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XV. Beef Production from Legume-Based Tropical Pastures
In general, progress in tropical beef production depends on persistent
and adapted legumes, regular application of superph,osphate (giving both
P and S), and use of adapted tropical cattle with tick. resistance and heat
tolerance (Schleger and Turner, 1965). Significant advances have been
made despite Whyte’s pessimistic conclusions ( 1962) concerning improvement of tropical grasslands. The following examples from areas in
the main tropical climates will make this clear.
A. WET TROPICS
Younge et al. (1964) estimated that about one-quarter of the Hawaiian
rangelands are unproductive low wetlands but capable of trebling the
current annual beef production. On the island of h4aui, pangolagrassD . intortum pastures fertilized once per acre with lime at about 3000 Ib
and a starting fertilizer comprising 44 Ib N, 84 P, 104 K, 3.5 B, and 2.5
Mo gave a mean over two years of 764 Ib liveweight gain per acre per
annum at a stocking rate of about two beasts an acre, which was highly
profitable. Also on Maui, pangola, dallis, kikuyu, and native grasses each
mixed with kaimi clover and given one dressing per acre of 6 tons of
calcium carbonate and starting fertilizer as in the previous experiment
produced over four years annual liveweight gains per acre of 720, 630,
575, and 524 Ib, respectively. At the Kauai Branch !station on an aluminous-ferruginous latosol, Younge and Plucknett (1966) with a pangolagrass-D. intortum pasture given an application of basic fertilizers and
four rates of P produced as high as I164 Ib liveweight gain per acre per
annum with yearling steers. Mean stocking rate varied from 1.18 beasts
an acre at the lowest P level to 2.38 an acre at the highest. There was a
curvilinear response to P, but the highest liveweighi: gain was obtained
from the heaviest P application. Unimproved pastures produce about 30
Ib liveweight gain per acre per annum.
Over two dry seasons at Katherine in the Northern Territory, liveweight of steers at a beast to 2 acres of Cenchrus-Townsville stylo pasture increased and that of steers at a beast to 17 acres on native pasture
declined substantially (Norman and Arndt, 1959). Shiiw (196 I ) at Rodd’s
Bay, Queensland, showed that year-round productivity of native speargrass pasture could be increased markedly by oversowing with Townsville stylo and topdressing annually with 1 cwt molybdenized superphosphate an acre. Carrying capacity of native pasture was trebled from a
steer to 9 acres to a steer to 3 acres, annual liveweight gain per acre was
E. M . HUTTON
increased five times, and steers were marketed one to two years earlier
than those on unimproved pasture. Shaw’s work ( 1 96 I ) was followed up
by Edye and Ritson ( 1 969) with a four-year study of cow fertility and
beef production in Droughtmasters (Shorthorn X Brahman) continuously
grazed on Townsville stylo-speargrass pasture (at Lansdown Pasture
Research Station) near Townsville, Queensland (Fig. 6). Pasture treatments were annual superphosphate applications per acre of nil, I cwt,
and 3 cwt, respectively. The breeders were carried at a cow to 3 acres or
6 acres, and application of superphosphate raised mean calving percentage from 6 1 to 8 1%. Weaner steers were carried at a beast to 2 acres or
4 acres and at 28-30 months of age were around 800 Ib liveweight without superphosphate and 1000-1 100 Ib with superphosphate.
FIG. 6. Droughtmaster cattle grazing on Townsville stylo-speargrass pasture at Lansdown Pasture Research Station, near Townsville, Queensland.
In the Northern Territory Norman and Stewart (1964) found that
pastures dominated by Townsville stylo gave the best liveweight gains.
