Research Articles (Animal Sciences)

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    Smallholder sheep farmers’ perceived impact of water scarcity in the dry ecozones of South Africa: determinants and response strategies
    (Elsevier B.V., 2021-09) Halimani, Twanani; Marandure, Tawanda; Chikwanha, Obert C.; Molotsi, Annelin H.; Abiodun, Babatunde J.; Dzama, Kennedy; Mapiye, Cletos
    Water scarcity is amongst the major challenges threatening smallholder sheep production in subsistence-oriented communal farms in dryland areas. Local contextual factors are a prerequisite for effective policy development and optimisation of water resources management for smallholder sheep production. Two-hundred and fifty-two structured questionnaires were administered to investigate the contextual factors that influence smallholder farmers’ perceived impact of water scarcity on sheep production in the dry ecozones of the Cape provinces in South Africa and identify their local response strategies. Logit regression findings showed that a unit increase in private commercially-oriented arid farms, males, education level, flock size, adapted breeds and income from livestock increased farmers’ probability to perceive impact of water scarcity on sheep production. Regardless of ecozone and farm types, sheep farmers switched between water sources, provided supplementary feed and shade, used adapted breeds and alternative markets to manage the impact of water scarcity. Interventions to build resilience to water scarcity in the surveyed areas should target sheep farmers with low adaptive capacity, particularly less educated women relying on livestock income and farming with non-adapted breeds on subsistence-oriented communal farms in the semiarid ecozone.
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    Emerging from Below? Understanding the Livelihood Trajectories of Smallholder Livestock Farmers in Eastern Cape Province, South Africa
    (MDPI, 2021-02-23) Gwiriri, Lovemore C.; Bennett, James; Mapiye, Cletos; Burbi, Sara
    In the context of current agrarian reform efforts in South Africa, this paper analyses the livelihood trajectories of ‘emergent’ farmers in Eastern Cape Province. We apply a rural livelihoods framework to 60 emergent cattle farmers to understand the different capitals they have drawn upon in transitioning to their current class positions and associated vulnerability. The analysis shows that, for the majority of farmers, no real ‘transition’ from subsistence farming has occurred. However, they draw limited resilience from increased livestock holdings, continued reliance on social grants and connections with communal villages. A transition into small-scale commercial farming is apparent for a small number of farmers through the deployment of financial, human and social capitals. However, in following these trajectories, most of these farmers have been made more vulnerable to shocks and stresses than previously. We suggest that key to mitigating this vulnerability will be access to low-risk financial capital, more targeted support, and strategies to support farmers that might not transition from subsistence production.
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    Effects of Saccharomyces cerevisiae, medium and forage type and their interactions on in vitro ruminal fermentation
    (Elsevier, 2020-09) Russouw, A.; Chevaux, E.; Chaucheyras-Durand, F.; Esposito, G.; Raffrenato, E.
    The objective of this study was to investigate the effects of a live yeast, Saccharomyces cerevisiae CNCM I-1077, at four doses (0, 1×105, 1×106 and 1 × 107 cfu/mL) according to the reducing medium used [Goering-Van Soest (GV), McDougall (MD) or Kansas State (KS)] on in vitro ruminal neutral detergent fibre digestibility (NDFd), rate of digestion of NDF (kd), organic matter digestibility (OMd), dry matter digestibility (DMd), pH as well as volatile fatty acids (VFA) concentration, using two forages (oat hay and wheat straw) with differing chemical composition. The maximum in vitro NDFd, DMd, OMd as well as kd were obtained with dose 1 × 106 cfu/mL, although differences between doses were not always significant. The pH estimates were the lowest with the 1 × 107 cfu/mL dose, but the differences were not all significant; however, 1 × 107 cfu/mL corresponded to significantly lower pH estimates compared to the control and 1×105 (6.51 vs. 6.60 and 6.59, respectively). The decrease in pH was accompanied by an increase in VFA concentrations as the yeast dose increased. The KS medium resulted in the lowest digestibility estimates, pH estimates as well as kd, regardless of yeast dose. The 1 × 106 cfu/mL was the better performing yeast dose in vitro resulting in higher digestibility estimates which indicates the yeasts ability to stimulate the microorganisms within the rumen by beneficially modifying rumen environment, thus promoting microbiota activity. The MD and GV media provide better environments for fermentation than the KS medium, resulting in higher in vitro NDFd, DMd, OMd, pH estimates as well as rate of NDF digestion. The MD and GV are also the media that resulted in more consistent results when analysing the effects of the live yeast. Our data suggest that the in vitro conditions have to be carefully chosen to be able to demonstrate rumen fermentation shifts with the use of live microbial additives.
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    Use of pawpaw (Carica papaya) seed in tilapia sex reversal
    (Reviews in Agricultural Science, 2020-10-18) Omeje, Victor Okonkwo; Lambrechts, Helet; Brink, Danie
    Tilapia breeds effortlessly in captivity, with this attribute which is considered as the “Achilles heel” of the species, because it predisposes pond systems to overcrowding and low weight at harvest. Efforts to mitigate this shortcoming include mono-sex culture using exogenous hormone to reverse the sex of sexually undifferentiated fish. This is premised on the fact that improvement in the growth by mono-sex culture will lead to shortened production times and a more uniform weight at harvest, which will ultimately benefit the producers. However, the use of exogenous hormones in aquaculture has recently raised concerns about the effect on farm workers, consumers and on the environment. Recently research has focused on the use of substances of plants origin which mimic the action of hormones as a potential approach to achieve sex reversal in fish. Pawpaw (Carica papaya) seed contains phytochemicals that hold great promise as a sex reversal and a reproductive inhibition agent in aquaculture. The purpose of this study was to conduct a systematic review of the relevant literature on the possibility of using a less harmful phytochemicals abundant in the plant to effect sex reversal of sexually undifferentiated tilapia.
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    Effects of honeybush (Cyclopia subternata) extract on physico-chemical, oxidative and sensory traits of typical Italian salami
    (Wiley, 2020-02-18) Smit, Paula; Cullere, Marco; Zotte, Antonella Dalle; Balzan, Stefania; Hoffman, Louwrens Christiaan; Novelli, Enrico
    Honeybush (Cyclopia subternata Vogel) is an indigenous South African shrub enjoyed as hot brewed tea. "Unfermented" honeybush is also a potential antioxidant bioactive extract for foodstuffs due to its polyphenol content. The effect of "unfermented" honeybush extract (Hob; 0.5%) was evaluated in typical Italian salami and compared with nitrate (Nit; 100 mg/kg) and a control (Ctl; without nitrate or honeybush). After 35 days of ripening, Hob had a higher (p < .01) water activity (0.928), compared with Ctl (0.923) and Nit (0.924). Final pH (5.35-5.24) was not affected by treatments. Lower lipid oxidation was observed in Hob and Nit treatments (p < .001) compared with Ctl. Internal color and odor intensity were similar among treatments. Salami with honeybush extract had less spontaneous outer surface mold growth whereas the Ctl showed intermediate growth (p < .05). Honeybush extract seems a promising natural ingredient with antioxidant action.