

The Map 1B (Senegal) antigen-based indirect ELISA was evaluated in Zimbabwe with field sera from heartwater-free and heartwater-endemic areas. Of 205 sheep sera samples from a heartwater-free area, 34 were negative and 171 were positive by immunoblotting. These 171 samples were classified as false positives. Of the same 205 samples, 199 were negative and only 6 were positive by the MAP 1B ELISA. Of 72 cattle samples tested from a similar area, 71 were negative, with only 1 sample positive by MAP 1B ELISA. By immunoblotting, 43 of 72 cattle sera were negative and 29 were positive. Of the 46 goat samples tested from a heartwater-free area, only 2 were positive by the MAP 1B ELISA. Based on these results, the MAP 1B ELISA was more specific for heartwater than the immunoblotting assay. Of 96 and 282 cattle sera analyzed from heartwater-endemic farms in the lowveld and highveld of Zimbabwe, respectively, approximately 33% were positive by the MAP 1B ELISA. Goat sera from the same farms had a higher sero-prevalence (> 90%). The implications of these results for serodiagnosis of heartwater using the MAP 1B ELISA will be discussed.

The effects of the brown ear-tick, Rhipicephalus appendiculatus, on milk production in dairy cattle.

The effect is reported of artificially controlled levels of infestation with adults of Rhipicephalus appendiculatus on the milk yield of twenty commercial Bos taurus dairy cattle on a high plane of nutrition and eighteen crossbred B.taurus x Sanga cattle on a lower plane of nutrition on the highveld of Zimbabwe. The results showed no significant effect on milk yield of infestations averaging twenty engorging ticks per animal per day, despite severe ear damage in some animals. They indicate that milk production of dairy cattle under commercial management is not sensitive to infestation with R.appendiculatus. The results have important implications for management of ticks in Africa, but need to be interpreted within the context of the control of tick-borne diseases.

The effects of the brown ear-tick, Rhipicephalus appendiculatus, on milk production of Sanga cattle.

Lactating Sanga cows of the Mashona breed from Zimbabwe, receiving either a low or high level of nutritional supplement, were exposed to two levels of infestation of adults of the brown ear-tick, Rhipicephalus appendiculatus in the highveld of Zimbabwe. The effect of the ticks on the milk yield was measured over an 11-week period during the rainy season from January to April 1986. A technique in which calves were weighed before and after suckling was used to estimate milk yield. There were significant treatment effects of ticks (P < 0.05) on milk production but no significant differences in liveweight gain between calves from tick-free and tick-infested dams. The loss in milk production was poorly related to the number of female ticks that engorged, being 9 g (SEM 4) per tick. A Friesian x Hereford (Bos taurus) reference group of cattle carried 50% more ticks than the Mashona cows, illustrating a difference in resistance between the breeds. Thirteen screw-worm (Chrysomya bezziana) strikes were recorded amongst the thirty-two Mashona cows compared with twenty-one amongst the ten Friesian x Hereford animals between January and the end of March.

Anthelmintic resistance of trichostrongylids in sheep in the highveld of Zimbabwe

A survey was conducted on the occurrence of anthelmintic resistance of trichostrongylids on commercial sheep farms in the highveld of Zimbabwe. On ten farms the efficacy of fenbendazole, levamisole and rafoxanide was tested by a faecal egg count reduction test. Benzimidazole resistance was additionally examined using an egg hatch assay with thiabendazole. Results of the faecal egg count reduction tests and larval differentiations showed fenbendazole resistance of Haemonchus sp. on all investigated farms. Resistance of Haemonchus sp. against rafoxanide was demonstrated on all farms with reliable egg counts. Levamisole resistance of Haemonchus sp. was found on most farms but 2 famrs showed an efficacy of 100%.