Following this finding Norman (1968) studied the performance of beef
cattle on different sequences of native pasture and fertilized Townsville
stylo and showed a linear inverse relationship between the time spent on
Townsville stylo and the total time from weaning to slaughter. The group
maintained on Townsville stylo continuously from weaning reached
slaughter weight at 30 months of age. All these results have stimulated
the use of Townsville stylo fertilized with superphosphate in many
areas of the monsoonal tropics of northern Australia. Woods (1969)
documented the rapid expansion in area of Townsville stylo pastures in
the Northern Territory since 1966; up to 10,000 acres a year are being
sown on individual properties. The practice has been shown to be profitable (Haug and Hirst, 1967) in the speargrass zone and is apparently
economic in the other areas where it is used.
In Nigeria, Okorie et al. (1965) demonstrated that ]productivepastures
of giant stargrass and centro fertilized with superphosphate could be maintained under rotational grazing and were suitable for fattening N’Dama
cattle. Crude protein level of the pasture varied from 7.2 to 16.4% and
organic matter digestibility from 68 to 77%. At a stocking rate of 1.7 to
2.7 steers an acre, mean annual liveweight gains per acre were 320 Ib. In
Uganda, Stobbs (1 966) compared production from small east African
Zebu cattle on grass and grass-legume pastures at stocking rates of 1 to
1.5 beasts an acre. Annual liveweight gain per acre was increased from
188 lb to 470 Ib by the addition of centro and Stylosanthes guyanensis
and fertilizers. Introduction of legumes without ferl ilizer gave smaller
increases and the pasture became dominated by H. rhfa and S . guyanensis. In further elaboration of his results, Stobbs (1 969c) noted that grasslegume (centro, S . guyanensis) pastures receiving P and S produced
liveweight gains similar to those from grass pastures given 140 lb N per
acre per annum in addition to P and S. Stobbs (1 969b,d) outlined the
effects of stocking rate and grazing frequency on legume-based pastures
in Uganda; increased liveweight gain per acre resulted from heavy stocking and from rotational grazing only in the dry season.
Milk production from a Setaria sphacelata-D. intorturn pasture was
studied by Deschuytener (1 967) in the Republic of Rwanda. At a stocking rate of a cow per 1.2 acres without a supplement, he obtained 445
gallons of milk per acre.
The development of beef production on the Wallum of southeastern
Queensland with its very poor sandy and acid soils and annual rainfall
varying from 70 inches in the south to 40 inches in the north resulted from
successful integration of research on plant nutrition, pasture species, and
E. M . HUTTON
grazing management. Bryan ( 1968a) described the initial grazing trials
at Beerwah in the southern Wallum of four pastures with a mean legume
content of 13% and based, respectively, on common paspalum, Paltridge scrobic, Rodd’s Bay plicatulum, and pangolagrass. Heavy dressings
of fertilizer as described previously were applied and the main legumes
were silverleaf desmodium, Miles lotononis, and white clover. Stocking
rate varied from a beast to 1 to 1.5 acres and mean annual liveweight
gain was 244 Ib an acre while the best pastures produced 262 Ib an acre.
Crude protein content of the pastures was probably a limiting factor in
autumn and winter. Bryan (1 968b) found that common grazing of eight
legumes and eight grasses in complex mixtures resulted in stabilized
pastures with a legume content of 25 to 30% which produced a mean annual liveweight gain of 300 Ib an acre. The most persistent species were
the legumes white clover, silverleaf desmodium, and Miles lotononis and
the grasses common paspalum, Rodd’s Bay. plicatulum, bahia, pangola,
and Rhodes. Bryan and Evans (1 968) showed that three pastures at Beerwah with legume contents from 13 to 30% gave increased animal production per acre with increasing legume content and that the least depression in liveweight gain in winter occurred with the highest legume content.
Using the legumes white clover, Miles lotononis, and greenleaf desmodiurn with pangolagrass, Bryan and Evans (1968, 1969) obtained 450 Ib
annual liveweight gain an acre over a three-year period at a stocking rate
of 1 to 1.5 beasts per acre and with a legume content of 27-30% in the
pasture. Economic studies in the southern Wallum by W. L. Moore ( 1 967)
have shown that investment there in beef production would be profitable.
