Feeding Systems with Legumes to Intensify Dairy Farms - cgiar

Table 2. Stocking rate (AU/ha)* of pastures evaluated at ECAG, Costa Rica.
Pastures
Brachiaria decumbens + Arachis
pintoi
Evaluation periods (years)
1996 1997 1998 1999 Average
2.5 3.2 4.4 4.6 4.6
B. decumbens + Hyparrhenia rufa 2.5 2.5 3.7 3.6 3.6
B. decumbens
* 1 AU = 450 kg animal liveweight.
2.5 2.6 3.5 3.7 3.7
It should be highlighted that these results correspond to the stocking
rate used during the rainy season and that cows consumed commercial
concentrate at a ratio of 3:1 (1kg concentrate per liter milk produced). On
the other hand, it is expected that this increase in stocking rate in nonassociated
pastures could be non-sustainable over time because of its
accelerated degradation.
Botanical composition. Figure 1 shows that the botanical
composition of the associated pasture increased from 23% A. pintoi in year 1
to 43% in subsequent years of grazing. The percentage of B. decumbens was
constant (59%), whereas the percentage of weeds decreased. Between 1996
and 1998, both grasses in the B. decumbens + H. rufa pasture increased
slightly (5% for B. decumbens and 8% for H. rufa). Weed incidence decreased
from 19% to 6% during the same period. However, in 1999, the percentage
of both grasses tended to decrease while that of weeds increased.
Between 1996 and 1997, in the grass pasture alone, the percentage of
B. decumbens increased from 70% to 94%, whereas that of other pasture
components decreased (Figure 3). In subsequent periods, the percentage of
B. decumbens decreased from 94% to 83%, and weeds increased 10%.
The botanical composition of the pastures partially explains the
changes in stocking rate during the experimental period (Table 2). Therefore,
as of 1997, the components of the associated pasture finally stabilized and
allowed the stocking rate to be increased to 4.6 AU/ha. In 1998, the
increased biomass of the B. decumbens + H. rufa pasture allowed the
stocking rate to be increased by 1 AU/ha, reaching 3.6 AU/ha. This
stocking rate, however, was apparently too high and favored pasture
degradation.
These results confirm that pastures of grasses and legumes in
association can support higher stocking rates than non-associated pastures,
without affecting their botanical composition and quality and without
increasing the presence of weeds.
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