The epidemiology of gastrointestinal nematode infections in communal cattle and commercial beef cattle on the highveld of Zimbabwe

An epidemiological study of gastrointestinal nematode infections of cattle was conducted on the highveld of Zimbabwe from June 1993 to May 1995. The study was carried out in two communal areas, two conventional beef farms and two commercial beef farms with irrigated pastures. On all farms/areas, faecal egg counts were low (< 500 eggs per g faeces) during the dry season. During the rainy season faecal egg counts were highest in communal areas and lowest in conventional beef farms. Those of irrigated farms had intermediate values. During the dry season pasture larval counts were low in irrigated pastures and conventional beef farms and virtually zero in communal areas. They increased and peaked during the rainy season, coinciding with the egg count peaks. Worm burdens of necropsied cattle indicated that 100% of the animals were infected with nematodes. The important species were Cooperia pectinata, C. punctata, Haemonchus placei, Trichostrongylus axei and Oesophagostomum radiatum in all farms/areas and Ostertagia ostertagi in a beef farm with irrigated pastures. Haemonchus survived the dry season as inhibited early fourth stage larvae whereas Cooperia and Trichostrongylus survived as adults.

Geographic compatibility of the freshwater snail Bulinus globosus and schistosomes from the Zimbabwe highveld

Populations of Bulinus globosus were sampled from two rivers, 60 kim apart, in nothern Zimbabwe, and offspring from each geographic strain reared in the laboratory. Schistosomes were harvested from each strain and also maintained in the laboratory. Cross-infection experiments were conducted, whereby snails of both geographic strains were exposed to parasites of both geographic strains. Compatibility was found to be related to: (i) the geographic origin of the snail, and (ii) an interaction between the geographic origin of snail and parasite, such that sympatric combinations of snails and parasites produced a greater proportion of compatible infections than allopatric combinations. Cercarial output of infected snails was found to be related to the geographic origin of the parasite, but not of that of the snail. It is suggested that, as the snails used were laboratory bred and naive to schistosome infection, differences in snail — schistosome compatibility were genetically determined, rather than an adaptive response. This study supports earlier work which suggests the existence of geographic compatibility amongst natural populations of snails and trematodes, indicative of either increased infectivity by the parasite, or decreased resistance by the snail.

Seasonal prevalence of gastrointestinal nematodes in communal land goats from the highveld of Zimbabwe

On six occasions during a 1 year period, goats run on communal pastures by small-scale farmers, were purchased, housed indoors for 3 weeks and autopsied for examination of their gastrointestinal nematode burden. All of the 32 goats examined were infected. The four dominant species, Haemonchus contortus, Trichostrongylus axei, Trichostrongylus colubriformis and Oesophagostomum columbianum, were present in 88–97% of the animals. Three other nematodes, Strongyloides papillosus, Bunostomum spp. and Trichuris spp. occurred respectively in 9%, 3% and 21% of the goats. The total nematode burden was least at the end of the dry season in November and increased gradually through the rainy season to reach a peak at the end of the rains in April. The population of H. contortus followed the same trend as that of the total worm burden. Trichostrongylus colubriformis showed a peak in April and T. axei in June. The fourth stage larvae (L 4) of H. contortus accounted for 0–6.8% of the total H. contortus population during most of the year except in August, when they comprised 46.1% of the burden. It can be concluded that there is a direct relationship between rainfall and intensity of infection with gastrointestinal nematodes.

Epidemiological observations on gastro-intestinal nematodes in communal land cattle from the highveld of Zimbabwe

Monthly individual faecal samples from 12 calves, 12 heifers, 17 steers, 12 lactating and 10 dry cows from the communal lands near Harare in the Mashonaland province of Zimbabwe, were collected over a period of one year. Eggs per gram (epg) were determined and the infective larvae (L3) examined, following culture of pooled samples from each group of animals. The lowest counts were found in steers and the highest in calves. The lactating cows had egg counts as high or higher than the heifers. The general trend of epg was related to the rainfall pattern. The egg counts rose from December to reach a peak during April and May, followed by a decline and low levels during the dry period, from June to December. Cooperia, Haemonchus, Trichostrongylus, Oesophagostomum and Strongyloides (in calves only) were identified on coproculture. About 73-83% of L3 belonged to Cooperia and Haemonchus. The high level of infection by nematodes in the communal land cattle was thought to be due to overstocking, overgrazing and poor pasture quality.

