Doctoral Degrees (Animal, Wildlife and Grassland Sciences)

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Browsing Doctoral Degrees (Animal, Wildlife and Grassland Sciences) by Author "De Waal, H. O."

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    The demography and population status of lions (Panthera leo) in the Mana Pools National Park, Zimbabwe
    (University of the Free State, 2008-11) Monks, Norman John; De Waal, H. O.
    English: Demographics of the lion population in the Mana Pools National Park were studied between 2001 and 2007. No detailed work had previously been carried out on this subject in the park. Demographic data was obtained from six prides, with two prides (Chitake and Jesse) being on the Zambezi Valley floor at the base of the Zambezi Escarpment in the south, and four prides on the Zambezi floodplain in the north. The Zambezi floodplain in the Mana Pools National Park is 95.5 km² in extent and in area comprises 11.2% of the park. Approximately 46% of the adult lion population occurs on the floodplain where approximately 63% of the lion prey base in the park is found. Not all prides could be studied at the same intensity, however, demographic data was obtained for all six prides. The Nyamepi pride on the floodplain was the most intensely studied. A population estimate of 67 adult and sub-adult lions was made for the Mana Pools National Park. Overall density throughout the park was 3.05 lions/100 km². Density ranged from 0.65/100 km² in the escarpment which held 0.3% of the prey species taken by lions to 12.7/100 km² on the floodplain. There were 1.8 adult males to 3.3 adult females and all prides were attended by a male. Mean group size (adults and sub-adults) was 7.8 (range 5-11). The adult and sub-adult age class made up 70.7% of the population and large and small cubs made up 29.3% of the population. Cub survival to one year of age was 66.7%. Females produced their first litter between 43-53 months of age and cohorts of cubs were produced on average every 38.5 months. Pride males had an average tenure with the pride of 33.25 months and sub-adult males dispersed from the pride between 36-57 months with a mean of 39.8 months. Home ranges varied on the floodplain from 28.1 km² to 278 km² and from 50.2 km² to 379.3 km² on the valley floor. The floodplain Nyamepi pride males had a home range two and a half times that of the females. Only the Valley floor lions had differences in dry and wet season home range size (dry season 57.7 km² and wet season 379.3 km²). Demographic variables, when compared to other lion populations in similar habitat in protected areas in Africa, did not differ and the Mana Pools National Park lion population appears to be normal. The Mana Pools National Park is surrounded in the west and east by Safari areas (administered by ZPWLMA) and has no man-made or natural barriers between them. No work was carried out on lions in the surrounding Safari areas but it was found that males frequently made excursions into the Safari areas (one collared male was shot in Chewore Safari area 80 km from the darting site in Mana Pools). Lions also frequently crossed the Zambezi River into the Lower Zambezi National Park, Zambia. It is presumed that there is a two-way movement between the Mana Pools National Park and Safari areas and the Park and the Lower Zambezi National Park, but could not be confirmed in this study. The spotted hyaena population in the Mana Pools National Park was found to be in the low-medium category when compared to other populations in protected areas in Africa (Purchase, 1999). All data accrued during the present study showed that this population do not pose a threat to lion conservation in and around the Mana Pools National Park.
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    The utilization by domestic ruminants in Botswana of treatment diets containing cereal crop stovers treated with urea or urea and molasses
    (University of the Free State, 2007-03) Letso, Moagi; De Waal, H. O.
    English: The studies were aimed at examining the effects of treatment with urea or urea and molasses on the physical and chemical composition of stovers of sorghum, maize and millet and assessing the potential of these treated cereal crop stovers as additional feed for domestic ruminants in Botswana. The trials were carried out at Sebele, Botswana College of Agriculture (BCA), Botswana. Sebele is situated at 24º 33'S and 25º 57'E and is at an altitude of 994 m above sea level. Cereal crop stovers were ground in a hammer mill and treated with 10 g urea/kg stover (T1), 25 g urea/kg stover (T2) or 10 g urea + 10 g molasses/kg stover (T3) for 3 weeks. The experimental design for the treatment of the cereal crop stovers was a 3 x 4 completely randomized factorial design [3 cereal crop stovers and 3 treatment methods (T1, T2, T3) plus untreated]. Samples of cereal crop stovers untreated or treated with T1, T2 or T3 were obtained and analysed for dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and in vitro DM digestibility (IVDMD). The physical changes on the cereal crop stovers due to treatments were noted. Six steers, four of which were fitted with rumen cannulae, and six goats and six sheep were used in a crossover experiment to evaluate the utilisation of treatment diets containing stovers of sorghum, maize and millet treated with T1, T2 or T3. The animals were kept in individual pens and fed a basal diet of veld grass hay plus a commercially available feed, namely Pen-feed. Each animal had unrestricted access to water and a mineral lick and were adapted to the respective treatment diets for 14 days, followed by 7-day sampling periods The data collected included the feed intake and digestibility coefficients of DM, OM, CP, NDF and ADF. Data were also obtained on metabolisable energy (ME) intake, average daily gains and the pH and ammonia concentration of rumen fluid. Treatment with T1, T2 and T3 increased the CP, NDF, ADF, ADL and IVDMD of the cereal crop stovers. The mean CP (g/kg DM) of cereal crop stovers increased from 69.75 (untreated) to 99.94, 112.63, and 110.50 when treated with T1, T2 and T3 respectively. Significant improvements in the total intake of DM and CP by steers compared to the Control diet were observed when feeding cereal crop stovers treated with T2 and T3. The improvements in the intake and nutrient digestibility coefficients when providing some treatment diets containing the treated stovers are comparable to those obtained when offering lucerne hay which implies that these treatment diets may be suitable replacements for lucerne hay. However, the treatment diets did not significantly improve the average daily gain and metabolic body weights of the steers, goats and sheep. Therefore, treatment diets containing stovers of sorghum, maize or millet treated with T1, T2 or T3 used in the present study are recommended for maintenance rather than production purposes.