Worldwide, the invasiveness of Opuntia spp. and its impact on various ecosystem services has been recognised especially in semi-arid areas where rainfall is erratic. The semi-arid environments are the habitats of plants which have adapted to be able to grow in severe hot and dry regions. Opuntia spp. normally thrives in conditions of high temperatures, low rainfall, saline soils and it can also adapt and survive in severely degraded soils which have a limited nutrients supply. Its positive impact includes its recognised value as livestock fodder. Opuntia’s adaptability to harsh conditions, high dry matter yield, palatability and significant levels of energy, as well as its availability at a low cost during the dry season, decreases the use of expensive supplements and conventional diets in many areas. There is a need to understand the importance of this invasive Opuntia species when incorporated in animal diets. As a part of its control measures, the use of livestock in controlling the spread of Opuntia may assist in reducing its abundance and invasiveness while at the same time providing a consistent supply of forage during the dry season. Information on its nutritive value, incorporating the species in animal diets and the means to control it must be well understood to recognise the species’ contribution to an ecosystem.

Among the possible impacts of plant invaders on South African biodiversity, water supplies, and rangeland production, Lantana camara is ranked the highest in terms of its environmental impact. Globally, L. camara is regarded as one of the most ecologically and economically destructive invasive alien plants. The spread of L. camara affects the environment and threatens livestock productivity due to its toxicity to animals (especial cattle and sheep) in most semi-arid areas of South Africa. Lantana camara is known to have high concentrations of nutrients that are beneficial to livestock, but most previous research has concentrated on its toxicity. To enrich our knowledge on its nutritive value, further research has to evaluate its dietary impact on the growth and health of different ruminant livestock species, particularly goats. This review evaluates L. camara as a potential browse species for goats in southern Africa, and its adverse effects on goats and other ruminant livestock are also presented. The review describes L. camara and its distribution globally, its poisonous effect to livestock, and potential use as an alternative forage to browsing animals such as goats, which have proved resistant to its harmful traits. The high crude protein content, low fibre and adequate macro-minerals for small ruminants makes L. camara a good ruminant protein supplement in semi-arid areas. In addition to other biological control strategies, the prospects of using goats as a biological management tool is discussed. The research will contribute to the understanding of the control measures of L. camara while improving the productivity of small stock, especially goats. This means that a balanced understanding of its nutritional value as a source of protein and its negative impact on the environment should be considered in developing mitigation strategies to arrest its spread. We, therefore, recommend the use of goats in the control of L. camara; however, further studies are needed to limit its toxic effects, and thus improve its value.

Globally, there have been differing views on whether the proliferation of invasive species will be of benefit as a livestock feed source or it will have detrimental effects on the ecosystem. The infestation of invasive plants such as Prosopis species does not only affect the groundwater levels but also threatens the grazing capacity and species richness of most of the semi-arid areas around South Africa. Though Prosopis is invasive, it is however of good nutritive value and can serve as an alternative source of protein and minerals for livestock during the dry season. Bush encroachment by browsable invasive species can be controlled through biological methods by using organisms such as livestock. The utilisation of Prosopis through browse benefits livestock production and at the same time reduces its spread, thereby preventing possible environmental harm that may arise. Although several studies have been carried out globally on the assessment of the Prosopis species’ nutritive value and also on the threat of this invasive species to the environment, there is a need to update the state of knowledge on this species, particularly in the context of the semi-arid areas of South Africa where the dry season is characterised by less herbage of poor quality. It is therefore critical to understand whether Prosopis is a beneficial invader, or a detriment that needs to be eradicated. This review will contribute knowledge towards finding practical solutions to controlling Prosopis species and whether utilising Prosopis as a feed source will limit its spread and result in a vegetation structure where Prosopis becomes part of the ecosystem with limited detrimental impact. This means that the several components of the species such as nutritive value and the negative impact associated with this plant species along with the means to control its spreading must be well understood to recognise the plant species’ vital contribution to the ecosystem.

