Browse silage as potential feed for captive wild ungulates in southern Africa: A review

Abstract

The objective of the review was to assess the potential of indigenous browse trees as sustainable feed supplement in the form of silage for captive wild ungulates. Several attempts to use silage as feed in zoos in temperate regions have been conducted with success. Information on silage from the indigenous browse trees preferred by wild ungulates in southern Africa is scanty. The use of silage from the browse trees is of interest as it has potential to reduce or replace expensive feed sources (pellets, fruits and farm produce) currently offered in southern African zoos, game farms and reserves, especially during the cold-dry season. Considerable leaf biomass from the indigenous browse trees can be produced for silage making. High nutrient content and minerals from indigenous browsable trees are highly recognised. Indigenous browse trees have low water-soluble carbohydrates (WSC) that render them undesirable for fermentation. Techniques such as wilting browse leaves, mixing cereal crops with browse leaves, and use of additives such as urea and enzymes have been studied extensively to increase WSC of silage from the indigenous browse trees. Anti-nutritional factors from the indigenous browse preferred by the wild ungulates have also been studied extensively. Indigenous browse silages are a potential feed resource for the captive wild ungulates. If the browse trees are used to make silage, they are likely to improve performance of wild ungulates in captivity, especially during the cold-dry season when browse is scarce. Research is needed to assess the feasibility of sustainable production and the effective use of silage from indigenous browse trees in southern Africa. Improving intake and nutrient utilisation and reducing the concentrations of anti-nutritional compounds in silage from the indigenous browse trees of southern Africa should be the focus for animal nutrition research that need further investigation.

Seasonal food habits of the four-horned antelope (Tetracerus quadricornis de Blainville, 1816) in tropical deciduous forests of Aravalli mountain range, Rajasthan, Western India

“…Trees also extract nutrients from deep soil layers using a deep root system, which is inaccessible to shallow-rooted plants like grasses and herbaceous plants. Thus, browse provides a good source of nutrients for wild ungulates (Mbatha & Bakare, 2018;Ngwa, Nsahlai, & Iji, 2004), but it also contains more secondary metabolites (condensed tannins, alkaloids, terpenes) than grasses, reducing digestibility (Robbins, 1993;Robbins, Spalinger, & Van Hoven, 1995). Nonetheless, some secondary metabolites such as tannins can also mitigate iron overload disorder in wild ungulates (Lavin, 2012).…”

Preference of intake of different tree leaves preserved with drying and ensiling by nyala antelope (Tragelaphus angasii)

“…b Difference from 0.50 (lack of preference). (Clauss et al, 2001;Hatt et al, 2005;Mbatha & Bakare, 2018).…”

“…However, large ruminants, such as giraffes, are unlikely to meet energy requirements only on a lucerne hay diet (Hatt et al, 2005). Browse is rapidly consumed by browsers, even when fed in high amounts, and thus may increase DM intake (Clauss et al, 2001; Hatt et al, 2005; Mbatha & Bakare, 2018). Therefore, there is a consensus among zoo nutritionists that browse should be fed in amounts as high as possible (e.g., for giraffes; Hummel & Clauss, 2006).…”

“…However, it can be speculated that browsers should have more precise recognition of tastes that are not preferred. Browse may contain many secondary, potentially poisonous substances (Clauss, Kaiser, & Hummel, 2008; Mbatha and Bakare, 2018). This innate taste preference may allow for avoiding poisonous plants or selecting feed with the highest nutritional value (Ginane et al, 2011; Provenza, Pfister, & Cheney, 1992).…”

Specialised for the Swamp, Catered for in Captivity? A Cross-Institutional Evaluation of Captive Husbandry for Two Species of Lechwe

“…Approximately 150,000 even-toed ungulates are held in captivity across all 863 species360 © (https: //www.species360.org/) member zoos (as of August 2020). Research into optimum management practices for exotic ungulates is a growing area of zoo science [1][2][3][4] and, given the diversity of populations held, and the multiple ways of exhibiting ungulates in zoos, the growth of ungulate-focussed research is useful to the development of good practice. However, not all commonly housed species are well understood.…”