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E. T. Clemens - One of the best experts on this subject based on the ideXlab platform.

  • Digestive efficiency in two small, wild ruminants: the dik-dik and suni Antelopes.
    Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 1999
    Co-Authors: Gmo Maloiy, E. T. Clemens
    Abstract:

    Abstract A comparative study, using six dik-dik and eight suni antelope, was undertaken to identify similarities and differences that may exist in the digestive process of these two small, East African ruminant browsers. The suni antelope was the more select feeder, preferring the native, Grewia sinilis leaves over that of lucerne hay. Daily forage consumption rate, per unity body weight, was greater in the dik-dik (40.4 g/kg) than for the suni (30.6 g/kg), while daily fluid intake was considerably less (i.e. dik-dik, 68 ml/kg versus suni, 106 ml/kg body weight). Rumen fermentation studies suggested that the suni antelope attained the more rapid rumen and caecal fermentation activities, when compared to the dik-dik antelope. The difference in ruminal and caecal digestive process of the two antelope is suggested to be partly the result of the dik-dik’s arid-adaptation strategies of less fluid intake and a more diverse (less selective) browse consumption, relative to the suni antelope.

Ming Tan - One of the best experts on this subject based on the ideXlab platform.

I Mouchová - One of the best experts on this subject based on the ideXlab platform.

  • Basic haematological values in Antelopes—II. the hippotraginae and the tragelaphinae
    Comparative Biochemistry and Physiology Part A: Physiology, 2003
    Co-Authors: Jakub Pospisil, F. Kaše, Jiří Váhala, I Mouchová
    Abstract:

    1. 1. Basic haematological values in 49 animals of five species of the subfamily Hippotraginae, namely the roan antelope Hippotragus equinus, sable antelope Hippotragus niger, adax antelope Addax nasomaculatus, gemsbok oryx Oryx gazella gazella and scimitar horned oryx Oryx damah and in 51 individuals of five species in the subfamily Tragelaphinae, including the bushbuck Tragelaphus scriptus, nyala Tragelaphus angasi, greater kudu Tragelaphus strepsiceros, cape eland Tautotragus oryx and bongo Bocercus euryceros are reported. 2. 2. The erythrocyte counts were in the range of 12.62 × 1012/1 in the gemsbok oryx to 6.44 × 1012/l in the bongo, the haematocrit values varied from 0.488 in the nyala to 0.380 in the roan antelope and for the haemoglobin highest levels (164.0 g/l) were noted in the adax antelope, and the lowest (105.5 g/l) in the bongo. 3. 3. Leukocyte counts were found mostly in the normal human range and varied from 7.17 × 109/l in the adax antelope to 4.05 × 109/l in the nyala, only in the greater kudu decreased values of 3.02 × 109 were estimated. 4. 4. These results are compared with findings taken from the literature, and with the normal human range.

H H T Prins - One of the best experts on this subject based on the ideXlab platform.

  • interspecific resource competition in Antelopes
    Antelope Conservation, 2016
    Co-Authors: H H T Prins
    Abstract:

    Intraspecific or interspecific competition is then fundamentally the same: scramble competition is a good example of this type of competition. Modern ecology increasingly is faced with the question whether the data or a paper provide evidence for the statement that is made or for testing the hypotheses one believes in. Much of the research on Antelopes and ungulates in general suffers from an exuberance of possible causes to explain numerical changes in study populations. Multi-causality is the bane of community ecology. The issue of facilitation of Antelopes by zebra has been a long-running theme in African savanna ecology. The cases of competition are as follows: small Antelopes competing with giraffe, cattle that compete with gaur, cattle that compete with deer, cattle that compete with impala, cattle that compete with buffalo, and buffalo that compete with African elephant and possibly blue wildebeest that compete with African elephant.

  • activity pattern relates to body temperature variation of differently sized south african Antelopes
    2015
    Co-Authors: F Van Langevelde, Anil Shrestha, S E Van Wieren, S De Bie, H H T Prins
    Abstract:

    Heat stress can limit the activity time budget of ungulates due to hyperthermia, which is relevant for African Antelopes in ecosystems where temperature routinely increases above 40 °C. Body size influences this thermal sensitivity as large bodied ungulates have a lower surface area to volume ratio than smaller ungulates, and therefore a reduced heat dissipation capacity. We first tested whether the activity pattern during the day of three antelope species of different body size— eland, blue wildebeest and impala—is negatively correlated with the pattern of black globe temperature (BGT) [1]. Furthermore, we tested whether the larger bodied eland and wildebeest are less active than the smaller impala during the hottest days and seasons. To understand this adaptive behaviour, we investigated daily and seasonal variation in body temperature (Tb) of these three species of antelope, using abdominally-implanted temperature data loggers [2]. The study was conducted at two climatically contrasting environments in South Africa, one with a less seasonal and mild winter (Mapungubwe National Park) and the other with a more seasonal, long and cold winter (Asante Sana Game Reserve) [1,2]. Since the habitat with long and cold winters would be suboptimal for these African Antelopes, which evolved in less seasonal and hot environments, Antelopes in Asante Sana were expected to exhibit a larger amplitude in Tb and a lower minimum body temperature (MinTb) during winter to reduce Tb and the ambient temperature (Tb-Ta) gradient to save energy. Our results show that BGT was negatively correlated with the diurnal activity of eland, wildebeest and impala, particularly during summer. During spring, only the activity of the larger bodied eland and wildebeest was negatively influenced by BGT, but not for the smallest of the three species, the impala. We argue that spring, with its high heat stress, coupled with poor forage and water availability, could be critical for survival of these large African Antelopes. In both eland and impala, 24-hour body temperature amplitude did not differ between the study sites, regardless of season. Conversely, wildebeest in Mapungubwe showed a higher variability in the 24-hour amplitude of body temperature and also a lower MinTb during winter and spring than the wildebeest in Asante Sana. This variation in Tb among Mapungubwe wildebeest was influenced by both the amplitude of ambient temperature (positive) and cumulative rainfall (negative), which was not the case for wildebeest in Asante Sana. We propose that the low MinTb of wildebeest in Mapungubwe was the result of nutritional stress during winter and spring; an evident response even during a year of average rainfall. Therefore, these wildebeest apparently live in a physiologically stressful environment. With the predicted increase in the frequency and intensity of drought periods in southern Africa, wildebeest, and other grazers, will likely experience greater nutritional stress in the future. Our study contributes to understanding how endothermic animals can cope with extreme climatic conditions, which are expected to occur more frequently due to climate change.