In the northern Wallum where annual rainfall is 40-45 inches, T. R.
Evans (1 968) produced vigorous pastures carrying a steer an acre and
giving annually 350-400 Ib liveweight gain an acre. The pastures have
been developed from siratro, greenleaf desmodium, or Miles lotononis
and one of the grasses Nandi setaria, Rhodes, P . plicatulum or P . colorarum. After .a heavy initial application of fertilizer annual dressings of 2
cwt superphosphate and 1 cwt potassium chloride an acre were needed.
At Mississippi in the southeastern United States with a 50-inch annual
rainfall, Hogg ( 1966) developed highly productive pastures of coastal
bermudagrass and white and red clovers. These produced quality forage
more economically than nitrogen-fertilized grass. Annual liveweight gain
per acre on coastal bermuda was 5 17 lb with white clover and 282 Ib with
In a relatively dry but fertile brigalow area of southern Queensland,
a mean cattle liveweight gain of 174 Ib an acre was obtained during a year
of below average rainfall from grass-legume pastures stocked at a beast
to 2.3 acres (Coaldrake and Smith, 1967). Animal production on sown
and native pastures in the brigalow was measured for three years by
Coaldrake et al. (1969) during conditions which changed from moderate
to severe drought. Sown pastures of a grass and Hunter River lucerne
were grazed continuously at a beast to 2.3 acres while native pasture
was stocked at a beast to 4.6 acres, but results were meaningful only in
the first two years. Annual liveweight gain per acre was lowest on native
pasture, highest on S. almum at 198 Ib in the firs1 year, and highest on
green panic at 166 lb in the second year when S. almum died. Lucerne
died out under continuous grazing, and buffel was the most droughtresistant grass. Drier subtropical areas like the brigalow (annual rainfall
24-27 inches) present difficult problems in grazing management and
Summary a n d Conclusions
In the last decade tropical pasture research has culminated in the provision of persistent and productive legumes and grasses for use in pastures throughout the tropics. It has shown that, with proper fertilization
and management of these cultivars, the tropics can produce considerably
more beef and milk than at present. Although nitrogen fertilization of high
quality grasses like pangola and kikuyu leads to high stocking rates and
high production, the costs involved in this system are high, so it will be
used only in special situations. Legume-based pasture will be the main
system used in development of the extensive unused areas of the tropics
for beef cattle as it is capable of markedly increasing production at relatively low cost.
The studies on the interrelationships between legume, rhizobium, plant
nutrients, and soil type have made it possible to successfully establish
legumes in pastures in most tropical areas. The finding that the majority
of tropical legumes and their assoicated rhizobia are: adapted to acid soils
is of special significance in tropical development. Determination of critical percentages of the major elements sufficient for maximum growth of
the different legumes has given a sound basis for fertilization of tropical
pastures. Characterization of the associate grasses in this respect has
commenced but requires much more attention if a proper understanding
of the mineral balance in tropical pastures is to be obtained. One question
which needs to be resolved is whether the mineral content of pasture
giving maximum dry matter yield is at a suffiiciently high level for maximum animal production.
More work is required on the physiological and biochemical character-
E. M. HUTTON
ization of the different species so that their deficiencies relative to pasture
and animal production in various tropical environments can be determined. This will provide a better basis for plant introduction and breeding
activities and for management studies aimed at maximizing yields of
digestible nutrients and animal products from the pasture. A proportion
of the physiological work needs to be done in the field so that it is possible
to ascertain the factors involved in the persistence and compatibility of
cultivars in grazed pastures. Determination of the biochemical and physiological bases for the relatively low feeding value of tropical grasses is an
important problem. Until this is solved, it will be difficult to improve the
efficiency of conversion of tropical pasture into animal products.
Future progress in tropical pasture research is dependent on maintaining the ecosystem approach, in which the interactions between soil,
pasture, and animal are intensively studied in pastures in different environments. Use of modern computer techniques are essential to fully
assess these interactions and devise methods for improving output from
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