Population Biology of the Freshwater Snail Biomphalaria pfeifferi in the Zimbabwe Highveld

1. The population dynamics of Biomphalaria pfeifferi (Krauss), an intermediate host for intestinal schistosomiasis, were studied at four river sites in the Zimbabwe highveld for up to 28 months. 2. Adult snail abundances were monitored at weekly intervals using a fractional sampling method. 3. At two sites a mark-recapture method was used to estimate absolute abundances and recruitment and loss rates. 4. Seasonal variations in abundance were related to temperature and water flow. Mortality rate was not significantly influenced by temperature but recruitment rate increased over the range 13-24°C

Seasonal activity patterns of julid millipedes in Zimbabwe

Seasonal activity patterns in animals are usually associated with feeding or reproduction. Many organisms use quite subtle environmental cues such as changes in temperature, rainfall, daylength and food availability to induce particular activity patterns (e.g. Delinger 1986). Although such factors may appear to vary very little in certain tropical environments, seasonality is still a common phenomenon (many examples in Wolda 1987). We have studied the millipede (Diplopoda) fauna of riverine, savanna and managed habitats in the highveld of Zimbabwe and report here on a seasonal pattern of surface activity for all julid species encountered. Millipedes are a diverse and abundant group in both temperate and tropical ecosystems (Blower 1985, Lawrence 1984). They are long lived, show a wide range of lifestyles and reproductive tactics and tend to be seasonally active. In southern Africa the millipede fauna is dominated by the Spirostreptida and Julida (Lawrence 1984). Individuals of species in these orders are typically large (1-30g body mass) and occupy a wide range of habitat types. Surface activity was measured as the mean number of animals collected in cryptozoan boards (Cole 1946) in three habitat types: natural miombo woodland (Wild & Barbosa 1967), fallow pasture and disturbed miombo woodland (no longer dominated by the canopy trees Brachystegia spiciformis (Benth.) and julbernardia globifora (Troupin)) near Marondera (1 8? 10' S, 340 30? E). The cryptozoan boards used to trap animals in this study were 20 cm x 30 cm x 1 cm corrugated roofing tiles. Animals were collected from beneath the boards by hand. Thirty traps were set in the miombo woodland, five in the fallow and

Stilesia hepatica infection of sheep in the highveld of Zimbabwe

Stilesia hepatica infection of sheep in the highveld of Zimbabwe

Immunization of cattle against Theileria parva bovis and their exposure to natural challenge

Theileria parva bovis isolates were tested for their immunizing capacity under natural field challenge on Willsbridge Farm in the highveld of Zimbabwe. Fifteen susceptible Sussex yearlings were immunized with the Boleni stock and 15 with a mixture of three isolates from the farm, using tick-derived sporozoite stabilates. No chemoprophylaxis was used. A dose of 0.1 ml of stabilate appeared to be safe in preliminary laboratort experiments, but the reactions were severe in the Sussex cattle and one died despite treatment. Twenty-nine immunized animals and 10 controls first experienced a mild infection, starting about 15 days after their arrival at the farm. Ten of the immunized animals and four controls had schizonts in peripheral lymph nodes for variable periods; one third of those had pyrexia. Nymphal Rhipecephalus appendiculatus ticks applied to three of the reacting immunized calves transmitted Theileria taurotragi to two animals and T. parva to a third. A second Theileria infection, due to T. parva bovis, was detected shortly after the first one. Schizonts were detected in seven out of 10 controls. Pyrexia was more severe and prolonged. Two of the controls died of theileriosis. At the same time schizonts were seen in three immune animals and eight of them had short periods of pyrexia. Intercurrent infections with Babesia bigemina, Borrelia theileri and Eperythrozoon were detected and may have contributed to the fever. Tick infestations were low during the exposure. In the second year of exposure, four out of eight new control animals had severe reactions, and one died. None of the immunized animals became ill, but one animal from the first year control group, which had not reacted previously, had clinical theileriosis. It is concluded that immunization provided an effective protection against field challenge.

Haemonchus contortus with low inhibited development in sheep from the highveld of Zimbabwe

The abomasa of sheep grazing on natural pastures in the highveld of Zimbabwe were examined for Haemonchus contortus. Of 304 abomasa, 213 (70%) harboured H. contortus. The worm burden increased during the rains to reach the peak in February–March. This was followed by a decline with low worm loads throughout the dry season. The fourth stage larvae (L4) accounted for 1–7% of the total H. contortus population, except during July and August when they comprised 22 and 54% of the worm burden, respectively. It appears that the inhibition of H. contortus is not common in the commercial farming sector where sheep are treated very frequently.