Browse Budgets and Why Goats Are Not Small Sheep

#Five times the goat, on one veld type

At Santombe, near Mount Ayliff in the Eastern Cape, researchers walked transects across four sites of communal veld and counted the browse. The poorest site came back at 429 browsing units per hectare. The richest came back at 2 310 (Tokozwayo et al. 2021). One district, one veld type, and a five-fold difference in the only resource a goat is actually built to use.

No official map in South Africa would have told you that. Not because the surveyors were careless: the national grazing capacity map states in its own background document that it left browse out. That is a stated exclusion, not an oversight you can read around.

#The map that leaves the goat's dinner out

The long-term grazing capacity map published under Conservation of Agricultural Resources Act 43 of 1983, Regulation 10 is the legal reference for how much stock your land may carry. Its background document states four limits on itself. Three are about precision: the values assume veld in relatively good condition, the map was drawn for use at 1:250 000, and revision requires a veld condition survey by a registered pasture scientist.

The fourth is not about precision. It is about scope. "Tree crown cover was not incorporated… Browsing capacity was also not incorporated into the grazing capacity value" (DALRRD map background).

That cuts both ways. On encroached bushveld the woody layer shades and out-competes grass, so the map's grass figure is too high — you cannot run the cattle it implies. At the same time the map counts that entire woody layer as nothing, so a farm with a real browse resource is told it has less feed than it has. The map over-counts your grass and under-counts your goats, on the same hectare, at the same time.

The wildlife side of South African rangeland science answered this by keeping two ledgers. A Grazer Unit is a mature 180 kg blue wildebeest; a Browser Unit is a mature 180 kg greater kudu — same body mass, different feeding class (Shepstone et al. 2025). A mixed feeder draws on both ledgers at once, so a property can be over its grass ceiling while still under its browse ceiling. The right response there is a species-selective destock, not a blanket one. Goat farming has the same problem and no equivalent published arithmetic.

And that is the gap. For sheep, South African practice publishes feed-budgeting factors you can work with — dry wool ewe 0.15 LSU, ewe with lamb 0.20, lamb 0.10, ram 0.19 (Elsenburg Central Karoo infopak). For goats there is no equivalent. No authoritative South African goat-to-LSU or goat-to-SSU feed conversion could be found from any departmental, ARC or industry-body source. That is a real hole in the national arithmetic, and the honest answer is to measure the resource rather than invent a factor. If someone hands you a goat conversion factor, ask who published it and against which feed resource — then ask your provincial extension officer or a registered pasture scientist.

#Drawing the 1.5-metre line

A Browsing Unit has a precise definition: the total browseable length of palatable trees and shrubs within 1.5 m of the soil surface (Teague 1989, as applied by Tokozwayo et al.). The height is not arbitrary. A goat spends about 8% of its browsing time on its hind legs and gets no higher (Indigenous Goat Production Handbook). Below the line is feed. Above it is scenery — and, on an encroacher, a seed source no animal can touch.

That one fact explains two things. It explains why goats suppress bush regrowth and coppice but never clear encroached veld: mature stems are out of reach and keep seeding. And it explains the failure mode of an overstocked browse camp — a browse line, a clean horizontal edge with nothing left below 1.5 m. When you see one, the handbook's instruction is that animals must be withdrawn until it is corrected. Goats do not wreck woody veld by being goats. They wreck it when nobody counted the browse first.

At the four Santombe sites, 64% of the 14 woody species were acceptable to goats — so 36% were not, including one of the two most dominant species there. A dense woody layer is not automatically a browse resource; a third of it may be furniture.

#Working it through on a real farm

Take a 200 ha Highveld grassland property sitting on the Grassland biome mean of 6 ha/LSU. Full-year grass ledger: 200 ÷ 6 = 33.3 LSU.

Now put 100 Boer goat does on it. At the legal Table 2 factor of 0,17 LSU, that herd is 17 LSU — over half the farm's grazing capacity, before a single cow. Counting heads, it looks like a side enterprise. Counting LSU, it is half the farm.

Then walk the browse transects. Suppose they come back at roughly 50 BU/ha across 180 ha of open grassland, and around 1 200 BU/ha along 20 ha of drainage line, old kraal sites and encroaching margin. Those figures are illustrative — only your own transects can give you the real ones. Nine thousand browsing units are spread across 90% of the farm; twenty-four thousand sit on 10% of it.

On that farm the goats spend most of their time on the grass ledger, competing directly with the cattle, and only earn their differential on 20 hectares. Either you run a small herd aimed at those margins — fence lines, drainage lines, old lands, encroaching patches — or you accept that you are running a grass enterprise with goats in it and size it as one. What you may not do is add goats on top of a correct cattle stocking rate and call it multi-species. That is overstocking with extra steps.

#What actually differs between a goat and a sheep

The most-quoted number in South African goat farming is not what people think it is.

Summarising a large body of earlier work, Marais & Roux at Grootfontein report that where grass dominated the diet, the digestibility of what sheep ate was on average 3.5 percentage units higher than goats'; where shrub and tree leaves made up the larger part, goats' was on average 7.0 percentage units higher than sheep' (GADI). That crossover is the cleanest statement of the difference in a South African source — and it is a summary of prior literature, it is in vitro, and their own trial fed lucerne and wheat straw with no browse in it at all. Treat the direction as reliable and the magnitude as soft. The decision rule does not need the exact numbers: put goats against the woody and forb component, and hold total pressure on the herbaceous layer constant.

What their own trial did establish, on Merinos, Dorpers, Angoras and Boer goats, matters more: significant interspecies differences in digestibility, in rate of degradation and rate of passage, and higher rumen ammonia-N in goats on the low-quality diet — with the conclusion that "extrapolation of feed energy values from one to other animal species could not be validated" (Marais & Roux, rumen fermentation). A goat is not a sheep with different ears, and a number written for one is not transferable to the other.

There is a chemical difference too. Browsers, goats included, secrete proline-rich proteins in their saliva. These bind tannins in the mouth and pass through the gut intact, neutralising some of the tannins' adverse effects — and because those proteins are rich in non-essential amino acids, the animal spends them instead of the essential amino acids in its feed. Grazers such as sheep "appear to be incapable of synthesizing" them (Marais, GADI). Read the wording carefully: some of the effects, and the author himself calls a broader survey across herbivores "an obvious need". This is not blanket tannin immunity.

Finally, behaviour. South African field guidance for indigenous goats puts them at roughly 75% browsing and 25% grazing even when grass is available, walking 4–6 km a day, with a herd-size threshold at around 80 head above which they cannot cover the ground in the available daylight and go into nutritional stress (Handbook). Herd size is therefore a management variable of its own, independent of stocking rate — which most farmers only learn after amalgamating two flocks.

Before you decide how many goats, decide where the browse is. Walk the transects at the end of the dry season, mark the acceptable species below 1.5 m on a farm map, and put the goats against that resource. If the map comes back nearly blank — and on Highveld grassland it often will — you have a grass enterprise, and you should size and sell it as one.