  • larger Antelopes are sensitive to heat stress throughout all seasons but smaller Antelopes only during summer in an african semi arid environment
    International Journal of Biometeorology, 2014
    Co-Authors: Anil Shrestha, F Van Langevelde, S E Van Wieren, S De Bie, Andrea Fuller, Robyn S Hetem, Leith C R Meyer, H H T Prins
    Abstract:

    Heat stress can limit the activity time budget of ungulates due to hyperthermia, which is relevant for African Antelopes in ecosystems where temperature routinely increases above 40 °C. Body size influences this thermal sensitivity as large bodied ungulates have a lower surface area to volume ratio than smaller ungulates, and therefore a reduced heat dissipation capacity. We tested whether the activity pattern during the day of three antelope species of different body size—eland, blue wildebeest and impala—is negatively correlated with the pattern of black globe temperature (BGT) during the day of the ten hottest days and each season in a South African semi-arid ecosystem. Furthermore, we tested whether the larger bodied eland and wildebeest are less active than the smaller impala during the hottest days and seasons. Our results show that indeed BGT was negatively correlated with the diurnal activity of eland, wildebeest and impala, particularly during summer. During spring, only the activity of the larger bodied eland and wildebeest was negatively influenced by BGT, but not for the smallest of the three species, the impala. We argue that spring, with its high heat stress, coupled with poor forage and water availability, could be critical for survival of these large African Antelopes. Our study contributes to understanding how endothermic animals can cope with extreme climatic conditions, which are expected to occur more frequently due to climate change.

  • body temperature variation of south african Antelopes in two climatically contrasting environments
    Journal of Thermal Biology, 2012
    Co-Authors: Anil Shrestha, F Van Langevelde, S E Van Wieren, S De Bie, Andrea Fuller, Robyn S Hetem, Leith C R Meyer, H H T Prins
    Abstract:

    Abstract To understand the adaptive capacity of a species in response to rapid habitat destruction and climate change, we investigated variation in body temperature (Tb) of three species of antelope, namely eland, blue wildebeest and impala, using abdominally-implanted temperature data loggers. The study was conducted at two climatically contrasting environments in South Africa, one with a less seasonal and mild winter (Mapungubwe National Park) and the other with a more seasonal, long and cold winter (Asante Sana Game Reserve). Since the habitat with long and cold winters would be suboptimal for these African Antelopes, which evolved in less seasonal and hot environments, Antelopes in Asante Sana were expected to exhibit a larger amplitude in Tb and a lower minimum body temperature (Min Tb) during winter to reduce Tb and the ambient temperature (Tb−Ta) gradient to save energy. In both eland and impala, 24-h body temperature amplitude did not differ between the study sites, regardless of season. Conversely, wildebeest in Mapungubwe showed a higher variability in the 24-h amplitude of body temperature and also a lower Min Tb during winter and spring than the wildebeest in Asante Sana. This variation in Tb among Mapungubwe wildebeest was influenced by both the amplitude of ambient temperature (positive) and cumulative rainfall (negative), which was not the case for wildebeest in Asante Sana. We propose that the low Min Tb of wildebeest in Mapungubwe was the result of nutritional stress during winter and spring; an evident response even during a year of average rainfall. Therefore, these wildebeest apparently live in a physiologically stressful environment. With the predicted increase in the frequency and intensity of drought periods in southern Africa, wildebeest and other grazers, will likely experience greater nutritional stress in the future.

Gmo Maloiy - One of the best experts on this subject based on the ideXlab platform.

  • Digestive efficiency in two small, wild ruminants: the dik-dik and suni Antelopes.
    Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 1999
    Co-Authors: Gmo Maloiy, E. T. Clemens
    Abstract:

    Abstract A comparative study, using six dik-dik and eight suni antelope, was undertaken to identify similarities and differences that may exist in the digestive process of these two small, East African ruminant browsers. The suni antelope was the more select feeder, preferring the native, Grewia sinilis leaves over that of lucerne hay. Daily forage consumption rate, per unity body weight, was greater in the dik-dik (40.4 g/kg) than for the suni (30.6 g/kg), while daily fluid intake was considerably less (i.e. dik-dik, 68 ml/kg versus suni, 106 ml/kg body weight). Rumen fermentation studies suggested that the suni antelope attained the more rapid rumen and caecal fermentation activities, when compared to the dik-dik antelope. The difference in ruminal and caecal digestive process of the two antelope is suggested to be partly the result of the dik-dik’s arid-adaptation strategies of less fluid intake and a more diverse (less selective) browse consumption, relative to the suni antelope.