The objective of this study was to investigate the nutritive value, in vitro dry matter degradability (IVDMD), and ensiling characteristics of legume foliage–maize straw silages. For silage, the proportion of legume to maize was 20%:80% (maize–lablab (ML), maize–indigenous cowpea (MI), maize–Betswit (MB), and maize–Dr Saunders (MD)). Maize alone (M) was used as a control, making up five treatments. Silages were opened after 45 days, and samples were taken for chemical composition, IVDMD, and fermentation characteristics analysis. Other samples were put through a seven-day aerobic stability test. All data were subjected to a one-way analysis of variance, in a completely randomized design (CRD). For the nutritive value of the silage, the ML had the highest (p < 0.05) crude protein (CP) content, when compared with other silages. Maize–Betswit had the lowest (p < 0.05) neutral detergent fibre (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) content, when compared with other silages. The lowest (p < 0.05) ether-extract (EE) and hemicellulose content was recorded for MI silage. The lowest (p < 0.05) pH was recorded for maize silage. All silages had similar (p > 0.05) amounts of lactic acid (LA), water-soluble carbohydrates (WSC), yeast, and mould counts. The MI had the lowest (p < 0.05) carbon dioxide (CO₂) concentration, when compared with other silages. The highest (p < 0.05) IVDMD was recorded for ML silage, from 24 h up to 72 h. The addition of legumes in maize straw resulted in improved silage quality and fermentation characteristics.

Forage legumes are commonly used as an absorbent additive in high-moisture silages. Thus this study was carried out to assess the nutritive value, fermentation characteristics and aerobic stability of Opuntia–legume browse mixed silages. Five browse legume species (Leucaena leucocephala, Acacia mellifera, Searsia lancea, Prosopis velutina, and Grewia flava) were mixed with Opuntia cladodes. The silage mixture was formulated at a ratio of 60 Opuntia cladodes: 40 leguminous browse species and ensiled in polythene bags and kept in a laboratory for 42 days to determine chemical composition and fermentation characteristics. Silage samples were also subjected to an aerobic stability test. One-way analysis of variance in a completely randomised design was used to analyse the data. The pH values for silages made from Opuntia cladodes with L. leucocephala, A. mellifera and G. flava were lower than 4.8, which is considered an indicator of good-quality silage. The water-soluble carbohydrates content of silages made with Opuntia cladodes and S. lancea and G. flava was within the range of 8–12 g/kg dry matter, which is sufficient for good fermentation. The highest CO2 production, which signifies poor aerobic stability, was recorded for the control silage (Opuntia) compared to all Opuntia–legume mixed silage treatments. The addition of legume browse leaf-meal to Opuntia cladodes improved nutritive value, fermentation characteristics, and silage quality. Therefore, despite some limitations, Opuntia–legume browse silages, particularly Opuntia–G. flava and Opuntia–L. leucocephala, proved to be beneficial for livestock, as they meet the nutritional requirement of a ruminant. Significance:This study underlines the importance of co-ensiling Opuntia cladodes and high protein legume browse hay to offer an alternative feeding strategy for ruminant livestock and ensure sustainable provision of high-quality feed during dry periods.

A cost-effective, alternative protein and mineral source such as the Viscum species can be key to livestock production. Viscum spp. are used as feed in many semi-arid and arid regions globally, particularly during feed shortages. The species’ feeding value, and their pharmaceutical attributes, have been recognized worldwide, albeit with variation in nutritive value from one host to another. The antinutritional factors found in Viscum spp. may benefit livestock when consumed in moderation due to their immunomodulatory, proapoptotic, and antimicrobial properties. The Vachellia species are known to be the common hosts for Viscum spp. Further, even though Viscum spp. inhibit host tree development by reducing carbon absorption and the host tree’s carbohydrates, the efforts to regulate their infestation should not result in the plant’s total eradication due to the benefits to livestock (as well as in fodder and medicine). This review will help to improve understanding of Viscum species control measures, while also increasing the productivity of ruminants.